TY - JOUR. T1 - Signal polarity restoration in a 3D inversion recovery sequence used with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC). AU - Szumowski, Jerzy. AU - Durkan, Michael G.. AU - Foss, Erik W.. AU - Brown, Dawson S.. AU - Schwarz, Erwin. AU - Crawford, Dennis C.. PY - 2012/11/1. Y1 - 2012/11/1. N2 - Purpose: To develop an image reconstruction algorithm that restores the signal polarity in a three-dimensional inversion-recovery (3D-IR) sequence used in delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). This approach effectively doubles the dynamic range of data used for T1 curve fitting. Materials and Methods: We applied this reconstruction algorithm to a 3D-IR TFE sequence used for T1 mapping, validated the technique in a phantom study, and performed T1-map calculations in postosteochondral allograft transplant (OAT) patients. In addition, we performed a signal simulation study to assess the algorithms capability to reduce the number of inversion ...
Differential diagnosis of ovarian cystadenofibromas should include stromal ovarian tumors with fibrous component, struma ovarri, ovarian metastases and endometriomas. Ovarian tumors with fibrous parts, including fibroma, fibrothecoma and Brenner tumor often present with a predominantly solid component of low signal intensity on T2-weighted images [7, 11, 12]. Struma ovarri has been described as multilocular ovarian mass, with variable signal intensity of the cystic parts and coexistence of hypointense areas on T2-weighted images, due to the presence of viscous colloid material [15, 16]. Ovarian metastases with a rich fibrous component, usually originating from the gastrointestinal tract often have areas of low signal intensity on T2-weighted images and display strong enhancement after contrast material administration [17 ...
Examples of coronal cUS and axial MR images performed during the first week after birth in infants presenting with neonatal seizures. (A) HIE: hyperechogenicity in both thalami on cUS and low signal intensity on the ADC map in thalami, optic radiation and splenium of the corpus callosum (D); (B) PAIS of main branch of the left-middle cerebral artery: wedge-shaped hyperechogenicity with a linear demarcation line in the left hemisphere on cUS and low signal intensity on the ADC map in territory of the left-middle cerebral artery, as well as optic radiation and splenium of the corpus callosum (E); (C) haemorrhage in the right temporal lobe recognised on cUS as a round area of hyperechogenicity and on T2WI as an area of low signal intensity surrounded by high signal intensity due to oedema (F).. ...
White matter hyperintensities (WMH) of presumed vascular origin, as seen on T2-weighted fluid attenuated inversion recovery magnetic resonance imaging, are known to increase with age and are elevated in Alzheimers disease (AD). The cognitive implications of these common markers are not well understood. Previous research has primarily focused on global measures of WMH burden and broad localizations that contain multiple white matter tracts. The aims of this study were to determine the pattern of WMH accumulation with age, risk for AD, and the relationship with cognitive function utilizing a voxel-wise analysis capable of identifying specific white matter regions. A total of 349 participants underwent T1-weighted and high-resolution T2-weighted fluid attenuated inversion recovery magnetic resonance imaging and neuropsychological testing. Increasing age and lower cognitive speed and flexibility (a component of executive function), were both significantly associated with regional WMH throughout the ...
By EDWARD F. JACKSON, PhD. One key advantage of MR is the wide range of intrinsic tissue properties that can be assessed by the appropriate choice of parameters defining the associated measurement technique.. In neuroimaging applications, for example, routine MR imaging provides a qualitative means of assessing the breakdown of the blood brain barrier as reflected by the extent of gadolinium contrast agent extravasation (T1-weighted sequences), the extent of vasogenic edema (T2-weighted and T2-weighted fluid attenuated inversion recovery sequences), the presence of blood products such as hemosiderin, methemoglobin (T1-weighted and T2* susceptibility-weighted images), and the ability to assess brain atrophy and regional white/gray matter abnormalities (using proton density-weighted and/or magnetization prepared gradient-echo sequences).. Neurovascular anatomy can be evaluated with or without the injection of exogenous contrast agents (using time-of-flight and/or phase-contrast MR angiography ...
We hypothesized that pediatric patients with type 1 diabetes have cardiac magnetic resonance (CMR) detectable differences in thoracic aortic wall properties and hemodynamics leading to significant local differences in indices of wall shear stress, when compared with age-matched control subjects without diabetes. Pediatric patients with type 1 diabetes were recruited from Childrens Hospital of Wisconsin and compared with controls. All underwent morning CMR scanning, 4-limb blood pressure, brachial artery reactivity testing, and venipuncture. Patient-specific computational fluid dynamics modeling with fluid-structure interaction, based on CMR data, determined regional time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI). Twenty type 1 diabetic subjects, median age 15.8 years (11.6-18.4) and 8 controls 15.4 years (10.3-18.2) were similar except for higher glucose, hemoglobin A1c, and triglycerides for type 1 diabetic subjects. Lower flow-mediated dilation was seen for those with type
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A) Diffusion tensor imaging (DTI) demonstrates a clear U-fibre density reduction in the left frontal area, illustrated by high signal in the colour scale. (B) Three-dimensional reconstructed brain surface created by coregistration of preoperative MRI and post-implantation CT shows placement of intracranial depth electrodes on the left hemisphere. Electrode 1 represents the innermost contact; A1-A12: left superior frontal gyrus (frontobasal, anterior); B1-B8: left superior frontal gyrus (frontobasal); C1-C10: left superior frontal gyrus (medial); D1-D8: left superior frontal gyrus (posterior); E1-E12: left middle frontal gyrus (anterior); F1-F8: left middle frontal gyrus (posterior); G1-G8: left inferior frontal gyrus; H1-H8: left anterior insula; J1-J6: left posterior insula; K1-K8: left anterior temporal lobe; L1-11: right superior frontal gyrus (frontobasal); and M1-12: right middle frontal gyrus. (C) Results of extraoperative electrical stimulation mapping (monopolar stimulation was performed ...
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BACKGROUND:Diabetes is a major risk factor for cardiovascular disease. In particular, type 1 diabetes compromises the cardiac function of individuals at a relatively early age due to the protracted course of abnormal glucose homeostasis. The functional abnormalities of diabetic myocardium have been attributed to the pathological changes of diabetic cardiomyopathy.METHODS:In this study, we used high field magnetic resonance imaging (MRI) to evaluate the left ventricular functional characteristics of streptozotocin treated diabetic Sprague-Dawley rats (8 weeks disease duration) in comparison with age/sex matched controls.RESULTS:Our analyses of EKG gated cardiac MRI scans of the left ventricle showed a 28% decrease in the end-diastolic volume and 10% increase in the end-systolic volume of diabetic hearts compared to controls. Mean stroke volume and ejection fraction in diabetic rats were decreased (48% and 28%, respectively) compared to controls. Further, dV/dt changes were suggestive of phase ...
Magnetic resonance images (MRI) of the brain revealed an intrasellar and suprasellar cystic mass with well defined smooth borders, which displaced the optic chiasm superiorly. The lesion displayed high signal intensity on T1 weighted images (Images 1a and 1b, sagittal and axial, respectively) and showed peripheral enhancement with Gadolinium administration (Image 1c). The lesion also showed high signal intensity on T2 weighted images (Image 1d). A previous brain MRI from 1991 did not reveal sellar or suprasellar lesions. PATHOLOGICAL FINDINGS. FINAL DIAGNOSIS. ...
BACKGROUND:Maintaining the quality of magnetic resonance images acquired with the current implantable coil technology is challenging in longitudinal studies. To overcome this challenge, the principle of inductive overcoupling is introduced as a method to tune and match a dual coil system. This system consists of an imaging coil built with fixed electrical elements and a matching coil equipped with tuning and matching capabilities. Overcoupling here refers to the condition beyond which the peak of the current in the imaging coil splits.METHODS:The combined coils are coupled inductively to operate like a transformer. Each coil circuit is electrically represented by equivalent lumped-elements. A theoretical analysis is given to identify the frequency response characteristics of the currents in each coil. The predictions from this analysis are translated into experiments and applied to locally image rat spinal cord at 9.4 T using an implantable coil as the imaging coil and an external volume coil ...
Lactating rats must continuously maintain a critical balance between caring for pups and aggressively responding to nest threats. We tested the neural response of lactating females to the presentation of their own pups and novel intruder males using blood oxygen level-dependent functional magnetic resonance imaging at 7 T. Dams were presented with a single sequence of a control stimulus, pups or a male intruder in one imaging session (n = 7-9). To further determine the selectivity of neural processing, dams were imaged for their response to a male intruder in both the absence and presence of their pups (n = 6). Several maternal cortical and limbic brain regions were significantly activated by intruder presentation but not by pups or a control stimulus. These included the nucleus accumbens, periaqueductal gray, anterior cingulate, anterior thalamus, basal nucleus of the amygdala, temporal cortex, prelimbic/orbital area and insula. The nucleus accumbens, periaqueductal gray, temporal cortex and
In animal models of Parkinsons disease (PD), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is one of the most widely used agents that damages the nigrostriatal dopaminergic pathway. However, brain structural changes in response to MPTP remain unclear. This study aimed to investigate in vivo longitudinal changes in gray matter (GM) volume and white matter (WM) microstructure in primate models administered with MPTP. In six cynomolgus monkeys, high-resolution magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) scans were acquired 7 times over 32 weeks, and assessments of motor symptoms were conducted over 15 months, before and after the MPTP injection ...
