Behavioral manifestations, electroencephalograms (EEGs) and visually evoked potentials (VEPs) were studied in beagles with Eck's fistula (portacaval shunt [PCS]), an established model of hyperammonemia, to determine whether they developed CNS disorders characteristic of hepatic encephalopathy. After PCS, behavioral changes occurred in the form of listlessness, sluggishness (altered gait, snapping and transient catatonia-like symptoms) and apparent blindness, which appeared in that order and progressed to coma and death in some animals. The EEGs from the frontal cortex showed a gradual decrease in voltage and frequency. Development of snapping and catatonia-like symptoms coincided with the occurrence of high voltage fast waves in the EEGs from the occipital cortex. In comatose Eck's fistula dogs. flattening of the EEGs was recorded from the frontal cortex and a lowered voltage was noted in the EEGs from the occipital cortex. After PCS, the latencies and amplitudes of the components of VEP were increased. The snapping and catatonia-like symptoms were markedly ameliorated by carbamazepine and the coma by flumazenil and thyrotropin-releasing hormone. These findings indicate that Eck's fistula dogs provide a useful model of hepatic encephalopathy.

Ammonia↗

PubMedDate not supplied

Pericallosal lipomas: MR features.

We report on six cases of pericallosal lipomas. The T1-weighted sagittal images best demonstrated the relationship between the lipoma and the corpus callosum. In four cases the lipomas surrounded the splenium of the corpus callosum and in two cases the tumors were situated posteriorly and caudally to the splenium. In no case did we encounter an exclusively dorsal pericallosal localization.

Adolescent↗

PubMedDate not supplied

Contrast-enhanced fluid-attenuated inversion recovery MRI is useful to detect the CSF dissemination of glioblastoma.

We present three cases of glioblastoma with CSF dissemination that contrast-enhanced fluid-attenuated inversion recovery MRI was sensitive enough to detect compared with contrast-enhanced T1-weighted MRI. An autopsy was performed on one patient, and its histologic findings proved the existence of CSF dissemination.

Adolescent↗

PubMedDate not supplied

Contrast enhancement of cystic portions in brain tumors on delayed image of gadolinium-DTPA-enhanced MR imaging.

This report describes three patients whose cystic portions were filled with intravenously injected Gadolinium-DTPA. Four cystic portions showed contrast enhancement of the whole wall on early MR images and enhancement of the content on delayed MR images. Two cystic portions showed no enhancement of content. We speculate that the difference is based upon the composition of the cyst walls.

Adolescent↗

PubMedDate not supplied

MR imaging of primary intracranial malignant lymphoma.

Magnetic resonance imaging (MRI) was performed in ten patients with intracranial lymphoma. Seven were pathologically confirmed and three were clinically diagnosed. Nineteen lesions were found among the ten cases. None had acquired immunodeficiency syndrome (AIDS) or had received immunosuppression therapy. Two lesions were in the lateral and third ventricles, and the others were predominantly in the corpus callosum, deep white matter, or central gray matter. Four patients had multiple lesions. All had mild to severe edema. On T1-weighted images, all lesions showed hypointensity. On T2-weighted images, three lesions showed definite hypointensity to gray matter, and the others showed hyperintensity. The contour of all lesions was well demarcated from the surrounding edema. Eight cases were scanned before and after intravenous administration of 0.1 mmol/kg of gadolinium-dimethylene triaminepentaacetic acid (Gd-DTPA), and all exhibited homogeneous enhancement. Three cases showed blurred enhancement margins. Four cases showed hemorrhage, and the frequency of hemorrhage was higher than in previous reports. Pathological examination was performed in seven cases. All showed dense concentric lymphoma cells without necrosis. There was no pathological difference between the hyperintense and hypointense lesions on T2-weighted images.

Adult↗

PubMedDate not supplied

MR diagnosis of myelofibrosis.

We present a case of secondary myelofibrosis in which magnetic resonance imaging (MRI) contributed to the diagnosis. On both T1- and T2-weighted images, bone marrow showed hypointensity. However, since blood transfusion therapy was performed prior to MRI, it was necessary to differentiate fibrosis from siderotic marrow. On gradient echo (GRASS) images, bone marrow also showed hypointensity, but not as prominent as that seen in siderotic marrow. After intravenous administration of gadolinium-dimethylene triaminepentaacetic acid (Gd-DTPA), enhancement of the marrow space may be induced by a fibrous change of the marrow. MR findings were confirmed by histological examination of the biopsy specimen.

Adolescent↗