Magnetic Resonance Imaging Findings in Japanese Encephalitis

Ten patients with Japanese encephalitis diagnosed by serological criteria underwent magnetic resonance imaging (MRI) in axial and coronal sections. In 6, a second MRI study was done. The MRI findings were compared with the clinical outcome. Four patients died within several months of onset, 2 had sequelae such as hemiparesis and dementia, and the remaining 4 had no sequelae. In 9 of 10 patients, either diffuse or patchy white matter lesions were observed bilaterally, together with abnormalities in areas such as the thalamus, basal ganglia, and brainstem. For 3 patients who died or remained demented, the second MRI revealed extensive, diffuse white matter abnormalities. This study indicates that Japanese encephalitis can produce white matter involvement, although gray matter structures such as the thalamus, basal ganglia, and brainstem are more severely affected. The severity of these MRI lesions correlated with the clinical outcome.     

Magnetic Resonance Imaging,Computed Tomography,and Autopsy Findings after Cardiorespiratory Arrest

A 29-year-old man had temporary cardiorespiratory arrest. Eight hours later, magnetic resonance imaging (MRI) of the brain revealed scattered hyperintense gyri and a marked high signal intensity of the caudate nuclei and the putamen. Computed tomography (CT) displayed no focal abnormalities but only diffuse brain swelling and blood in the subarachnoid space. The patient died 17 hours after the arrest. Histopathological findings were consistent with early ischemic brain damage. Perivascular infiltrates, probably inflammatory, involved the entire brainstem. Neither MRI nor CT demonstrated brainstem encephalitis, the presumed cause for the arrest. This observation suggests a high sensitivity of MRI for cerebral damage caused by global hypoxemia, yielding valuable diagnostic and prognostic information after resuscitation.     

Lumbosacral Spinal Intradural Extramedullary Paciniomyolipoma: Magnetic Resonance Imaging. Computed Tomography. and Pathology Findings

This report desmbes a paciniomyolipoma as an intradural tumor of the lumbar spiriai cord composed of adipose tissue, stnated skeletal muscle, and paciriian corpuscles. Simple lipomas, myolipomas, and other vanant lipomas of the spinal cord have been described in the literature; to the authors' knowledge, however, this IS the first report of this unusual and unique lipoma.     

Magnetic Resonance Imaging Evaluation of Focal Computed Tomography Abnormality in Epilepsy

Sixty-seven patients with epilepsy and isolated enhancing computed tomography (CT) scan lesion were studied with magnetic resonance imaging (MRI). Fifty-six patients (83.5%) had partial seizures and 11 (16.4%) had generalized seizures. Four distinct groups were identified by MRI: nonspecific 16 cases (23.8%), tuberculoma 38 cases (56.7%), cysticercosis 12 cases (17.9%), and abscess 1 case (1.4%). Patients in the non-specific group had lesions that were hyperintense on T2 images and hypointense or isointense on T1 images. Such lesions resolved completely in 5 months with serial MRIs while the patients were receiving antiepileptic drugs (AEDs). Virologic studies, including cerebrospinal fluid (CSF) serology, are suggested for patients with such MRI lesions.     

Quantitative Computed Tomography and Magnetic Resonance Imaging in Aging and Alzheimer's Disease; A Review

In recent aging research, quantitative techniques have been used to overcome limitations of qualitative interpretation of magnetic resonance and computed tomographic imaging. The purpose of this review is to summarize imaging results emphasizing quantitative studies using these two modalities in human aging. Magnetic resonance spectroscopy is viewed as an extension of imaging, and results of in vivo spectroscopic studies are included. Because Alzheimer's disease (AD) is closely related to aging, a discussion of quantitative imaging techniques that may distinguish normal elderly from patients with AD is included.     

原发性脑淋巴瘤CT与MRI诊断

目的分析原发性脑淋巴瘤的CT和MRI表现,以提高对其的认识,减少误诊。方法回顾性分析17例经手术病理证实的原发性脑淋巴瘤的CT和MRI资料。结果CT和MRI主要表现为：（1）CT平扫示脑内单发或多发的等密度或较高密度瘤灶,肿瘤可沿脑脊液播散;MRI T1WI呈等或稍低信号,T2WI呈等或稍高信号;1例出现坏死及出血;②少部分病例瘤周水肿及占位效应轻至中度;（3）MRI增强扫描大多呈团块状均匀强化;1例环形强化。④除病变主体位于胼胝体膝部和压部外,瘤灶长轴多与颅脑前后径走行平行或大致相同。结论原发性脑淋巴瘤多在大脑深部,明显强化,CT和MRI表现具有一定的特异性,结合CT与MRI影像特点和临床资料综合分析,有可能在术前作出正确诊断。     