A new method of detecting structured changes in trabecular bone, such as those associated with osteoporosis, was evaluated on magnetic resonance images of the wrist. The method was based on gray-scale morphological granulometries which classify image texture by iteratively filtering an image and measuring the rate of change of structural diminution in a filtered-image sequence. A classification scheme capable of distinguishing structural changes in trabecular bone starting from normal trabeculae through sclerotic, cystic, and grossly porotic bone is presented. Results of the application of this technique to the evaluation of high resolution magnetic resonance images of the wrist are presented ...
The prevalence of PML has increased greatly over the last 15 years, concomitantly with the rise of AIDS (1). Since the introduction of HAART, reports have indicated that AIDS-associated PML may show clinical and neuroradiologic improvement with longer survival (2-10). However, in our series of four consecutive AIDS patients with PML treated with HAART, two were short-term survivors and two were long-term survivors.. On MR images, PML typically appears as multifocal, scalloping lesions located in the white matter. The lesions are hypointense on T1-weighted images and show high signal intensity on T2-weighted images (11). Increased hypointensity on T1-weighted images has been observed on follow-up MR studies, and has been suggested to be indicative of an aggressive form of the disease (12, 13). This feature has also been described in pathologic series (14). It was suggested recently that such imaging findings as increased atrophy, confluence of lesions, and increased hypointensity on follow-up ...
PURPOSE: To prospectively compare the black-blood ( BB black blood ) imaging efficiency of a delay alternating with nutation for tailored excitation ( DANTE delay alternating with nutation for tailored excitation ) preparation module with conventional double inversion-recovery ( DIR double inversion recovery ) and motion-sensitive driven equilibrium ( MSDE motion-sensitive driven equilibrium ) preparation modules and to introduce a new three-dimensional ( 3D three-dimensional ) T1-weighted magnetic resonance (MR) imaging sequence. MATERIALS AND METHODS: Carotid artery wall imaging was performed in 10 healthy volunteers and 15 patients in accordance with an institutional review board-approved protocol. Two-dimensional ( 2D two-dimensional ) turbo spin-echo ( TSE turbo spin echo ) and 3D three-dimensional fast low-angle shot ( FLASH fast low-angle shot ) sequences served as readout modules. DANTE delay alternating with nutation for tailored excitation -prepared T1-, T2-, and proton density-weighted 2D two
Background and Purpose- Relative signal intensity of acute ischemic stroke lesions in fluid-attenuated inversion recovery (fluid-attenuated inversion recovery relative signal intensity [FLAIR-rSI]) magnetic resonance imaging is associated with time elapsed since stroke onset with higher intensities signifying longer time intervals. In the randomized controlled WAKE-UP trial (Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke Trial), intravenous alteplase was effective in patients with unknown onset stroke selected by visual assessment of diffusion weighted imaging fluid-attenuated inversion recovery mismatch, that is, in those with no marked fluid-attenuated inversion recovery hyperintensity in the region of the acute diffusion weighted imaging lesion. In this post hoc analysis, we investigated whether quantitatively measured FLAIR-rSI modifies treatment effect of intravenous alteplase. Methods- FLAIR-rSI of stroke lesions was measured relative to signal intensity in a mirrored ...
Results A 73 year old male with rheumatic heart disease presented with blood pressure dependent dizziness, dysarthria, and right sided weakness. Workup revealed basilar occlusion above the left AICA with minimal leptomeningeal flow to the superior basilar segment, posterior cerebral and superior cerebellar arteries. The patient improved with, and thus was maintained on, IV vasopressor medications but could not be weaned from these medications after 8 days. High resolution MRI of the basilar segment was obtained. Endovascular revascularisation with mechanical thrombectomy (stent retriever) followed by stenting of the basilar artery was performed. The patient was neurologically stable after recanalisation despite return of blood pressure to baseline. Pathological evaluation of the removed thrombus was obtained.. ...
Neurosurgery may be the only option for the 15%-30% of people suffering from epilepsy who are refractory to drug therapy. Due to excellent soft tissue contrast...
STUDY DESIGN Postoperative back muscle injury was evaluated in rats by magnetic resonance imaging and histologic analyses. OBJECTIVE To compare the magnetic resonance imaging manifestation of back muscle injury with the histologic findings in rats and to subsequently clarify the histopathologic appearance of the high intensity regions on T2-weighted images in human postoperative back muscles. SUMMARY OF BACKGROUND DATA In a previous study, it was found that the signal intensity on T2-weighted images of the postoperative back muscles was increased in patients who had postsurgical lumbar muscle impairment, especially in those with a prolonged surgery duration. However, the specific histopathologic changes that cause the high signal intensity on T2-weighted images remain unclear. METHODS Rats were divided into three groups: sham operation group, 1-hour retraction group, and 2-hour retraction group. Magnetic resonance imaging and histology of the multifidus muscles were examined before surgery and at
A 33-year-old woman underwent buttock liposuction and fat injection to the breast at a cosmetic clinic 2 years previously. After the operation, she became aware of indurations and disfiguration of both breasts and visited our facility. Asymmetry of the breasts and huge indurations were palpable (Fig. 18). On preoperative blood examination, high levels of antinuclear antibodies were detected. On mammography, huge masses were detected in the subcutaneous tissue (Fig. 19). Chest computed tomography revealed multiple low-density areas encapsulated with high-density areas in the subdermis in both breasts. Magnetic resonance imaging indicated multiple injected fat with high-iso signal intensity on T1-weighted images and low signal intensity on T2-weighted images (Fig. 20). Surgery to remove the subcutaneous masses was performed. Our routine examination for foreign bodies using nuclear magnetic resonance detected a small amount of silicone contamination. This suggests that the high levels of ...
To clarify whether amnesia after treatment of anterior communicating aneurysm (ACoA)is related to infarcts caused by occlusion or damage of the perforating artery of the ACoA, we used 3.0-T 3D high resolution MR imaging to identify and localize infarcts in patients with amnesia following treatment of ACoA aneurysm ...
TY - JOUR. T1 - Automated method for accurate abdominal fat quantification on water-saturated magnetic resonance images. AU - Peng, Qi. AU - McColl, Roderick W.. AU - Ding, Yao. AU - Wang, Jihong. AU - Chia, Jonathan M.. AU - Weatherall, Paul T.. PY - 2007/9. Y1 - 2007/9. N2 - Purpose: To introduce and evaluate the performance of an automated fat quantification method for water-saturated magnetic resonance images. Materials and Methods: A fat distribution model is proposed for fat quantification on water saturated magnetic resonance images. Fat from both full- and partial-volume voxels are accounted for in this model based on image intensity histogram analysis. An automated threshold method is therefore proposed to accurately quantify total fat. This method is compared to a traditional full-volume-fat-only method in phantom and human studies. In the phantom study, fat quantification was performed on MR images obtained from a human abdomen oil phantom and was compared with the true oil volumes. ...
Recent Advances in MRI-based Diagnosis and Treatment of Back Pain. Recent advances suggest that axial-loaded MRI is preferable to recumbent MRI in obese patients suffering from back pain. It may enhance the diagnostic benefit of lumbar spine MRI in such individuals with possible spinal canal stenosis.[14]. Screening with a rapid lumbar spine (LS) MRI protocol using a single 3D-T2 fat-saturation sequence in patients with acute back pain admitted to the emergency department revealed fractures, cord signal abnormalities, and severe spinal canal stenosis in addition to detecting cord compression more rapidly and effectively than conventional LS MRI.[15]. The coronal short tau inversion recovery (STIR)-weighted magnetic resonance (MR) sequence, incorporated in lumbar spine MRI allowed the detection of extraspinal degenerative conditions contributing to lower back pain: sacroiliac joint defects, sacroiliitis, degeneration of the coxofemoral joint, renal and adrenal masses, genitourinary infarcts, ...
