title: Can noninvasive imaging accurately depict intracranial aneurysms? A systematic review.
abstract: OBJECTIVE
  To perform a systematic review to determine the accuracy of computed tomographic (CT) angiography, magnetic resonance (MR) angiography, and transcranial Doppler ultrasonography (US) in depicting intracranial aneurysms.
  
  
  METHODS
  A 1988-1998 literature search for studies with 10 or more subjects in which noninvasive imaging was compared with angiography was undertaken. Studies meeting initial criteria were evaluated by using intrinsically weighted standardized assessment to determine suitability for inclusion. Studies scoring greater than 50% were included.
  
  
  RESULTS
  Of 103 studies that met initial criteria, 38 scored greater than 50%. CT angiography and MR angiography had accuracies per aneurysm of 89% (95% CI: 87%, 91%) and 90% (95% CI: 87%, 92%), respectively. For US, data were scanty and accuracy was lower, although the CIs overlapped those of CT angiography and MR angiography. Sensitivity was greater for detection of aneurysms larger than 3 mm than for detection of aneurysms 3 mm or smaller-for CT angiography, 96% (95% CI: 94%, 98%) versus 61% (95% CI: 51%, 70%), and for MR angiography, 94% (95% CI: 90%, 97%) versus 38% (95% CI: 25%, 53%). Diagnostic accuracy was similar for anterior and posterior circulation aneurysms.
  
  
  CONCLUSIONS
  CT angiography and MR angiography depicted aneurysms with an accuracy of about 90%. Most studies were performed in populations with high aneurysm prevalence, which may have introduced bias toward noninvasive examinations.
authors.affiliation: Depts of Neurosurgery and Neuroradiology, Institute of Neurological Sciences, Southern General Hosp, Glasgow, Scotland. pmw@skull.dcn.ed.ac.uk
authors.forename: P M
authors.initials: PM
authors.lastname: White
authors.forename: J M
authors.initials: JM
authors.lastname: Wardlaw
authors.forename: V
authors.initials: V
authors.lastname: Easton
mesh_terms: D002533:Cerebral Angiography; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D017585:Ultrasonography, Doppler, Transcranial