title: Irregular Shape of Intracranial Aneurysm Indicates Rupture Risk Irrespective of Size in a Population-Based Cohort.
abstract: Size and shape of saccular intracranial aneurysms (sIA) reflect the condition of the sIA wall and were risk factors for rupture in previous follow-up studies. We investigated how well size or shape identify rupture-prone sIAs.
  
  
  
  In a population-based registry, we investigated the characteristics of ruptured sIAs treated in a single neurosurgical center (1980-2014). In addition to univariate analysis, logistic regression was used in multivariate analysis, and sensitivity and specificity of size or shape were calculated using receiver operating characteristic curves.
  
  
  
  Ruptured sIAs were on average larger than unruptured sIAs (median, 7 versus 4 mm; P<0.000), but location and patient background affected the size at rupture. Of the ruptured sIAs, 38% were smaller than 7 mm and 18% were smaller than 4 mm. Of those sIAs that had ruptured at a small (<7 mm) size, 87% had an irregular shape. In multivariate analysis, irregular shape had the strongest association with presentation as ruptured sIA (odds ratio, 7.1; 95% confidence interval, 6.0-8.3), with better sensitivity (91%) and specificity (76%), in contrast to smoking (odds ratio, 0.7; 95% confidence interval, 0.6-0.9; sensitivity, 28%; specificity 57%) and Population, Hypertension, Age, Size of sIA, Earlier SAH from another sIA, Site of sIA score (odds ratio, 1.5; 95% confidence interval, 1.4-1.6).
  
  
  
  Irregular or multilobular shape is strongly associated with rupture in sIAs of all sizes and independent of location and patient background. Especially sIAs with irregular shape should be considered as high rupture risk lesions, even if small in diameter and in nonsmoking patients with low PHASES scores.
authors.affiliation: From the Department of Neurosurgery, KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland (A.E.L., T.K., J.B., M.v.u.z.F., K.H., J.E.J., J.F.); Department of Neurosurgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland (T.K., M.v.u.z.F., J.E.J., J.F.); and Kuopio Intracranial Aneurysm Database (A.E.L., T.K., M.v.u.z.F., K.H., J.E.J.) and Hemorrhagic Brain Pathology Research Group (A.E.L., J.B., J.F.), KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Antti E
authors.initials: AE
authors.lastname: Lindgren
authors.affiliation: From the Department of Neurosurgery, KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland (A.E.L., T.K., J.B., M.v.u.z.F., K.H., J.E.J., J.F.); Department of Neurosurgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland (T.K., M.v.u.z.F., J.E.J., J.F.); and Kuopio Intracranial Aneurysm Database (A.E.L., T.K., M.v.u.z.F., K.H., J.E.J.) and Hemorrhagic Brain Pathology Research Group (A.E.L., J.B., J.F.), KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Timo
authors.initials: T
authors.lastname: Koivisto
authors.affiliation: From the Department of Neurosurgery, KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland (A.E.L., T.K., J.B., M.v.u.z.F., K.H., J.E.J., J.F.); Department of Neurosurgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland (T.K., M.v.u.z.F., J.E.J., J.F.); and Kuopio Intracranial Aneurysm Database (A.E.L., T.K., M.v.u.z.F., K.H., J.E.J.) and Hemorrhagic Brain Pathology Research Group (A.E.L., J.B., J.F.), KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Joel
authors.initials: J
authors.lastname: Björkman
authors.affiliation: From the Department of Neurosurgery, KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland (A.E.L., T.K., J.B., M.v.u.z.F., K.H., J.E.J., J.F.); Department of Neurosurgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland (T.K., M.v.u.z.F., J.E.J., J.F.); and Kuopio Intracranial Aneurysm Database (A.E.L., T.K., M.v.u.z.F., K.H., J.E.J.) and Hemorrhagic Brain Pathology Research Group (A.E.L., J.B., J.F.), KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Mikael
authors.initials: M
authors.lastname: von Und Zu Fraunberg
authors.affiliation: From the Department of Neurosurgery, KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland (A.E.L., T.K., J.B., M.v.u.z.F., K.H., J.E.J., J.F.); Department of Neurosurgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland (T.K., M.v.u.z.F., J.E.J., J.F.); and Kuopio Intracranial Aneurysm Database (A.E.L., T.K., M.v.u.z.F., K.H., J.E.J.) and Hemorrhagic Brain Pathology Research Group (A.E.L., J.B., J.F.), KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Katariina
authors.initials: K
authors.lastname: Helin
authors.affiliation: From the Department of Neurosurgery, KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland (A.E.L., T.K., J.B., M.v.u.z.F., K.H., J.E.J., J.F.); Department of Neurosurgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland (T.K., M.v.u.z.F., J.E.J., J.F.); and Kuopio Intracranial Aneurysm Database (A.E.L., T.K., M.v.u.z.F., K.H., J.E.J.) and Hemorrhagic Brain Pathology Research Group (A.E.L., J.B., J.F.), KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Juha E
authors.initials: JE
authors.lastname: Jääskeläinen
authors.affiliation: From the Department of Neurosurgery, KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland (A.E.L., T.K., J.B., M.v.u.z.F., K.H., J.E.J., J.F.); Department of Neurosurgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland (T.K., M.v.u.z.F., J.E.J., J.F.); and Kuopio Intracranial Aneurysm Database (A.E.L., T.K., M.v.u.z.F., K.H., J.E.J.) and Hemorrhagic Brain Pathology Research Group (A.E.L., J.B., J.F.), KUH NeuroCenter, Kuopio University Hospital, Kuopio, Finland. juhana.frosen@kuh.fi.
authors.forename: Juhana
authors.initials: J
authors.lastname: Frösen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging* / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012042:Registries; D012306:Risk
keywords: aneurysm; intracranial aneurysm; registries; rupture; subarachnoid hemorrhage