Nonaneurysmal Perimesencephalic Hemorrhage Is Associated with Deep Cerebral Venous Drainage Anomalies: A Systematic Literature Review and Meta-Analysis

Abstract

Background and purpose: Mechanisms underlying bleeding in nonaneurysmal perimesencephalic SAH remain unclear. Previous investigators have suggested a relationship between nonaneurysmal perimesencephalic SAH and primitive venous drainage of the basal vein of Rosenthal. We performed a meta-analysis to evaluate the relation between primitive basal vein of Rosenthal drainage and nonaneurysmal perimesencephalic SAH.

Materials and methods: We performed a comprehensive literature search of all studies examining the prevalence of primitive basal vein of Rosenthal drainage in patients with aneurysmal SAH and nonaneurysmal perimesencephalic SAH. Data collected were primitive basal vein of Rosenthal drainage (direct connection of perimesencephalic veins into the dural sinuses instead of the Galenic system) in at least 1 cerebral hemisphere, normal bilateral basal vein of Rosenthal drainage systems, and the number of overall primitive venous systems in the nonaneurysmal perimesencephalic SAH and aneurysmal SAH groups. Statistical analysis was performed by using a random-effects meta-analysis.

Results: Eight studies with 888 patients (334 with nonaneurysmal perimesencephalic SAH and 554 with aneurysmal SAH) and 1657 individual venous systems were included. Patients with nonaneurysmal perimesencephalic SAH were more likely to have a primitive basal vein of Rosenthal drainage in at least 1 hemisphere (47.7% versus 22.1%; OR, 3.31; 95% CI, 2.15-5.08; P < .01) and were less likely to have bilateral normal basal vein of Rosenthal drainage systems than patients with aneurysmal SAH (18.3% versus 37.4%; OR, 0.27; 95% CI, 0.14-0.52; P < .01). When we considered individual venous systems, there were higher rates of primitive venous systems in patients with nonaneurysmal perimesencephalic SAH than in patients with aneurysmal SAH (34.9% versus 15.3%; OR, 3.90; 95% CI, 2.37-6.43; P < .01).

Conclusions: Patients with nonaneurysmal perimesencephalic SAH have a higher prevalence of primitive basal vein of Rosenthal drainage in at least 1 hemisphere than patients with aneurysmal SAH. This finding suggests a venous origin of some nonaneurysmal perimesencephalic SAHs. A primitive basal vein of Rosenthal pattern is an imaging finding that has the potential to facilitate the diagnosis of nonaneurysmal perimesencephalic SAH.

Fig 2.

Lateral venous phase DSA images illustrating the different variants of the basal vein of Rosenthal: BVR (yellow arrows), vein of Galen (red arrow), and straight sinus (dark blue arrow). A, Type A (normal continuous pattern). The BVR is continuous and drains mainly posteriorly into the vein of Galen. B, Type B (normal discontinuous pattern). Discontinuous dual drainage of the BVR anterior into the cavernous sinus via the uncal vein and posterior to the vein of Galen. The green dotted line and the 2 green arrows illustrate anterior and posterior drainage. C, Type C (primitive pattern). BVR drains into veins (the uncal, anterior pontomesencephalic, or lateral mesencephalic veins or the tentorial sinus) other than the vein of Galen. The anterior segment of the BVR (yellow arrow) drains into the lateral mesencephalic vein to the petrosal sinus (light blue arrows), ultimately into the sigmoid sinus. The middle and posterior segments are absent (normal course is illustrated by the pink dotted line).

Fig 1.

Pattern of nonaneurysmal perimesencephalic hemorrhage. Nonaneurysmal perimesencephalic hemorrhage in a 54-year-old man with a headache after sneezing. The CT demonstrates blood isolated to the perimesencephalic cistern with some extension into the right ambient cistern. No blood is seen in the bilateral Sylvian fissures, and there was no intraventricular hemorrhage.

Fig 3.

Meta-analyses. A, Comparison of the proportion of patients with at least 1 primitive BVR drainage. B, Comparison of the proportion of patients with a normal bilateral BVR drainage pattern. C, Comparison of the proportion of abnormal BVR drainage by the venous system.