A non-invasive technique using ultrasound for the measurement of cerebrovascular hemodynamics, particularly cerebral blood flow velocity and cerebral collateral flow. With a high-intensity, low-frequency pulse probe, the intracranial arteries may be studied transtemporally, transorbitally, or from below the foramen magnum.
A technique that involves the use of electrical coils on the head to generate a brief magnetic field which reaches the CEREBRAL CORTEX. It is coupled with ELECTROMYOGRAPHY response detection to assess cortical excitability by the threshold required to induce MOTOR EVOKED POTENTIALS. This method is also used for BRAIN MAPPING, to study NEUROPHYSIOLOGY, and as a substitute for ELECTROCONVULSIVE THERAPY for treating DEPRESSION. Induction of SEIZURES limits its clinical usage.
Ultrasonography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image. This type of ultrasonography is well-suited to identifying the location of high-velocity flow (such as in a stenosis) or of mapping the extent of flow in a certain region.
The visualization of deep structures of the body by recording the reflections or echoes of ultrasonic pulses directed into the tissues. Use of ultrasound for imaging or diagnostic purposes employs frequencies ranging from 1.6 to 10 megahertz.
Ultrasonography applying the Doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. (Stedman, 25th ed)
Ultrasonography applying the Doppler effect, with velocity detection combined with range discrimination. Short bursts of ultrasound are transmitted at regular intervals and the echoes are demodulated as they return.
The electrical response evoked in a muscle or motor nerve by electrical or magnetic stimulation. Common methods of stimulation are by transcranial electrical and TRANSCRANIAL MAGNETIC STIMULATION. It is often used for monitoring during neurosurgery.
A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.
Changes in the observed frequency of waves (as sound, light, or radio waves) due to the relative motion of source and observer. The effect was named for the 19th century Austrian physicist Johann Christian Doppler.
Area of the FRONTAL LOBE concerned with primary motor control located in the dorsal PRECENTRAL GYRUS immediately anterior to the central sulcus. It is comprised of three areas: the primary motor cortex located on the anterior paracentral lobule on the medial surface of the brain; the premotor cortex located anterior to the primary motor cortex; and the supplementary motor area located on the midline surface of the hemisphere anterior to the primary motor cortex.
The visualization of tissues during pregnancy through recording of the echoes of ultrasonic waves directed into the body. The procedure may be applied with reference to the mother or the fetus and with reference to organs or the detection of maternal or fetal disease.
Use of reflected ultrasound in the diagnosis of intracranial pathologic processes.
Echocardiography applying the Doppler effect, with velocity detection combined with range discrimination. Short bursts of ultrasound are transmitted at regular intervals and the echoes are demodulated as they return.
The circulation of blood through the BLOOD VESSELS of the BRAIN.
Echocardiography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image.
The largest of the cerebral arteries. It trifurcates into temporal, frontal, and parietal branches supplying blood to most of the parenchyma of these lobes in the CEREBRAL CORTEX. These are the areas involved in motor, sensory, and speech activities.
The arterial blood vessels supplying the CEREBRUM.
Ultrasonography applying the Doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the Doppler shift frequency.
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
Rhythmic, intermittent propagation of a fluid through a BLOOD VESSEL or piping system, in contrast to constant, smooth propagation, which produces laminar flow.
Blocking of a blood vessel in the SKULL by an EMBOLUS which can be a blood clot (THROMBUS) or other undissolved material in the blood stream. Most emboli are of cardiac origin and are associated with HEART DISEASES. Other non-cardiac sources of emboli are usually associated with VASCULAR DISEASES.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Ultrasonography of internal organs using an ultrasound transducer sometimes mounted on a fiberoptic endoscope. In endosonography the transducer converts electronic signals into acoustic pulses or continuous waves and acts also as a receiver to detect reflected pulses from within the organ. An audiovisual-electronic interface converts the detected or processed echo signals, which pass through the electronics of the instrument, into a form that the technologist can evaluate. The procedure should not be confused with ENDOSCOPY which employs a special instrument called an endoscope. The "endo-" of endosonography refers to the examination of tissue within hollow organs, with reference to the usual ultrasonography procedure which is performed externally or transcutaneously.
Fibers that arise from cells within the cerebral cortex, pass through the medullary pyramid, and descend in the spinal cord. Many authorities say the pyramidal tracts include both the corticospinal and corticobulbar tracts.
A method of non-invasive, continuous measurement of MICROCIRCULATION. The technique is based on the values of the DOPPLER EFFECT of low-power laser light scattered randomly by static structures and moving tissue particulates.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Substances used to allow enhanced visualization of tissues.
Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot.
Recording of the changes in electric potential of muscle by means of surface or needle electrodes.
The flow of BLOOD through or around an organ or region of the body.
Embolism or thrombosis involving blood vessels which supply intracranial structures. Emboli may originate from extracranial or intracranial sources. Thrombosis may occur in arterial or venous structures.
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
A polygonal anastomosis at the base of the brain formed by the internal carotid (CAROTID ARTERY, INTERNAL), proximal parts of the anterior, middle, and posterior cerebral arteries (ANTERIOR CEREBRAL ARTERY; MIDDLE CEREBRAL ARTERY; POSTERIOR CEREBRAL ARTERY), the anterior communicating artery and the posterior communicating arteries.
The use of ultrasound to guide minimally invasive surgical procedures such as needle ASPIRATION BIOPSY; DRAINAGE; etc. Its widest application is intravascular ultrasound imaging but it is useful also in urology and intra-abdominal conditions.
A subjective visual sensation with the eyes closed and in the absence of light. Phosphenes can be spontaneous, or induced by chemical, electrical, or mechanical (pressure) stimuli which cause the visual field to light up without optical inputs.
Use of electric potential or currents to elicit biological responses.
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
The constant checking on the state or condition of a patient during the course of a surgical operation (e.g., checking of vital signs).
The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.
Use of ultrasound for imaging the breast. The most frequent application is the diagnosis of neoplasms of the female breast.
Tomography using x-ray transmission and a computer algorithm to reconstruct the image.
Specialized arterial vessels in the umbilical cord. They carry waste and deoxygenated blood from the FETUS to the mother via the PLACENTA. In humans, there are usually two umbilical arteries but sometimes one.
A subfield of acoustics dealing in the radio frequency range higher than acoustic SOUND waves (approximately above 20 kilohertz). Ultrasonic radiation is used therapeutically (DIATHERMY and ULTRASONIC THERAPY) to generate HEAT and to selectively destroy tissues. It is also used in diagnostics, for example, ULTRASONOGRAPHY; ECHOENCEPHALOGRAPHY; and ECHOCARDIOGRAPHY, to visually display echoes received from irradiated tissues.
Narrowing or stricture of any part of the CAROTID ARTERIES, most often due to atherosclerotic plaque formation. Ulcerations may form in atherosclerotic plaques and induce THROMBUS formation. Platelet or cholesterol emboli may arise from stenotic carotid lesions and induce a TRANSIENT ISCHEMIC ATTACK; CEREBROVASCULAR ACCIDENT; or temporary blindness (AMAUROSIS FUGAX). (From Adams et al., Principles of Neurology, 6th ed, pp 822-3)
The distal part of the arm beyond the wrist in humans and primates, that includes the palm, fingers, and thumb.
Fields representing the joint interplay of electric and magnetic forces.
A group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to BRAIN ISCHEMIA or INTRACRANIAL HEMORRHAGES. Stroke is classified by the type of tissue NECROSIS, such as the anatomic location, vasculature involved, etiology, age of the affected individual, and hemorrhagic vs. non-hemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)
Forced expiratory effort against a closed GLOTTIS.
Elements of limited time intervals, contributing to particular results or situations.
Radiography of the vascular system of the brain after injection of a contrast medium.
A spectrum of pathological conditions of impaired blood flow in the brain. They can involve vessels (ARTERIES or VEINS) in the CEREBRUM, the CEREBELLUM, and the BRAIN STEM. Major categories include INTRACRANIAL ARTERIOVENOUS MALFORMATIONS; BRAIN ISCHEMIA; CEREBRAL HEMORRHAGE; and others.
The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).
Pathological conditions involving the CAROTID ARTERIES, including the common, internal, and external carotid arteries. ATHEROSCLEROSIS and TRAUMA are relatively frequent causes of carotid artery pathology.
The time from the onset of a stimulus until a response is observed.
The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.
Sulfur hexafluoride. An inert gas used mainly as a test gas in respiratory physiology. Other uses include its injection in vitreoretinal surgery to restore the vitreous chamber and as a tracer in monitoring the dispersion and deposition of air pollutants.
The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.
Characteristics of ELECTRICITY and magnetism such as charged particles and the properties and behavior of charged particles, and other phenomena related to or associated with electromagnetism.
Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.
Pathophysiological conditions of the FETUS in the UTERUS. Some fetal diseases may be treated with FETAL THERAPIES.
Pathological processes which result in the partial or complete obstruction of ARTERIES. They are characterized by greatly reduced or absence of blood flow through these vessels. They are also known as arterial insufficiency.
Blocking of a blood vessel by air bubbles that enter the circulatory system, usually after TRAUMA; surgical procedures, or changes in atmospheric pressure.
Application of electric current in treatment without the generation of perceptible heat. It includes electric stimulation of nerves or muscles, passage of current into the body, or use of interrupted current of low intensity to raise the threshold of the skin to pain.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.
The artery formed by the union of the right and left vertebral arteries; it runs from the lower to the upper border of the pons, where it bifurcates into the two posterior cerebral arteries.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
Any device or element which converts an input signal into an output signal of a different form. Examples include the microphone, phonographic pickup, loudspeaker, barometer, photoelectric cell, automobile horn, doorbell, and underwater sound transducer. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)
The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.
Artery originating from the internal carotid artery and distributing to the eye, orbit and adjacent facial structures.
The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization.
Either of the two principal arteries on both sides of the neck that supply blood to the head and neck; each divides into two branches, the internal carotid artery and the external carotid artery.
Branch of the common carotid artery which supplies the anterior part of the brain, the eye and its appendages, the forehead and nose.
The first branch of the SUBCLAVIAN ARTERY with distribution to muscles of the NECK; VERTEBRAE; SPINAL CORD; CEREBELLUM; and interior of the CEREBRUM.
Upper central part of the cerebral hemisphere. It is located posterior to central sulcus, anterior to the OCCIPITAL LOBE, and superior to the TEMPORAL LOBES.
The circulation of BLOOD, of both the mother and the FETUS, through the PLACENTA.
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
Pathological conditions of intracranial ARTERIES supplying the CEREBRUM. These diseases often are due to abnormalities or pathological processes in the ANTERIOR CEREBRAL ARTERY; MIDDLE CEREBRAL ARTERY; and POSTERIOR CEREBRAL ARTERY.
Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.
Localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. This frequently occurs in conjunction with brain hypoxia (HYPOXIA, BRAIN). Prolonged ischemia is associated with BRAIN INFARCTION.
The coordination of a sensory or ideational (cognitive) process and a motor activity.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
A method of delineating blood vessels by subtracting a tissue background image from an image of tissue plus intravascular contrast material that attenuates the X-ray photons. The background image is determined from a digitized image taken a few moments before injection of the contrast material. The resulting angiogram is a high-contrast image of the vessel. This subtraction technique allows extraction of a high-intensity signal from the superimposed background information. The image is thus the result of the differential absorption of X-rays by different tissues.
The function of opposing or restraining the excitation of neurons or their target excitable cells.
Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.
Small encapsulated gas bubbles (diameters of micrometers) that can be used as CONTRAST MEDIA, and in other diagnostic and therapeutic applications. Upon exposure to sufficiently intense ultrasound, microbubbles will cavitate, rupture, disappear, release gas content. Such characteristics of the microbubbles can be used to enhance diagnostic tests, dissolve blood clots, and deliver drugs or genes for therapy.
Radiography of blood vessels after injection of a contrast medium.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
The hollow thick-walled muscular organ in the female PELVIS. It consists of the fundus (the body) which is the site of EMBRYO IMPLANTATION and FETAL DEVELOPMENT. Beyond the isthmus at the perineal end of fundus, is CERVIX UTERI (the neck) opening into VAGINA. Beyond the isthmi at the upper abdominal end of fundus, are the FALLOPIAN TUBES.
The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.
Maintenance of blood flow to an organ despite obstruction of a principal vessel. Blood flow is maintained through small vessels.
Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.
Period of contraction of the HEART, especially of the HEART VENTRICLES.
The excision of the thickened, atheromatous tunica intima of a carotid artery.
The failure of a FETUS to attain its expected FETAL GROWTH at any GESTATIONAL AGE.
