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 1,549 records · Page 86Linked to original sources
PubMedDate not supplied

Transient MR signal changes in the splenium of the corpus callosum in rotavirus encephalopathy: value of diffusion-weighted imaging.

The authors report serial brain MR findings from a 2-year-old girl with rotavirus encephalopathy. The lesion in the splenium of the corpus callosum showed restricted proton diffusion, suggesting local cytotoxic edema. Diffusion-weighted images demonstrated the lesion more conspicuously than other techniques, such as fluid-attenuated inversion-recovery and T1- and T2-weighted images. The findings were reversible on follow-up MRI obtained 4 days later. Diffusion-weighted MRI is a potentially useful method for detecting early changes of rotavirus encephalopathy, although the mechanism of the restricted diffusion is not clearly identified.

Child, Preschool↗
PubMed2005

Magnetic resonance imaging of experimental testicular torsion.

We investigated the feasibility of contrast enhanced (CE)-dynamic magnetic resonance imaging (MRI) for the detection of testicular torsion induced hypoperfusion in an experimental rat model. Adult Sprague-Dawley rats were subjected to unilateral testicular torsion of 360 or 720 degrees. After 1 h, the tail veins of the anaesthetized rats were cannulated and T2 -, diffusion-weighted and T1-weighted CE-dynamic MRI were subsequently performed by a 1.5 T MRI scanner. On apparent diffusion coefficient (ADC) images, the region of interest values of the ischaemic and control testes was compared. From CE-dynamic MR images, the maximal slopes of contrast enhancement were calculated and compared. In testicular torsion of 360 degrees, the maximal slope of contrast enhancement was 0.072%/s vs. 0.47%/s in the contralateral control testis (p < 0.001). A torsion of 720 degrees diminished the slope of contrast enhancement to 0.046%/s vs. 0.37%/s in the contralateral testis (p < 0.001). Diminished blood flow during torsion also followed in decreased ADC values in both 360 degrees (12.4% decrease; p < 0.05) and 720 degrees (10.8% decrease; p < 0.001) of torsion. Torsion of the testis causes ipsilateral hypoperfusion and decreased gadolinium uptake in a rat model that can be easily detected and quantified by CE-dynamic MRI. In diffusion-weighted MRI images, acute hypoperfusion results in a slight decrease of ADC values. Our results suggest that CE-dynamic MRI in combination with diffusion-weighted MRI can be used to detect compromised blood flow due to acute testicular torsion.

Animals↗
PubMed2005

Netherton syndrome with extensive skin peeling and failure to thrive due to a homozygous frameshift mutation in SPINK5.

BACKGROUND: Netherton syndrome (NTS) is a rare autosomal recessive multisystem disorder characterized by congenital erythroderma and ichthyosis, hair shaft abnormalities and immune dysregulation. The disorder is caused by deleterious mutations in the SPINK5 gene, encoding the serine protease inhibitor LEKTI. OBJECTIVE: Our objective was to investigate if the erythrodermic variant of peeling skin syndrome is also caused by SPINK5 mutations and to study the consequences of the disease on infantile brain development. METHODS: In an infant with extensive erythroderma, peeling skin and failure to thrive, we analyzed the SPINK5 gene for pathogenic mutations by direct DNA sequencing and performed repeated brain MRI studies with diffusion-weighted imaging. RESULTS: We identified a homozygous 4-base-pair insertion in exon 5 of SPINK5, which introduces a premature termination codon and appears to be a common mutation among West Indies islanders. MRI analyses revealed a persistent diffuse volume loss. CONCLUSION: Our results confirm that early truncation mutations of the coding sequence of SPINK5 produce a severe phenotype and that generalized peeling skin is one of the manifestations of NTS. We further demonstrate for the first time that NTS may be associated with MRI abnormalities indicative of a permanent tissue injury of the brain.

Biopsy, Needle↗
PubMed1996

Primary leptomeningeal histiocytic lymphoma in a young child.

