A noninvasive method for assessing BODY COMPOSITION. It is based on the differential absorption of X-RAYS (or GAMMA RAYS) by different tissues such as bone, fat and other soft tissues. The source of (X-ray or gamma-ray) photon beam is generated either from radioisotopes such as GADOLINIUM 153, IODINE 125, or Americanium 241 which emit GAMMA RAYS in the appropriate range; or from an X-ray tube which produces X-RAYS in the desired range. It is primarily used for quantitating BONE MINERAL CONTENT, especially for the diagnosis of OSTEOPOROSIS, and also in measuring BONE MINERALIZATION.

Examination of any part of the body for diagnostic purposes by means of X-RAYS or GAMMA RAYS, recording the image on a sensitized surface (such as photographic film).

A method of producing a high-quality scan by digitizing and subtracting the images produced by high- and low-energy x-rays.

X-ray visualization of the chest and organs of the thoracic cavity. It is not restricted to visualization of the lungs.

The amount of mineral per square centimeter of BONE. This is the definition used in clinical practice. Actual bone density would be expressed in grams per milliliter. It is most frequently measured by X-RAY ABSORPTIOMETRY or TOMOGRAPHY, X RAY COMPUTED. Bone density is an important predictor for OSTEOPOROSIS.

The chemical reactions involved in the production and utilization of various forms of energy in cells.

A rapid, low-dose, digital imaging system using a small intraoral sensor instead of radiographic film, an intensifying screen, and a charge-coupled device. It presents the possibility of reduced patient exposure and minimal distortion, although resolution and latitude are inferior to standard dental radiography. A receiver is placed in the mouth, routing signals to a computer which images the signals on a screen or in print. It includes digitizing from x-ray film or any other detector. (From MEDLINE abstracts; personal communication from Dr. Charles Berthold, NIDR)

Extraoral body-section radiography depicting an entire maxilla, or both maxilla and mandible, on a single film.

Total number of calories taken in daily whether ingested or by parenteral routes.

The relative amounts of various components in the body, such as percentage of body fat.

Improvement in the quality of an x-ray image by use of an intensifying screen, tube, or filter and by optimum exposure techniques. Digital processing methods are often employed.

The constricted portion of the thigh bone between the femur head and the trochanters.

Reduction of bone mass without alteration in the composition of bone, leading to fractures. Primary osteoporosis can be of two major types: postmenopausal osteoporosis (OSTEOPOROSIS, POSTMENOPAUSAL) and age-related or senile osteoporosis.

Technique involving the passage of X-rays through oral structures to create a film record while a central tab or wing of dental X-ray film is being held between upper and lower teeth.

The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.

VERTEBRAE in the region of the lower BACK below the THORACIC VERTEBRAE and above the SACRAL VERTEBRAE.

The longest and largest bone of the skeleton, it is situated between the hip and the knee.

Tomography using x-ray transmission and a computer algorithm to reconstruct the image.

Computer systems or networks designed to provide radiographic interpretive information.

Metabolic bone diseases are a group of disorders that affect the bones' structure and strength, caused by disturbances in the normal metabolic processes involved in bone formation, resorption, or mineralization, including conditions like osteoporosis, osteomalacia, Paget's disease, and renal osteodystrophy.

Screens which absorb the energy in the x-ray beam that has penetrated the patient and convert this energy into a light pattern which has as nearly as possible the same information as the original x-ray beam. The more light a screen produces for a given input of x-radiation, the less x-ray exposure and thus shorter exposure time are needed to expose the film. In most film-screen systems, the film is sandwiched between two screens in a cassette so that the emulsion on each side is exposed to the light from its contiguous screen.

Radiographic visualization of the body between the thorax and the pelvis, i.e., within the peritoneal cavity.

Neural tracts connecting one part of the nervous system with another.

The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).

Devices or objects in various imaging techniques used to visualize or enhance visualization by simulating conditions encountered in the procedure. Phantoms are used very often in procedures employing or measuring x-irradiation or radioactive material to evaluate performance. Phantoms often have properties similar to human tissue. Water demonstrates absorbing properties similar to normal tissue, hence water-filled phantoms are used to map radiation levels. Phantoms are used also as teaching aids to simulate real conditions with x-ray or ultrasonic machines. (From Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990)

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.

A film base coated with an emulsion designed for use with x-rays.

The amount of fat or lipid deposit at a site or an organ in the body, an indicator of body fat status.

Specialized connective tissue composed of fat cells (ADIPOCYTES). It is the site of stored FATS, usually in the form of TRIGLYCERIDES. In mammals, there are two types of adipose tissue, the WHITE FAT and the BROWN FAT. Their relative distributions vary in different species with most adipose tissue being white.

