Magnetic resonance venogram of the intracranial circulation. Technique, anatomy, indications]

The authors standardized the MR-venography technique in 50 patients for the study of intracranial venous circulation and identified, for each vessel and district, the best acquisitions and rotations. The possible diagnostic applications of MR-angiography were also evaluated. The examinations were performed with a 1.5-T superconductive magnet (Magnetom, Siemens) and linear head coil. Fifty subjects were examined--40 healthy volunteers, 5 patients affected with multiple sclerosis (MS) and 5 patients with pathologic conditions of intracranial venous circulation. The 40 volunteers were studied with FISP 2D techniques; in 10 of them the images were acquired on the coronal plane, in 10 on the sagittal plane, in 10 on the axial plane, and in 10 on the axial plane after a 90 degrees saturation pulse to obtain saturation of the arterial signal. The FISP 3D sequence acquired on the axial plane and after i.v. gadolinium administration was used in the study of the 5 patients affected with MS. In the post-processing all the acquired images were rotated on the axial (z), sagittal (x), and coronal (y) axes, from 0 degrees to 180 degrees with a 15 degrees step. Data correlation showed that the veins of the postero-superior group were well visualized with 2D sequences on the sagittal plane and rotated, in the post-processing, on the z axis 0 degrees-180 degrees and on the coronal axis from -45 degrees to 45 degrees. The veins of the antero-inferior group were clearly demonstrated with 2D sequences acquired on the axial plane and after arterial saturation, rotated in the post-processing on the sagittal and coronal axes from -45 degrees to 45 degrees. Small veins--i.e., veins of the scalp, diploic and emissary veins, and inferior sagittal sinus--were well visualized with 2D sequences acquired on the coronal plane an rotated during post-processing on the z and x axes 0 degrees-180 degrees following i.v. injection of gadolinium. MR-venography is a new technique which can be useful to answer such specific diagnostic questions as the staging of brain neoplasm contiguous to intracranial venous vessels, the study of arteriovenous malformations and thrombosis on intracranial venous sinuses, as it has been demonstrated in 5 pathologic cases.