Variants of the basal vein of Rosenthal and perimesencephalic nonaneurysmal hemorrhage

BackgroundThe cause of perimesencephalic nonaneurysmal SAH or PMH is not known. Earlier studies reported a possible contribution of a primitive variant of the BVR in the pathogenesis of PMH. We compared the variants of BVR in a case control study between patients with PMH and aneurysmal SAH by studying the venous phase of the DSA.MethodsTwo observers reviewed the DSAs of 59 patients with PMH and 59 patients with aneurysmal SAH. The variants of BVR were classified into (1) normal continuous: BVR is continuous with the deep middle cerebral vein and drains mainly into the VG; (2) normal discontinuous: drainage anterior to uncal veins and posterior to the VG; and (3) primitive variant: drainage into veins other than the VG.ResultsOne hundred eighteen patients were enrolled, with a mean age of 49 ± 12 years. There were 31 men and 28 women in each group. Patients with PMH were older than patients with aneurysmal SAH (52 vs 46, P = .01). Primitive variants were found in 21% on the left side and 29% on the right side (P = .27). There was no association between PMH and the presence of a primitive variant on the left (25% in PMH vs 19% in aneurysmal SAH, P = .65) or on the right side (31% in PMH vs 30% in aneurysmal SAH, P = .92) in univariate analysis. After correction for age and sex, variants on neither side were associated with PMH (OR: 1.4, P = .53 for left variants and 1.2, P = .67 for right variants).ConclusionsIn this large controlled study, we were unable to confirm a contribution of a primitive variant of the BVR in the pathogenesis of PMH.