A 20-month-old boy had an 8-week history of vomiting, lethargy, generalized muscle weakness, and seizures. There was no history or clinical signs of an underlying systemic disease or an immunodeficiency. Cerebrospinal fluid (CSF) had 99 nucleated cells/cu mm, malignant cells, high protein and normal glucose. CT and MRI scans showed diffuse meningeal enhancement around the brain and spinal cord, but no parenchymal involvement. Biopsy of the leptomeninges showed malignant cells with marked nuclear pleomorphism and prominent clear to eosinophilic cytoplasm. The immunohistochemical studies were positive for histiocyte-macrophage markers and were negative with T and B cells, Ki-1, neural and glial cell antibodies. Multiple tests revealed no other site of disease. The patient died 3 months after onset of treatment despite intensive i.v. and intrathecal chemotherapy. We have not found any other reported case of primary histiocytic leptomeningeal lymphoma in a young child.

Humans↗
PubMed2003

New syndrome of simplified gyral pattern, micromelia, dysmorphic features and early death.

We report two sisters with a new syndrome of simplified gyral pattern, normal head circumference at birth but with subsequent development of microcephaly, intractable seizures, and early death. Dysmorphic features included coarse face, hypertrichosis, short nose, paranasal widening, long philtrum, short neck, upper limb micromelia, single transverse palmar lines, and clasp thumbs. The proband had repeated convulsions from shortly after birth and she required continuous artificial ventilation. Neurological examination showed absent sucking, rooting, Moro and grasping reflexes. MRI revealed a diffuse simplified gyral pattern with apparent agyria over the frontal lobes. Biochemical screening gave normal results. Her older sister had bilateral renal pelvic dilatation on prenatal ultrasound. She also developed severe convulsions on the first day of life, and she had to be artificially ventilated for 38 days. She had severe developmental retardation and neurological examination showed absence of spontaneous movements and Moro reflex, weak sucking reflex, and hypertonicity. CT scan of the brain showed a simplified gyral pattern. At 3 months, she developed hypocalcemia and hyperphosphatemia with normal levels of vitamin D and alkaline phosphatase, and parathyroid hormone level was low. Other biochemical tests gave normal results. She died at 5 months due to a massive aspiration event. Based on the unique clinical and radiological features found in our patients, we propose that this is a new syndrome.

Brain Diseases↗
PubMed1995

Familial tremulous and myoclonic dystonia with white matter changes in brain magnetic resonance imaging.

We report two families with a disorder, probably autosomal recessive, characterized by tremor of juvenile onset, dystonia, and myoclonus with preserved cognitive, cerebellar, and peripheral nervous system functions. During 4 years' follow-up, mild spasticity appeared. Magnetic resonance imaging (MRI) revealed mild diffuse changes in the white matter. Central conduction times for visual, motor, and sensory systems were all prolonged. Extensive metabolic work-up failed to reveal lysosomal, peroxisomal, mitochondrial, or other metabolic abnormalities.

Adolescent↗
PubMed2002

Real-time autoshimming for echo planar timecourse imaging.

Head motion within an applied magnetic field alters the effective shim within the brain, causing geometric distortions in echo planar imaging (EPI). Even if subtle, change in shim can lead to artifactual signal changes in timecourse EPI acquisitions, which are typically performed for functional MRI (fMRI) or diffusion tensor imaging. Magnetic field maps acquired before and after head motions of clinically realistic magnitude indicate that motion-induced changes in magnetic field may cause translations exceeding 3 mm in the phase-encoding direction of the EPI images. The field maps also demonstrate a trend toward linear variations in shim changes as a function of position within the head, suggesting that a real-time, first-order correction may compensate for motion-induced changes in magnetic field. This article presents a navigator pulse sequence and processing method, termed a "shim NAV," for real-time detection of linear shim changes, and a shim-compensated EPI pulse sequence for dynamic correction of linear shim changes. In vivo and phantom experiments demonstrate the detection accuracy of shim NAVs in the presence of applied gradient shims. Phantom experiments demonstrate reduction of geometric distortion and image artifact using shim-compensated EPI in the presence of applied gradient shims. In vivo experiments with intentional interimage subject motion demonstrate improved alignment of timecourse EPI images when using the shim NAV-detected values to update the shim-compensated EPI acquisition in real time.

