MRI Study (mri + study)

Distribution by Scientific Domains
Distribution within Medical Sciences

Selected Abstracts

Cerebral Damage in Epilepsy: A Population-based Longitudinal Quantitative MRI Study

EPILEPSIA, Issue 9 2005
Rebecca S. N. Liu
Summary:,Purpose: Whether cerebral damage results from epileptic seizures remains a contentious issue. We report on the first longitudinal community-based quantitative magnetic resonance imaging (MRI) study to investigate the effect of seizures on the hippocampus, cerebellum, and neocortex. Methods: One hundred seventy-nine patients with epilepsy (66 temporal lobe epilepsy, 51 extratemporal partial epilepsy, and 62 generalized epilepsy) and 90 control subjects underwent two MRI brain scans 3.5 years apart. Automated and manual measurement techniques identified changes in global and regional brain volumes and hippocampal T2 relaxation times. Results: Baseline hippocampal volumes were significantly reduced in patients with temporal lobe epilepsy and could be attributed to an antecedent neurologic insult. Rates of hippocampal, cerebral, and cerebellar atrophy were not syndrome specific and were similar in control and patient groups. Global and regional brain atrophy was determined primarily by age. A prior neurologic insult was associated with reduced hippocampal and cerebellar volumes and an increased rate of cerebellar atrophy. Significant atrophy of the hippocampus, neocortex, or cerebellum occurred in 17% of patients compared with 6.7% of control subjects. Patients with and without significant volume reduction were comparable in terms of seizure frequency, antiepileptic drug (AED) use, and epilepsy duration, with no identifiable risk factors for the development of atrophy. Conclusions: Overt structural cerebral damage is not an inevitable consequence of epileptic seizures. In general, brain volume reduction in epilepsy is the cumulative effect of an initial precipitating injury and age-related cerebral atrophy. Significant atrophy developed in individual patients, particularly those with temporal lobe and generalized epilepsy. Longer periods of observation may detect more subtle effects of seizures. [source]

A Magnetization Transfer MRI Study of Deep Gray Matter Involvement in Multiple Sclerosis

Jitendra Sharma MD
ABSTRACT Background/Purpose: Gray matter involvement in multiple sclerosis (MS) is of growing interest with respect to disease pathogenesis. Magnetization transfer imaging (MTI), an advanced MRI technique, is sensitive to disease in normal appearing white matter (NAWM) in patients with MS. Design/Methods: We tested if MTI detected subcortical (deep) gray matter abnormalities in patients with MS (n= 60) vs. age-matched normal controls (NL, n= 20). Magnetization transfer ratio (MTR) maps were produced from axial proton density, conventional spin-echo, 5 mm gapless slices covering the whole brain. Region-of-interest,derived MTR histograms for the caudate, putamen, globus pallidus, thalamus, and NAWM were obtained. Whole brain MTR was also measured. Results: Mean whole brain MTR and the peak position of the NAWM MTR histogram were lower in patients with MS than NL (P < .001) and mean whole brain MTR was lower in secondary progressive (SP, n= 10) than relapsing-remitting (RR, n= 50, P < .001) patients. However, none of the subcortical gray matter nuclei showed MTR differences in MS vs. NL, RR vs. SP, or SP vs. NL. Conclusions: The MTI technique used in this cohort was relatively insensitive to disease in the deep gray matter nuclei despite showing sensitivity for whole brain disease in MS. It remains to be determined if other MRI techniques are more sensitive than MTI for detecting pathology in these areas. [source]

Topographic Patterns of Small Subcortical Infarcts Associated with MCA Stenosis: A Diffusion-Weighted MRI Study