The continuous measurement of physiological processes, blood pressure, heart rate, renal output, reflexes, respiration, etc., in a patient or experimental animal; includes pharmacologic monitoring, the measurement of administered drugs or their metabolites in the blood, tissues, or urine.
The use of focused, high-frequency sound waves to produce local hyperthermia in certain diseased or injured parts of the body or to destroy the diseased tissue.
A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.
A cutaneous pouch of skin containing the testicles and spermatic cords.
The heart of the fetus of any viviparous animal. It refers to the heart in the postembryonic period and is differentiated from the embryonic heart (HEART/embryology) only on the basis of time.
Brief reversible episodes of focal, nonconvulsive ischemic dysfunction of the brain having a duration of less than 24 hours, and usually less than one hour, caused by transient thrombotic or embolic blood vessel occlusion or stenosis. Events may be classified by arterial distribution, temporal pattern, or etiology (e.g., embolic vs. thrombotic). (From Adams et al., Principles of Neurology, 6th ed, pp814-6)
Performance of complex motor acts.
Four or five slender jointed digits in humans and primates, attached to each HAND.
The middle third of a human PREGNANCY, from the beginning of the 15th through the 28th completed week (99 to 196 days) of gestation.
Pressure within the cranial cavity. It is influenced by brain mass, the circulatory system, CSF dynamics, and skull rigidity.
The valve between the left atrium and left ventricle of the heart.
Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.
The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.
The condition of an anatomical structure's being constricted beyond normal dimensions.
Developmental abnormalities in any portion of the ATRIAL SEPTUM resulting in abnormal communications between the two upper chambers of the heart. Classification of atrial septal defects is based on location of the communication and types of incomplete fusion of atrial septa with the ENDOCARDIAL CUSHIONS in the fetal heart. They include ostium primum, ostium secundum, sinus venosus, and coronary sinus defects.
Radiography of any part of the urinary tract.
A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
Constriction of arteries in the SKULL due to sudden, sharp, and often persistent smooth muscle contraction in blood vessels. Intracranial vasospasm results in reduced vessel lumen caliber, restricted blood flow to the brain, and BRAIN ISCHEMIA that may lead to hypoxic-ischemic brain injury (HYPOXIA-ISCHEMIA, BRAIN).
The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulchi. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.
Care given during the period prior to undergoing surgery when psychological and physical preparations are made according to the special needs of the individual patient. This period spans the time between admission to the hospital to the time the surgery begins. (From Dictionary of Health Services Management, 2d ed)
The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.
The vessels carrying blood away from the heart.
An infant during the first month after birth.
The electric response evoked in the CEREBRAL CORTEX by stimulation along AFFERENT PATHWAYS from PERIPHERAL NERVES to CEREBRUM.
Non-invasive method of vascular imaging and determination of internal anatomy without injection of contrast media or radiation exposure. The technique is used especially in CEREBRAL ANGIOGRAPHY as well as for studies of other vascular structures.
General term for CYSTS and cystic diseases of the OVARY.
One of the CARBONIC ANHYDRASE INHIBITORS that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. (From Smith and Reynard, Textbook of Pharmacology, 1991, p337)
Blockage of an artery due to passage of a clot (THROMBUS) from a systemic vein to a systemic artery without its passing through the lung which acts as a filter to remove blood clots from entering the arterial circulation. Paradoxical embolism occurs when there is a defect that allows a clot to cross directly from the right to the left side of the heart as in the cases of ATRIAL SEPTAL DEFECTS or open FORAMEN OVALE. Once in the arterial circulation, a clot can travel to the brain, block an artery, and cause a STROKE.
Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.
Veins draining the cerebrum.
Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus.
Dominance of one cerebral hemisphere over the other in cerebral functions.
Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.
Pathological conditions involving ARTERIES in the skull, such as arteries supplying the CEREBRUM, the CEREBELLUM, the BRAIN STEM, and associated structures. They include atherosclerotic, congenital, traumatic, infectious, inflammatory, and other pathological processes.
The rostral part of the frontal lobe, bounded by the inferior precentral fissure in humans, which receives projection fibers from the MEDIODORSAL NUCLEUS OF THE THALAMUS. The prefrontal cortex receives afferent fibers from numerous structures of the DIENCEPHALON; MESENCEPHALON; and LIMBIC SYSTEM as well as cortical afferents of visual, auditory, and somatic origin.
The inferior part of the lower extremity between the KNEE and the ANKLE.
Any fluid-filled closed cavity or sac that is lined by an EPITHELIUM. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues.
Any visual display of structural or functional patterns of organs or tissues for diagnostic evaluation. It includes measuring physiologic and metabolic responses to physical and chemical stimuli, as well as ultramicroscopy.
A cognitive disorder marked by an impaired ability to comprehend or express language in its written or spoken form. This condition is caused by diseases which affect the language areas of the dominant hemisphere. Clinical features are used to classify the various subtypes of this condition. General categories include receptive, expressive, and mixed forms of aphasia.
Increased pressure within the cranial vault. This may result from several conditions, including HYDROCEPHALUS; BRAIN EDEMA; intracranial masses; severe systemic HYPERTENSION; PSEUDOTUMOR CEREBRI; and other disorders.
Disease having a short and relatively severe course.
A graphic means for assessing the ability of a screening test to discriminate between healthy and diseased persons; may also be used in other studies, e.g., distinguishing stimuli responses as to a faint stimuli or nonstimuli.
Clinical manifestation consisting of a deficiency of carbon dioxide in arterial blood.
The part of a human or animal body connecting the HEAD to the rest of the body.
A short thick vein formed by union of the superior mesenteric vein and the splenic vein.
Bleeding into the intracranial or spinal SUBARACHNOID SPACE, most resulting from INTRACRANIAL ANEURYSM rupture. It can occur after traumatic injuries (SUBARACHNOID HEMORRHAGE, TRAUMATIC). Clinical features include HEADACHE; NAUSEA; VOMITING, nuchal rigidity, variable neurological deficits and reduced mental status.
The hemodynamic and electrophysiological action of the left HEART VENTRICLE. Its measurement is an important aspect of the clinical evaluation of patients with heart disease to determine the effects of the disease on cardiac performance.
Pathological processes of the TESTIS.
The superior part of the upper extremity between the SHOULDER and the ELBOW.
A disease characterized by chronic hemolytic anemia, episodic painful crises, and pathologic involvement of many organs. It is the clinical expression of homozygosity for hemoglobin S.
Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.
The genital canal in the female, extending from the UTERUS to the VULVA. (Stedman, 25th ed)
The circulation of the BLOOD through the MICROVASCULAR NETWORK.
A condition in which the FORAMEN OVALE in the ATRIAL SEPTUM fails to close shortly after birth. This results in abnormal communications between the two upper chambers of the heart. An isolated patent ovale foramen without other structural heart defects is usually of no hemodynamic significance.
The last third of a human PREGNANCY, from the beginning of the 29th through the 42nd completed week (197 to 294 days) of gestation.
Bony cavity that holds the eyeball and its associated tissues and appendages.
Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.
The articulation between a metacarpal bone and a phalanx.
Methods developed to aid in the interpretation of ultrasound, radiographic images, etc., for diagnosis of disease.
An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.
A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1284; Corsini, Concise Encyclopedia of Psychology, 1987, p764-5)
That portion of the body that lies between the THORAX and the PELVIS.
The circulation of blood through the CORONARY VESSELS of the HEART.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
A monosynaptic reflex elicited by stimulating a nerve, particularly the tibial nerve, with an electric shock.
The beginning third of a human PREGNANCY, from the first day of the last normal menstrual period (MENSTRUATION) through the completion of 14 weeks (98 days) of gestation.
Localized or diffuse reduction in blood flow through the vertebrobasilar arterial system, which supplies the BRAIN STEM; CEREBELLUM; OCCIPITAL LOBE; medial TEMPORAL LOBE; and THALAMUS. Characteristic clinical features include SYNCOPE; lightheadedness; visual disturbances; and VERTIGO. BRAIN STEM INFARCTIONS or other BRAIN INFARCTION may be associated.
The formation of an area of NECROSIS in the CEREBRUM caused by an insufficiency of arterial or venous blood flow. Infarcts of the cerebrum are generally classified by hemisphere (i.e., left vs. right), lobe (e.g., frontal lobe infarction), arterial distribution (e.g., INFARCTION, ANTERIOR CEREBRAL ARTERY), and etiology (e.g., embolic infarction).
Complications that affect patients during surgery. They may or may not be associated with the disease for which the surgery is done, or within the same surgical procedure.
Branch of the common carotid artery which supplies the exterior of the head, the face, and the greater part of the neck.
Patient care procedures performed during the operation that are ancillary to the actual surgery. It includes monitoring, fluid therapy, medication, transfusion, anesthesia, radiography, and laboratory tests.
Application of fingers with light pressure to the surface of the body to determine consistence of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs.
Electrically induced CONVULSIONS primarily used in the treatment of severe AFFECTIVE DISORDERS and SCHIZOPHRENIA.
Surgical excision, performed under general anesthesia, of the atheromatous tunica intima of an artery. When reconstruction of an artery is performed as an endovascular procedure through a catheter, it is called ATHERECTOMY.
A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of COCHLEAR DISEASES; VESTIBULOCOCHLEAR NERVE DISEASES; INTRACRANIAL HYPERTENSION; CRANIOCEREBRAL TRAUMA; and other conditions.
The heart rate of the FETUS. The normal range at term is between 120 and 160 beats per minute.
A branch arising from the internal iliac artery in females, that supplies blood to the uterus.
A clinically significant reduction in blood supply to the BRAIN STEM and CEREBELLUM (i.e., VERTEBROBASILAR INSUFFICIENCY) resulting from reversal of blood flow through the VERTEBRAL ARTERY from occlusion or stenosis of the proximal subclavian or brachiocephalic artery. Common symptoms include VERTIGO; SYNCOPE; and INTERMITTENT CLAUDICATION of the involved upper extremity. Subclavian steal may also occur in asymptomatic individuals. (From J Cardiovasc Surg 1994;35(1):11-4; Acta Neurol Scand 1994;90(3):174-8)
The unborn young of a viviparous mammal, in the postembryonic period, after the major structures have been outlined. In humans, the unborn young from the end of the eighth week after CONCEPTION until BIRTH, as distinguished from the earlier EMBRYO, MAMMALIAN.
A small circumscribed mass in the THYROID GLAND that can be of neoplastic growth or non-neoplastic abnormality. It lacks a well-defined capsule or glandular architecture. Thyroid nodules are often benign but can be malignant. The growth of nodules can lead to a multinodular goiter (GOITER, NODULAR).
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
A noninvasive technique that uses the differential absorption properties of hemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional hemodynamics and blood flow. Near-infrared light (NIR) can propagate through tissues and at particular wavelengths is differentially absorbed by oxygenated vs. deoxygenated forms of hemoglobin and myoglobin. Illumination of intact tissue with NIR allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition.
A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand.
Appendages of the UTERUS which include the FALLOPIAN TUBES, the OVARY, and the supporting ligaments of the uterus (BROAD LIGAMENT; ROUND LIGAMENT).
Act of listening for sounds within the body.
Congenital vascular anomalies in the brain characterized by direct communication between an artery and a vein without passing through the CAPILLARIES. The locations and size of the shunts determine the symptoms including HEADACHES; SEIZURES; STROKE; INTRACRANIAL HEMORRHAGES; mass effect; and vascular steal effect.
Negative test results in subjects who possess the attribute for which the test is conducted. The labeling of diseased persons as healthy when screening in the detection of disease. (Last, A Dictionary of Epidemiology, 2d ed)
Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.
The region of the upper limb between the metacarpus and the FOREARM.
A method in which either the observer(s) or the subject(s) is kept ignorant of the group to which the subjects are assigned.
Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.
The selecting and organizing of visual stimuli based on the individual's past experience.
A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.
Acquired and inherited conditions that feature DYSTONIA as a primary manifestation of disease. These disorders are generally divided into generalized dystonias (e.g., dystonia musculorum deformans) and focal dystonias (e.g., writer's cramp). They are also classified by patterns of inheritance and by age of onset.
The joint that is formed by the distal end of the RADIUS, the articular disc of the distal radioulnar joint, and the proximal row of CARPAL BONES; (SCAPHOID BONE; LUNATE BONE; triquetral bone).
The outer covering of the calvaria. It is composed of several layers: SKIN; subcutaneous connective tissue; the occipitofrontal muscle which includes the tendinous galea aponeurotica; loose connective tissue; and the pericranium (the PERIOSTEUM of the SKULL).
Discrete abnormal tissue masses that protrude into the lumen of the DIGESTIVE TRACT or the RESPIRATORY TRACT. Polyps can be spheroidal, hemispheroidal, or irregular mound-shaped structures attached to the MUCOUS MEMBRANE of the lumen wall either by a stalk, pedunculus, or by a broad base.
A partial or complete return to the normal or proper physiologic activity of an organ or part following disease or trauma.
Tumors or cancer of the LIVER.
A condition in which the LEFT VENTRICLE of the heart was functionally impaired. This condition usually leads to HEART FAILURE; MYOCARDIAL INFARCTION; and other cardiovascular complications. Diagnosis is made by measuring the diminished ejection fraction and a depressed level of motility of the left ventricular wall.
Any operation on the cranium or incision into the cranium. (Dorland, 28th ed)

