title: Susceptibility-weighted imaging is more reliable than T2*-weighted gradient-recalled echo MRI for detecting microbleeds.
abstract: OBJECTIVE
  We investigated the sensitivity and reliability of MRI susceptibility-weighted imaging (SWI) compared with routine MRI T2*-weighted gradient-recalled echo (GRE) for cerebral microbleed (CMB) detection.
  
  
  METHODS
  We used data from a prospective study of cerebral amyloid angiopathy (n=9; mean age, 71±8.3) and healthy non-cerebral amyloid angiopathy controls (n=22; mean age, 68±6.3). Three raters (labeled 1, 2, and 3) independently interpreted the GRE and SWI sequences (using the phase-filtered magnitude image) blinded to clinical information.
  
  
  RESULTS
  In 9 cerebral amyloid angiopathy cases, the raters identified 1146 total CMBs on GRE and 1432 CMBs on SWI. In 22 healthy control subjects, the raters identified ≥1 CMBs in 6/22 on GRE (total 9 CMBs) and 5/22 on SWI (total 19 CMBs). Among cerebral amyloid angiopathy cases, the reliability between raters for CMB counts was good for SWI (intraclass correlation coefficient, 0.87) but only moderate for GRE (intraclass correlation coefficient, 0.52). In controls, agreement on the presence or absence of CMBs in controls was moderate to good on both SWI (κ coefficient ranged from 0.57 to 0.74 across the 3 combinations of rater pairs) and GRE (κ range, 0.31 to 0.70). A review of 114 hypointensities identified as possible CMBs indicated that increased detection and reliability on SWI was related to both increased contrast and higher resolution, allowing better discrimination of CMBs from the background and better anatomic differentiation from pial vessels.
  
  
  CONCLUSIONS
  SWI confers greater reliability as well as greater sensitivity for CMB detection compared with GRE, and should be the preferred sequence for quantifying CMB counts.
authors.affiliation: From the Department of Radiology (A.-L.C., C.R.M., M.L.L., R.F., M.G., E.E.S.), Seaman Family MR Research Centre (S.B., C.R.M., M.L.L., R.F., M.G., E.E.S.), Hotchkiss Brain Institute (R.F., M.G., E.E.S.), and Department of Clinical Neurosciences, University of Calgary, Calgary, Canada (E.E.S.).
authors.forename: Ah-Ling
authors.initials: AL
authors.lastname: Cheng
authors.forename: Saima
authors.initials: S
authors.lastname: Batool
authors.forename: Cheryl R
authors.initials: CR
authors.lastname: McCreary
authors.forename: M L
authors.initials: ML
authors.lastname: Lauzon
authors.forename: Richard
authors.initials: R
authors.lastname: Frayne
authors.forename: Mayank
authors.initials: M
authors.lastname: Goyal
authors.forename: Eric E
authors.initials: EE
authors.lastname: Smith
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016657:Cerebral Amyloid Angiopathy / Q000150:complications / Q000000981:diagnostic imaging*; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging* / Q000209:etiology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: cerebral hemorrhage; magnetic resonance imaging; microbleeds