Xin Wang MD
ABSTRACT Background and Purpose. Small subcortical infarcts (SSI, maximum lesion diameter ,2.0 cm) are usually considered as infarcts caused by small vessel disease. However, SSI can also be associated with large artery occlusive disease such as middle cerebral artery (MCA) stenosis. We performed a prospective study to investigate the relationship between MCA stenosis and SSI distribution and further to investigate the mechanism of SSI caused by MCA stenosis. Methods. Magnetic resonance angiography (MRA) and diffusion-weighed MRI (DWI) of consecutive acute ischemic stroke patients with recent SSI were studied. The distribution of acute infarcts on DWI was categorized as cortical infarct (CI), border zone infarct (BI), or perforating artery infarct (PAI). Results. Totally, 93 cases were recruited, among which 12 had single SSI with MCA stenosis (group 1) and 26 patients had multiple SSI with MCA stenosis (group 2), while 55 patients without MCA stenosis had single SSI (group 3). For patients with single SSI and MCA stenosis, 6 had BI and 6 had PAI; for patients with multiple SSI and MCA stenosis, 25 had BI, 4 had PAI and 9 had CI (compared with group1: P= .001); for patients with single SSI but without MCA stenosis, 20 had BI and 35 had PAI (compared with group1: P= .58). Conclusion. Multiple acute infarcts along the border zone are the commonest pattern in small infarcts with MCA stenosis, especially among those with multiple acute infarcts. Our data suggest that hemodynamic compromise and artery-to-artery embolism may be both important factors for infarcts in patients with MCA stenosis. [source]

Corpus callosum and posterior fossa development in monozygotic females: a morphometric MRI study of Turner syndrome

Susannah L Fryer BA
Previous neuroimaging research in Turner syndrome (TS) has indicated parietal lobe anomalies, while anomalies in other brain loci have been less well-substantiated. This study focused on potential cerebellar abnormalities and possible disruptions of interhemispheric (parietal) callosal connections in individuals with TS. Twenty-seven female children and adolescents with TS (mean age 13 years, SD 4 years 2 months) and 27 age-matched female control individuals (mean age 13 years 2 months, SD 4 years 1 month) underwent MRI. Age range of all participants was 7 to 20 years. Morphometric analyses of midline brain structures were conducted using standardized, reliable methods. When compared with control participants, females with TS showed reduced areas of the genu of the corpus callosum, the pons, and vermis lobules VI,VII, and an increased area of the fourth ventricle. No group difference in intracranial area measurements was observed. The reduced area of the genu in TS may reflect compromised connectivity between inferior parietal regions. Further, cerebellar vermis hypoplasia associated with TS agrees with literature that suggests the posterior fossa as a region prone to structural alterations in the face of early developmental insult. [source]

Development of cortical and subcortical brain structures in childhood and adolescence: a structural MRI study

Elizabeth R Sowell PhD
The purpose of the present study was to describe in greater anatomical detail the changes in brain structure that occur during maturation between childhood and adolescence. High-resolution MRI, tissue classification, and anatomical segmentation of cortical and subcortical regions were used in a sample of 35 normally developing children and adolescents between 7 and 16 years of age (mean age 11 years; 20 males, 15 females). Each cortical and subcortical measure was examined for age and sex effects on raw volumes and on the measures as proportions of total supratentorial cranial volume. Results indicate age-related increases in total supratentorial cranial volume and raw and proportional increases in total cerebral white matter. Gray-matter volume reductions were only observed once variance in total brain size was proportionally controlled. The change in total cerebral white-matter proportion was significantly greater than the change in total cerebral gray-matter proportion over this age range, suggesting that the relative gray-matter reduction is probably due to significant increases in white matter. Total raw cerebral CSF volume increases were also observed. Within the cerebrum, regional patterns varied depending on the tissue (or CSF) assessed. Only frontal and parietal cortices showed changes in gray matter, white matter, and CSF measures. Once the approximately 7% larger brain volume in males was controlled, only mesial temporal cortex, caudate, thalamus, and basomesial diencephalic structures showed sex effects with the females having greater relative volumes in these regions than the males. Overall, these results are consistent with earlier reports and describe in greater detail the regional pattern of age-related differences in gray and white matter in normally developing children and adolescents. [source]