A Case of Adult Influenza A Virus–Associated Encephalitis: Magnetic Resonance Imaging Findings

A 27-year-old man presented with fever, convulsive seizure, and sudden impairment of consciousness. Magnetic resonance imaging (MRI) abnormalities were found in the bilateral thalami, including the brain stem and white matter. The possibility of a previous influenza A virus infection was considered, and cerebrospinal fluid cells and interleukin-6 were elevated. The MRI findings closely resembled those found in cases of childhood acute necrotizing encephalopathy (ANE). The present case suggests that adult influenza A virus-associated encephalitis/encephalopathy or ANE can occur during winter influenza epidemics.     

The Usefulness of Brain Magnetic Resonance Imaging with Mild Head Injury and the Negative Findings of Brain Computed Tomography

Objective

To investigate the cases of intracranial abnormal brain MRI findings even in the negative brain CT scan after mild head injury.

Methods

During a 2-year period (January 2009-December 2010), we prospectively evaluated both brain CT and brain MRI of 180 patients with mild head injury. Patients were classified into two groups according to presence or absence of abnormal brain MRI finding even in the negative brain CT scan after mild head injury. Two neurosurgeons and one neuroradiologist validated the images from both brain CT scan and brain MRI double blindly.

Results

Intracranial injury with negative brain CT scan after mild head injury occurred in 18 patients (10.0%). Headache (51.7%) without neurologic signs was the most common symptom. Locations of intracranial lesions showing abnormal brain MRI were as follows; temporal base (n=8), frontal pole (n=5), falx cerebri (n=2), basal ganglia (n=1), tentorium (n=1), and sylvian fissure (n=1). Intracranial injury was common in patients with a loss of consciousness, symptom duration >2 weeks, or in cases of patients with linear skull fracture (p=0.00013), and also more frequent in multiple associated injury than simple one (35.7%>8.6%) (p=0.105).

Conclusion

Our investigation showed that patients with mild head injury even in the negative brain CT scan had a few cases of intracranial injury. These findings indicate that even though the brain CT does not show abnormal findings, they should be thoroughly watched in further study including brain MRI in cases of multiple injuries and when their complaints are sustained.     

Single Photon Emission Computed Tomography, Magnetic Resonance Imaging Hyperintensity, and Cognitive Impairments in Patients With Vascular Dementia

BACKGROUND: The relationship between subcortical hyperintensity (SH) on magnetic resonance imaging (MRI), cortical perfusion on single photon emission computed tomography (SPECT), and cognitive function is not well understood. The authors examined these relationships in individuals with vascular dementia (VaD), paying particular attention to frontal lobe function to determine whether the presence of SH on MRI was associated with frontal hypoperfusion on SPECT, which in turn would be associated with impairments of executive-attention function. METHODS: Patients with vascular dementia (n = 26) were assessed on neurocognitive tests and brain MRI and SPECT. SH volume was quantified from the axial T2-weighted fluid attenuated inversion recovery MRI. Total counts of activation across voxels for 12 cortical regions of interest were determined from SPECT. Perfusion ratios of both total cortical and frontal activation relative to cerebellum activation were derived, and regression analyses were performed to determine the relationships between cognitive, MRI, and SPECT indices. RESULTS: SH volume on MRI was significantly associated with frontal lobe perfusion, but not with global cortical perfusion as measured by SPECT. Frontal lobe perfusion did not consistently correlate with performance on measures of executive-attention function, although both total and frontal perfusion ratios were significantly associated with other cognitive functions. CONCLUSIONS: These results suggest that a functional "disconnection" between the frontal lobes and subcortical structures does not fully account for the magnitude of global cognitive impairment in VaD. Cortical perfusion as measured by SPECT appears to be associated with cognitive performance, but not specifically executive-attention dysfunction. Additional studies are needed to further examine the relationship between subcortical and cortical function in VaD.     