Orbital magnetic resonance imaging (MRI) scans show rhabdomyosarcoma in left ethmoid sinus with low signal intensity on T1-weighted image (A,B) and moderate enh
On MRI a subchondral fracture is best seen on T1-weighted images as linear subcortical low signal intensity. It may not be well seen on T2-weighted images unless there is trabecular impaction, which causes a low signal intensity line on both T1 and T2-weighted images. The "double line sign" on T2-weighted images is considered diagnostic of osteonecrosis. The inner increased signal intensity line represents vascularized granulation tissue and the outer low signal intensity line is due to sclerotic appositional new bone.6 The double line sign can be visible in epiphyseal or metadiaphyseal lesions and has no predictive value in and of itself for eventual outcome in cases of pre-existing osteonecrosis, which can either resolve, stabilize, or progress to cortical collapse. However, the development of the double line sign in follow up imaging of a previously uncomplicated subchondral fracture may herald the progression to irreversible damage. It is only in the relatively more recent literature of ...
Coronary heart disease (CHD) has been associated with impaired cognition, but the mechanisms underlying these changes remain unclear. We designed this study to determine whether adults with CHD show regional brain losses of grey matter volume relative to controls. We used statistical parametric mapping (SPM5) to determine regional changes in grey matter volume of T 1-weighted magnetic resonance images of 11 adults with prior history of myocardial infarction relative to seven healthy controls. All analyses were adjusted for total grey and white matter volume, age, sex and handedness. CHD participants showed a loss of grey matter volume in the left medial frontal lobe (including the cingulate), precentral and postcentral cortex, right temporal lobe and left middle temporal gyrus, and left precuneus and posterior cingulate. CHD is associated with loss of grey matter in various brain regions, including some that play a significant role in cognitive function and behaviour. The underlying causes of ...
Purpose To refine methods that assess structural brain abnormalities and calculate intracranial volumes in fetuses with congenital heart diseases (CHD) using in utero MR (iuMR) imaging. Our secondary objective was to assess the prevalence of brain abnormalities in this high-risk cohort and compare the brain volumes with normative values. Methods We performed iuMR on 16 pregnant women carrying a fetus with CHD and gestational age ≥ 28-week gestation and no brain abnormality on ultrasonography. All cases had fetal echocardiography by a pediatric cardiologist. Structural brain abnormalities on iuMR were recorded. Intracranial volumes were made from 3D FIESTA acquisitions following manual segmentation and the use of 3D Slicer software and were compared with normal fetuses. Z scores were calculated, and regression analyses were performed to look for differences between the normal and CHD fetuses. Results Successful 2D and 3D volume imaging was obtained in all 16 cases within a 30-min scan. Despite ...
The dorsolateral prefrontal cortex (DLPFC) is a brain region that has figured prominently in studies of schizophrenia and working memory, yet the exact neuroanatomical localization of this brain region remains to be defined. DLPFC primarily involves the superior frontal gyrus and middle frontal gyrus (MFG). The latter, however is not a single neuroanatomical entity but instead is comprised of rostral (anterior, middle, and posterior) and caudal regions. In this study we used structural MRI to develop a method for parcellating MFG into its component parts. We focused on this region of DLPFC because it includes BA46, a region involved in working memory. We evaluated volume differences in MFG in 20 patients with chronic schizophrenia and 20 healthy controls. Mid-rostral MFG (MR-MFG) was delineated within the rostral MFG using anterior and posterior neuroanatomical landmarks derived from cytoarchitectonic definitions of BA46. Gray matter volumes of MR-MFG were then compared between groups, and a ...
Objective To ascertain whether high-field magnetic resonance imaging (MRI) allows accurate estimation of the weight of various fetal organs at postmortem before 20 weeks gestation. Methods From 23 fetuses at 920 weeks, following termination of pregnancy or in-utero fetal death (IUFD), 207 assorted fetal organs were evaluated by high-field MRI at 9.4 T prior to conventional autopsy. Fetal organ density was calculated by correlating volume and weight at autopsy using linear regression analysis, and this was used to estimate fetal organ weight by MRI. The relative error in MRI estimation of organ weight was calculated as follows: (,MRI weight - autopsy weight,/autopsy weight) x 100 (%). Multiple regression analysis was used to investigate the effect on the relative error of MRI organ weight estimates of gestational age at TOP or delivery following IUFD, autopsy weight, fetal organ examined, IUFD and fetal maceration. Results Of the 207 organs evaluated, 133 (64%) were examined for fetal organ ...
MRI signal abnormalities in the disc have been described predominantly as low signal intensity on T2 weighted images. Loss of disc height and disc
Background: Magnetic Resonance Imaging (MRI) of the carotid artery can detect features of atherosclerotic plaque that may be associated with an increased stroke risk. This study tested the ability of MRI at 3 Tesla to identify features of acutely symptomatic carotid plaques and their association with downstream brain injury.. Methods: 41 patients presenting acutely with TIA or minor stroke and 40 asymptomatic controls underwent dark-blood T1, T2 and proton density-weighted turbo spin echo MRI of the carotid arteries, followed by diffusion-weighted (DWI) and FLAIR imaging of the brain on 2 separate occasions. Plaques were graded (MRI modified American Heart Association system) and related to the extent of MRI-determined brain injury.. Results: AHA type VI (ruptured) plaque was seen in 22 / 41 (54 %) in the symptomatic group vs. 8 / 40 (20 %) in the asymptomatic group (P , 0.05), and was due to intra-plaque haemorrhage (34% vs. 18%, P = 0.08; figure A), luminal thrombus (7% vs. 0%, P = 0.24; ...
Gd3L is a trinuclear Gd3R complex of intermediate size, designed for contrast agent applications in high field magnetic resonance imaging (H12L is based on a trimethylbenzene core bearing three methylene-diethylenetriamine-N,N,N00,N00-tetraacetate moieties). Thanks to its appropriate size, the presence of two inner sphere water molecules and a fast water exchange, Gd3L has remarkable proton relaxivities at high magnetic field (r1¼10.2 vs 3.0mM S1 sS1 for GdDOTA at 9.4 T, 37-C, in H2O). Here we report an in vivo MRI feasibility study, complemented with dynamic g scintigraphic imaging and biodistribution experiments using the 153Sm-enriched analog. MRI experiments were performed at 9.4 T in mice with Gd3L and the commercial contrast agent gadolinium(III)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (GdDOTA). Gd3L was well tolerated by the animals at the dose of 8mmol Gd kgS1 body weight. Dynamic contrast enhanced (DCE) images showed considerably higher signal enhancement in the kidney medulla and
Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major challenges associated with constructing phased array coils for monkeys are the variation in head size and space constraints. Here, we apply phased array technology to a 4-channel phased array coil capable of improving the resolution and image quality of full brain awake monkey fMRI and diffusion MRI experiments. The phased array coil is that can adapt to different rhesus monkey head sizes (ages 4-8) and fits in the limited space provided by monkey stereotactic equipment and provides SNR gains in primary visual
Major depression is a prevalent disease among the elderly, significantly decreasing the quality of life. The age of first onset of depression can be early in life, so called early-onset depression (EOD), as well as first occur in old age, i.e. late-onset depression (LOD). Some previous studies have suggested aetiological ... read more differences between EOD and LOD in the elderly. However, the number of these studies investigating elderly EOD and LOD patients is small. Therefore the importance of age of onset in the aetiology of late-life depression remains unclear. We used Magnetic Resonance Imaging (MRI) to examine hippocampal volume and subcortical white matter lesions in elderly patients with EOD and LOD and healthy elderly subjects. Both the hippocampus and subcortical white matter lesions have been implicated in the aetiology and treatment outcome of late-life depression. Hippocampal volume decrease and increased prevalence of subcortical white matter lesions in depressed patients might ...
MR allows local staging better than other techniques, particularly with regard to bone marrow and soft tissue involvement. MR signal intensity of bone lymphoma is dishomogeneous: isointense/hypointense to muscle on T1; hypo/iso/hyperintense to subcutaneous fat on T2; hypointense on T1/T2 for conspicuous fibrosis. Fast tumor growth with deficient vascular supply promotes necrotic areas, contributing to heterogeneity of signal intensity. Lymphomatous bone marrow is detected as a low signal on T1, due to fat replacement, in contrast with hyperintense normal marrow. Soft tissue involvement appears as isointense to muscle on T1 and hyperintense on T2, with diffuse enhancement. Short tau inversion-recovery (STIR) fat suppression sequences yield signal enhancement on T1 and T2 ...