Evolution of striatal degeneration in McLeod syndrome

P. O. Valko
Background and purpose:, McLeod neuroacanthocytosis syndrome (MLS) is an X-linked multisystem disorder with CNS manifestations resembling Huntington disease. Neuroimaging studies revealed striatal atrophy with predominance of the caudate nucleus. Our previous cross-sectional MRI study showed an association of volume loss in the caudate nucleus and putamen with the disease duration. Methods:, In the present study, we examined three brothers with genetically confirmed diagnosis of MLS using an observer-independent and fully automated subcortical segmentation procedure to measure striatal volumes. Results:, In a cross-sectional comparison with 20 healthy age-matched control men, the volumes of the caudate nucleus of the three patients were significantly smaller as confirmed by z -score transformations. On an individual basis, volumes in the two more severely affected and older patients were smaller than in the less affected younger brother. Longitudinal MRI-based measurements over 7 years demonstrated a statistical trend towards significant decreased caudate volumes in McLeod patients. Conclusions:, Our findings indicate that structural MRI combined with fully automated computational morphometric analyses represents an objective and observer-independent imaging tool for the representation of progressive striatal degeneration in MLS and might be a valuable methodology for cross-sectional as well as longitudinally volumetric studies in other rare neurodegenerative diseases, even on individual patients. [source]

Sensitivity of prefrontal cortex to changes in target probability: A functional MRI study

B. J. Casey
Abstract Electrophysiological studies suggest sensitivity of the prefrontal cortex to changes in the probability of an event. The purpose of this study was to determine if subregions of the prefrontal cortex respond differentially to changes in target probabilities using functional magnetic resonance imaging (fMRI). Ten right-handed adults were scanned using a gradient-echo, echo planar imaging sequence during performance of an oddball paradigm. Subjects were instructed to respond to any letter but "X". The frequency of targets (i.e., any letter but X) varied across trials. The results showed that dorsal prefrontal regions were active during infrequent events and ventral prefrontal regions were active during frequent events. Further, we observed an inverse relation between the dorsal and ventral prefrontal regions such that when activity in dorsal prefrontal regions increased, activity in ventral prefrontal regions decreased, and vice versa. This finding may index competing cognitive processes or capacity limitations. Most importantly, these findings taken as a whole suggest that any simple theory of prefrontal cortex function must take into account the sensitivity of this region to changes in target probability. Hum. Brain Mapping 13:26,33, 2001. © 2001 Wiley-Liss, Inc. [source]

Magnetic resonance imaging in the detection of pancreatic neoplasms

Recently, with the rapid scanning time and improved image quality, outstanding advances in magnetic resonance (MR) methods have resulted in an increase in the use of MRI for patients with a variety of pancreatic neoplasms. MR multi-imaging protocol, which includes MR cross-sectional imaging, MR cholangiopancreatography and dynamic contrast-enhanced MR angiography, integrates the advantages of various special imaging techniques. The non-invasive all-in-one MR multi-imaging techniques may provide the comprehensive information needed for the preoperative diagnosis and evaluation of pancreatic neoplasms. Pancreatic neoplasms include primary tumors and pancreatic metastases. Primary tumors of the pancreas may be mainly classified as ductal adenocarcinomas, cystic tumors and islet cell tumors (ICT). Pancreatic adenocarcinomas can be diagnosed in a MRI study depending on direct evidence or both direct and indirect evidence. The combined MRI features of a focal pancreatic mass, pancreatic duct dilatation and parenchymal atrophy are highly suggestive of a ductal adenocarcinoma. Most cystic neoplasms of the pancreas are either microcystic adenomas or mucinous cystic neoplasms. Intraductal papillary mucinous tumors are the uncommon low-grade malignancy of the pancreatic duct. ICT are rare neoplasms arising from neuroendocrine cells in the pancreas or the periampullary region. ICT are classified as functioning and non-functioning. The most frequent tumors to metastasize to the pancreas are cancers of the breast, lung, kidney and melanoma. The majority of metastases present as large solitary masses with well-defined margins. [source]

