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Corpus callosal signal changes in patients with obstructive hydrocephalus after ventriculoperitoneal shunting.

BACKGROUND AND PURPOSE: Few reports have documented signal abnormalities within the corpus callosum on MR studies obtained after ventricular decompression in patients with hydrocephalus. Our purpose was to establish the frequency of this finding in shunted patients and attempt to elucidate its cause and clinical significance. METHODS: All patients with hydrocephalus shunted between 1989 and 1999 with postoperative MR studies available for review were included in the study group. Imaging analysis consisted of documenting hypointense signal on T1-weighted sagittal images and hyperintense signal on double-echo T2-weighted axial images within the corpus callosum. RESULTS: Characteristic signal abnormalities in the corpus callosum were noted in nine of 161 patients with shunted hydrocephalus studied with MR imaging. All nine patients were asymptomatic in regard to these MR findings. Comparison with preoperative scans and surgical records revealed that all patients with signal changes on postshunt scans had chronic obstructive hydrocephalus at presentation. Preshunt MR images were notable for marked elevation of the corpus callosum, which subsequently descended after ventricular decompression, suggesting that the cause of the signal changes was related to compression of the corpus callosum against the rigid falx. CONCLUSION: Signal abnormalities within the corpus callosum after ventricular shunting for obstructive hydrocephalus are not uncommon and are probably produced by compression of the corpus callosum against the falx before ventricular decompression. This distinctive appearance should not be mistaken for significant disease. Recognition of this pattern of signal abnormality will help avoid unnecessary intervention.

Adult↗

Developmental changes in line bisection: a result of callosal maturation?

Normal adults tend to bisect horizontal lines to the left of the objective middle, especially when using the left hand. This bias has been attributed to the dominance of the right hemisphere in spatial attention. The authors investigated the effect of hand use and line position in visual line bisection in right-handed children and adults, classified into 4 different age groups: 10-12, 13-15, 18-21, and 24-53 years (N = 98). All 4 groups showed the characteristic leftward bias when using the left hand. When using the right hand, the youngest group showed a rightward bias, whereas the other 3 groups all showed a leftward bias. This suggests a shift from contralateral to right-hemispheric control during puberty and may reflect maturation of the corpus callosum.

Adolescent↗

[Aplasia of the right internal carotid artery presenting with callosal hemorrhage: case report and review of the literature].

A 73-year-old woman without a history of cerebral ischemia suffered from sudden onset headache. Brain computed tomography (CT) showed intracerebral hemorrhage in the corpus callosum with intraventricular hemorrhage and thin subarachnoid hemorrhage in the basal cistern. Cerebral angiography showed narrowing of the right internal carotid artery just distal to its origin in the neck and abrupt occlusion just after branching of the ophthalmic artery with moyamoya-like vessels. The right A2 segment showed irregular dilatation and stenosis. The right middle cerebral artery was supplied from the basilar artery via the right posterior communicating artery. There was neither aneurysm nor arteriovenous malformation. Thin-slice bone-window CT of the skull base revealed hypoplasia of the right carotid canal. Aplasia of the right internal carotid artery was diagnosed. The origin of the hemorrhage was thought to be the irregularly opacified right A2 segment, which had been subjected to long-standing hemodynamic stress as collateral vessel.

Aged↗