Magnetic resonance (MR) imaging was performed in 94 patients who sustained closed head injury of varying severity. Results of MR studies obtained after the intensive care phase of treatment disclosed that intracranial lesions were present in about 88% of the patients. Consistent with the centripetal model of progressive brain injury proposed in 1974 by Ommaya and Gennarelli, the depth of brain lesion was positively related to the degree and duration of impaired consciousness. Further analysis indicated that the relationship between depth of brain lesion and impaired consciousness could not be attributed to secondary effects of raised intracranial pressure or to the size of intracranial lesion(s).

To investigate evidence for diffuse white matter injury and hemispheric disconnection sequelae after severe closed head injury (CHI), this study evaluates the degree of posttraumatic atrophy of the corpus callosum. Corpus callosal atrophy was quantitatively determined using a digitizer to measure sagittal magnetic resonance images of 32 patients with moderate-to-severe CHI and those of 31 control subjects of similar age. In the CHI patients, measurements were significantly reduced for the areas of the anterior four-fifths, the posterior one-fifth, and the total corpus callosum. Moreover, the minimum width of the callosal body was reduced in the CHI patients as compared to that of control individuals. Indices of corpus callosal atrophy were significantly correlated with the chronicity of injury and the degree of lateral ventricular enlargement. There was no difference in callosal measurements between men and women. Magnetic resonance imaging provides an in vivo determination of corpus callosal atrophy which may reflect the severity of diffuse axonal injury and predict the type and severity of hemispheric disconnection effects.

Three cases of documented sarcoid meningoencephalitis were reviewed. Computed tomography (CT) showed enhancing, perivascular, linear, and nodular areas along the subarachnoid space, extending deep into the white matter. In one case the perivascular granulomatous infiltration, which caused small vessel periangiitis, gave rise to a CT pattern closely resembling that of arteriovenous malformation or infarction with gyral enhancement. This infiltrative pattern might be seen in other chronic meningeal processes. The pathophysiology responsible for the unusual CT appearance and the differential diagnosis are discussed.

The authors prospectively evaluated 82 neonates, ranging in gestational age from 29 to 44 weeks postconception, with magnetic resonance (MR) imaging at 0.6 T. Twenty-two cases of hemorrhage in 15 infants were identified. Ultrasound (US) and computed tomography (CT) were superior to MR in the first few days after parenchymal hemorrhage, since at this time lesions were apparent on only T2-weighted images. After the first 3 days, MR was the single best modality because (a) hemorrhage on CT became imperceptible in the 2d week, whereas the high signal of hemorrhage on MR persisted for 2-11 weeks; (b) MR permitted rough dating of hemorrhage according to changes in signal intensity; and (c) MR was superior in identifying subdural or epidural hemorrhage. Because of the nonspecificity and restricted field of view of US and the inability of CT to depict hemorrhage after 7-10 days, the authors conclude that MR significantly improves the detection of intracranial hemorrhage in neonates.

The importance of stereotactic aspiration to the successful management of three cases of brain stem abscess is discussed with special reference to the advantages offered over medical treatment alone. Stereotactic aspiration allows evacuation of pus, accurate bacteriological diagnosis, selection of an optimal antibiotic regimen, and instillation of antibiotics directly into the abscess cavity. In two of the three cases described here, the abscess reaccumulated after initial aspiration despite appropriate maximal medical therapy. A repeat aspiration was required before resolution occurred. We conclude that medical management alone is not adequate for some cases of brain stem abscess. There was no morbidity that could be attributed to the procedure, suggesting that the risk of stereotactic aspiration is probably quite low and is likely to be less than the risk of incorrect diagnosis, suboptimal choice of antibiotics, or progression of the lesion despite appropriate maximal medical therapy.