The effects of ACE inhibitor therapy on left ventricular myocardial mass and diastolic filling in previously untreated hypertensive patients: A Cine MRI study

U. Hoffmann MD
Abstract Cardiac remodeling in case of hypertension induces hypertrophy of myocytes and elevated collagen content and, subsequently, impaired diastolic filling of the left ventricle. The purpose of this prospective study was to evaluate changes of left ventricular (LV) myocardial mass, as well as diastolic filling properties, in hypertensive patients treated with the ACE inhibitor fosinopril. Sixteen hypertensive patients with echocardiographically documented LV hypertrophy and diastolic dysfunction received fosinopril (10,20 mg daily). Measurements of LV myocardial mass and properties of diastolic filling (peak filling fraction (PFF); peak filling rate (PFR)) were performed prior to medication, as well as after 3 and 6 months of therapy using cine magnetic resonance imaging (MRI). Ten healthy subjects served as a control group. LV myocardial mass (g/m2) decreased continuously within 3,6 months of follow-up by 32% (148 ± 40 vs. 120 ± 26 vs. 101 ± 22 g/m2; P < 0.0001/0.005). The extent of regression correlated to the severity of LV hypertrophy at baseline (r = 0.77; P < 0.004). Early diastolic filling increased significantly within 6 months of therapy (PFF (%): 36 ± 6 vs. 61 ± 7, P < 0.0001; PFR (mL/second): 211 ± 48 vs. 282 ± 48, P < 0.001). Cine MRI can be used to assess the time course of pharmacological effects on cardiac remodeling in the course of hypertension. ACE inhibitor therapy results in a significant reduction of LV mass within 3 months and is accompanied by a normalization of diastolic filling that is completed after 6 months. J. Magn. Reson. Imaging 2001;14:16,22. © 2001 Wiley-Liss, Inc. [source]

Necropsy by magnetic resonance in a case of conjoined thoracopagus twins

A.C. Manzano MD
Abstract A case of thoracopagus conjoined stillborn twins studied with magnetic resonance imaging (MRI) is presented. Due to the parents' denial of authorization for an autopsy of the fetuses, the MRI study was performed as an alternative to necropsy. High-resolution images of the fetuses demonstrated relevant anatomic features, providing noninvasive pathological insight with preservation of the fetal specimen. J. Magn. Reson. Imaging 2001;13:976,981. © 2001 Wiley-Liss, Inc. [source]

Temporal Changes in Brain Volume and Cognition in a Randomized Treatment Trial of Vascular Dementia

Joseph P. Broderick MD
ABSTRACT Objective. To measure changes in brain and ischemic volume over time by magnetic resonance imaging (MRI) as part of a randomized treatment trial of vascular dementia. Methods. Participants who met criteria for vascular dementia underwent comprehensive neurological and neuropsychological testing on entrance, during, and at completion of the 1-year study. For those centers who had easily available MRI, MRI of the brain was to be performed on entry and completion of the study. Image analysis was performed on all balanced and T2-weighted MR films to determine ventricular, sulcal, ischemic, and hemispheric brain volumes. Results. Of the 105 patients who met the criteria for vascular dementia, 40 had a baseline MRI study that met protocol requirements and was of excellent image quality. The baseline ventricular volume in these 40 patients with high-quality MR correlated with most measures of cognitive and behavioral function, including the total Alzheimer's Disease Assessment Score (ADAS) (r= 0.51, P= .0024), as well as activities of daily living (r= 0.61, P= .0002). The baseline ischemic brain volume correlated well only with the gait and postural stability scale (r= 0.74, P= .009). Of the 40 participants, 25 had MRI studies at baseline and at completion of the study that were comparable and of excellent image quality. For these 25 patients, the mean ventricular volumes increased by 9% over the study year (P= .001) and the mean ischemic brain volume increased by 18% (P= .01). Temporal changes in the sulcal and nonischemic brain volume did not reach significance. None of the 14 clinical score measures changed significantly between baseline and completion of the study in these 25 patients. Conclusion. In summary, ventricular volume correlated well with cognitive measures in patients with vascular dementia and was a more sensitive marker for change during the study year than the clinical scales used in this study. This study also points out the practical limitations of brain imaging as a surrogate measure of clinical outcome in multicenter randomized treatment trials of brain disease. [source]

