A true isolated cognitive relapse in multiple sclerosis.

Isolated cognitive relapses (ICRs) have been a matter of debate for the past few years. Currently, there is no clear consensus on such an entity, as cognitive decline usually accompanies typical multiple sclerosis (MS) relapses. Herein, we present the neuropsychological and neurophysiological manifestations of a patient who suddenly complained of confusion and memory loss, showing insight into her deficit, in absence of sensorimotor disturbances. Neuroimaging revealed a large tumefactive gadolinium-enhancing lesion localized in the left medial temporal lobe. The patient's symptoms persisted for months afterwards, despite corticosteroid treatment. We believe our patient experienced a true ICR. ICRs are rare entities in MS, but we should be alert to their existence in order to treat them promptly. Deepening their pathophysiology is equally important and neuropsychology combined with neurophysiology may be useful in this regard.

Grey matter volume alterations in CADASIL: a voxel-based morphometry study.

CADASIL is a hereditary disease characterized by cerebral subcortical microangiopathy leading to early onset cerebral strokes and progressive severe cognitive impairment. Until now, only few studies have investigated the extent and localization of grey matter (GM) involvement. The purpose of our study was to evaluate GM volume alterations in CADASIL patients compared to healthy subjects. We also looked for correlations between global and regional white matter (WM) lesion load and GM volume alterations. 14 genetically proved CADASIL patients and 12 healthy subjects were enrolled in our study. Brain MRI (1.5 T) was acquired in all subjects. Optimized-voxel based morphometry method was applied for the comparison of brain volumes between CADASIL patients and controls. Global and lobar WM lesion loads were calculated for each patient and used as covariate-of-interest for regression analyses with SPM-8. Compared to controls, patients showed GM volume reductions in bilateral temporal lobes (p < 0.05; FDR-corrected). Regression analysis in the patient group revealed a correlation between total WM lesion load and temporal GM atrophy (p < 0.05; uncorrected), not between temporal lesion load and GM atrophy. Temporal GM volume reduction was demonstrated in CADASIL patients compared to controls; it was related to WM lesion load involving the whole brain but not to lobar and, specifically, temporal WM lesion load. Complex interactions between sub-cortical and cortical damage should be hypothesized.

Identification of the pyramidal tract by neuronavigation based on intraoperative magnetic resonance tractography: correlation with subcortical stimulation.

OBJECTIVE: To demonstrate the accuracy of magnetic resonance tractograpghy (MRT) in localizing the cortical spinal tract (CST) close to brain tumours by using intraoperative electric subcortical stimulation. METHODS: Nine patients with intra-axial brain tumours underwent neurosurgery. Planning was based on analysis of the course of streamlines compatible with the CST. After tumour removal, intraoperative MRT was reacquired. Sites at various distance from the CST were repeatedly stimulated to assess whether registered motor evoked potential (MEP) could be elicited. All patients were assessed clinically both pre- and postoperatively. RESULTS: The motor function was preserved in all patients. In all patients intraoperative MRT demonstrated shift of the bundle position caused by the surgical procedure. The distance between the estimated intraoperative CST and the point of elicited MEP was 1 cm or less in all nine patients. At distances greater than 2 cm, no patient reported positive MEP. CONCLUSION: Intraoperative MRT is a reliable technique for localization of CST. In all patients MEP were elicited by direct subcortical electrical stimulation at a distance below 1 cm from the CST as represented by MRT. Brain shifting might impact this evaluation since CST position may change during surgery in the range of 8 mm.

Pre- and intraoperative tractographic evaluation of corticospinal tract shift.

BACKGROUND: Magnetic resonance with diffusion tensor image (DTI) may be able to estimate trajectories compatible with subcortical tracts close to brain lesions. A limit of DTI is brain shifting (movement of the brain after dural opening and tumor resection). OBJECTIVE: To calculate the brain shift of trajectories compatible with the corticospinal tract (CST) in patients undergoing glioma resection and predict the shift directions of CST. METHODS: DTI was acquired in 20 patients and carried out through 12 noncollinear directions. Dedicated software "merged" all sequences acquired with tractographic processing and the whole dataset was sent to the neuronavigation system. Preoperative, after dural opening (in 11) and tumor resection (in all) DTI acquisitions were performed to evaluate CST shifting. The extent of shifting was considered as the maximum distance between the preoperative and intraoperative contours of the trajectories. RESULTS: An outward shift of CST was observed in 8 patients and an inward shift in 10 patients during surgery. In the remaining 2 patients, no intraoperative displacement was detected. Only peritumoral edema showed a statistically significant correlation with the amount of shift. In those patients in which DTI was acquired after dural opening as well (11 patients), an outward shifting of CST was evident in that phase. CONCLUSION: The use of intraoperative DTI demonstrated brain shifting of the CST. DTI evaluation of white matter tracts can be used during surgical procedures only if updated with intraoperative acquisitions.