Metabolic disorder associated with fractures of the femoral neck, vertebrae, and distal forearm. It occurs commonly in women within 15-20 years after menopause, and is caused by factors associated with menopause including estrogen deficiency.

A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principle cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.

The spinal or vertebral column.

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)

The technique that deals with the measurement of the size, weight, and proportions of the human or other primate body.

The comparison of the quantity of meaningful data to the irrelevant or incorrect data.

The projecting part on each side of the body, formed by the side of the pelvis and the top portion of the femur.

The lectin wheatgerm agglutinin conjugated to the enzyme HORSERADISH PEROXIDASE. It is widely used for tracing neural pathways.

The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.

Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.

Breaks in bones.

Computed tomography modalities which use a cone or pyramid-shaped beam of radiation.

The outer shorter of the two bones of the FOREARM, lying parallel to the ULNA and partially revolving around it.

An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)

X-ray screening of large groups of persons for diseases of the lung and heart by means of radiography of the chest.

The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.

The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.

The articulation between a metacarpal bone and a phalanx.

A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.

Elements of limited time intervals, contributing to particular results or situations.

The largest of the TARSAL BONES which is situated at the lower and back part of the FOOT, forming the HEEL.

The anterior pair of the quadrigeminal bodies which coordinate the general behavioral orienting responses to visual stimuli, such as whole-body turning, and reaching.

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.

Information systems, usually computer-assisted, designed to store, manipulate, and retrieve information for planning, organizing, directing, and controlling administrative activities associated with the provision and utilization of radiology services and facilities.

Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.

Fatty tissue in the region of the ABDOMEN. It includes the ABDOMINAL SUBCUTANEOUS FAT and the INTRA-ABDOMINAL FAT.

Nerve structures through which impulses are conducted from a nerve center toward a peripheral site. Such impulses are conducted via efferent neurons (NEURONS, EFFERENT), such as MOTOR NEURONS, autonomic neurons, and hypophyseal neurons.

The resistance to the flow of either alternating or direct electrical current.

A defense mechanism, operating unconsciously, whereby that which is emotionally unacceptable in the self is rejected and attributed (projected) to others.

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.

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.

A type of FLUORESCENCE SPECTROSCOPY using two FLUORESCENT DYES with overlapping emission and absorption spectra, which is used to indicate proximity of labeled molecules. This technique is useful for studying interactions of molecules and PROTEIN FOLDING.

Roentgenography of a joint, usually after injection of either positive or negative contrast medium.

Tomography using x-ray transmission.

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.

Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.

Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard X-rays are the higher energy, shorter wavelength X-rays. Soft x-rays or Grenz rays are less energetic and longer in wavelength. The short wavelength end of the X-ray spectrum overlaps the GAMMA RAYS wavelength range. The distinction between gamma rays and X-rays is based on their radiation source.

Substances used to identify the location and to characterize the types of NEURAL PATHWAYS.

Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.

An enzyme isolated from horseradish which is able to act as an antigen. It is frequently used as a histochemical tracer for light and electron microscopy. Its antigenicity has permitted its use as a combined antigen and marker in experimental immunology.

Hospital department which is responsible for the administration and provision of x-ray diagnostic and therapeutic services.

The continuous turnover of BONE MATRIX and mineral that involves first an increase in BONE RESORPTION (osteoclastic activity) and later, reactive BONE FORMATION (osteoblastic activity). The process of bone remodeling takes place in the adult skeleton at discrete foci. The process ensures the mechanical integrity of the skeleton throughout life and plays an important role in calcium HOMEOSTASIS. An imbalance in the regulation of bone remodeling's two contrasting events, bone resorption and bone formation, results in many of the metabolic bone diseases, such as OSTEOPOROSIS.

Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.

Radiation protection, also known as radiation safety, is the science and practice of protecting people and the environment from harmful ionizing radiation exposure while allowing for the safe medical, industrial, and research uses of such radiation.

The joint that is formed by the articulation of the head of FEMUR and the ACETABULUM of the PELVIS.

Increase in the longest dimension of a bone to correct anatomical deficiencies, congenital, traumatic, or as a result of disease. The lengthening is not restricted to long bones. The usual surgical methods are internal fixation and distraction.

Progressive decline in muscle mass due to aging which results in decreased functional capacity of muscles.

Fractures occurring as a result of disease of a bone or from some undiscoverable cause, and not due to trauma. (Dorland, 27th ed)

STILBENES with AMIDINES attached.

Planned management, use, and preservation of energy resources.

