title: Neuroradiologic Diagnosis of Minor Leak prior to Major SAH: Diagnosis by T1-FLAIR Mismatch.
abstract: OBJECTIVE
  In major SAH, the only method to diagnose a preceding minor leak is to ascertain the presence of a warning headache by interview; however, poor clinical condition and recall bias can cause inaccuracy. We devised a neuroradiologic method to diagnose previous minor leak in patients with SAH and attempted to determine whether warning (sentinel) headaches were associated with minor leaks before major SAH.
  
  
  METHODS
  We retrospectively evaluated 127 patients who were admitted with SAH within 48 hours of ictus. Previous minor leak before major SAH was defined as T1WI-detected clearly bright hyperintense subarachnoid blood accompanied by SAH blood on FLAIR images that was distributed over a larger area than bright hyperintense subarachnoid blood on T1WI (T1-FLAIR mismatch).
  
  
  RESULTS
  The incidence of warning headache before SAH was 11.0% (14 of 127 patients, determined by interview). The incidence of T1-FLAIR mismatch (neuroradiologic diagnosis of minor leak before major SAH) was 33.9% (43 of 127 patients). Of the 14 patients with warning headache, 13 had a minor leak diagnosed by T1-FLAIR mismatch at the time of admission. Variables identified by multivariate analysis as significantly associated with minor leak diagnosed by T1-FLAIR mismatch included 80 years of age or older, rebleeding after admission, intracerebral hemorrhage on CT, and mRS scores of 3-6.
  
  
  CONCLUSIONS
  We conclude that warning headaches diagnosed by interview are not a product of recall bias but are the result of actual leaks from aneurysms.
authors.affiliation: From the Department of Neurosurgery (S.O., M.S., A.H., M.I., F.K., H.S., J.N.), Tokai University Hachioji Hospital, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Oda
authors.affiliation: From the Department of Neurosurgery (S.O., M.S., A.H., M.I., F.K., H.S., J.N.), Tokai University Hachioji Hospital, Tokyo, Japan mashimoda-nsu@umin.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Shimoda
authors.affiliation: From the Department of Neurosurgery (S.O., M.S., A.H., M.I., F.K., H.S., J.N.), Tokai University Hachioji Hospital, Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Hirayama
authors.affiliation: From the Department of Neurosurgery (S.O., M.S., A.H., M.I., F.K., H.S., J.N.), Tokai University Hachioji Hospital, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Imai
authors.affiliation: From the Department of Neurosurgery (S.O., M.S., A.H., M.I., F.K., H.S., J.N.), Tokai University Hachioji Hospital, Tokyo, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Komatsu
authors.affiliation: From the Department of Neurosurgery (S.O., M.S., A.H., M.I., F.K., H.S., J.N.), Tokai University Hachioji Hospital, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shigematsu
authors.affiliation: From the Department of Neurosurgery (S.O., M.S., A.H., M.I., F.K., H.S., J.N.), Tokai University Hachioji Hospital, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Nishiyama
authors.affiliation: Department of Neurosurgery (M.M.), Tokai University School of Medicine, Kanagawa, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Matsumae
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006261:Headache / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging / Q000379:methods; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis* / Q000209:etiology