Posterior leukoencephalopathy syndrome as a cause of reversible blindness during pregnancy

Lutfu S. Onderoglu
Abstract Cortical blindness is a rare and dramatic complication of pre-eclampsia. The precise nature of the pathogenesis of this condition has not previously been understood. Three preeclamptic patients with unremarkable previous medical history presented with acute blindness between the 28th and 33rd weeks of pregnancy. They were all diagnosed as posterior leukoencephalopathy syndrome (PLES). In all these patients, MRI study revealed the typical feature of gray-white matter edema localized to the temporo-parieto-occipital areas. Vision and MRI findings were restored in all patients after delivery. Although PLES has been described as a puerperal clinicoradiologic entity, it may be seen in preeclamptic-eclamptic patients during the pregnancy. Therefore neuro-imaging studies should be carried out in pregnant patients with visual disturbances in order to exclude PLES. Prompt diagnosis, immediate control of blood pressure, and elimination of possible causes resolves clinical and imaging findings. [source]

Effect of aging and degeneration on disc volume and shape: A quantitative study in asymptomatic volunteers

Christian W. A. Pfirrmann
Abstract Debate continues on the effect of disc degeneration and aging on disc volume and shape. So far, no quantitative in vivo MRI data is available on the factors influencing disc volume and shape. The objective of this MRI study was to quantitatively investigate changes in disc height, volume, and shape as a result of aging and/or degeneration omitting pathologic (i.e., painful) disc alterations. Seventy asymptomatic volunteers (20,78 years) were investigated with sagittal T1- and T2-weighted MR-images encompassing the whole lumbar spine. Disc height was determined by the Dabbs method and the Farfan index. Disc volume was calculated by the Cavalieri method. For the disc shape the "disc convexity index" was calculated by the ratio of central disc height and mean anterior/posterior disc height. Disc height, disc volume, and the disc convexity index measurements were corrected for disc level and the individuals age, weight, height, and sex in a multilevel regression analysis. Multilevel regression analysis showed that disc volume was negatively influenced by disc degeneration (p,<,0.001) and positively correlated with body height (p,<,0.001) and age (p,<,0.01). Mean disc height and the disc convexity index were negatively influenced by disc degeneration but not by gender, weight, and height. Disc height was positively correlated with age (p,<,0.01). From the results of this study, it can be concluded that disc degeneration generally results in a decrease of disc height and volume as well as a less convex disc shape. In the absence of disc degeneration, however, age tends to result in an inverse relationship on disc height, volume, and shape. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source]

Influence of perfusion on high-intensity focused ultrasound prostate ablation: A first-pass MRI study,

Marlčne Wiart
Abstract Our aim was to evaluate the influence of regional prostate blood flow (rPBF) on high-intensity focused ultrasound (HIFU) treatment outcome. A total of 48 patients with clinically localized prostate cancer were examined by dynamic contrast-enhanced (DCE)-MRI prior to HIFU therapy. A prostate-specific antigen (PSA) nadir threshold of 0.2 ng/ml was used to define the populations of responders and nonresponders. A dedicated tracer kinetic model, namely "monoexponential plus constant" (MPC) deconvolution, was implemented to provide quantitative estimates of rPBF. The results were compared with those obtained by semiquantitative (steepest slope, mean gradient) and quantitative (Fermi deconvolution) approaches. Of the four methods studied, quantitative rPBF obtained by MPC deconvolution proved the most sensitive to the perfusion changes encountered in this study. Furthermore, blood-flow values obtained with MPC deconvolution in the prostate and muscle (12 ± 8 and 5 ± 3 ml/min/100 g, respectively) were in good agreement with literature data. The mean pretreatment rPBF obtained with MPC deconvolution was significantly higher in nonresponders compared to responders (16 ± 9 vs. 10 ± 6 ml/min/100 g), suggesting a correlation between baseline perfusion and treatment outcome. The present work describes and validates the use of dynamic MRI to estimate rPBF in patients, which in the future may help to refine the conduct of HIFU therapy. Magn Reson Med 58:119,127, 2007. © 2007 Wiley-Liss, Inc. [source]