Choi, J.Soo.; Ko, E.Sook.; Ko, E.Young.; Han, B-Kyung.; Nam, S.Jin., 2016: Background Parenchymal Enhancement on Preoperative Magnetic Resonance Imaging: Association With Recurrence-Free Survival in Breast Cancer Patients Treated With Neoadjuvant Chemotherapy
CONTEXT: Disruption of frontal-subcortical and limbic networks is hypothesized to have a key role in late-life depression (LLD) and can be examined using magnetic resonance imaging (MRI) techniques. Gray matter can be examined using T1-weighted MRI, white matter using T2-weighted MRI and diffusion tensor imaging, and functional connectivity in resting-state networks using functional MRI. Although independent MRI studies have supported gray and white matter abnormalities in frontosubcortical and limbic networks and increased functional connectivity in the default-mode network in depression, no study has concurrently examined gray matter, white matter, and functional connectivity. OBJECTIVE: To examine whether results of different MRI techniques are complementary, multimodal MRI was used to compare gray matter, white matter, and resting-state networks between LLD and control groups. DESIGN: Cross-sectional, case-control, multimodal MRI analysis. SETTING: University research department. PARTICIPANTS:
http://sig2perspectives.pubs.asha.org/article.aspx?articleid=1758160 A Primer on Functional Magnetic Resonance Imaging (fMRI) The use of neuroimaging techniques is becoming increasingly prevalent in the study of cognitive processes, including language. Understanding how the brain works in the service of transforming simple sensory signals-such as sounds, hand motions, or lines on a page- into the infinitely creative and flexible code that is human ... 2003-04-01T00:00:00 Article Susan A. McLaughlin ...
14. A magnetic resonance apparatus to correct distortions due to inhomogeneities of a basic magnetic field in magnetic resonance image data, comprising: a magnetic resonance data acquisition unit comprising a basic field magnet that generates a basic magnetic field exhibiting inhomogeneities, a gradient coil system and a radio-frequency system; a control unit configured to operate said magnetic resonance data acquisition unit to excite nuclear spins, with said radio-frequency system, in an examination subject at least partially located in said basic magnetic field and to acquire a first measurement data set and at least one additional measurement data set representing magnetic resonance signals resulting from the excitation of said nuclear spins, each of said first and said at least one additional measurement data set comprising a plurality of measurement points, said measurement points in said first measurement data set being acquired by operating said gradient coil system to activate a first ...
Type I Decreased signal on T1, and increased signal on T2.. Represents marrow edema.. Associated with an acute process.. Histological examination shows disruption and fissuring of the endplate and vascularized fibrous tissues within the adjacent marrow. Type II - the most common type Increased signal on T1, and isointense or slightly hyperintense signal on T2.. Represents fatty degeneration of subchondral marrow.. Associated with a chronic process.. Histological examination shows endplate disruption with yellow marrow replacement in the adjacent vertebral body.. Type I changes convert to Type II changes with time, while Type II changes seem to remain stable.. Type III Decreased signal on both T1 and T2.. Correlate with extensive bony sclerosis on plain radiographs.. Histological examination shows dense woven bone; hence, no marrow to produce MRI signal.. ...
The fluctuations in a brain regions activation levels over a functional magnetic resonance imaging (fMRI) time-course are used in functional connectivity (FC) to identify networks with synchronous responses. It is increasingly recognized that multi-voxel activity patterns contain information that cannot be extracted from univariate activation levels. Here we present a novel analysis method that quantifies regions synchrony in multi-voxel activity pattern discriminability, rather than univariate activation, across a timeseries. We introduce a measure of multi-voxel pattern discriminability at each time-point, which is then used to identify regions that share synchronous time-courses of condition-specific multi-voxel information. This method has the sensitivity and access to distributed information that multi-voxel pattern analysis enjoys, allowing it to be applied to data from conditions not separable by univariate responses. We demonstrate this by analyzing data collected while people viewed four
As a graduate student 15 years ago, I was extremely interested in regional brain contributions to motor learning. Magnetic resonance imaging scanners were not common, and to address my research questions, I was forced to recruit subjects with focal brain lesions. This was a tedious and inexact process that certainly extended my doctoral studies by a year. How times change. In my research laboratory today, we can induce temporary, virtual lesions with just a few minutes of noninvasive brain stimulation. Coupled with a stereotaxic system that employs the research participants own magnetic resonance imaging-based anatomy, we can target any location and easily increase or decrease cortical excitability. Pairing noninvasive brain stimulation with practice of novel tasks has rapidly become a primary research tool for scientists who study motor learning and recovery of function after brain damage. This is just one small example; overall, rehabilitation-related technology has rapidly advanced to a ...
7 Tesla MR scanning provides 34 µ resolution ocular anatomy which is an order of magnitude higher than 3 tesla MR scans. High frequency ocular ultrasound (20 - 50 MHz) provide high resolution of the eye, however, only the anterior portion of the globe can be imaged. The 5 - 10 MHz probes used for the posterior segment are significantly lower resolution. Spectral domain OCT give very high resolution images, however OCT is light based and depends on clear media and only displays the superficial anatomy of the posterior pole of the eye. This suggests that 7T MR may be superiorfor imaging the retro-laminar optic nerve, the posterior chamber the episclera, and the retina and choroid anterior to the equator. ...
Ischemic strokes appear iso- to hypointense on T1-weighted images and hyperintense on T2-weighted and FLAIR sequences (fig. 1). Enhancement is not seen until reperfusion is noted 7-14 days following the stroke and at this time is faint and on the periphery of the lesion. Enhancement along with the lesion tends to resolve by 6-8 weeks post-injury.. More recent advances have included the use of diffusion-weighted imaging (DWI; fig. 2) and ADC mapping. Acute infarction results in water trapping within cells and causes reduced diffusion, which is seen as increased signal on the DWI. Some other lesions that are hyperintense on T2 will also be hyperintense on DWI, which is called "T2 shine through." To differentiate this from true restricted diffusion from ischemic stroke, an ADC can be calculated. Areas with restricted diffusion will have low ADC values and will appear as a hypointensity on most ADC maps. Abnormalities on DWI can be seen within one hour of onset of ischemia with a reduction in ADC ...
Sorry vegans and vegetarians, but it takes a long time removing a fibroid tumor your body to absorb iron through non-meat products. MRI characteristics that indicate a successful treatment include high signal intensity on T1W images and homogenously decreased T2 signal intensity. Most patients undergoing UAE will experience this syndrome, which includes pain, cramping, nausea, vomiting, fever, tiredness, body aches. We used data from a case-control study on risk factors for uterine fibroids conducted in Italy between 1986 and 1997.
During a 46-month period, 143 patients underwent 152 DBS surgeries including 289 lead placements utilizing intraoperative 1.5-T MR imaging. Imaging was supervised by an MR imaging physicist to maintain the specific absorption rate below the required level of 0.1 W/kg and always included T1 magnetization-prepared rapid gradient echo and T2* gradient echo sequences with selected use of T2 fluid attenuated inversion recovery (FLAIR) and T2 fast spin echo (FSE). Retrospective review of the intraoperative MR imaging examinations was performed to quantify the amount of hemorrhage and the amount of air introduced during the DBS surgery. ...
All our patients will have access to cutting-edge genetic testing, organ-specific imaging (including magnetic resonance imaging-based volumetric measurements of cystic disease burden, magnetic resonance angiogram to rule out intracranial arterial aneurysm if indicated), and an experienced team of academic physicians with expertise in both medical and surgical (including interventional radiology, neurosurgery, dialysis and transplantation) management of kidney and non-kidney related complications.. Our philosophy is to involve all patients in their clinical decision making process as much as possible. In addition, we encourage all patients to participate in research studies so that we can generate new knowledge to advance treatment in polycystic kidney disease. During your clinic visit, we will go over one or more of the following aspects of your care:. ...
Aysel Sabuncu Brain Research Center. Ultra-high field (UHF) MRI offers improved signal- and contrast-to-noise ratio (SNR/CNR), which can be leveraged towards higher-resolution images. However, acquiring higher-resolution images increases scan times, making MRI scans prone to patient motion. Motion may become a problem especially with uncooperative patients such as in paediatric imaging and patients with Parkinsons or dementia. A common solution in such cases is to use sedatives. Unfortunately, sedation makes MRI an invasive imaging modality, and may commonly have side effects. Alternatively, real-time motion correction techniques can adapt the scan parameters accordingly and freeze patient motion from a data processing perspective these techniques are not directly applicable at UHF MRI.. At higher field strengths, artificial contrast variations are imposed on the acquired images due to the shorter wavelength. To correct such effects, parallel-transmit (pTx) arrays are commonly used. However, ...
MRI, with its superior contrast resolution, is increasingly preferred over computed tomography in the evaluation of suspected dementia.2 A basic dementia sequence including a high resolution structural volumetric T1 weighted scan and T2 weighted or fluid attenuated inversion recovery (FLAIR) sequences can be obtained in approximately 20 minutes. MRI does not involve ionising radiation, but claustrophobia may be a limiting factor in some patients. MRI is contraindicated in patients with pacemakers and certain metallic implants, and earplugs should be worn to prevent the possibility of cochlear damage.. T1 weighted volumetric MRI scanning provides a very detailed assessment of brain structure, allowing for the assessment of the presence or absence and pattern of brain volume loss, ie, atrophy. When evaluating a patient with cognitive impairment it is particularly valuable to assess for medial temporal lobe atrophy on coronal reformats, either qualitatively or using simple rating scales. The ...