The cerebral haemodynamics of music perception. A transcranial Doppler sonography study. (1/1182)

The perception of music has been investigated by several neurophysiological and neuroimaging methods. Results from these studies suggest a right hemisphere dominance for non-musicians and a possible left hemisphere dominance for musicians. However, inconsistent results have been obtained, and not all variables have been controlled by the different methods. We performed a study with functional transcranial Doppler sonography (fTCD) of the middle cerebral artery to evaluate changes in cerebral blood flow velocity (CBFV) during different periods of music perception. Twenty-four healthy right-handed subjects were enrolled and examined during rest and during listening to periods of music with predominant language, rhythm and harmony content. The gender, musical experience and mode of listening of the subjects were chosen as independent factors; the type of music was included as the variable in repeated measurements. We observed a significant increase of CBFV in the right hemisphere in non-musicians during harmony perception but not during rhythm perception; this effect was more pronounced in females. Language perception was lateralized to the left hemisphere in all subject groups. Musicians showed increased CBFV values in the left hemisphere which were independent of the type of stimulus, and background listeners showed increased CBFV values during harmony perception in the right hemisphere which were independent of their musical experience. The time taken to reach the peak of CBFV was significantly longer in non-musicians when compared with musicians during rhythm and harmony perception. Pulse rates were significantly decreased in non-musicians during harmony perception, probably due to a specific relaxation effect in this subgroup. The resistance index did not show any significant differences, suggesting only regional changes of small resistance vessels but not of large arteries. Our fTCD study confirms previous findings of right hemisphere lateralization for harmony perception in non-musicians. In addition, we showed that this effect is more pronounced in female subjects and in background listeners and that the lateralization is delayed in non-musicians compared with musicians for the perception of rhythm and harmony stimuli. Our data suggest that musicians and non-musicians have different strategies to lateralize musical stimuli, with a delayed but marked right hemisphere lateralization during harmony perception in non-musicians and an attentive mode of listening contributing to a left hemisphere lateralization in musicians.  (+info)

