Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Diffusion MRI”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72Linked to original sources
PubMed1994

[Concentric sclerosis (Baló)].

Seventeen autopsy cases were collected in the Philippines. Mean age of onset 32.5 years, male/female ratio 1/2, no seasonal change, and the patients' occupation variable. A half had prodromal symptoms: mild fever, general malaise and headache. The disease was characterized by acute onset with behavioral changes, reticence, hemi- or quadriplegia with pyramidal signs, and incontinence. A quarter of patients had generalized seizure. There were no specific abnormalities in the routine blood examination, and CSF showed unexpectedly mild change. CT scan and MRI show diffuse or multifocal abnormalities in the centrum semiovale. They died of cerebral herniation or secondary infection. The brain was characterized by diffuse or multifocal necrotic and concentric demyelination in the cerebral white matter with marked gemistocytosis.

Adult↗
PubMed1993

[Cytomegalovirus ascending myelitis in an immunocompetent adult].

A 32-year-old man was hospitalized because of tetraparesis, sensory loss below cervical line, and urinary bladder dysfunction. Two months prior to this admission, he had suffered from cytomegalovirus (CMV) mononucleosis characterized by fever, presence of atypical lymphocytes and high serum titers of CMV-IgG/IgM antibodies. A lumbar puncture yielded clear fluid with 104 leukocytes (predominantly mononuclear cells)/mm3; protein, 102 mg/dl; and CMV-IgG antibodies (EIA), 1210. CMV antibody serum/CSF ratio was decreased to 2.08 (normal range > or = 20), indicating intrathecal production of CMV antibodies. T2-weighted images of spinal MRI showed diffuse high signal intensity lesions throughout the cord below C3 vertebral body level. A diagnosis of ascending myelitis secondary to CMV infection was made. Methylprednisolone pulse therapy led to some improvement in his neurologic dysfunctions. This is the first case report of CMV ascending myelitis in a previously healthy adult.

Adult↗
PubMed1993

[Juvenile Binswanger-type encephalopathy with alopecia and spondylosis deformans--a case report].

The patient is a 33-year-old male and his parents are first cousins. He noticed his hair loss since about the age 14. At age 29, he manifested gait disturbance and urinary incontinence, which gradually progressed. Neurologically, he showed dementia (WAIS < 64), pyramidal and extrapyramidal signs, and pseudobulbar palsy. His blood pressure was normal. He also had dry skin with sclerema and marked cervical and lumbar spondylosis. His brain CT showed enlargement of the lateral ventricles and the periventricular low density areas. T2 weighted image of MRI showed diffuse high intensity in the periventricular white matter. Yamada et al presented a case progressive subcortical vascular encephalopathy (Binswanger type) with alopecia and spondylosis as a possible new syndrome, and this patient has the same syndrome. The etiology of this syndrome has not been known at the present time. The biopsied skin from the patient showed much hyaline deposits like glycoprotein in perivascular area of dermis. These morphological changes are very similar to those of lipoid proteinosis. These findings suggested that the pathological mechanism of this syndrome might be related to the biochemical disturbance in lipoid proteinosis.

Adult↗
PubMed1996

[A Japanese family with probably autosomal dominant adult-onset leukodystrophy].

We report here a family with leukodystrophy clinical features of which are characterized as adult onset, probably autosomal dominant inheritance, hyperreflexia, cerebellar ataxia, autonomic dysfunction and no peripheral nerve involvement. T2-weighted brain MRI revealed diffuse high signal areas in the cerebral white matter. The disorder in our subjects can be distinguished from most leukodystrophies in terms of genetic inheritance, clinical manifestations and laboratory data. Our family is quite similar to the kindred which Eldridge et al. described in 1984 as "hereditary adult-onset leukodystrophy simulating chronic progressive multiple sclerosis". Our family is the third report of this type of leukodystrophy and the first among non-Irish/Scottish family.

Age of Onset↗
PubMed1997

[Progress of the therapy for virus related neurological disorders].

In this review of the therapy of infectious diseases and immune mediated nervous system diseases, we summarized the latest reports of antiviral drugs, immunosuppressants, immuno-modulatory and anti-inflammatory agents. Those include, acyclovir, vidarabine for herpes simplex encephalitis, ganciclovir for cytomegaro virus infection, inosine pranobex for SSPE, steroid therapy, interferon, plasma exchange and high-dose intravenous gamma globulin therapy for HTLV-I associated myelopathy, and multiple sclerosis. Diagnostic application of the PCR and the newly developed neuroimaging techniques, like diffusion weighted MRI, high speed MRI, and SPECT, we now being introduced to enable early recognition of viral infection of the CNS. And since speed of spread of HIV infection through the world, we are needed specific treatment for HIV infection, and various studies including genetic therapy is going on today.