Artifacts↗
PubMed1999

Plurihormonal Bronchial Carcinoid Associated with Ectopic Cushing's Syndrome.

A 31-year-old woman presented with progressive weight gain, facial acne, round facies, hirsutism, and secondary amenorrhea. Her plasma cortisol, urinary free cortisol, and plasma ACTH were elevated. CT scan of abdomen revealed bilateral diffuse adrenal enlargement. MRI of pituitary failed to identify a lesion. CT scan of chest revealed an 8 mm nodule in the lower lobe of the left lung. The diagnosis of ectopic Cushing's syndrome was made. The lung tumor was surgically removed. The tumor measured up to 1.5 cm in diameter. By light microscopy, a tumor with characteristic features of bronchial carcinoid was noted. Immunostains were positive for neuron-specific enolase, synaptophysin, chromogranin, low-molecular-weight keratin, ACTH, beta endorphin, corticotropin-releasing hormone, bombesin, alpha subunit, and somatostatin. Electron microscopy revealed an endocrine neoplasm. The secretory granules displayed great variation subdividing the endocrine neoplasm. The secretory granules displayed great variation subdividing the cell population into an undetermined number of phenotypes. In situ hybridization demonstrated positivity for pro-opiomelanocortin mRNA in the tumor cells. Postoperatively, plasma cortisol had fallen. The patient remained symptom-free one year later. The case presented here was regarded as a plurihormonal bronchial carcinoid associated with ectopic Cushing's syndrome. This unique plurihormonal bronchial carcinoid tumor produced three hormones, ACTH, CRH, and bombesin, that may have contributed to the patient's ectopic Cushing's syndrome.

Journal Article↗
PubMed2003

Posterior encephalopathy with vasospasm: MRI and angiography.

Posterior encephalopathy is characterised by headache, impairment of consciousness, seizures and progressive visual loss. MRI shows bilateral, predominantly posterior, cortical and subcortical lesions with a distribution. Our aim was to analyse the MRI lesion pattern and angiographic findings because the pathophysiology of posterior encephalopathy is incompletely understood. We report three patients with clinical and imaging findings consistent with posterior encephalopathy who underwent serial MRI including diffusion-weighted imaging (DWI) and construction of apparent diffusion coefficient (ADC) maps, and four-vessel digital subtraction angiography (DSA). DWI revealed symmetrical subcortical and cortical parieto-occipital high signal. High and also low ADCs indicated probable vasogenic and cytotoxic oedema. On follow-up there was focal cortical laminar necrosis, while the white-matter lesions resolved almost completely, except in the arterial border zones. DSA revealed diffuse arterial narrowing, slightly more marked in the posterior circulation. These findings suggest that posterior encephalopathy may in some cases be due to diffuse, severe vasospasm affecting especially in the parieto-occipital grey matter, with its higher vulnerability to ischemia. Cerebral vasospasm due to digitoxin intoxication, resulting in posterior encephalopathy, has not yet been described previously.

Adult↗
PubMed2000

Reversible posterior leukoencephalopathy after combination chemotherapy.

We describe a young woman with Burkitt's lymphoma, treated with intravenous adriamycine and cyclophosphamide and intrathecal cytarabine. She developed a reversible posterior leukoencephalopathy syndrome (RPLS) with typical MRI findings. Diffusion-weighted images during the first days after the onset of symptoms predicted a small irreversible lesion in the frontal lobe, verified on T2-weighted images 1 month later. The patient showed full recovery after high-dose steroid treatment.

Adolescent↗
PubMed2005

MRI of a family with leukoencephalypathy with vanishing white matter.

Leukoencephalopathy with vanishing white matter (VWM) is a newly described entity with characteristic MRI features. We report the cranial MRI findings in three sisters with slowly progressive neurological deterioration. The MRI showed symmetrical diffuse abnormalities of cerebral white matter with hypointensity on FLAIR images. The diagnosis of leukoencephalopathy with VWM was made on the basis of genetic analysis.

Adolescent↗
PubMed1998

Intraarticular epithelioid sarcoma.