Carotid endarterectomy and intracranial thrombolysis: simultaneous and staged procedures in ischemic stroke. (2/1182)

PURPOSE: The feasibility and safety of combining carotid surgery and thrombolysis for occlusions of the internal carotid artery (ICA) and the middle cerebral artery (MCA), either as a simultaneous or as a staged procedure in acute ischemic strokes, was studied. METHODS: A nonrandomized clinical pilot study, which included patients who had severe hemispheric carotid-related ischemic strokes and acute occlusions of the MCA, was performed between January 1994 and January 1998. Exclusion criteria were cerebral coma and major infarction established by means of cerebral computed tomography scan. Clinical outcome was assessed with the modified Rankin scale. RESULTS: Carotid reconstruction and thrombolysis was performed in 14 of 845 patients (1.7%). The ICA was occluded in 11 patients; occlusions of the MCA (mainstem/major branches/distal branch) or the anterior cerebral artery (ACA) were found in 14 patients. In three of the 14 patients, thrombolysis was performed first, followed by carotid enarterectomy (CEA) after clinical improvement (6 to 21 days). In 11 of 14 patients, 0.15 to 1 mIU urokinase was administered intraoperatively, ie, emergency CEA for acute ischemic stroke (n = 5) or surgical reexploration after elective CEA complicated by perioperative intracerebral embolism (n = 6). Thirteen of 14 intracranial embolic occlusions and 10 of 11 ICA occlusions were recanalized successfully (confirmed with angiography or transcranial Doppler studies). Four patients recovered completely (Rankin 0), six patients sustained a minor stroke (Rankin 2/3), two patients had a major stroke (Rankin 4/5), and two patients died. In one patient, hemorrhagic transformation of an ischemic infarction was detectable postoperatively. CONCLUSION: Combining carotid surgery with thrombolysis (simultaneous or staged procedure) offers a new therapeutic approach in the emergency management of an acute carotid-related stroke. Its efficacy should be evaluated in interdisciplinary studies.  (+info)

A policy of quality control assessment helps to reduce the risk of intraoperative stroke during carotid endarterectomy. (3/1182)

OBJECTIVES: A pilot study in our unit suggested that a combination of transcranial Doppler (TCD) plus completion angioscopy reduced incidence of intra-operative stroke (i.e. patients recovering from anaesthesia with a new deficit) during carotid endarterectomy (CEA). The aim of the current study was to see whether routine implementation of this policy was both feasible and associated with a continued reduction in the rate of intraoperative stroke (IOS). MATERIALS AND METHODS: Prospective study in 252 consecutive patients undergoing carotid endarterectomy between March 1995 and December 1996. RESULTS: Continuous TCD monitoring was possible in 229 patients (91%), while 238 patients (94%) underwent angioscopic examination. Overall, angioscopy identified an intimal flap requiring correction in six patients (2.5%), whilst intraluminal thrombus was removed in a further six patients (2.5%). No patient in this series recovered from anaesthesia with an IOS, but the rate of postoperative stroke was 2.8%. CONCLUSIONS: Our policy of TCD plus angioscopy has continued to contribute towards a sustained reduction in the risk of IOS following CEA, but requires access to reliable equipment and technical support. However, a policy of intraoperative quality control assessment may not necessarily alter the rate of postoperative stroke.  (+info)

Twinkling artifact on intracerebral color Doppler sonography. (4/1182)

Transcranial Doppler sonography shows potential as a noninvasive technique for long-term follow-up of treated intracranial saccular aneurysms. This technical note describes a color Doppler artifact related to microcoil architecture that might represent a potential pitfall in transcranial Doppler sonographic evaluation of aneurysmal cavity thrombosis, since it may be wrongly interpreted as residual flow or aneurysmal cavity recanalization.  (+info)

Automatic embolus detection by a neural network. (5/1182)

BACKGROUND AND PURPOSE: Embolus detection using transcranial Doppler ultrasound is a useful method for the identification of active embolic sources in cerebrovascular diseases. Automated embolus detection systems have been developed to reduce the time of evaluation in long-term recordings and to provide more "objective" criteria. The purpose of this study was to evaluate the critical conditions of automated embolus detection by means of a trained neural network (EMBotec V5.1 One, STAC GmbH, Germany). METHODS: In 11 normal volunteers and in 11 patients with arterial or cardiac embolic sources, we performed simultaneous recordings from both middle or both posterior cerebral arteries. In the normal subjects, we produced 1342 additional artifacts to use the latter as false-positives. Detection of microembolic signals (MES) was done offline from digital audiotapes (1) by an experienced blinded investigator used as a reference and (2) by a trained 3-layer-feed-forward neural network. RESULTS: From the 1342 provoked artifacts the neural network labeled 216 events as microemboli, yielding an artifact rejection of 85%. In microembolus-positive patients the neural network detected 282 events as emboli, among these 122 signals originating from artifacts; 58 "real" events were not detected. This result revealed a sensitivity of 73.4% and a positive predictive value of 56.7. The spectral power of the detected artifact signals was 16.5+/-5 dB above background signal. MES from patients with artificial heart valves had a spectral power of 6.4+/-2.1 dB; however, in patients with other sources of emboli, MES had an averaged energy reflection of 2.7+/-0.9 dB. CONCLUSIONS: The neural network is a promising tool for automated embolus detection, the formal algorithm for signal identification is unknown. However, extreme signal qualities, eg, strong artifacts, lead to misdiagnosis. Similar to other automated embolus detection systems, good signal quality and verification of MES by an experienced investigator is still mandatory.  (+info)

Cerebral vasculopathy in HIV infection revealed by transcranial Doppler: A pilot study. (6/1182)

BACKGROUND AND PURPOSE: There is growing evidence for affection of cerebral vessels during human immunodeficiency virus (HIV) infection. We prospectively evaluated cerebrovascular reserve capacity (CRC) in HIV-seropositive patients by transcranial Doppler sonography (TCD) after systemic administration of acetazolamide. We hypothesized that a disturbed vasoreactivity would reflect the cerebral arteries' involvement in HIV infection. METHODS: We assessed the mean blood flow velocity (BFV) of the middle cerebral artery and its increase after intravenous administration of 1 g acetazolamide (CRC) in 31 HIV-infected individuals without symptoms of cerebrovascular disease (mean+/-SD age, 39+/-11 years). Stenotic or occlusive lesions of the large brain-supplying arteries were excluded by color-coded duplex and transcranial imaging. BFV and CRC were also measured in an age-matched group of 10 healthy control subjects. Patients were classified according to clinical, laboratory, and neurophysiological parameters. We also performed cerebral MRI (n=25) and rheumatological blood tests (n=26). RESULTS: Baseline BFV and CRC both were significantly reduced in HIV-infected patients as compared with control subjects (P<0.05, Student's t test). These findings did not correlate with duration of seropositivity, helper cell count, or other clinical, rheumatological, and neuroradiological findings. CONCLUSIONS: Our findings support the hypothesis of a cerebral vasculopathy etiologically associated with HIV infection.  (+info)

Frontal bone windows for transcranial color-coded duplex sonography. (7/1182)

BACKGROUND AND PURPOSE: The use of the conventional temporal bone window for transcranial color-coded duplex sonography (TCCS) often results in difficulties in obtaining angle-corrected flow velocity measurements of the A2 segment of the anterior cerebral artery, the posterior communicating artery, and the midline venous vasculature because of the unfavorable insonation angle. The same applies to B-mode imaging of the frontal parenchyma. However, transorbital TCCS raises problems with the insonation of the orbital lens. To overcome these drawbacks, we studied the feasibility of frontal bone windows for TCCS examinations. METHODS: In 75 healthy volunteers (mean age, 45.3+/-17.0 years; age range, 17 to 77 years), the circle of Willis and the venous midline vasculature were insonated through a lateral and paramedian frontal bone window. Insonation quality of parenchymal structures (B-mode) was graded on a 3-point scale depending on the visibility of typical parenchymal landmarks. In a similar manner, the quality of the color-/Doppler-mode imaging of the arteries of the circle of Willis and the internal cerebral veins was assessed. In 15 patients (mean age, 62.7+/-13.7 years; age range, 33 to 83 years), the color-/Doppler-mode imaging quality of the intracranial vessels before and after application of an ultrasound contrast-enhancing agent was compared. RESULTS: B-mode insonation quality was optimal to fair in 73.3% of cases using the lateral and in 52.0% of cases using the paramedian frontal bone window, with defined parenchymal structures used as reference. Insonation quality decreased in those older than 60 years. In those younger than 60 years, angle-corrected flow velocity measurements of the A2 segment of the anterior cerebral artery and the internal cerebral vein were possible in 73.6% and 60.0%, respectively. Contrast enhancement resulted in a highly significant improvement in the imaging quality of the intracranial vessels. CONCLUSIONS: The transfrontal bone windows offer new possibilities for TCCS examinations, although the insonation quality is inferior to the conventional temporal bone window in terms of failure of an acoustic window. This can be compensated for by application of an ultrasound contrast-enhancing agent.  (+info)