The measurement of subcutaneous fat located directly beneath the skin by grasping a fold of skin and subcutaneous fat between the thumb and forefinger and pulling it away from the underlying muscle tissue. The thickness of the double layer of skin and subcutaneous tissue is then read with a caliper. The five most frequently measured sites are the upper arm, below the scapula, above the hip bone, the abdomen, and the thigh. Its application is the determination of relative fatness, of changes in physical conditioning programs, and of the percentage of body fat in desirable body weight. (From McArdle, et al., Exercise Physiology, 2d ed, p496-8)

The physiological period following the MENOPAUSE, the permanent cessation of the menstrual life.

Energy transmitted from the sun in the form of electromagnetic radiation.

A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)

A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.

The largest and strongest bone of the FACE constituting the lower jaw. It supports the lower teeth.

Deposits of ADIPOSE TISSUE throughout the body. The pattern of fat deposits in the body regions is an indicator of health status. Excess ABDOMINAL FAT increases health risks more than excess fat around the hips or thighs, therefore, WAIST-HIP RATIO is often used to determine health risks.

A status with BODY WEIGHT that is grossly above the acceptable or desirable weight, usually due to accumulation of excess FATS in the body. The standards may vary with age, sex, genetic or cultural background. In the BODY MASS INDEX, a BMI greater than 30.0 kg/m2 is considered obese, and a BMI greater than 40.0 kg/m2 is considered morbidly obese (MORBID OBESITY).

The application of scientific knowledge or technology to the field of radiology. The applications center mostly around x-ray or radioisotopes for diagnostic and therapeutic purposes but the technological applications of any radiation or radiologic procedure is within the scope of radiologic technology.

Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.

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).

Set of nerve fibers conducting impulses from olfactory receptors to the cerebral cortex. It includes the OLFACTORY NERVE; OLFACTORY BULB; OLFACTORY TRACT; OLFACTORY TUBERCLE; ANTERIOR PERFORATED SUBSTANCE; and OLFACTORY CORTEX.

The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)

Bone loss due to osteoclastic activity.

Several groups of nuclei in the thalamus that serve as the major relay centers for sensory impulses in the brain.

Broken bones in the vertebral column.

The growth and development of bones from fetus to adult. It includes two principal mechanisms of bone growth: growth in length of long bones at the epiphyseal cartilages and growth in thickness by depositing new bone (OSTEOGENESIS) with the actions of OSTEOBLASTS and OSTEOCLASTS.

A nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126.90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.

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.

Calcium compounds used as food supplements or in food to supply the body with calcium. Dietary calcium is needed during growth for bone development and for maintenance of skeletal integrity later in life to prevent osteoporosis.

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.

Vitamin K-dependent calcium-binding protein synthesized by OSTEOBLASTS and found primarily in BONES. Serum osteocalcin measurements provide a noninvasive specific marker of bone metabolism. The protein contains three residues of the amino acid gamma-carboxyglutamic acid (Gla), which, in the presence of CALCIUM, promotes binding to HYDROXYAPATITE and subsequent accumulation in BONE MATRIX.

The directed transport of ORGANELLES and molecules along nerve cell AXONS. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (Alberts et al., Molecular Biology of the Cell, 3d ed, pG3)

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.

The part of a tooth from the neck to the apex, embedded in the alveolar process and covered with cementum. A root may be single or divided into several branches, usually identified by their relative position, e.g., lingual root or buccal root. Single-rooted teeth include mandibular first and second premolars and the maxillary second premolar teeth. The maxillary first premolar has two roots in most cases. Maxillary molars have three roots. (Jablonski, Dictionary of Dentistry, 1992, p690)

Inanimate objects that become enclosed in the body.

Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.

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.

Forms of energy that are constantly and rapidly renewed by natural processes such as solar, ocean wave, and wind energy. (from McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

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.

Any visible result of a procedure which is caused by the procedure itself and not by the entity being analyzed. Common examples include histological structures introduced by tissue processing, radiographic images of structures that are not naturally present in living tissue, and products of chemical reactions that occur during analysis.

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.

Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.

The articulation between the head of one phalanx and the base of the one distal to it, in each finger.

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)

A nonhormonal medication for the treatment of postmenopausal osteoporosis in women. This drug builds healthy bone, restoring some of the bone loss as a result of osteoporosis.

The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.

Harm or hurt to the ankle or ankle joint usually inflicted by an external source.

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.

Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.

State of the body in relation to the consumption and utilization of nutrients.

Computer-based representation of physical systems and phenomena such as chemical processes.

Agents that inhibit BONE RESORPTION and/or favor BONE MINERALIZATION and BONE REGENERATION. They are used to heal BONE FRACTURES and to treat METABOLIC BONE DISEASES such as OSTEOPOROSIS.

