Intracranial aneurysms: endovascular evaluation with three-dimensional-display MR angiography.

To augment information at digital subtraction angiography, 17 patients with 22 intracranial aneurysms underwent three-dimensional-display magnetic resonance (MR) angiography. Reconstructions created to simulate vascular endoscopy provided additional information in 18 aneurysms about the aneurysmal sac, its orifice and neck, and/or its relation to the parent vessel and nearby vasculature. No additional information was provided in two aneurysms, and two aneurysms were not depicted.

Cerebellorubral degeneration after resection of cerebellar dentate nucleus neoplasms: evaluation with MR imaging.

The authors describe the magnetic resonance (MR) findings in seven patients who developed severe cerebellar symptoms and atrophy of the contralateral red nucleus following removal of unilateral neoplasms in the deep nuclei of the cerebellum. For most patients, pre- and postoperative spin-echo MR images were obtained with long repetition times (TRs) at 1.5 T. The long TR images obtained before surgery demonstrated unilateral masses involving the dentate nucleus. Long TR images obtained after surgical resection of the dentate nucleus showed increased signal intensity in all of seven contralateral red nuclei, three of seven ipsilateral superior cerebellar peduncles, and two of seven contralateral inferior olivary nuclei. Three other patients who underwent surgery for cerebellar neoplasms without resection of the dentate nuclei showed no postoperative brain stem changes on MR images. The authors speculate that the changes in the contralateral red nuclei are due to cerebellorubral degeneration (since well-described neural tracts interconnect the dentate nucleus and the contralateral red nucleus). Injury of the dentate nucleus may result in degeneration of distant neural connections.