A case of an intraarticular epithelioid sarcoma is presented. The patient was a 35 year old man who presented with a 10 months history of a chronic monoarthritis. The MRI showed a diffuse lesion involving the synovial membrane of the knee. There was a marked increased signal on T2 weighted images. Most epithelioid sarcomas involve the subcutaneous tissues of the hands or feet. This presentation is unusual and this entity should be considered in the differential diagnosis of an intraarticular proliferative process.

Adult↗
PubMed2004

Differences in number, size and location of intracranial microembolic lesions after surgical versus endovascular treatment without protection device of carotid artery stenosis.

BACKGROUND AND PURPOSE: The benefit of carotid endarterectomy in symptomatic high-grade stenosis has long been proven. The role of angioplasty as an alternative is still a matter of debate. We compared the occurrence of intraprocedural microembolic signals and ischemic lesions between carotid endarterectomy (CEA) and carotid angioplasty with stent placement (CAS) without a protection device. METHODS: 88 patients who underwent a CEA and 41 patients who underwent CAS were prospectively investigated. One day before and after the intervention diffusion weighted MRI-studies were obtained. In 21 CEA and 18 CAS patients transcranial Doppler (TCD) monitoring was performed during the procedure to detect microembolic signals (MES). RESULTS: DWI-lesions could be detected after intervention in 17% of the CEA patients compared with 54% of the CAS patients (p<0.005). The median lesion volume was 0.08 cm(3) in the CEA group and 0.02 cm(3) in the CAS group (p<0.001). Ischemic complications consisted of 2 strokes (2.3%) with symptoms lasting more than seven days in the CEA group and 1 stroke (2.4 %) in the CAS group. The median number of MES in the CEA group was 17 versus 61 in the CAS group (p<0.001). No significant correlation was found between the total number of MES and ischemic lesions in either group. CONCLUSION: A larger number of emboligenic particles with smaller volume is detached during CAS. Additionally DWI lesions were observed in different territories after CAS but not after CEA. Conventional TCD emboli detection is not useful to compare interventional therapies of the carotid arteries.

Aged↗
PubMed2002

Supratentorial leptomeningeal metastasis of a medulloblastoma without cerebellar tumor recurrence.

The authors report on a 15-year-old girl presenting with headache and nausea. Cranial magnetic resonance imaging (MRI) showed a diffuse leptomeningeal contrast enhancement 5 years after resection of a posterior fossa medulloblastoma followed by radio- and chemotherapy. A left frontal biopsy revealed tumor spread. Histopathological findings of the tumor were identical to those obtained from the original medulloblastoma. To the authors' knowledge this is the first report of late supratentorial leptomeningeal metastasis from a medulloblastoma while no local recurrence or spinal leptomeningeal dissemination had occurred.

Adolescent↗
PubMed2005

The European Multiple System Atrophy-Study Group (EMSA-SG).

Introduction. The European Multiple System Atrophy-Study Group (EMSA-SG) is an academic network comprising 23 centers across Europe and Israel that has constituted itself already in January 1999. This international forum of established experts under the guidance of the University Hospital of Innsbruck as coordinating center is supported by the 5th framework program of the European Union since March 2001 (QLK6-CT-2000-00661). Objectives. Primary goals of the network include (1) a central Registry for European multiple system atrophy (MSA) patients, (2) a decentralized DNA Bank, (3) the development and validation of the novel Unified MSA Rating Scale (UMSARS), (4) the conduction of a Natural History Study (NHS), and (5) the planning or implementation of interventional therapeutic trials. Methods. The EMSA-SG Registry is a computerized data bank localized at the coordinating centre in Innsbruck collecting diagnostic and therapeutic data of MSA patients. Blood samples of patients and controls are recruited into the DNA Bank. The UMSARS is a novel specific rating instrument that has been developed and validated by the EMSA-SG. The NHS comprises assessments of basic anthropometric data as well as a range of scales including the UMSARS, Unified Parkinson's Disease Rating Scale (UPDRS), measures of global disability, Red Flag list, MMSE (Mini Mental State Examination), quality of live measures, i.e. EuroQoL 5D (EQ-5D) and Medical Outcome Study Short Form (SF-36) as well as the Beck Depression Inventory (BDI). In a subgroup of patients dysautonomic features are recorded in detail using the Queen Square Cardiovascular Autonomic Function Test Battery, the Composite Autonomic Symptom Scale (COMPASS) and measurements of residual urinary volume. Most of these measures are repeated at 6-monthly follow up visits for a total study period of 24 months. Surrogate markers of the disease progression are identified by the EMSA-SG using magnetic resonance and diffusion weighted imaging (MRI and DWI, respectively). Results. 412 patients have been recruited into the Registry so far. Probable MSA-P was the most common diagnosis (49% of cases). 507 patients donated DNA for research. 131 patients have been recruited into the NHS. There was a rapid deterioration of the motor disorder (in particular akinesia) by 26.1% of the UMSARS II, and - to a lesser degree - of activities of daily living by 16.8% of the UMSARS I in relation to the respective baseline scores. Motor progression was associated with low motor or global disability as well as low akinesia or cerebellar subscores at baseline. Mental function did not deteriorate during this short follow up period. Conclusion. For the first time, prospective data concerning disease progression are available. Such data about the natural history and prognosis of MSA as well as surrogate markers of disease process allow planning and implementation of multi-centre phase II/III neuroprotective intervention trials within the next years more effectively. Indeed, a trial on growth hormone in MSA has just been completed, and another on minocycline will be completed by the end of this year.