Classification analysis view. Classification analysis view presenting the result of executing a Bayes Net classifier using a 10-fold cross validation scheme. Th
In a magnetic resonance imaging system of this invention, a static magnetic field is applied to a patient, and a gradient magnetic field and an excitation pulse signal are applied to the patient in accordance with a predetermined pulse sequence, so as to cause a magnetic resonance phenomenon in a selected slice of the patient. The magnetic resonance data of the magnetic resonance phenomenon is acquired, and the magnetic resonance image is obtained from the magnetic resonance data. The system has an announcement section for intermittently urging the patient to stop a body movement. In this system, a data acquisition section is operated under the control of a control section only while the patient stands still in response to the announcement of the announcement section, thereby intermittently acquiring magnetic resonance data in units of a predetermined volume.
A gradient coil system of a magnetic resonance tomography apparatus is fashioned as a hollow cylinder whose hollow interior cross-section is an ellipse with a minor ellipse axis and a major ellipse axis, and contains first and second transverse gradient coils. A first gradient field having a first gradient can be generated with the gradient coil in an imaging volume, and a second gradient field having a second gradient can be generated in said imaging volume with the second gradient coil. The gradient coils are arranged so that the first and the second gradients exhibit an oblique position relative to the major and the minor ellipse axes.
We thank Dr. Mewton and colleagues for adding to the discussion regarding T2-weighted cardiac magnetic resonance (CMR). Often, a candid debate will invoke strong reactions, but we are hopeful that readers of our Pro/Con article (1) with Dr. Friedrich will carefully consider the merits of the respective arguments. Here, we present our perspective on the issues raised by Dr. Mewton and colleagues.. At the outset, philosophically, we take exception to the comment that: "As always, in such a debate truth probably relies somewhere in between." At issue is whether or not T2-weighted CMR depicts post-infarct myocardium at risk. Fundamentally, it can only be one or the other.. With regard to the other issues raised:. 1. We agree that T2-CMR can show myocardial edema-which we believe is a marker of necrosis in the setting of acute ischemic injury.. 2. We agree that T2-CMR can provide incremental data to delayed-enhancement imaging.. 3. We agree that T2-short tau inversion recovery (as well as ...
Both HIV disease and advanced age have already been associated with alterations to cerebral white matter as measured with white matter hyperintensities (WMH) on fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) and more recently with diffusion tensor imaging (DTI). HJC0350 spatial statistics (TBSS). An age by HIV connection was found indicating a significant association between WMH and older age in HIV+ participants only. Similarly significant age group by HIV connections were discovered indicating stronger organizations between older age group and reduced FA in the posterior limbs of the inner tablets cerebral peduncles and anterior corona radiata in HIV+ vs. HIV- individuals. The interactive ramifications of HIV and age group were stronger regarding whole-brain WMH than for just about any from the FA methods. Among HIV+ individuals better WMH and lower anterior corona radiata FA had been associated with energetic hepatitis C trojan infection a brief history of Helps ...
We prospectively collected data from 420 consecutive patients with acute ischemic stroke admitted to our neurology ward from January 1998 to September 2000 and from control subjects recruited during the same period. A stroke was defined as rapidly developing signs of focal or global disturbance of cerebral function lasting ,24 hours with no apparent cause other than vascular. Exclusion criteria were age ,45 years, isolated transient ischemic attacks (TIAs), and history of previous stroke. Neurological status was assessed by the National Institutes of Health Stroke Scale. All patients underwent a CT scan on admission as part of standard stroke patient care. MRI (or CT when MRI was unperformable because of the presence of a metal implant or if the patient refused or was claustrophobic) was performed within 1 week from the onset of symptoms. Axial T1-,T2-, and proton density-weighted images were obtained with a 1.5-T MRI (Gyroscan ACS, NT Philips Medical Systems). Images were evaluated at a central ...
Whitman et al. (1) should be congratulated for their important contribution on the electrocardiogram (ECG) diagnosis of right ventricular hypertrophy (RVH). The authors database comprised 3,719 patients with normal left ventricular morphology and function who had an ECG and a cardiac magnetic resonance imaging-based assessment for RVH and were free of clinical cardiac disease, although some patients had hypertension, diabetes, or hypercholesterolemia. The authors implemented 22 ECG diagnostic criteria (Table 1 in their paper) and found that "a total of 6% had RVH, which was generally mild," and that the "ECG criteria were specific (many ,95%) but had low sensitivity…The positive predictive values were not sufficiently high as to be clinically useful (maximum 12%)" (Table 4 in their paper). Use of these criteria for the diagnosis of RVH may be different in patients with cardiac disease, although "the clinical usefulness of screening ECG would be precisely in individuals without a previous ...
To identify magnetic resonance imaging (MRI) features associated with colorectal surgical bowel resection for treatment of deep infiltrating endometriosis (DIE). 122 preoperative pelvic MRIs in women with laparoscopically-proven DIE and subsequent surgery (2006-2015) were identified, and retrospective cohort analysis performed. MRIs were reviewed independently by two radiologists blinded to surgical/histopathological outcomes. Associations between MRI characteristics of middle/posterior compartment endometriosis and surgical outcomes were investigated to identify MRI features associated with colorectal surgical bowel resection. MRI features associated with colorectal surgical intervention were: presence of an MRI bowel lesion (sensitivity 95.3%, specificity 63.3%, ROC-AUC 0.79); MRI bowel lesions ≥20 mm in length (sensitivity 91%, specificity 77%, ROC-AUC 0.84); MRI bowel lesions invading the muscularis or submucosa/mucosa layers (sensitivity 95.3%, specificity 63.3%, ROC-AUC 0.90). This study ...
inproceedings{d7fcf505-986e-4837-bf28-860c89055d97, abstract = {This paper presents a post processing strategy for myocardial velocity fields obtained by phase contrast magnetic resonance imaging. Such data can be used to track cardiac motion and to calculate strain. The method combines data regularization with optical flow estimation to overcome the partial volume effect in the image acquisition. Validation is performed both in vitro and in vivo and it is shown that the method improves the accuracy of cardiac motion tracking.}, author = {Bergvall, Erik and Markenroth Bloch, Karin and Hedstom, Erik and Arheden, Håkan and Sparr, Gunnar}, booktitle = {Computers in Cardiology}, issn = {0276-6574}, language = {eng}, pages = {33--36}, publisher = {IEEE - Institute of Electrical and Electronics Engineers Inc.}, title = {Regularization of phase contrast magnetic resonance images using optical flow and smoothness constraints}, url = {http://dx.doi.org/10.1109/CIC.2005.1588026}, doi = ...
Nuclear magnetic resonance (NMR) can be used in-vivo in a vast array of applications, such as anatomical imaging (magnetic resonance imaging, MRI), localized chemical composition characterization (magnetic resonance spectroscopy, MRS), cellular structure assessment (diffusion tensor imaging, DTI) and cerebral activity mapping (functional imaging, fMRI) for the most important one. This thesis focused on the development of diffusion NMR spectroscopy and imaging methods at ultra-high magnetic field, with the aim of a better characterization of the diffusion mechanism in-vivo. DTI measures the water molecule displacement due to the thermal agitation in the sample. In cellular tissue, the molecules are restrained in compartments delimited by the cell membranes, which mean that DTI can provide information on the cerebral cellular microstructure. DTI is thus widely used to investigate cerebral disorders such as brain ischemia, trauma, and tumors, as well as the structural changes occurring during brain ...
Background: Previous studies have shown that the activity of the amygdala is elevated in people experiencing clinical and subclinical levels of anxiety and depression (negative affect). It has been proposed that a reduction in inhibitory input to the amygdala from the prefrontal cortex and resultant over-activity of the amygdala underlies this association. Prior studies have found relationships between negative affect and 1) amygdala over-activity and 2) reduced amygdala-prefrontal connectivity. However, it is not known whether elevated amygdala activity is associated with decreased amygdala-prefrontal connectivity during negative affect states. Methods: Here we used resting-state arterial spin labeling (ASL) and blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) in combination to test this model, measuring the activity (regional cerebral blood flow, rCBF) and functional connectivity (correlated fluctuations in the BOLD signal) of one subregion of the amygdala ...
During language comprehension, readers or listeners routinely infer information that has not been stated literally in a given text or utterance in order to construct a coherent mental representation (situation model). We used a verification task in a behavioral study and in an event-related functional magnetic resonance imaging (fMRI) experiment to investigate the inference construction process. After having read sentences that mention the outcome of an event explicitly, implicitly, or not at all, participants verified the plausibility of short statements with respect to the context of the just read sentence. The results of the behavioral study established the verification task as a valid method for studying inferences. In the fMRI study, the dorsomedial prefrontal cortex was the most prominent area that was involved in the processing of inference statements. Regions in the left and right temporal lobes were associated with comparison processes that are based on the propositional representations ...