The distance from the sole to the crown of the head with body standing on a flat surface and fully extended.

Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.

The measurement of the density of a material by measuring the amount of light or radiation passing through (or absorbed by) the material.

Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.

A 16-kDa peptide hormone secreted from WHITE ADIPOCYTES. Leptin serves as a feedback signal from fat cells to the CENTRAL NERVOUS SYSTEM in regulation of food intake, energy balance, and fat storage.

Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.

An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC 3.1.3.1.

A water-soluble, enzyme co-factor present in minute amounts in every living cell. It occurs mainly bound to proteins or polypeptides and is abundant in liver, kidney, pancreas, yeast, and milk.

Most generally any NEURONS which are not motor or sensory. Interneurons may also refer to neurons whose AXONS remain within a particular brain region in contrast to projection neurons, which have axons projecting to other brain regions.

Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.

A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.

A period in the human life in which the development of the hypothalamic-pituitary-gonadal system takes place and reaches full maturity. The onset of synchronized endocrine events in puberty lead to the capacity for reproduction (FERTILITY), development of secondary SEX CHARACTERISTICS, and other changes seen in ADOLESCENT DEVELOPMENT.

Combination or superimposition of two images for demonstrating differences between them (e.g., radiograph with contrast vs. one without, radionuclide images using different radionuclides, radiograph vs. radionuclide image) and in the preparation of audiovisual materials (e.g., offsetting identical images, coloring of vessels in angiograms).

The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.

The use of a device composed of thermoluminescent material for measuring exposure to IONIZING RADIATION. The thermoluminescent material emits light when heated. The amount of light emitted is proportional to the amount of ionizing radiation to which the material has been exposed.

Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX.

NEURAL PATHWAYS and connections within the CENTRAL NERVOUS SYSTEM, beginning at the hair cells of the ORGAN OF CORTI, continuing along the eighth cranial nerve, and terminating at the AUDITORY CORTEX.

Radiographic examination of the breast.

Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.

The physical activity of a human or an animal as a behavioral phenomenon.

Use of electric potential or currents to elicit biological responses.

Use of optic and geometric techniques to enhance radiographic image quality and interpretation. It includes use of microfocal X-ray tubes and intensifying fluoroscopic screens.

A specialty concerned with the use of x-ray and other forms of radiant energy in the diagnosis and treatment of disease.

Heat production, or its measurement, of an organism at the lowest level of cell chemistry in an inactive, awake, fasting state. It may be determined directly by means of a calorimeter or indirectly by calculating the heat production from an analysis of the end products of oxidation within the organism or from the amount of oxygen utilized.

The eight bones of the wrist: SCAPHOID BONE; LUNATE BONE; TRIQUETRUM BONE; PISIFORM BONE; TRAPEZIUM BONE; TRAPEZOID BONE; CAPITATE BONE; and HAMATE BONE.

Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.

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 vitamin that includes both CHOLECALCIFEROLS and ERGOCALCIFEROLS, which have the common effect of preventing or curing RICKETS in animals. It can also be viewed as a hormone since it can be formed in SKIN by action of ULTRAVIOLET RAYS upon the precursors, 7-dehydrocholesterol and ERGOSTEROL, and acts on VITAMIN D RECEPTORS to regulate CALCIUM in opposition to PARATHYROID HORMONE.

Organic compounds which contain P-C-P bonds, where P stands for phosphonates or phosphonic acids. These compounds affect calcium metabolism. They inhibit ectopic calcification and slow down bone resorption and bone turnover. Technetium complexes of diphosphonates have been used successfully as bone scanning agents.

A group of glucose polymers made by certain bacteria. Dextrans are used therapeutically as plasma volume expanders and anticoagulants. They are also commonly used in biological experimentation and in industry for a wide variety of purposes.

Injuries involving the vertebral column.

Reference points located by visual inspection, palpation, or computer assistance, that are useful in localizing structures on or within the human body.

Beverages consumed as stimulants and tonics. They usually contain a combination of CAFFEINE with other substances such as herbal supplements; VITAMINS; AMINO ACIDS; and sugar or sugar derivatives.

A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.

Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.

In humans, one of the paired regions in the anterior portion of the THORAX. The breasts consist of the MAMMARY GLANDS, the SKIN, the MUSCLES, the ADIPOSE TISSUE, and the CONNECTIVE TISSUES.

Methods of creating machines and devices.

A state of insufficient flesh on the body usually defined as having a body weight less than skeletal and physical standards. Depending on age, sex, and genetic background, a BODY MASS INDEX of less than 18.5 is considered as underweight.

The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.