Interpreting Magnetic Resonance Imaging Findings in Bipolar Disorder

The episodic nature of bipolar disorder together with the ostensibly polar extremes of mania and depression have favored the acceptance of a functional model postulating regionally disturbed brain activity returning to normal with time or treatment. Seemingly contrary to that view, anatomical imaging studies have demonstrated abnormalities in brain structure which could reflect neurodegeneration or represent disturbed neuronal development. Resolution may come from an appreciation of adult neurogenesis, especially given the neuroprotective properties of drugs, such as lithium and their effects on brain volume. The brain regions vulnerable to structural changes also show evidence of dysfunction, giving rise to corticolimbic dysregulation interpretations of bipolar disorder. This article reviews the structural and functional magnetic resonance imaging data in bipolar disorder. Its focus is on the interpretation of findings in light of recent developments in the fields of neurobiology and image analysis, with particular attention paid to both the confounding effects of medication and the baseline energy state of the brain.     

Magnetic Resonance Imaging Findings on Carbon Monoxide Intoxication

Four patients who had carbon monoxide intoxication were examined by brain magnetic resonance imaging (MRI) and computed tomography (CT). Three were unconscious in the acute stage of intoxication. On regaining consciousness. neuropsychological symptoms and signs remained. In these patients, T2-weighted MRI demonstrated hyperintensity lesions in the cerebral cortex, most prominent in the watershed zone. The fourth patient had only memory disturbance and was not unconscious during the acute intoxication. The T1-weighted MRI showed hyperintensity in the bilateral pallidal regions. MRI demonstrated lesions more clearly than did CT.     

Sturge-Weber Syndrome: Brain Magnetic Resonance Imaging and Neuropathology Findings

BackgroundWe describe the brain magnetic resonance imaging (MRI) abnormalities and neuropathologic findings of patients with Sturge-Weber syndrome and medically refractory epilepsy.MethodsWe reviewed the clinical features, preoperative MRI studies, and pathologic findings of all patients with Sturge-Weber syndrome who underwent excisional surgery for intractable epilepsy at Boston Children's Hospital between 1993 and 2011.ResultsEleven patients (male/female = 4/7) with Sturge-Weber syndrome were identified who underwent surgery for intractable epilepsy (mean age 13 ± 6.2 months), including hemispherectomy (n = 10) and focal cortical resection (n = 1). Mean age at seizure onset was 15 ± 11 weeks. Fifty-five percent (n = 6) of patients exhibited two different types of seizures, and 18% (n = 2) had three types of seizures. Focal clonic seizures were the most common type, occurring in nine patients; apnea was the second most common, occurring in four patients. Brain MRIs were reviewed in five patients. Histopathologic examination revealed varied degrees of cortical morphologic anomaly in seven of 11 patients. Overall, there were no abnormalities in the MRIs that corresponded directly with the pathologic findings except in one patient with polymicrogyria.ConclusionsIn spite of pathologic findings of cortical anomalies in varied degrees, these findings could not be readily detected on brain MRIs. The failure to detect focal cortical dysplasia on MRIs may be attributable to the subtle microscopic nature of the abnormalities; in some of the older individuals, the imaging studies available for review were done during an advanced stage of the disease.     

Cognitive Disturbances and Magnetic Resonance Imaging Findings in Multiple Sclerosis

Twenty patients (mean age ± standard deviation, 42 ± 14 yr) with multiple sclerosis were studied to define a possible relation between cognitive decline and pathology seen on magnetic resonance images (MRis). In all, a battery of psychometric tests and MRis were conducted. MRI results were classified according to cerebral lesions and different ventricle indexes. A rating scale graded the severity of cerebral lesions. MRI and psychometric data from the patients were compared with the results of an age- and sex-matched control group. The results suggest that evidence of cognitive decline shows a stronger relation to substance loss, defined by ventricle indexes, than to the lesion score.     

Magnetic Resonance Imaging and Spectroscopy Findings After Focal Status Epilepticus

Summary: The etiology of cerebral abnormalities after focal status epilepticus (SE) is unknown. Possible causes include hypoxia and the excessive release of excitatory amino acids. Magnetic resonance imaging (MRI) of a 21–year-old patient with "cryptogenic" continuous motor seizures showed swelling and signal hyperintensity of the contralateral panetotemporal cortex, the thalamus, and the ipsilateral cerebellum on T₂-weighted images. These regions are connected by glutamatergic pathways. Proton magnetic resonance spectroscopy (MRS) of the cortical lesion yielded a signal peak at the resonance frequency of 2.29 ppm, suggesting a focal increase of glutamate or its degradation product glutamine. At 3–month follow-up, structural alterations had disappeared, but the N-acetylaspartatelcholine ratio was still reduced in the previously abnormal area. These findings are the first to demonstrate the contribution of MRS to pathophysiologic studies of focal SE in humans and, in combination with the pattern of imaging abnormalities, support a major role of glutamate for seizure-related brain damage.