TY - JOUR. T1 - Cervical degenerative disease at flexion-extension MR imaging. T2 - Prediction criteria. AU - Chen, Chi J.. AU - Hsu, Hui-Ling. AU - Niu, Chi Chien. AU - Chen, Tzu Yung. AU - Chen, Min C.. AU - Tseng, Ying C.. AU - Wong, Yon Cheong. AU - Wang, Li J.. PY - 2003/4/1. Y1 - 2003/4/1. N2 - PURPOSE: To determine if there are any neutral-position imaging criteria that can help predict functional cord impingement at flexion-extension cervical magnetic resonance (MR) imaging. MATERIALS AND METHODS: Sixty-two patients with cervical degenerative disease were evaluated with regard to the dynamic changes of canal stenosis at flexion-extension MR imaging. Functional cord impingement was considered if the cord was impinged or more impinged after neck flexion or extension. Selection criteria for neutral-position MR imaging, such as cervical curvature, canal space, degenerative stage, intramedullary high signal intensity on T2-weighted images, and resting instability, were evaluated for their ...
OBJECTIVE: The limbic structures in early-onset schizophrenia-spectrum illness (SZ) and bipolar disorder (BPD) were studied to discern patterns associated with diagnosis and sex. METHODS: Thirty-five youths with DSM-IV BPD without psychosis, 19 with BPD with psychosis, 20 with SZ, and 29 healthy controls (HC), similar in age (6-17 years) and sex, underwent structured and clinical interviews, neurological examination, and cognitive testing. Structural magnetic resonance images (MRIs) were acquired on a 1.5 Tesla, General Electric Signa Scanner. Differences in subcortical brain volumes, including the amygdala and hippocampus, were evaluated using two-way (diagnosis, sex) univariate analyses covarying for total cerebral volume and age. RESULTS: Youth with SZ and BPD showed no differences in amygdala and hippocampal volumes. However, boys with SZ had smallest left amygdala and girls with BPD had the smallest left hippocampal volumes. In exploratory analyses, SZ showed reduced thalamic volumes bilaterally
The cohort included 110 patients with a total of 121 masses. The mean tumor size was 2.4 cm, and 50% of the lesions were clear cell carcinoma.. The mpMRI studies were performed on both 1.5-tesla and 3-tesla MRI scanners at several institutions. Sequences included T2-weighted, axial chemical shift T1-weighted, and dynamic contrast enhanced T1-weighted imaging. Because diffusion-weighted MR images were routinely acquired at UT Southwestern -- but not always at other facilities -- the researchers did not evaluate results using that sequence (Journal of Urology, October 2017, Vol. 198:4, pp. 780-786).. Seven radiologists independently reviewed the results; the radiologists had different levels of experience and were blinded to the final pathology findings. Their task was to rank the likelihood of clear cell carcinoma on a six-point scale, with 1 as "definitely not" cancer and 5 as "definitely" cancer.. By setting a parameter score of 4 or greater for clear cell carcinoma, the researchers achieved ...
Nociceptive processing within the human brain takes place within two distinct and parallel systems: the lateral and medial pain systems. Current knowledge indicates that the lateral system is involved in processing the sensory-discriminative aspects of pain, and that the medial system is involved in processing the affective-motivational aspects of pain. Hemispheric differences in brain activation (lateralisation) during nociceptive processing were studied to further clarify the division of function between the lateral and medial pain systems. Hemispheric lateralisation was studied by applying painful CO(2) laser stimuli of 3-s duration sequentially to the left and right medial lower calves of five normal right-handed human subjects. The resultant brain activity was measured using 3-T functional magnetic resonance imaging, by determining significant changes in blood oxygen level dependent (BOLD) signal and applying a general linear modelling approach. Volumes of interest were defined for the primary and
Poster: ECR 2019 / C-1999 / Role of Multiparametric MRI in Brainstem Lesions by: M. Harley, M. D. Patel, M. Bowen, W. Muhammad, S. Jacob, M. Douglas, I. Ughratdar, J. Herbert, V. Sawlani; Birmingham/UK
Multiparametric MRI in the assessment of response of rectal cancer to neoadjuvant chemoradiotherapy: A comparison of morphological, volumetric and functional MRI parameters Academic Article ...
A higher frequency resolution enables a nuclear magnetic resonance tomography (NMR) for individual proteins, as demonstrated by a team led by Jörg Wrachtrup from the Max Planck Institute for Solid State Research and the University of Stuttgart.
TY - JOUR. T1 - A topography of executive functions and their interactions revealed by functional magnetic resonance imaging. AU - Fassbender, Catherine. AU - Murphy, K.. AU - Foxe, J. J.. AU - Wylie, G. R.. AU - Javitt, D. C.. AU - Robertson, I. H.. AU - Garavan, H.. PY - 2004/7/1. Y1 - 2004/7/1. N2 - We used fMRI to study the brain processes involved in the executive control of behavior. The Sustained Attention to Response Task (SART), which allows unpredictable and predictable NOGO events to be contrasted, was imaged using a mixed (block and event-related) fMRI design to examine tonic and phasic processes involved in response inhibition, error detection, conflict monitoring and sustained attention. A network of regions, including right ventral prefrontal cortex (PFC), left dorsolateral PFC (DLPFC) and right inferior parietal cortex, was activated for successful unpredictable inhibitions, while rostral anterior cingulate was implicated in error processing and the pre-SMA in conflict ...
A large-scale, coordinate-based meta-analysis of task-related deactivations was performed on studies archived in the BrainMap database to identify consistent nodes of the default mode network. Using ALE (Eickhoff et al., 2009b), DMN regions were identified in the precuneus, posterior and ventral anterior cingulate cortices, medial prefrontal cortex, bilateral inferior parietal lobules, bilateral middle temporal gyri, and left middle frontal gyrus. For each DMN node, behavioral profiles were constructed using BrainMap tools to quantitatively assess their functional attributes when active (not during rest), and MACM were created to identify dissociable patterns of functional connectivity when unconstrained by any specific task. MACM maps were compared to determine which DMN nodes had the greatest degree of connectivity with other nodes, yielding a meta-analytic model of connectivity between default mode regions. Behavioral profiles of node sets were tested to determine significant functional ...
An application which greatly benefits from Ultra High Field (UHF) MRI is Blood Oxygenation Level Dependent (BOLD) fMRI. The increased susceptibility effects at UHF translate into a greater observable BOLD signal change and therefore improved fMRI experiments [1], as demonstrated in rat forepaw stimulation study at 15.2 Tesla, where an over 11% BOLD response was seen [2]. Functional MRI is used to study functional connectivity to further understand brain function in health and disease [3]. Using the high sensitivity provided by UHF, high resolution fMRI preclinical experiments thus become feasible [4]. Forepaw somatosensory stimulation, for example, only commonly shows BOLD response in S1FL. A recent study at 9.4 T and 15.2 T, however, detected only S1FL response at 9.4 T, but S2 and thalamus as well as S1FL at 15.2 T [5]. Functional sensitivity will additionally benefit from UHF in situations where thermal noise is dominant, as it is directly dependent on sensitivity and indirectly dependent on ...
The objective of this study was to investigate how acetylcholinesterase inhibitor (ChEI) treatment affects brain function in Parkinsons disease (PD). Twelve patients with PD and either dementia or mild cognitive impairment underwent task-free functional magnetic resonance imaging before and after 3 months of ChEI treatment and were compared with 15 age- and sex-matched neurologically healthy controls. Regional spontaneous brain activity was measured using the fractional amplitude of low-frequency fluctuations. At baseline, patients showed reduced spontaneous brain activity in regions important for motor control (eg, caudate, supplementary motor area, precentral gyrus, thalamus), attention and executive functions (eg, lateral prefrontal cortex), and episodic memory (eg, precuneus, angular gyrus, hippocampus). After treatment, the patients showed a similar but less extensive pattern of reduced spontaneous brain activity relative to controls. Spontaneous brain activity deficits in the left ...
Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is a powerful approach to defining activity in the healthy and diseased human brain. BOLD fMRI detects local increases in relative blood oxygenation that are most probably a direct consequence of neurotransmitter action and thus reflect local neuronal signalling. The method allows localisation to volumes of the order of a few to several cubic millimetres and can be used in serial studies of individual subjects. Basic approaches to experimental design and analysis are reviewed briefly, as well as potential clinical applications. The latter include three broad areas: anatomical characterisation of normal or pathological patterns of brain functioning; distinguishing pathological traits; and monitoring treatment responses. New research is emphasising the integration of fMRI with other techniques, particularly electrophysiological. In conjunction with MRI methods for characterising pathological load, fMRI promises a refined
Neuroimaging studies have revealed that low-back pain (LBP) alters spatiotemporal dynamics of the blood oxygen level-dependent signal in response to persistent noxious stimulus. This study aimed to investigate changes in spontaneous neural activity of various brain regions in acute LBP using resting...
