[Cerebral perfusion computerized tomography in vasospasm after subarachnoid hemorrhage: diagnostic value of MTT].

Purpose: Analysis of the value of the perfusion parameter mean transit time (MTT) for the diagnosis of cerebral vasospasm after Subarachnoid Hemorrhage (SAH). Comparison with other perfusion parameters. An MTT threshold indicating the necessity of conventional angiography will be defined.

Determination of histopathological tumor grade in neuroepithelial brain tumors by using spectral pattern analysis of in vivo spectroscopic data.

Object: In this study, 1H magnetic resonance (MR) spectroscopy was prospectively tested as a reliable method for presurgical grading of neuroepithelial brain tumors.

Methods: Using a database of tumor spectra obtained in patients with histologically confirmed diagnoses, 94 consecutive untreated patients were studied using single-voxel 1H spectroscopy (point-resolved spectroscopy; TE 135 msec, TE 135 msec, TR 1500 msec). A total of 90 tumor spectra obtained in patients with diagnostic 1H MR spectroscopy examinations were analyzed using commercially available software (MRUI/VARPRO) and classified using linear discriminant analysis as World Health Organization (WHO) Grade I/II, WHO Grade III, or WHO Grade IV lesions.

Is V1 necessary for conscious vision in areas of relative cortical blindness?

Visual field defects result from postgeniculate lesions. It is generally assumed that absolute defects are caused by total destruction or denervation of primary visual cortex (V1) and that the degraded but conscious vision that remains or returns in relative or partial defects is mediated by compromised V1 cortex that retains a sufficiently large population of functional neurons. We here report the results of three patients with long-standing postgeniculate lesions who underwent functional magnetic resonance imaging while their partial defect was stimulated with high-contrast reversing checkerboard stimuli.