title: Detecting subarachnoid hemorrhage: comparison of combined FLAIR/SWI versus CT.
abstract: OBJECTIVE
  Aim of this study was to compare the utility of susceptibility weighted imaging (SWI) with the established diagnostic techniques CT and fluid attenuated inversion recovery (FLAIR) in their detecting capacity of subarachnoid hemorrhage (SAH), and further to compare the combined SWI/FLAIR MRI data with CT to evaluate whether MRI is more accurate than CT.
  
  
  METHODS
  Twenty-five patients with acute SAH underwent CT and MRI within 6 days after symptom onset. Underlying pathology for SAH was head trauma (n=9), ruptured aneurysm (n=6), ruptured arteriovenous malformation (n=2), and spontaneous bleeding (n=8). SWI, FLAIR, and CT data were analyzed. The anatomical distribution of SAH was subdivided into 8 subarachnoid regions with three peripheral cisterns (frontal-parietal, temporal-occipital, sylvian), two central cisterns and spaces (interhemispheric, intraventricular), and the perimesencephalic, posterior fossa, superior cerebellar cisterns.
  
  
  RESULTS
  SAH was detected in a total of 146 subarachnoid regions. CT identified 110 (75.3%), FLAIR 127 (87%), and SWI 129 (88.4%) involved regions. Combined FLAIR and SWI identified all 146 detectable regions (100%). FLAIR was sensitive for frontal-parietal, temporal-occipital and Sylvian cistern SAH, while SWI was particularly sensitive for interhemispheric and intraventricular hemorrhage.
  
  
  CONCLUSIONS
  By combining SWI and FLAIR, MRI yields a distinctly higher detection rate for SAH than CT alone, particularly due to their complementary detection characteristics in different anatomical regions. Detection strength of SWI is high in central areas, whereas FLAIR shows a better detection rate in peripheral areas.
authors: University Institute of Diagnostic and Interventional Neuroradiology, Support Center for Advanced Neuroimaging, University of Bern, Inselspital, Freiburgstrasse 4, 3010 Bern, Switzerland. rajeev.verma@insel.ch
authors: Rajeev Kumar
authors: RK
authors: Verma
authors: Raimund
authors: R
authors: Kottke
authors: Lukas
authors: L
authors: Andereggen
authors: Christian
authors: C
authors: Weisstanner
authors: Christoph
authors: C
authors: Zubler
authors: Jan
authors: J
authors: Gralla
authors: Claus
authors: C
authors: Kiefer
authors: Johannes
authors: J
authors: Slotboom
authors: Roland
authors: R
authors: Wiest
authors: Gerhard
authors: G
authors: Schroth
authors: Christoph
authors: C
authors: Ozdoba
authors: Marwan
authors: M
authors: El-Koussy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis*; D013346:Subarachnoid Space / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
keywords: Computer tomography; Intracranial hemorrhage; Magnet resonance imaging; Subarachnoid hemorrhage; Susceptibility weighted imaging