To determine whether frontal lobe regions, including Brocas area, dorsolateral prefrontal cortex (DLPFC) and supplementary motor area (SMA), are differentially activated during lexical and semantic language tasks, we used functional magnetic resonance imaging in eight healthy right-handed subjects silently performing two semantic tasks (adjective and verb generation) and a lexical retrieval task (noun recall). Activation was observed in Brocas area, DLPFC and SMA for all tasks. Brocas area activation was approximately doubled during the semantic tasks compared with the lexical task (verbs vs nouns: 19.1 ± 4.5 vs 8.9 ± 1.6 voxels, p = 0.02; adjectives vs nouns 24.4 ± 7.5 vs 10.1 ± 2.8 voxels, p = 0.04); however, there were no significant differences in the DLFPC or SMA across tasks. We conclude that Brocas area is more active during tasks that have a semantic content, whereas areas involved in preparatory processing (SMA) and memory retrieval (DLPFC) are engaged equally during both types ...
Previous imaging studies that investigated morphometric group differences of subcortical regions outside the substantia nigra between non-demented Parkinsons patients and controls either did not find any significant differences, or reported contradictory results. Here, we performed a comprehensive morphometric analysis of 20 cognitively normal, early-stage PD patients and 19 matched control subjects. In addition to relatively standard analyses of whole-brain grey matter volume and overall regional volumes, we examined subtle localized surface shape differences in striatal and limbic grey matter structures and tested their utility as a diagnostic marker. Voxel-based morphometry and volumetric comparisons did not reveal significant group differences. Shape analysis, on the other hand, demonstrated significant between-group shape differences for the right pallidum. Careful diffusion tractography analysis showed that the affected parts of the pallidum are connected subcortically with the subthalamic
INTRODUCTION: White matter hyperintensities (WMHs) are areas of abnormal signal on magnetic resonance images (MRIs) that characterize various types of histopathological lesions. The load and location of WMHs are important clinical measures that may indicate the presence of small vessel disease in aging and Alzheimers disease (AD) patients. Manually segmenting WMHs is time consuming and prone to inter-rater and intra-rater variabilities. Automated tools that can accurately and robustly detect these lesions can be used to measure the vascular burden in individuals with AD or the elderly population in general. Many WMH segmentation techniques use a classifier in combination with a set of intensity and location features to segment WMHs, however, the optimal choice of classifier is unknown. METHODS: We compare 10 different linear and nonlinear classification techniques to identify WMHs from MRI data. Each classifier is trained and optimized based on a set of features obtained from co-registered MR ...
The ability to stop motor responses depends critically on the right inferior frontal cortex (IFC) and also engages a midbrain region consistent with the subthalamic nucleus (STN). Here we used diffusion-weighted imaging (DWI) tractography to show that the IFC and the STN region are connected via a white matter tract, which could underlie a hyperdirect pathway for basal ganglia control. Using a novel method of triangulation analysis of tractography data, we also found that both the IFC and the STN region are connected with the presupplementary motor area (preSMA). We hypothesized that the preSMA could play a conflict detection/resolution role within a network between the preSMA, the IFC, and the STN region. A second experiment tested this idea with functional magnetic resonance imaging (fMRI) using a conditional stop-signal paradigm, enabling examination of behavioral and neural signatures of conflict-induced slowing. The preSMA, IFC, and STN region were significantly activated the greater the
NBD can be defined as meningoencephalitis with predilection for brainstem, basal ganglia and thalamus, subcortical white matter damage and spinal cord lesions.1 Well-known conventional MRI features of acute/subacute parenchymal NBD include hyperintense lesions on T2WI with contrast enhancement on T1-weighted imaging. These lesions tend to resolve or decrease in size in the chronic phase.2 The DWI findings in NBD are (A) hyperintensity with ADC values (possibly due to vasogenic oedema and vasculitis) in acute/active disease2 and (B) hyperintensity on DWI with decreased ADC value (due to cytotoxic oedema following ischaemic changes caused by vasculitis) in subacute NBD.3 Furthermore, chronic lesions may show high ADC values consistent with demyelisation or reactive gliosis.2 ...
Based on the basic principle of MR imaging, the different content of water hydrogen nuclei in different organizations results in different image contrast along the longitudinal and transverse planes of the applied magnetic field. Consequently, like other MRI contrast agents that can increase the MRI signal intensity by shortening the hydrogen longitudinal relaxation time (T1) or decreasing the signal intensity by shortening the hydrogen transverse relaxation time (T2), as a superparamagnetic contrast agent, SPIO can significantly decrease the signal intensity by shortening the hydrogen transverse relaxation time (T2) and can cause darkening of the interfered regions. A normal lymph node with phagocytic function can take a substantial amount of contrast agent particles and, therefore, significantly reduce the T2 signal intensity of MRI. However, in the metastasis of lymph nodes, the macrophages are decreased due to the normal tissue being replaced by tumor cells [13, 20, 21], the fewer macrophage ...
A segmentation framework is proposed to determine the wall thickness, carotid artery plaque volume as morphological markers. MRI features, NMR peaks, oxida
PURPOSE: Extremely low gestation age newborns (ELGANs) are at high risk for developmental brain abnormalities, which can lead to cognitive, physical, emotional and behavioral deficits. This study is to determine potential brain volumetric abnormalities of ELGAN children at 9 to 10 years of age. METHODS: High-resolution magnetic resonance imaging (MRI) scans were obtained from 82 ELGAN children using a dual-echo turbo spin-echo (DE-TSE) pulse sequence at 3.0T (or 1.5T at only one site). The DICOM MR images were processed with quantitative MRI algorithms programmed in Mathcad. The brain gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) volumes were quantified using semi-automated clustering segmentation algorithms. RESULTS: Total brain volumes (GM+WM) of ELGAN children showed a large distribution range from 400 to 1500 mL. About 63% of the children had smaller brain volumes while 5% of them had larger brain volumes compared to the published data from normal children at the same ...
The intrinsic functional connectivity networks of human lateral frontal cortex are displayed for a 4-mm seed region that is gradually moved along the cortical surface. The functional connectivity networks are estimated on the surface using resting-state functional MRI data from 1000 young adults. The seed region begins in a region at or near the human homologue of FEF and gradually moves through distinct lateral frontal regions including those primarily coupled to limbic regions. The borders reflect estimates of networks from the 17-network parcellation of Yeo et al. (2011; see Figure 13). Note that multiple interdigitated networks converge on contiguous regions of frontal cortex. Some of these regions are embedded within sensory-motor circuits; others are absent coupling to sensory or motor regions and are embedded within networks comprising what has come to be known as the default network. Thus, human lateral frontal cortex represents a nexus of multiple, interdigitated association pathways. ...
The intrinsic functional connectivity networks of human lateral frontal cortex are displayed for a 4-mm seed region that is gradually moved along the cortical surface. The functional connectivity networks are estimated on the surface using resting-state functional MRI data from 1000 young adults. The seed region begins in a region at or near the human homologue of FEF and gradually moves through distinct lateral frontal regions including those primarily coupled to limbic regions. The borders reflect estimates of networks from the 17-network parcellation of Yeo et al. (2011; see Figure 13). Note that multiple interdigitated networks converge on contiguous regions of frontal cortex. Some of these regions are embedded within sensory-motor circuits; others are absent coupling to sensory or motor regions and are embedded within networks comprising what has come to be known as the default network. Thus, human lateral frontal cortex represents a nexus of multiple, interdigitated association pathways. ...
A key challenge in functional neuroimaging is the meaningful combination of results across subjects. Even in a sample of healthy participants, brain morphology and functional organization exhibit considerable variability, such that no two individuals have the same neural activation at the same location in response to the same stimulus. This inter-subject variability limits inferences at the group-level as average activation patterns may fail to represent the patterns seen in individuals. A promising approach to multi-subject analysis is group independent component analysis (GICA), which identifies group components and reconstructs activations at the individual level. GICA has gained considerable popularity, particularly in studies where temporal response models cannot be specified. However, a comprehensive understanding of the performance of GICA under realistic conditions of inter-subject variability is lacking. In this study we use simulated functional magnetic resonance imaging (fMRI) data to ...
A system and method for facilitating RF pulse sequence generation and modification and for real-time sequence input modification for use in conjunction with magnetic resonance imaging equipment. A graphical user interface is provided through a display coupled to a digital computer operating as the primary control system for a magnetic resonance imaging scanner and associated hardware. Through the graphical user interface, an operator may choose or design sequences of radiofrequency pulses, gradient waveforms and other input parameters for the magnetic resonance imaging apparatus. Real-time information is also communicated to the operator through the graphical user interface allowing for real-time manipulation of the magnetic resonance imaging inputs and for displaying the magnetic resonance response thereto.