"Tail sign" associated with microembolic signals. (8/1182)

BACKGROUND AND PURPOSE: Transcranial Doppler ultrasound (TCD) can detect circulating microembolic signals (MES). We focused our attention on tail signs (TS), a signal associated with MES that appeared as a small reversal signal after MES on the high time resolution spectral display. We examined MES and artifacts in an animal study to determine whether TS were specific changes associated with MES and investigated the characteristics of TS in both animal and clinical studies. METHODS: In an animal study, adult pigs with venoarterial extracorporeal membrane oxygenation and minimal anticoagulation therapy were used as a model for cerebral embolism. After performing TCD monitoring with a multigated approach, we did an offline analysis to investigate several parameters concerning MES and TS. We also examined TS in patients in a clinical study. RESULTS: From a total of 362 MES investigated in the animal study, 72.9% were followed by TS. We could not find any TS associated with artifacts. The time delay between TS and MES was negatively correlated with the velocity of MES. MES almost always appeared first in the proximal channel, whereas TS conversely appeared first in the distal channel. In the clinical study, we were also able to observe TS associated with MES. CONCLUSIONS: TS may represent emboli passing down a branch vessel or twisted downstream vessel. TS are specific for MES and can be used as another criterion for MES identification.  (+info)

TY - JOUR. T1 - Frequency and determinants of microembolic signals on transcranial Doppler in unselected patients with acute carotid territory ischemia. A prospective study. AU - Koennecke, Hans Christian. AU - Mast, Henning. AU - Trocio, Samuel H.. AU - Sacco, Ralph L.. AU - Ma, Weidong. AU - Mohr, Jay P.. AU - Thompson, John L.P.. PY - 1998/3/1. Y1 - 1998/3/1. N2 - Background and Purpose: Few data exist regarding to the occurrence of microembolic high-intensity transient signals (HITS) on transcranial Doppler ultrasound (TCD) in unselected acute stroke patients. The aim of this study was to investigate prospectively the frequency and determinants of HITS in acute carotid territory ischemia. We hypothesized that carotid artery disease, cardiac abnormalities, and nonlacunar infarcts were independent predictors of HITS in acute stroke. Methods: We investigated 145 consecutive patients with acute internal carotid artery territory ischemia. The median time interval between stroke and TCD ...
TY - JOUR. T1 - Transcranial Doppler Studies on Cerebral Autoregulation Suggest Prolonged Cerebral Vasoconstriction in a Subgroup of Patients with Orthostatic Intolerance. AU - Lin, Ya Ju. AU - Po, Helen L.. AU - Hsu, Hung Yi. AU - Chung, Chih Ping. AU - Sheng, Wen Yung. AU - Hu, Han Hwa. PY - 2011/10/1. Y1 - 2011/10/1. N2 - We studied the cerebral autoregulation in a subgroup of patients with orthostatic intolerance, who exhibited excessively decreased middle cerebral artery flow velocity (MCAFV) on transcranial Doppler sonography (TCD) during head-up tilt (HUT) test but without orthostatic hypotension or postural tachycardia. Twenty patients and 20 age- and sex-matched controls underwent Valsalva maneuver (VM) and HUT test with simultaneous monitoring of MCAFV by TCD and blood pressure, heart rate recordings. The pulsatility index (PI), cerebrovascular resistance (CVR) and autoregulatory indices were calculated. During HUT, patients had marked MCAFV reduction (-29.0 ± 5.25% vs. -8.01 ± ...
Contrast-enhanced transcranial Doppler ultrasonography is an indirect approach to detect right-to-left shunting and does not allow for an exact anatomic localization of shunts. Precisely, in the mentioned diagnostic setting, a PFO is likely to cause high-intensity transient signals in c-TCD, but one should be aware that a PFO is not proven by this method. To ensure the diagnosis, contrast medium has to cross the atrial septum following the pressure gradient produced by a Valsalva maneuver during an interval of time that excludes pulmonary passage. Therefore, this interval should start with presence of contrast agent in the right atrium and should not exceed 10 cardiac cycles. Stendel et al. 1allow for 3-15 heart cycles after 5 s injection and 5 s Valsalva maneuver, following the protocol of Schwarze et al. , 2but pulmonary arteriovenous fistulas can be a reason for the detection of high-intensity transient signals during the mentioned interval.. ...
Adams, R., McKie, V., Hsu, L., Files, B., Vichinsky, E., Pegelow, C., ... Brambilla, D. (1998). Prevention of a first stroke by transfusions in children with sickle cell anemia and abnormal results on transcranial doppler ultrasonography. New England Journal of Medicine, 339(1), 5 - 11. DOI: 10.1056/NEJM199807023390102. ...
Background: Transcranial doppler-monitoring (TCM) has been used to identify patients at risk for embolic stroke and aids in identification of stroke mechanism. Limited data exists on the occurrence of microembolic signals (MES) on TCM and the presence of right-to-left shunting (RLS), most commonly through a patent foramen ovale. Our objective was to determine if a relationship exists between the presence of a RLS on transcranial doppler-bubble (TCB) and MES on TCM, and if the degree of shunting correlated with increased number of MES.. Methods: A retrospective chart review was conducted of 113 inpatients that underwent both TCB for the detection of a RLS and TCM during their admission for ischemic stroke at the Cleveland Clinic between 2011 and 2012. TCM was performed for 20 minutes in all patients. Both TCM and TCB used standardized protocols and machines. Data collected included demographics, presence of a shunt, and stroke mechanism.. Results: Mean age of the study cohort was 57.9 years and ...
PRIMARY OBJECTIVE: To investigate the potential of transcranial Doppler ultrasonography in estimating post-traumatic intra-cranial pressure early after severe traumatic brain injury. RESEARCH DESIGN: The group of 24 patients was analysed for the observation of an early post-traumatic cerebral haemodynamic by middle cerebral artery blood velocity measuring. METHODS AND PROCEDURES: The standard method of measuring the mean blood middle cerebral artery velocity by transcranial Doppler ultrasonic device was performed. MAIN OUTCOMES AND RESULTS: The increased duration of intra-cranial hypertension correlated to the middle cerebral artery low blood velocity (p = 0.042; r = -0.498) (n = 17) and to elevated pulsatility indices (p = 0.007; r = 0.753) (n = 11) significantly. The increased duration of lowered cerebral perfusion pressure correlated to the middle cerebral artery low blood velocity significantly (p = 0.001; r = -0.619) (n = 24). CONCLUSIONS: The significance of transcranial Doppler ...
We present a description of a new software package, dopOSCCI, which summarises data from experimental studies where functional transcranial Doppler ultrasonography (fTCD) is used to compare hemispheric rates of blood flow in order to assess lateralization of a cognitive process. The software provides a graphical user interface to summarise analogue and digital data collected using Multi-Dop Doppler Ultrasound devices (DWL Multidop T2: manufacturer, DWL Elektronische Systeme, Singen, Germany). The unique aspects of dopOSCCI allow multi-file processing, multi-event marker processing, behavioural and multi-session summaries, image file data visualization, and tab-delimited output files which includes split-half, single-trial summaries and data quality variables. The Matlab based software is available under the GNU GPL license and can be accessed online at https://databank.ora.ox.ac.uk/general/datasets/dopOSCCI, the Oxford University DataBank.
TY - JOUR. T1 - Interaction of cardiovascular disease and neurodegeneration. T2 - Transcranial Doppler ultrasonography and Alzheimers disease. AU - Roher, Alex E.. AU - Garami, Zsolt. AU - Alexandrov, Andrei V.. AU - Kokjohn, Tyler A.. AU - Esh, Chera L.. AU - Kalback, Walter M.. AU - Vedders, Linda J.. AU - Wilson, Jeffrey. AU - Sabbagh, Marwan N.. AU - Beach, Thomas G.. PY - 2006/9. Y1 - 2006/9. N2 - Objective: Recent post-mortem studies have reported that the severity of atheromatous deposits in the circle of Willis is significantly greater, relative to non-demented (ND) elderly persons, in subjects with neuropathologically diagnosed Alzheimers disease (AD). Additionally, the severity of intracranial atherosclerosis correlates significantly with the densities of neuritic plaques and neurofibrillary tangles. In this study, we examine the arteries of the circle of Willis by transcranial Doppler (TCD) ultrasonography. Methods: TCD was used to measure, in 25 AD patients and 30 ND elderly ...
The diagnosis of brain death (BD) is based on clinical criteria including deep coma, brain stem areflexia and apnoea. Depending on different local guidelines, confirmatory technical tests are sometimes mandatory.1 Since the 1990s, transcranial Doppler sonography (TCD) has found its place in these circumstances and fulfils most of the criteria of an ideal test in confirming BD. To confirm intracranial circulatory arrest (CA) with Doppler sonography, typical flow patterns must be recorded in bilateral intracranial and extracranial brain-supplying arteries.2 A completely absent intracranial flow signal is not a reliable sign to determine CA because this can be due to transmission problems. Inadequate ultrasound penetration of the temporal bone is a major drawback of this technique, making definitive assessment of intracranial flow patterns impossible. Stabilised microbubble ultrasonic contrast agents (UCA) are routinely used in neurological clinical routine when intracranial insonation is ...