Humans↗
PubMed1997

Alexia and agraphia in posterior cortical atrophy.

A 65-year-old woman with progressive visuospatial dysfunction for 2 years complained of later-onset associated memory impairment. MRI revealed diffuse cerebrocortical atrophy, which was especially severe in both parieto-occipital regions but spared the calcarine and pericalcarine cortices. Examination 5 years after onset revealed left visual hemi-neglect, oculomotor apraxia, optic ataxia, simultanagnosia, verbal alexia, lexical and spatial agraphia, and anterograde amnesia. This patient's disorder is considered in the context of previous reports on the array of cognitive disturbances associated with posterior cortical atrophy (pCA). Special emphasis is made on her reading and writing disturbances, because their prevalence and range of individual variability have not been established in pCA. This array of neuropsychological manifestations may help to distinguish among different clinical and etiological types of pCA, and to elucidate the pathophysiology of a syndrome that has been associated with conditions as diverse as Alzheimer's disease, subcortical gliosis, and prion diseases. The parameters described in our case may thus help to address these issues in clinico-pathological studies with large numbers of patients with pCA.

Aged↗
PubMedDate not supplied

Hashimoto's encephalopathy: clinical and laboratory findings.

We describe a patient with a clinical picture characterized by subacute onset of confusion, myoclonus, tremor and generalized convulsive seizures with a relapsing course, which was attributed to Hashimoto's encephalopathy. EEG and MRI were diffusely abnormal. High titers of antithyroid antibodies were detected in her serum. She responded well to corticosteroids and her condition remained good during a one-year follow-up.

Brain Diseases↗
PubMed1997

[A case of incomplete Kearns-Sayre syndrome with a stroke like episode].

A 32-year-old woman developed chronic progressive hearing impairment, trunkal ataxia, bilateral ptosis and external ophthalmoplegia. She also showed slowly progressive mild to moderate proximal dominant muscle weakness and atrophy. ECG showed incomplete right bundle branch block. An aerobic exercise test showed abnormal blood lactate elevation and muscle biopsy revealed ragged-red fibers in addition to the myopathic change. Analysis of mitochondrial DNA extracted from biopsied muscle and fibroblast samples revealed a 1,758bp deletion from the cytochrome b to ND6 coding regions. Common mutations in tRNALeu(UUR) coding region to the mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) were not present. She was diagnosed as having incomplete Kearns-Sayre syndrome (KSS). Since the age of 35, she developed complex partial seizure attacks with secondary generalization frequently and at the age of 42, she had a severe generalized seizure with delayed consciousness loss followed by left hemiplegia. MRI showed wide T2-high signal lesions in the right temporo-parieto-occipital area. The proton MR-spectroscopy showed prominent increase of lactate beyond the lesions detected by MRI, indicating diffuse aerobic metabolic dysfunction in the central nervous system. We reviewed two other KSS cases with a stroke like episode, who also had epilepsy and large deletion but no tRNALeu(UUR) mutation, in mitochondrial DNA. Patients with KSS who have seizure may develop the stroke-like episode as seen in MELAS patients.

Adult↗
PubMed1997

[Non-Fukuyama type congenital muscular dystrophy--merosin deficient and positive forms].

The classical form of congenital muscular dystrophy (CMD) is now classified into merosin-deficient and -positive forms. The merosin (laminin alpha 2) is one of three subunits of a muscle basement membrane protein, laminin. Patients with the merosin-deficient form have generalized muscle weakness and hypotonia from early infancy as seen in FCMD but with no significant central nervous system involvement. The serum creatine kinase (CK) is markedly elevated. Strikingly all patients examined by a CT/ MRI have diffuse white matter abnormalities mimicking leukodystrophy. The gene has been mapped to chromosome 6q2 in the coding region for merosin. Since the responsible gene and protein have not been identified in the merosin-positive form, this CMD is probably a group of heterogeneous diseases. The overall symptoms are mild, approximately 90% of patients learned to walk alone.

Animals↗
PubMed1998

[A case of hypertrophic cranial pachymeningitis associated with intramedullary lesion developed seizure marching from right lower extremity].

A case of hypertrophic cranial pachymeningitis associated with intramedullary lesion was reported. A 57-year-old male presented with the symptoms of Jacksonian seizure and weakness of right lower extremity. Neurological examination showed weakness and muscular atrophy of right lower extremity (MMT 1-2) and hyperreflexia. Superficial sensation and position sense were normal, however cortical sensory disturbance was recognized in his right lower extremity. MRI revealed diffuse dural thickening with gadolinium enhancement in the left convexity and hyperintense lesion in the bilateral (left dominant) frontal to parietal lobe on T2 weighted image. Magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) showed occlusion of the superior sagittal sinus. Histological examination revealed extensive fibrous tissue with lymphocytes infiltration around the vessels. The cause of the intramedullary lesion in this patient may have been related to the occlusion of superior sagittal sinus, due to thickening dura mater and influence of inflammation.