MRI measurement of liver regeneration in mice following partial hepatectomy

J.R. Garbow
Abstract Improvements in noninvasive imaging modalities are crucial for preoperative in vivo assessments of liver condition and potential for regeneration after liver resection for removal of liver tumors. To that end, an MRI study of liver regeneration in mice following partial hepatectomy is described and validated. Hepatic volumes were accurately measured from contrast-enhanced, gradient-echo images of the liver. Regeneration curves were constructed for a series of mice (N = 6) from a longitudinal MR study, with images collected 1, 2, 3, 4, 5, and 9 days following surgery. We validated the MR method by correlating serial MR-measured volumes with liver wet weight. The success of this method will enable future studies to better elucidate the factors that affect regeneration, and help to optimize the timing and dosing of chemotherapeutics to minimize their deleterious effects on liver regeneration. Magn Reson Med 52:177,180, 2004. © 2004 Wiley-Liss, Inc. [source]

Extracranially extended meningothelial meningiomas with a high MIB-1 index: A report of two cases

Shoko M. Yamada
Meningiomas that extend from the meninges to the extracranial tissue and result in skull osteolysis have been known to take an aggressive clinical course. Two such cases in elderly patients are reported. Case 1 is an 82-year-old woman who had undergone removal of the parasagittal meningioma (meningothelial meningioma with 5% of MIB-1 index) 4 years and 6 months previously, developed recurrence of the tumor that extended to extracranial soft tissue. Biopsy obtained from the subcutaneous tissue showed an atypical meningothelial meningioma with 20% of MIB-1 index. In case 2 an 84-year-old man, who developed rapidly progressing dementia and gait disturbance, the MRI study revealed an intracranial-extraaxial right frontal tumor with an extracranial extension resulting in skull osteolysis. Pathological examination of the totally resected tumor identified meningothelial meningioma, but MIB-1 index of the intracranial portion of the tumor was less than 0.1%, while that of the extracranial portion was approximately 15%. Although the meningiomas presently reported failed to show histological features of malignancy, the high MIB-1 index indicated that they were rapidly growing tumors. In the present report it is considered that meningioma cells that invade the skull and extracranial tissue are biologically aggressive and require total resection, as long as the condition of the patients is feasible for surgery. [source]

Ultrastructural and MRI study of the substantia nigra evolving exofocal post-ischemic neuronal death in the rat

Fengyu Zhao
To clarify the morphological characteristics of exofocal post-ischemic neuronal death (EPND) in the substantia nigra (SN), we investigated the course of light- and electron-microscopic changes of the SN of rats subjected to occlusion of the left middle cerebral artery (MCA) for 1, 2, 4, 7 and 12 days. To assess cellular edema, sequential magnetic resonance (MR) mapping of the apparent diffusion coefficient (ADC) and the T2 value test was performed. Histological and electron-microscopic examination on day 1 showed dotted chromatin clumps in the nuclei of some neurons and mild swelling of the perivascular endfeet of astrocytes in the ipsilateral SN. On day 2, a few cells of the ipsilateral SN pars reticulata (SNr) revealed key morphological signs of apoptosis , apoptotic body-like condensation and segregation of the chromatin and DNA fragmentation-like nuclear remnants. On day 4, 38% of neurons became swollen (pale neurons) with cytoplasmic microvacuoles, which appeared to originate from rough endoplasmic reticulum (rER), mitochondria and Golgi apparatus. Twenty percent of neurons showed massive proliferation of the cisternae of the rER, some of which were fragmented or had lost their normal parallel arrangement. In addition, MR mapping revealed a transient ADC decrease with a T2 increase (signifying a phase of cellular edema), which coordinated with the phase of ultrastructural cellular swelling. Further, the total number of neurons started to decrease gradually, the perivascular endfeet of astrocytes were markedly swollen, and the neuropil became loose on day 4. On day 7, reactive astrocytes and dark neurons occurred most frequently. These results suggest that the EPND in the SN after occlusion of the MCA in adult rats is due to both apoptosis and necrosis, although necrosis seems to be the dominant mechanism of the EPND. However, the morphologic resemblances of EPND to delayed neuronal death suggest these processes have a common pathomechanism. [source]