Magnetic resonance imaging (MRI) is a sensitive technique for assessing white matter (WM) lesions in multiple sclerosis (MS), but there is a low correlation between MRI findings and clinical disability. Because of this, other pathological changes are of interest, including changes in normal appearing white matter (NAWM) and diffusely abnormal white matter (DAWM). Even so, the mechanisms leading to permanent disability in MS remain unclear.. In contrast to conventional MRI, quantitative MRI (qMRI) is aimed at the direct measurement of the physical tissue properties, such as the relaxation times, T1 and T2, as well as the proton density (PD). QMRI is promising for characterising and quantifying changes in MS and for brain tissue segmentation.. The present work describes a novel method of qMRI for the human brain (QMAP), and a segmentation method based on this. The developed methods were validated in control subjects and MR phantoms. Furthermore, an application in diseased human brain was ...
The refurbished GE EchoSpeed Plus 1.5 T MRI machine is a high resolution 4 channel, whole body imaging system known for its excellent performance. The magnet is Short Bore LCC/K4 which has a zero boil off technology. This used GE EchoSpeed Plus 1.5 T MRI Scanner is uniquely designed with a dock able table that allows for patient preparation and transportation outside the exam room. Moreover, your same GE EchoSpeed Plus 1.5 T MRI scanner can be upgraded to Signa Excite or any other higher models like Signa HD, Signa HDx or Signa HDxt. The magnet will remain the same. Only the Electronics, Coils and Computer will be changed. So if you have a limited budget now, you can go for this model now with an eye on the upgrade economically. ...
SIU2017, prostate cancer, Multiparametric MRI, improves significant PC, predict individual significant PC-risk for biopsy-naive men, after a previous biopsy, Radtke JP, Hanan Goldberg
Abstract: : Purpose: To compare the BOLD (Blood Oxygen Level Dependant) responses to magnocellular (M) and parvocellular (P) biased stimuli in normal subjects using functional magnetic resonance imaging (fMRI). Methods: Seven normal subjects underwent fMRI scanning. The M-biased stimulus was a 60 black and white chequerboard reversing at 10 Hz (50% duty cycle). The P-biased stimulus was a 10 black and white chequerboard, reversing at 2 Hz (50% duty cycle). The fMRI paradigm was an on/off design with a 21 second on and 21 second off period. The viewing distance was 2 metres with a visual field of 13 degrees. Stimuli were presented at 5, 10, 20, 40 and 80% contrast and were viewed monocularly using a mirror mounted on the head coil of the magnet. Scans were performed in a 1.5 Tesla scanner and analysed using in-house software (1). Analysis of variance was performed using the F-test. Results: The M-biased stimulus produced significant activation of V1at all contrast levels, with the exception of ...
Phosphatidylinositol 3-kinases (PI3Ks) have recently been implicated in apoptosis and ischemic cell death. We tested the efficacy of early intervention with a peptide PI3K activator in focal cerebral ischemia. After determining the most effective dose (24 mu g/kg) and time window (2 h after MCAO) of treatment, a total of 48 rats were subjected to middle cerebral artery occlusion (MCAO). Diffusion weighted MRI (DWI) was performed 1 h after MCAO and rats with lesion sizes within a predetermined range were randomized to either PI3K activator or vehicle treatment arms. Fluid attenuated inversion recovery (FLAIR) MRI, neurological function, western blots, and immunohistochemistry were blindly assessed. Initial DWI lesion volumes were nearly identical between two groups prior to treatment. However, FLAIR showed significantly smaller infarct volumes in the PI3K activator group compared with vehicle (146 +/- 81 mm(3) and 211 +/- 96 mm(3), p = 0.045) at 48 h. The PI3K activator group also had better ...
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THURSDAY, Oct. 11, 2018 (HealthDay News) - Common carotid artery (CCA) wall thickness measured using magnetic resonance imaging (MRI) is more consistently associated with incident cardiovascular disease (CVD) outcomes than intima-media thickness measured by ultrasound, according to a study published online Oct. 9 in Radiology.. Yiyi Zhang, Ph.D., from the Johns Hopkins University Bloomberg School of Public Health in Baltimore, and colleagues conducted a prospective study involving 698 participants without a history of clinical cardiovascular disease from the Multi-Ethnic Study of Atherosclerosis. CCA wall thickness was measured with ultrasound and with non-contrast proton density-weighted and intravenous gadolinium-enhanced MRI. The correlations between wall thickness measured with ultrasound and MRI were assessed with CVD outcomes.. The researchers found that per standard deviation increase in intima-media thickness, the adjusted hazard ratios for coronary heart disease, stroke, and CVD were ...
This chapter focuses on potential confounding factors in the interpretation of the blood oxygen level dependent (BOLD) signal in fMRI studies of cognitive aging. Studies generally attribute age-related changes in BOLD signal to age-related changes in neural activity, thereby assuming that the coupling between BOLD signal and neural activity is the same for young and older adults. However, this coupling may be altered by age-related changes in the neurovascular system and by comorbidities associated with aging. Age-related changes of the neurovascular system likely to affect the BOLD signal include changes in ultrastructure (e.g., sclerosis), resting cerebral blood flow (CBF), vascular reactivity, and cerebral metabolic rate of oxygen consumption. The BOLD signal may also be affected by comorbidities associated with aging, such as leukoariosis and small strokes, and by medications. ...
The University Hospital at the University of Navarra and the Applied Medicine Research Centre (CIMA) of the University has recently acquired a 3 Teslas magnetic resonance imager for joint use, the first for research applications in Spain. The 3 Teslas is the magnetic resonance imaging unit with the highest strength currently permitted by international medical bodies for the morphological study of the human body.
After arterial occlusion, cytotoxic edema can be detected within minutes via DWI, whereas vasogenic edema increases slowly, inducing progressively higher T2 relaxation time measures that significantly correlate with time from symptom onset.8,15 As b0 images also present a long echo time, we have hypothesized that an ischemic lesion would appear brighter on b1000 sooner than on b0 images and that this difference would disappear over time.. This study confirmed that patients with acute ischemic stroke with lesions detected on b1000 but not on b0 were likely to be within the current therapeutic time window for acute stroke, with a high PPV. The main drawback of this method is its moderate sensitivity and specificity, as well as low negative predictive value; however, these values were similar to values previously reported with DWI-FLAIR mismatch3,5-7 and that we have also obtained.. Quantitative analysis of b0 SIR confirmed changes detected through visual inspection, indicating a relative increase ...
TY - JOUR. T1 - Magnetic Resonance Imaging of Brain Involvement in Dogs Using Paramagnetic Contrast Enhancement with Mn(II)-DCTA P. AU - Ussov, W. Yu.. AU - Belyanin, M. L.. AU - Bezlepkin, A. I.. AU - Borodin, O. Yu.. AU - Bobrikova, E. E.. AU - Shimanovskii, N. L.. PY - 2016. Y1 - 2016. N2 - Experimental study of a new paramagnetic complex Mn-DCTA is carried out. The complex (0.5 M manganese(II) solution with trans-1,2-diamine cyclohexane-N,N,N,N-tetraacetic acid; Cyclomang) was used for contrast magnetic resonance imaging visualization of CNS involvement in dogs with severe forms of Babesia canis infection. CNS injuries were visualized in all cases, with highly intense contrasting at the expense of Mn-DCTA accumulation at the periphery of the damaged zone. Quantitative evaluation of the paramagnetic accumulation in the focus showed that the amplification index wa s 1.19±0.11 for the central areas and 1.47±0.17 for the peripheral ones. The pituitary (1.18±0.05) and vascular plexuses of ...
Purpose: Pancreatic cancer is one of the cancers with the poorest survival prognosis. At the time of diagnosis most of pancreatic cancers are unresectable and those patients can be treated by radiotherapy. Radiotherapy for pancreatic cancer is limited due to uncertainties in CT-based delineations. MRI provides an excellent soft tissue contrast. Here, an MR protocol is developed to improve delineations for radiotherapy treatment of pancreatic cancer. In a later stage this protocol can also be used for on-line visualization of the pancreas during MRI guided treatments. Methods: Nine pancreatic cancer patients were included. The MR protocol included T2 weighted(T2w), T1 weighted(T1w), diffusion weighted(DWI) and dynamic contrast enhanced(DCE) techniques. The tumor was delineated on T2w and T1w MRI by an experienced radiation oncologist. Healthy pancreas or pancreatitis (assigned by the oncologist based on T2w) areas were also delineated. Apparent diffusion coefficient(ADC), and area under the ...