Fractures of the skull which may result from penetrating or nonpenetrating head injuries or rarely BONE DISEASES (see also FRACTURES, SPONTANEOUS). Skull fractures may be classified by location (e.g., SKULL FRACTURE, BASILAR), radiographic appearance (e.g., linear), or based upon cranial integrity (e.g., SKULL FRACTURE, DEPRESSED).

The prediction or projection of the nature of future problems or existing conditions based upon the extrapolation or interpretation of existing scientific data or by the application of scientific methodology.

The consumption of edible substances.

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 part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.

Production of an image when x-rays strike a fluorescent screen.

The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.

Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.

A polypeptide hormone (84 amino acid residues) secreted by the PARATHYROID GLANDS which performs the essential role of maintaining intracellular CALCIUM levels in the body. Parathyroid hormone increases intracellular calcium by promoting the release of CALCIUM from BONE, increases the intestinal absorption of calcium, increases the renal tubular reabsorption of calcium, and increases the renal excretion of phosphates.

A vesicular glutamate transporter protein that is predominately expressed in the DIENCEPHALON and lower brainstem regions of the CENTRAL NERVOUS SYSTEM.

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.

A single lung lesion that is characterized by a small round mass of tissue, usually less than 1 cm in diameter, and can be detected by chest radiography. A solitary pulmonary nodule can be associated with neoplasm, tuberculosis, cyst, or other anomalies in the lung, the CHEST WALL, or the PLEURA.

Studies in which variables relating to an individual or group of individuals are assessed over a period of time.

Calculation of the energy expenditure in the form of heat production of the whole body or individual organs based on respiratory gas exchange.

Moving a patient into a specific position or POSTURE to facilitate examination, surgery, or for therapeutic purposes.

Striped GRAY MATTER and WHITE MATTER consisting of the NEOSTRIATUM and paleostriatum (GLOBUS PALLIDUS). It is located in front of and lateral to the THALAMUS in each cerebral hemisphere. The gray substance is made up of the CAUDATE NUCLEUS and the lentiform nucleus (the latter consisting of the GLOBUS PALLIDUS and PUTAMEN). The WHITE MATTER is the INTERNAL CAPSULE.

Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.

The most common form of fibrillar collagen. It is a major constituent of bone (BONE AND BONES) and SKIN and consists of a heterotrimer of two alpha1(I) and one alpha2(I) chains.

Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.

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.

A gamma-emitting radionuclide imaging agent used primarily in skeletal scintigraphy. Because of its absorption by a variety of tumors, it is useful for the detection of neoplasms.

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.

Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts.

A synovial hinge connection formed between the bones of the FEMUR; TIBIA; and PATELLA.

Systematic and thorough inspection of the patient for physical signs of disease or abnormality.

Refers to animals in the period of time just after birth.

Fatty tissue inside the ABDOMINAL CAVITY, including visceral fat and retroperitoneal fat. It is the most metabolically active fat in the body and easily accessible for LIPOLYSIS. Increased visceral fat is associated with metabolic complications of OBESITY.

Neurons which activate MUSCLE CELLS.

Those characteristics that distinguish one SEX from the other. The primary sex characteristics are the OVARIES and TESTES and their related hormones. Secondary sex characteristics are those which are masculine or feminine but not directly related to reproduction.

Extensions of the nerve cell body. They are short and branched and receive stimuli from other NEURONS.

The first seven VERTEBRAE of the SPINAL COLUMN, which correspond to the VERTEBRAE of the NECK.

Diagnostic and therapeutic procedures that are invasive or surgical in nature, and require the expertise of a specially trained radiologist. In general, they are more invasive than diagnostic imaging but less invasive than major surgery. They often involve catheterization, fluoroscopy, or computed tomography. Some examples include percutaneous transhepatic cholangiography, percutaneous transthoracic biopsy, balloon angioplasty, and arterial embolization.

A diffuse parenchymal lung disease caused by inhalation of dust and by tissue reaction to their presence. These inorganic, organic, particulate, or vaporized matters usually are inhaled by workers in their occupational environment, leading to the various forms (ASBESTOSIS; BYSSINOSIS; and others). Similar air pollution can also have deleterious effects on the general population.

Decrease in existing BODY WEIGHT.

The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.

The period before MENOPAUSE. In premenopausal women, the climacteric transition from full sexual maturity to cessation of ovarian cycle takes place between the age of late thirty and early fifty.

Devices capable of receiving data, retaining data for an indefinite or finite period of time, and supplying data upon demand.

Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.

General or unspecified injuries involving the foot.

The total amount of a chemical, metal or radioactive substance present at any time after absorption in the body of man or animal.

Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.