Diagnostic role of 99mTc hexamethyl-propyleneamine oxime brain single photon emission computed tomography in Sydenham's chorea

Kaan Demirören
AbstractBackground:,The objective of this study was to determine whether technetium-99m hexamethyl-propyleneamine oxime (HMPAO) brain single photon emission computed tomography (SPECT) imaging is capable of detecting perfusional abnormalities in Sydenham's chorea (SC) patients and contributing to diagnosis of SC. Methods:,In this study, 17 SC patients were evaluated. HMPAO SPECT was performed on all patients at the acute phase and six of them at the recovery phase. Magnetic resonance imaging (MRI) of the brain was performed to 13 patients. SPECT images of basal ganglia and thalamus were evaluated both visually and by measuring the radioactivity uptakes. Ten subjects constituted the control group. Results:,HMPAO SPECT was visually evaluated as indicating hyperperfusion in the basal ganglia and thalamus in 16 patients, and evaluated as normal in one patient at the acute phase. The radioactivity uptakes of basal ganglia and thalamus of the patients at the acute phase were found statistically higher than those of the patients at the recovery phase, and also higher than those of the control group (P < 0.05). A significant difference between the radioactivity uptake of the patients at the recovery phase and those of the control group was not found (P > 0.05). Only one patient did not show any abnormality in both acute and recovery phases. MRI study did not show any abnormality in the basal ganglia and thalamus. Conclusion:,It is suggested that brain SPECT can contribute to the diagnosis of SC as an objective tool. Resolving of the hyperperfusion at the recovery phase provides further support for the diagnosis of SC. [source]

Detailed Visualization of the Functional Regions of the Rat Pituitary Gland by High-Resolution T2-Weighted MRI

E. Theunissen
With 5 figures and 1 table Summary This high-resolution MRI study focuses on the visualization of the detailed morphology of the rat's pituitary gland by means of post-mortem as well as in vivo MRI at 9.4 T. Determination of the local T1- and T2-relaxation decay times allows to explain the regional image intensities which reflects the degree of tissue organization at the molecular level. Detailed characterization of the molecular level of the pituitary gland, as provided by the relaxation decay times, can offer a rigid platform with respect to functional or pathological explorations. It is demonstrated that T1-weighted imaging, as is routinely used in the clinic, can differentiate between the posterior and anterior lobe but not between the posterior and intermediate lobe. T2-weighted images, however, clearly show the three distinct lobes of the rat pituitary gland without the use of contrast agents, i.e. the posterior, the intermediate and the anterior lobe. Histological analysis of the rat's pituitary gland confirms the morphological structures seen on the MR images. Although the intermediate lobe is less defined in humans and can neither be differentiated by T1-weighted MRI, its clinical visualization might be possible in T2-weighted images. [source]

Hippocampal sclerosis is a progressive disorder: A longitudinal volumetric MRI study

Darren Fuerst PhD
Twelve patients with refractory temporal lobe epilepsy and unilateral hippocampal sclerosis had repeat volumetric magnetic resonance imaging scans after a mean of 3.4 years to determine whether progressive hippocampal volume loss occurred. Seizure-free patients showed no change in hippocampal volume. Patients with continuing seizures had a decline in ipsilateral hippocampal volume that correlated with seizure frequency. Patients with medically refractory temporal lobe epilepsy and unilateral hippocampal sclerosis have progressive hippocampal atrophy. Ann Neurol 2003;53:413,416 [source]