Angiography, Digital Subtraction↗
PubMed1998

[Fulminant orthochromatic leukodystrophy in an adult].

A 27-year-old man from Marocco developed a progressive dementia leading within a year to a mutic akinetic state. The course of the disease was also marked by epileptic seizures. MRI revealed diffuse white matter involvement. A frontal white matter brain biopsy was consistent with the diagnosis of orthochromatic leucodystrophy, i.e: presence of sudanophilic lipids and pigmented cells associated with myelin loss. Adult forms of orthochromatic leucodystrophy are very rare. Our case was characterized by a fulminant course.

Adult↗
PubMed1996

Mitochondrial encephalomyopathy of mixed MELAS type.

A 27-year-old man with slowly progressing symptoms of pigmentary retinal degeneration, cerebellar, pyramidal and extrapyramidal syndrome and atrophy of lower limb muscles, was admitted to the Department of Neurology. During the final stage of disease, generalized, tonic and clonic seizures, absence and myoclonic epilepsy as well as Jackson's motor seizures were observed. A computed tomographic (CT) scan showed a considerable atrophy of cerebellum and pons. A magnetic resonance imaging (MRI) revealed diffuse cortical and subcortical atrophy, especially in structures of posterior intracranial fossa and bilateral foci of increased signal intensity in cerebral cortex and subcortical gray structures. A morphological study of a biceps specimen revealed the presence of so called ragged-red fibers characterized by abnormal mitochondria with paracrystalline inclusions. A considerable atrophy of the central nervous system, especially of cerebral and cerebellar cortex was revealed by a macroscopic study of the brain. Numerous focal and so called pseudolaminar cortical necroses in the brain, regardless of vascular supply, with characteristic proliferation of capillary vessels were predominating in a microscopic study. The clinical data and especially histopathological features count for the diagnosis of mitochondrial encephalomyopathy of MELAS type. The presence of additional features such as pigmentary retinal degeneration, characteristic of Kearns-Sayre syndrome and myoclonic seizures typical of MERRF syndrome allows the classification of this case as mixed MELAS syndrome.

Adult↗
PubMed2002

BOLD signal compartmentalization based on the apparent diffusion coefficient.

Functional MRI (fMRI) can detect blood oxygenation level dependent (BOLD) hemodynamic responses secondary to neuronal activity. The most commonly used method for detecting fMRI signals is the gradient-echo echo-planar imaging (EPI) technique because of its sensitivity and speed. However, it is generally believed that a significant portion of these signals arises from large veins, with additional contribution from the capillaries and parenchyma. Early experiments using diffusion-weighted gradient-echo EPI have suggested that intra-voxel incoherent motion (IVIM) weighting inherent in the sequence can selectively attenuate contributions from different vessels based on the differences in the mobility of the blood within them. In the present study, we used similar approach to characterize the apparent diffusion coefficient (ADC) distribution within the activated areas of BOLD contrast. It is shown that the voxel values of the ADCs obtained from this technique can infer various vascular contributions to the BOLD signal.

Algorithms↗
PubMed1990

Early detection of ischemic injury: comparison of spectroscopy, diffusion-, T2-, and magnetic susceptibility-weighted MRI in cats.

Within one hour following MCA-occlusion in cats, heavily diffusion-weighted spin-echo MR images exhibited a well-defined hyperintensity in the gray matter and basal ganglia of the occluded side over normal side. This hyperintensity correlated with lactate and inorganic phosphate increases in peak areas from MR surface coil spectroscopy. T2-weighted MRI showed no significant abnormality in signal intensity from the occluded hemisphere within several hours post-occlusion. Using a paramagnetic MR contrast agent, dysprosium-DTPA-BMA together with heavily T2-weighted spin-echo or with T2*-weighted echo-planar (EPI) MR imaging, perfusion deficits resulting from MCA-occlusion were detected as a relative hyperintensity of ischaemic tissues compared to normally-perfused cerebral tissues in the contralateral hemisphere. Evidence of these deficits was observed within minutes of occlusion, and spatially correlated well with the hyperintensity seen on the diffusion-weighted images. Diffusion- and susceptibility-weighted MRI was superior to conventional T2-weighted MRI in the detection of early ischaemic events. In contrast to surface coil spectroscopy, both techniques mapped regions of jeopardy throughout the brain, which later showed T2-weighted hyperintensity and lack of vital (TTC) staining.

Animals↗
PubMed1999

Diffusion-weighted images and vasogenic edema in eclampsia.