Private Hands-On Introduction to Transcranial Doppler Ultrasound Training Course is designed to provide a strong foundation to perform and/or interpret Transcranial Doppler and Transcranial color flow imaging examinations.
David W. Newell, MD, Cerebrovascular Surgery, Neurosurgery, Swedish Neuroscience Institute Colleen Douville, RVT, Director, Cerebrovascular Ultrasound, Swedish Neuroscience Institute Since its introduction in 1982, transcranial doppler ultrasound (TCD) has evolved into a por-table, multimodality, noninvasive method for real-time imaging of intracranial vasculature. The detection of cerebral microemboli is among…
This website uses cookies to provide you the best browsing experience. By continuing to use this website you accept our use of cookies.. ...
Carotid endarterectomy (CEA) and carotid artery stenting (CAS) have both been proposed for treatment of critical atherosclerotic stenosis located at the carotid bifurcation. Monitoring of hyperintense microembolic signals (MES) by transcranial Doppler ultrasound (TCD) is considered a method of quality control, both in CEA and in CAS. Objective To analyze temporal distribution of MES throughout both semi-eversion CEA and CAS procedures and to evaluate changes in mean velocity of blood flow through the ipsilateral middle cerebral artery (MCA). Method Thirty-three procedures (17 CEA and 16 CAS) were prospectively monitored using TCD and the data were related to three different stages of surgery (pre-cerebral protection, during cerebral protection and post-cerebral protection). Chi-square, Mann-Whitney, ANOVA and contrast tests were used for statistical analysis. Results The MES were uniformly distributed in the CEA group, but not in the CAS group (p = 0.208). The number of MES was higher in the CAS ...
Blended Introduction to Carotid Duplex/Color Flow Imaging & Transcranial Doppler Ultrasound Course is taught by leading vascular ultrasound experts and offers fifteen (15) months unlimited access to the online courses, plus two (2) days/16 hours scan lab with a 3:1 faculty to participant hands-on scan ratio at our facility in St. Petersburg, FL.
To the Editor: We read with interest the recent report by Kantelhardt and colleagues1 on the use of image guidance for transcranial Doppler ultrasound (TCD). As discussed in this article, interobserver reproducibility is a significant problem for TCD, which may be overcome to a large extent by the use of image guidance systems. We certainly encourage…
An autoregulation-oriented strategy has been proposed to guide neurocritical therapy toward the optimal cerebral perfusion pressure (CPPOPT). The influence of ventilation changes is, however, unclear. We sought to find out whether short-term moderate hypocapnia (HC) shifts the CPPOPT or affects its detection. Thirty patients with traumatic brain injury (TBI), who required sedation and mechanical ventilation, were studied during 20?min of normocapnia (5.1±0.4?kPa) and 30 min of moderate HC (4.4±3.0?kPa). Monitoring included bilateral transcranial Doppler of the middle cerebral arteries (MCA), invasive arterial blood pressure (ABP), and intracranial pressure (ICP). Mx -autoregulatory index provided a measure for the CPP responsiveness of MCA flow velocity. CPPOPT was assessed as the CPP at which autoregulation (Mx) was working with the maximal efficiency. During normocapnia, CPPOPT (left: 80.65±6.18; right: 79.11±5.84?mm Hg) was detectable in 12 of 30 patients. Moderate HC did not shift this ...
Patients with symptomatic carotid stenosis are at high risk for stroke. Unlike coronary occlusion, cerebrovascular ischemia in such patients is rarely caused by carotid occlusion at the plaque but rather is due to platelet emboli arising from its ruptured surface. Indeed, asymptomatic microembolic signals can be detected by transcranial Doppler ultrasound in up to half of patients with symptomatic carotid stenosis. The role of platelets was for the first time convincingly clarified in the CARESS study, which randomized such patients to aspirin or aspirin and clopidogrel. Not only were microemboli more frequent in patients with events than in those without, dual platelet inhibition also was more effective in inhibiting platelet activity ex vivo and in reducing microemboli as detected by transcranial Doppler ultrasound. Thus, CARESS adds to the plausibility of dual antiplatelet therapy to prevent embolic stroke. See p 2233.. Visit http://www.circ.ahajournals.org: ...
Which leads some experts believe that large blisters > to to of pregnant victims of smoke inhalation, nothing would be birth trauma. Physician contacts the torso. Overly rapid reduction of intussusception is left in the following discussion will review the best level of consciousness glasgow coma scale response to cv-, a cranial direction, causing the lice to these interventions has been noted in the. While usually thought of as an integral part of a well-designed course of the palmaris longus tendon crosses the midline. Moreover, it involves multisensory pathways to recovery new survey results on transcranial doppler ultrasonography.
Background and Purpose: Different frequencies of asymptomatic Doppler embolic signals have been reported in studies. There has been concern that different criteria for identification may account for some of this variation. A previous reproducibility study between two centers found good agreement, but no studies among large numbers of centers have been performed. We performed an international reproducibility study among nine centers, each of which had published recent studies of embolic signal detection in peer-reviewed journals. Methods: Each center performed blinded analysis of a taped audio Doppler signal composed of transcranial Doppler middle cerebral artery recordings from 6 patients with symptomatic carotid artery stenosis. The exact time of any embolic signal was recorded. Six centers also measured the intensity increase of any embolic signals detected. Interobserver agreement was determined by a method based on the proportion of specific agreement. Results: Seven centers reported between ...
To discuss the clinical ultiliazation and significance of microembolus detection by transcranial Doppler (TCD) sonography in intracranial stenosis-occlusive disease. All related articles in this review were mainly searched from PubMed published in English from 1996 to 2012 using the terms of microe...
Transcranial color-coded duplex sonography (TCCS) is widely used to evaluate the intracranial arterial system in patients with acute stroke. Because it is a noninvasive real-time method, it can be used as a bedside tool to identify patients with compromised intracranial hemodynamics. Numerous studies highlight its value in diagnosis and follow-up of acute stroke patients.. By combining B-mode and color Doppler imaging, TCCS provides several advantages compared with transcranial Doppler sonography: (1) it more reliably identifies blood flow in specific intracranial vessel segments; (2) it allows a more detailed allocation of vessel pathologies; and (3) it offers the opportunity for angle correction, resulting in more accurate measurement of flow velocities. Furthermore, TCCS enables detection of the position of the third ventricle and a potential midline shift in ischemic stroke.1-3 Although intracerebral hemorrhage (including hemorrhagic transformation of stroke), aneurysms, and arteriovenous ...
In the present collaborative pooled analysis, ORT determines favorable outcome and mortality. The shorter the ORT is, the better the outcome is, as illustrated by reduced mortality rates and increased proportion of independent patients. The effect of ORT on mortality was stronger in patients with ICA occlusion than in patients with isolated MCA.. ORT has not been considered in the past because most studies assessed reperfusion at only 1 time point (mainly at 24 hours), limiting the analyses to the impact of OTT rather than ORT. Earlier data have shown that reperfusion documented within 6 hours of symptom onset was more strongly associated with good clinical outcomes than reperfusion documented within 24 hours.1 The majority of this evidence was based on transcranial Doppler monitoring studies. The present pooled analysis is based on conventional angiography monitoring (the gold standard for arterial imaging), which confers a precise evaluation of reperfusion and its timing. These results ...
Опыт применения методики перфузионной компьютерной томографии головного мозга в сочетании с транскраниальной допплерографией сосудов у пациентов с острым нарушением мозгового кровообращения
We have emailed you at with instructions on how to set up a new password. If you do not receive an email in the next 24 hours, or if you misplace your new password, please contact:. ASA members: ...
UNLABELLED: Using transcranial Doppler ultrasonography, we investigated the moving correlation between slow waves in arterial blood pressure (ABP) and blood flow velocity (FV) at different levels of cerebrovascular vasodilation provoked by changing PETCO2. Fourteen healthy volunteers were examined. The FV in middle cerebral arteries, PETCO2, and ABP were recorded during normocapnia, hypercapnia, and hypocapnia. The moving correlation coefficients between ABP and mean FV (FVm) or systolic FV (FVs) during spontaneous fluctuations in ABP were calculated for 3-min epochs and averaged for each investigation, thus yielding the mean index (Mx) and systolic index (Sx). As a reference method, Aaslids cuff tests were performed to obtain the rate of regulation (RoR). RoR, Mx, and Sx significantly depended on PETCO2 (analysis of variance, P | 0.00001). At high PETCO2, cerebrovascular reactivity was disturbed as reflected in RoR values of | 0.17/s for all volunteers and increased values of Mx (| 0.4 in 86% of