Pattern of skeletal muscle involvement in primary dysferlinopathies: a whole-body 3.0-T magnetic resonance imaging study

K. Kesper
Objectives and methods,,, Mutations in the gene encoding dysferlin cause limb girdle muscular dystrophy type 2B (LGMD2B), distal Miyoshi myopathy (MM), and a rare form of distal anterior compartment myopathy. To study the correlations between clinical manifestations and muscle imaging changes we conducted a 3.0-T magnetic resonance imaging (MRI) study in six German patients with primary dysferlinopathies defined by absence of dysferlin expression in muscle (MM, n = 3; LGMD2B, n = 2; hyperCKemia without clinical symptoms, n = 1). Results,,, Patients with manifest myopathy had widespread muscular pathology. In analogy to previous imaging studies, we confirmed an involvement of the anterior and posterior thigh compartments and a predominant involvement of posterior lower legs. However, our whole-body MRI study further provided evidence of signal alterations in the glutei, erector spinae and shoulder girdle muscles. Correlation of clinical findings with imaging demonstrated the potential of MRI to detect subclinical muscle pathology. Conclusions,,, Whole-body 3.0-T MRI is a non-invasive method to demonstrate various degrees of skeletal muscle alterations and disease progression in muscular dystrophies. Furthermore, whole-body high-field MRI may serve as a helpful diagnostic tool in differentiating primary dysferlinopathies from other forms of LGMD and distal myopathies. [source]

Brain abnormalities in extremely low gestational age infants: a Swedish population based MRI study

Sandra Horsch
Abstract Aims: Brain abnormalities are common in preterm infants and can be reliably detected by magnetic resonance (MR) imaging at term equivalent age. The aim of the present study was to acquire population based data on brain abnormalities in extremely low gestational age (ELGA) infants from the Stockholm region and to correlate the MR findings to perinatal data, in order to identify risk factors. Methods: All infants with gestational age <27 weeks, born in the Stockholm region between January 2004 and August 2005, were scanned on a 1.5 T MR system at term equivalent age. Images were analysed using a previously established scoring system for grey and white matter abnormalities. Results: No or only mild white matter abnormalities were observed in 82% and moderate to severe white matter abnormalities in 18% of infants. The Clinical Risk Index for Babies (CRIB II) score, use of inotropes, the presence of high-grade intraventricular haemorrhages and posthaemorrhagic ventricular dilatation were associated with white matter abnormalities. Conclusion: The incidence of moderate to severe white matter abnormalities in a population-based cohort of ELGA infants from the Stockholm region was 18%. To examine the clinical relevance of these promising results, neurodevelopmental follow up at 30 month corrected age, is ongoing. [source]

Brain herniation and chronic otitis media: diagnosis and surgical management

I. Mosnier
Herniation of the brain into the middle ear is a rare, but potentially life-threatening complication of chronic otitis media. Fifty patients with a tegmen defect associated with chronic otitis media were operated on between 1985 and 1998. Among these 50, 15 patients presented brain herniation associated with the bony defect. Fourteen patients had undergone previous mastoid surgery for chronic otitis media. Neurological symptoms were encountered in five patients. In 10, magnetic resonance imaging (MRI) was performed before surgery, and a diagnosis of brain herniation could be made. The hernia was repaired in all patients using a middle fossa craniotomy, combined with a transmastoid approach in 11 cases where a large hernia, and/or inflammatory tissues were present in the mastoid. The herniated brain tissue was resected in all, and the dural and bony defects were closed with fascia and bone. No complication or recurrence occurred, during a mean follow-up of 2 years. In conclusion, the occurrence of severe neurological complications as a consequence of brain herniation emphasizes the necessity for recognition and appropriate management of this disease. Computerized tomography (CT) scanning allows the suspicion of brain herniation, but a definitive diagnosis can best be established with an MRI study. The hernia should be repaired using a middle fossa craniotomy, combined with a transmastoid approach in one or two stages, when necessary. [source]