Animals↗
PubMed2004

An Italian case of CADASIL with mutation CGC-TCG in codon 1006, exon 19 Notch3 gene.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is commonly overlooked or misdiagnosed owing to its recent identification. It is characterized clinically by recurrent cerebral infarcts, usually appearing between the ages of 30 and 50 years, subcortical dementia, and pseudobulbar palsy. It begins with migraine with aura in approximately one-third of patients. The pathological hallmark of angiopathy is the presence of characteristic granular osmiophilic material (GOM) within the basal lamina of smooth muscle cells. The defective gene in CADASIL is Notch3, which encodes a large transmembrane receptor, and 70% of missense mutations are in exons 3 and 4. Each gene defect leads to either a gain or loss of a cysteine residue in the extracellular N-terminal domain of the molecule. We report the case of a 53-year-old woman admitted to the hospital for transient ischemic attack and stroke-like episodes recurrent since age 43 years. The patient had pseudobulbar palsy, pyramidal signs, and cognitive impairment but not frank dementia. Cerebral MRI showed periventricular diffuse and confluent ischemic lesions. Ultrastructural study revealed an abnormal deposition of granular osmiophilic material (GOM) within the basal lamina in skin capillaries. Direct sequence analysis of the Notch3 gene was performed. Since no mutation was detected in exons 3 and 4, the remaining exons were sequenced and a missense mutation, CGC-TGC in codon 1006 of exon 19 was found. The mutation led to a gain of a cysteine residue. This is the first missense mutation in codon 1006 of exon 19 of the Notch3 gene to be described in Italy and the second reported in the literature.

Brain↗
PubMed2005

Imaging and skeletal muscle disease.

Imaging techniques have assumed increasing importance in the diagnostic approach to patients with muscle disease. These techniques include computed tomography, ultrasound, and magnetic resonance imaging (MRI). For most disorders of muscle, ultrasound and MRI are more useful than computed tomography. Advantages of ultrasound include accessibility at the bedside and lower cost. However, MRI remains the gold standard for detecting changes in muscle tissue. In some cases, MRI examinations can take the place of muscle biopsy for diagnosis. New advances in MRI include diffusion-weighted imaging, which permits assessment of fluid motion in muscles, and blood-oxygen-level-dependent imaging to evaluate tissue oxygenation.

Humans↗
PubMedDate not supplied

Magnetic resonance imaging and positron emission tomography of band heterotopia.

A case of band heterotopia was reported with findings of positron emission tomography (PET). The patient was an 8-year-old girl who had mild mental retardation and intractable partial epilepsy. Her MRI showed another diffuse layer of gray matter underlying the normal-looking cortex and separated from it by an apparently normal layer of white matter. PET scan with [18F]fluorodeoxyglucose revealed that band heterotopia had the same degree of glucose metabolism as that of the overlying cortex.

Animals↗