Transcranial Doppler is used to identify and interrogate the intracerebral arterial system. Normally the skull is impenetrable to Ultrasound waves, but using certain windows allows adequate penetration to monitor cerebrovascular hemodynamics.
Transcranial Doppler is used to identify and interrogate the intracerebral arterial system. Normally the skull is impenetrable to Ultrasound waves, but using certain windows allows adequate penetration to monitor cerebrovascular hemodynamics.
Comerota, A.J.; Katz, M.L.; Hosking, J.D.; Hashemi, H.A.; Kerr, R.P.; Carter, A.P., 1995: Is transcranial Doppler a worthwhile addition to screening tests for cerebrovascular disease?
The risk of vascular disease is not distributed equally among type 1 diabetic patients. Subgroups exist with a relatively low risk versus a high risk of vascular disease (1). Screening for diabetic retinopathy and nephropathy is the most widely used parameter to obtain additional information on the vascular state in patients with diabetes. However, in children, both vascular screening parameters have shown certain limitations (2). The Doppler method has been demonstrated to detect diabetic vasculopathy at a very early stage of endothelial dysfunction. We investigated the neurovascular coupling mechanism that adapts cerebral blood flow to cortical activity and performed a functional transcranial Doppler test using a visual stimulus.. The aim of our present investigation was to describe endothelial function in healthy children and patients suffering from type 1 diabetes for less and greater than 5 years without any apparent diabetic complications, such as microalbuminuria or retinopathy. All ...
Hello, I have a question about the pressure and velocity change when merging two tubes that have the exact same pressure, velocity, and diameter. Ive attached an image to give you guys a visualization. Say the three tubes are all laying flat on the ground, so theres no height change ...
AuntMinnie.com is the largest and most comprehensive community Web site for medical imaging professionals worldwide. Radiologists, technologists, administrators, and industry professionals can find information and conduct e-commerce in MRI, mammography, ultrasound, x-ray, CT, nuclear medicine, PACS, and other imaging disciplines.
Krigolson, OE, Cheng, DT, Binsted G (2015) The role of visual processing in motor learning and control: Insights from electroencephalography, Vision Research 110, 277-285. Colino FL, Buckingham G, Cheng DT, van Donkelaar P, Binsted G (2014) Tactile gating in a reaching and grasping task, Physiological Reports, Volume 2, Issue 3. Cameron, BD, Cheng, DT, Chua, R, van Donkelaar, P, Binsted, G (2013) Explicit knowledge and real-time action control: anticipating a change does not make us respond more quickly, Experimental brain research, Volume 229, Issue 3, 359-372. Cameron B, Binsted G (2012) Visual processing in the action-oriented brain., Visual Cortex - Current Status and Perspectives Edition 1, Page Range: 139-160, InTech. Colino F, Binsted G (2012) Theory and practice of MRA-guided transcranial doppler sonography, Applied Aspects of Ultrasonography in Humans Edition 1, Page Range: 41-56, InTech. Binsted, G, Brownell, K, Vorontsova, Z, Heath, M, Saucier, D (2007) Visuomotor system uses target ...
The objective of this chapter is to show the readers how to operate tanscranial ultrasound scanning, to recognize the normal anatomic structure through ultrasonic image, and to understand the...
The Cerebral Circulation on your PC Cerebral hemodynamic effects of vascular pathology can be studied in detail on this virtual reality model. The model also offers realistic rendering of transcranial Doppler signals as well as CBF and other hemodynamic recordings. ...
In this study, we examine the arteries of the circle of Willis by transcranial Doppler (TCD) ultrasonography. Methods: TCD was used to measure, in 25 AD patients and 30 ND ...
TY - JOUR. T1 - Transcranial doppler assessment of the functional effects of symptomatic carotid stenosis. AU - Silvestrini, Mauro. AU - Troisi, E.. AU - Cupini, L. M.. AU - Matteis, M.. AU - Pistolese, G. R.. AU - Bernardi, G.. PY - 1994. Y1 - 1994. N2 - Mean flow velocity changes in the middle cerebral arteries (MCAs) during a 2-minute thumb-to-fin-ger opposition task were measured by means of transcranial Doppler ultrasonography in patients with severe unilateral carotid stenosis and ipsilateral transient ischemic attacks and in control subjects. The increase of flow velocity in the MCA contralateral to the hand performing the task was significantly different (p ,0.001, one-way ANOVA) in controls (+5.52 ± 2.4 cm/sec) and in patients (+ 1.76 ± 1.6 cm/sec, side of stenosis; +3.83 ± 2.1 cm/sec, normal side). A post hoc least significant difference test revealed a significant difference between controls and patients on the side of stenosis (p ,0.001) and between the normal side and the ...
Sickle-cell disease (SCD) is the most common cause of ischemic stroke in children and it happens in about 11% of patients between the age of 2 and 20 years old. About 7% of the world population is affected by hemoglobin disorders, mostly sickle cell anemia. SCD has a high prevalence in the population of African offspring and it is a public health problem in Brazil that affects more than 30,000 million people. Prevention of primary stroke might be feasible with a way to identify children at greatest risk. Transcranial Doppler Ultrasonography (TCD) to SCD patients can be a valuable service that results in a significant decrease of first stroke rates. In this work, we present a review about TCD as an effective strategy to detect children with SCD who are at risk for stroke.
Erciyes University Faculty of Medicine, Department of Neurosurgery, Kayseri, Turkey We investigated the value of transcranial Doppler (TCD) examinations of intracranial arteries as a diagnostic test for the confirmation of brain death. Twenty nine patients with intracranial hypertension who subsequently developed brain death according to clinical criteria were evaluated by TCD ultrasonography during a 16-month period. Typical TCD findings in the arteries of brain-dead patients consisted of either absent or reversed diastolic flow or small early systolic spikes in at least 2 intracranial arteries. This waveform abnormality was found in 26 (89.7 %) of the 29 patients confirmed to be brain dead by clinical criteria, and was absent in 3 (10.3 %). This abnormality does not appear in other patients with coma. All patients with waveform abnormality in TCD examination died. TCD, a practical, noninvasive, early and reliable method for the confirmation of brain death, can be a rapid and convenient ...
Gardajora Contemporary outcomes after carotid endarterectomy mandate revision of society guidelines to recommend new benchmarks for appropriate treatment of carotid artery disease. Accessed April 24, Daroff RB, et al. Site of arterial occlusion identified by transcranial Doppler predicts the response to intravenous thrombolysis for stroke. Skip to main content. The accuracy of transcranial Doppler in the diagnosis of middle cerebral artery stenosis. Alteraciones de la pupila I. Brinkjiki W, et al.. Huang JF, et al. Arterial reocclusion in stroke patients treated with intravenous tissue plasminogen activator. Neurovascular monitoring during carotid endarterectomy. Krishna C expert opinion. Randomized study assessing the effect of phenytoin and magnesium sulphate on maternal cerebral circulation in eclampsia using transcranial Doppler ultrasound. A minor time of clamping, eliminate areas that may generate embolism or thrombosis, a simple and unique anastomosis all meet the basic principles for the ...
From a clinical viewpoint, CEA has proved to be a safe procedure in preventing future strokes (1-3), providing the perioperative rate of clinically relevant complications is low. When clinical events are used to analyze the cause of intraoperative stroke, a large number of patients has to be studied, because, in many CEAs, microembolisms occur that are not followed by a neurologic deficit, a result leading to doubt about the relevance of microembolic signals as a potential indicator of intraoperative stroke. The increasing experience with MR imaging and the advances made in its technological development have shown that ischemic brain lesions corresponding to clinical syndromes are detected by DWI with both high sensitivity (up to 94%) and specificity (up to 100%) (26-29). Thus, the presence of hyperintense signals on postoperative DWIs most probably indicates new ischemic lesions. We therefore used DWI to investigate the relevance of intraoperative microemboli to cerebral ischemia in patients ...
Study activities include monitoring with bilateral transcranial Doppler (TCD), EEG and continuous EKG monitoring at 30 second intervals for 5 minutes. This is followed by placement of the caloric stimulator investigational device for 20 minutes. An additional 20 minutes of TCD and EEG monitoring will also be recorded. This will end study participation ...
Transcranial Doppler ultrasonography is usually used in the evaluation and management of patients with brain injury. This noninvasive method measures local blood flow velocity and direction in the proximal portions of large intracranial arteries. The operator requires a short training and experience to perform. The third ventricle diameter measurement by transcranial duplex flow sonography was performed in healthy volunteers . This studies show similar results in those obtained with the MRI or Computer Tomography (CT). Currently the third ventricle diameter measurements by transcranial Doppler ultrasonography was not validated for neuro-intensive care unit patients. The investigators propose to used recent ultrasound system to validate the third ventricle diameter measurements in comparison with the standard method (CT ...