BACKGROUND: In eclampsia, it is mandatory to recognize specific cerebrovascular complications before initiation of treatment. Diffusion-weighted magnetic resonance imaging (MRI) is a new technique that differentiates between cerebral infarction and hypertensive encephalopathy with vasogenic edema. CASE: A 23-year-old primigravida developed eclampsia at 29 weeks' gestation. Focal neurologic signs and neuroimaging findings by computed tomography and MRI were consistent with acute infarction or vasogenic edema. Diffusion-weighted MRI did not show an abnormal signal, indicating vasogenic edema. Control of the severe hypertension without anticoagulation therapy was begun. After delivery, the woman's neurologic abnormalities disappeared. CONCLUSION: Diffusion-weighted MRI differentiated between cerebral infarction and vasogenic edema, helping in the management of eclampsia.

Adult↗
PubMed1994

Diffusion-weighted imaging differentiates ischemic tissue from traumatized tissue.

BACKGROUND AND PURPOSE: Diffusion-weighted magnetic resonance imaging (MRI) has been shown to be particularly effective in detecting early (0 to 4 hours) pathophysiological changes in localized brain regions after cerebral ischemia. The present study sought to establish whether diffusion-weighted MRI would be similarly effective in predicting outcome after traumatic brain injury. METHODS: Diffusion-weighted MRI images and T2-weighted MRI images were obtained over 4 hours after either moderate fluid percussion-induced traumatic brain injury or unilateral carotid ligation in rats. RESULTS: Diffusion-weighted MRI images of traumatic brain injury demonstrated focal regions of image hypointensity as early as 1 hour after trauma. The relative diffusion coefficient in these hypointense regions was significantly increased (P < .005) by 4 hours after trauma compared with the noninjured hemisphere, but only in the transverse plane in the x direction. In contrast, induction of diffuse, nonfocal ischemia by unilateral carotid ligation resulted in scattered regions of hyperintensity with a significant (P < .001) decrease in relative diffusion coefficient as early as 1 hour after ligation compared with the noninjured hemisphere. This decrease exhibited no directionality. CONCLUSIONS: We conclude that traumatic brain injury results in an increased water diffusion distance with the directionality indicative of bulk flow of extracellular fluid toward the lateral ventricles (vasogenic edema). In contrast, the decreased water diffusion distance with no apparent directionality observed in ischemia is most likely indicative of cytotoxic edema. Diffusion-weighted MRI therefore has the potential to differentiate cases of traumatic brain injury with no focal ischemia from those instances of traumatic brain injury in which focal ischemia is a complication.

Animals↗
PubMed1997

A new leukoencephalopathy with vanishing white matter.

We identified nine children with a leukoencephalopathy of similar type according to clinical and MRI findings. The patients included three affected sibling pairs. The age range was 3 to 19 years. The onset of the disease was in childhood; the course was both chronic-progressive and episodic. There were episodes of deterioration following infections and minor head traumas, and these could results in unexplained coma. In eight patients with advanced disease, MRI revealed a diffuse cerebral hemispheric leukoencephalopathy, in which increasing areas of the abnormal white matter had a signal intensity close to that of CSF on all pulse sequences. In one patient in the early stages of disease, initial MRI showed diffusely abnormal cerebral white matter, which only reached the signal characteristics of CSF at a later stage. In the patients in whom the disease was advanced, magnetic resonance spectroscopy (MRS) of the white matter showed an almost complete disappearance of all normal signals and the presence of glucose and lactate, compatible with the presence of mainly CSF and little brain tissue. Spectra of the cortex were much better preserved. However, in addition to the normal resonances, there were signals representing lactate and glucose. MRS of the white matter in the patient whose disease was at an early stage was much less abnormal. Autopsy in one patient confirmed the presence of extensive cystic degeneration of the cerebral white matter with reactive change and a preserved cortex. Typical involvement of pontine tegmental white matter was suggested by MRI and confirmed by autopsy. The disease probably has an autosomal recessive mode of inheritance, but the basic metabolic defect is not known.

Adolescent↗
PubMed2005

Fatal toxic leukoencephalopathy: clinical, radiological, and necropsy findings in two patients.

BACKGROUND: Toxic leukoencephalopathy has been described with inhalation and intravenous consumption of heroin and cocaine. The clinical picture varies widely but the imaging and histological features are characteristic. Magnetic resonance imaging (MRI) typically reveals diffuse bihemispheric white matter lesions. Histologically there is extensive spongiform degeneration of the cerebral white matter. OBJECTIVE: To report two cases of fatal toxin associated leukoencephalopathy, along with detailed imaging and neuropathological studies. RESULTS: MRI revealed diffuse white matter changes. Histologically there was widespread confluent vacuolar degeneration of the deep white matter. In both cases, there was sparing of the brain stem and cerebellar white matter. There was evidence of severe and extensive axonal injury. CONCLUSIONS: This pattern of radiological involvement and histological findings has not previously been reported and may reflect the presence of a yet unidentified impurity.

Adult↗