title: Nonaneurysmal Perimesencephalic Hemorrhage Is Associated with Deep Cerebral Venous Drainage Anomalies: A Systematic Literature Review and Meta-Analysis.
abstract: 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.
  
  
  
  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.
  
  
  
  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).
  
  
  
  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.
authors.affiliation: From the Departments of Radiology (A.R., V.TL., H.J.C., E.P.L., D.F.K., W.B.) aymeric.rouchaud@gmail.com.
authors.forename: A
authors.identifier: 0000-0003-0902-3375
authors.initials: A
authors.lastname: Rouchaud
authors.affiliation: From the Departments of Radiology (A.R., V.TL., H.J.C., E.P.L., D.F.K., W.B.).
authors.forename: V T
authors.identifier: 0000-0002-8713-8293
authors.initials: VT
authors.lastname: Lehman
authors.affiliation: Preventive Medicine and Center for the Science of Healthcare Delivery (M.H.M.).
authors.forename: M H
authors.identifier: 0000-0001-5502-5975
authors.initials: MH
authors.lastname: Murad
authors.affiliation: Neurosurgery (A.B.)., Mayo Clinic, Rochester, Minnesota.
authors.forename: A
authors.identifier: 0000-0002-0468-4070
authors.initials: A
authors.lastname: Burrows
authors.affiliation: From the Departments of Radiology (A.R., V.TL., H.J.C., E.P.L., D.F.K., W.B.).
authors.forename: H J
authors.identifier: 0000-0003-2590-3815
authors.initials: HJ
authors.lastname: Cloft
authors.affiliation: From the Departments of Radiology (A.R., V.TL., H.J.C., E.P.L., D.F.K., W.B.).
authors.forename: E P
authors.identifier: 0000-0002-4228-895X
authors.initials: EP
authors.lastname: Lindell
authors.affiliation: From the Departments of Radiology (A.R., V.TL., H.J.C., E.P.L., D.F.K., W.B.).
authors.forename: D F
authors.identifier: 0000-0002-8495-0040
authors.initials: DF
authors.lastname: Kallmes
authors.affiliation: From the Departments of Radiology (A.R., V.TL., H.J.C., E.P.L., D.F.K., W.B.).
authors.forename: W
authors.identifier: 0000-0001-5271-5524
authors.initials: W
authors.lastname: Brinjikji
mesh_terms: D002550:Cerebral Veins / Q000002:abnormalities*; D006801:Humans; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000209:etiology*