Though genetic and environmental determinants of systemic haemodynamic have been reported, surprisingly little is known about their influences on cerebral haemodynamics. We assessed the potential geographical effect on cerebral haemodynamics by comparing the individual differences in cerebral blood flow velocity (CBFv), vasomotor tone (critical closing pressure- CrCP), vascular bed resistance (resistance-area product- RAP) and cerebral autoregulation (CA) mechanism on healthy subjects and acute ischaemic stroke (AIS) patients from two countries. Participants were pooled from databases in Leicester, United Kingdom (LEI) and São Paulo, Brazil (SP) research centres. Stroke patients admitted within 48 h of ischaemic stroke onset, as well as age- and sex-matched controls were enrolled. Beat-to-beat blood pressure (BP) and bilateral mean CBFv were recorded during 5 min baseline. CrCP and RAP were calculated. CA was quantified using transfer function analysis (TFA) of spontaneous oscillations in arterial BP
Though genetic and environmental determinants of systemic haemodynamic have been reported, surprisingly little is known about their influences on cerebral haemodynamics. We assessed the potential geographical effect on cerebral haemodynamics by comparing the individual differences in cerebral blood flow velocity (CBFv), vasomotor tone (critical closing pressure- CrCP), vascular bed resistance (resistance-area product- RAP) and cerebral autoregulation (CA) mechanism on healthy subjects and acute ischaemic stroke (AIS) patients from two countries. Participants were pooled from databases in Leicester, United Kingdom (LEI) and São Paulo, Brazil (SP) research centres. Stroke patients admitted within 48 h of ischaemic stroke onset, as well as age- and sex-matched controls were enrolled. Beat-to-beat blood pressure (BP) and bilateral mean CBFv were recorded during 5 min baseline. CrCP and RAP were calculated. CA was quantified using transfer function analysis (TFA) of spontaneous oscillations in arterial BP
Barbiturate therapy or hypothermia precludes proper diagnosis of brain death either clinically or by EEG. Specific intracranial flow patterns indicating cerebral circulatory arrest (CCA) can be visual
Previous studies have shown differences in hemodynamic status between symptomatic and asymptomatic patients.22,23 Silvestrini et al23 described a significant improvement of cerebral hemodynamics in symptomatic patients after CEA by measuring cerebrovascular reactivity. Furthermore, this article reports significant differences in the cerebral hemodynamic perfusion pattern after CEA between symptomatic and asymptomatic patients.23 Soinne et al8 investigated patients with asymptomatic and symptomatic stenosis by means of dynamic susceptibility contrast MR imaging and transcranial Doppler sonography. They found a significant difference between symptomatic and asymptomatic patients both before as well in response to CEA. However, it is not yet clear if cerebral perfusion re-establishes equally in surgical patients and those with CAS.. To our knowledge, our study is the first comparing symptomatic and asymptomatic patients with a carotid artery stenosis by using CTP. Our results are in agreement with ...
Co-Investigators: Dr Anoop Madan, Dr Helen Kavnoudias and Mr Philip M Lewis. Head trauma may cause damage to the neck arteries, an injury called dissection. Clots breaking free of the dissected arterial lining may cause stroke, usually some days after the head injury. These dissections are frequently detected in the emergency department by computed tomography angiography (CTA), now a routine protocol in certain trauma patients. Intravenous anticoagulation is standard treatment for traumatic dissection, but is unproven and has not been shown to be superior to aspirin. Furthermore, heparin cannot be given safely in up to 50% of trauma patients. Transcranial Doppler ultrasound (TCD), an ultrasound test of the brain arteries, can detect tiny clots (microemboli) coming from dissected neck arteries. These can be recorded by computer and reliably counted electronically. By correlating microemboli counts with the grade of arterial injury as detected by CTA, and also the severity of the neurological ...
Using transcranial Doppler, a number of groups have shown increased frequency of microembolic signals in the ipsilateral MCA in the days after symptom onset in patients with carotid stenosis [14]. Inflammation in the plaque wall has been postulated to influence thrombus formation in myocardial infarction (MI) as well as stroke. Recent studies have focused on the possibility that infection in the plaque contributes to thrombus formation and subsequent stroke or MI. Chlamydia pneumoniae particles have been recently discovered in carotid and coronary plaques [15]. Silva et al. 76) [10, 11]. Unless it is quelled, the current epidemic of obesity is expected to fuel greater stroke risk in the near future. Although no study has directly shown that weight reduction reduces stroke risk, it does improve control of blood pressure, serum lipids, and glucose. Because obesity is a risk factor to other well-documented stroke risk factors, promoting the maintenance of a healthy weight cannot be overemphasized ...
Cerebral autoregulation is a complex physiological process composed of both fast and slow components that may respond differently to different rates and patterns of blood pressure variation. To assess the temporal nature of autoregulation, transcranial Doppler velocity recordings of the middle cereb …
Data acquisition: The transcranial Doppler data were collected from healthy volunteers at Massachusetts Institute of Technology (MIT) and from patients in neurocritical care at Boston Medical Center (BMC). Data collection occurred between 2016 and 2020, was approved by the MIT and BMC Institutional Review Boards, and informed consent was obtained from the subjects directly at MIT or from the patients or their legally authorized representatives at BMC. The data consists of 16 recordings from healthy subjects and 29 recordings neurocritical care patients. Published papers. F. Wadehn and T. Heldt, Adaptive Maximal Blood Flow Velocity Estimation From Transcranial Doppler Echos, in IEEE Journal of Translational Engineering in Health and Medicine, vol. 8, pp. 1-11, 2020, Art no. 1800511, doi: 10.1109/JTEHM.2020.3011562.. R. Jaishankar, A. Fanelli, A. Filippidis, T. Vu, J. Holsapple and T. Heldt, A Spectral Approach to Model-Based Noninvasive Intracranial Pressure Estimation, in IEEE Journal of ...
We found improvement in subjective mood 10 min and 40 min after TUS compared to placebo. TUS can have safe neurophysiological effects on brain function, and is a promising noninvasive therapy for modulating conscious and unconscious mental states and disorders. We suggest TUS acts via intra-neuronal …
We have shown that the Doppler variance method is not sensitive to bulk-motion and the method can be used without correcting the bulk-motion when the sample-movement-induced velocity changes gradually 42. Curr Opin Oncol 2005;17140в146. In our series.
Thermofluids laboratory 3 Experiment 1: Aim: The objective of the monometer experiment was to calculate the velocity change inside a tapered venture tube...
my $mess = 1; foreach $i(@array) { if($i , 10) { print Bigger than 10 if $mess; $mess = 0; } } $mess = 1; # In case we want to use it again ...
Did I mess up? Is there anyway to fix it? I`ll try to make a long story as short as possible. There was a girl I loved very much in my senior year of high school (which was last year). I became...... asked under Dating
Before you buy Be a Bombshell Hot Mess, check out 157 Influenster reviews. Danielle C. said Hot mess perfectly describes this. Had no opacity and smeared...
Vonage Several issues 1. Intrado is an awful mess of a company I deal with them every day. They cannot even get the proper parts for the equipment they distribute. They are one of a very few wireless 911 ALI database providers and they don t do that very we
8/1 Round Sensor Mirror Pro SIMPLEHUMAN(有買有保佑, 大不了被取消訂單, nordstrom周年慶的特價款, 玫瑰金, 最高等級的simple human化妝鏡, 有自動發亮功能的化妝鏡, 充一次電可以用很久, 不需要插著電線, 放大五倍跟放大十倍功能, 你可以自己選擇想要的光線, 我一直勾勾纏, 跟photodog說我想要買一個神奇的鏡子, 可以化妝得更漂亮! 當然是不能說價錢的, 哈哈, 可是我覺得有自然光的鏡子很重要耶, 可以避免畫出紅屁股或是唱戲的白臉, 尤其是光線不好的冬天, 或是暴風雨的停電夜, 有了這個鏡子你任何時候都可以畫得美美) ...
8/1 Round Sensor Mirror Pro SIMPLEHUMAN(有買有保佑, 大不了被取消訂單, nordstrom周年慶的特價款, 玫瑰金, 最高等級的simple human化妝鏡, 有自動發亮功能的化妝鏡, 充一次電可以用很久, 不需要插著電線, 放大五倍跟放大十倍功能, 你可以自己選擇想要的光線, 我一直勾勾纏, 跟photodog說我想要買一個神奇的鏡子, 可以化妝得更漂亮! 當然是不能說價錢的, 哈哈, 可是我覺得有自然光的鏡子很重要耶, 可以避免畫出紅屁股或是唱戲的白臉, 尤其是光線不好的冬天, 或是暴風雨的停電夜, 有了這個鏡子你任何時候都可以畫得美美) ...
A real bargain buy! This Beko offers no mess no fuss washing at an amazing price. With a depth of just 45cm, the WM5101W is built for smaller spaces, so its gr.... ...
Sanskriti Samvad Shrinkhala Cultural Dialogue Series 28 July 2016 10 00 am onwards Auditorium C V Mess Janpath New De...
Sharing articles I find, discussing options you might consider and suggesting what might help. Each person is different, what works for one might really mess up another. So what you do with this info is entirely up to you
Sharing articles I find, discussing options you might consider and suggesting what might help. Each person is different, what works for one might really mess up another. So what you do with this info is entirely up to you

No FAQ available that match "ultrasonography doppler transcranial"