title: Cerebral microbleeds on MR imaging: comparison between 1.5 and 7T.
abstract: OBJECTIVE
  The detection of microbleeds differs strongly between studies, due to differences in scan protocol. This study aims to compare the visualization of microbleeds with 3D T2*-weighted imaging at 1.5T with 3D dual-echo T2*-weighted imaging at 7T.
  
  
  METHODS
  Thirty-four patients (29 male; mean age, 58 ± 12 years) with atherosclerotic disease from the Second Manifestations of ARTerial Disease study were included. 3D T2*-weighted imaging at 1.5T and dual-echo T2*-weighted imaging at 7T were done in all patients. The presence and number of definite microbleeds were recorded on minimal intensity projections. Inter- and intraobserver reliability was assessed with Cohen κ test and the ICC. The difference in presence and number of microbleeds was tested with the McNemar test and Wilcoxon signed rank test.
  
  
  RESULTS
  The interobserver ICC at 7T was 0.61 and the intraobserver ICC was 0.94, whereas at 1.5T the interobserver ICC was 0.50 and the intraobserver ICC was 0.59. Microbleeds were detected in significantly more patients on 7T (50%) than on 1.5T scans (21%) (P = .001). The number of microbleeds was also higher at 7T (median, 0.5; range, 0-5) than on 1.5T (median, 0.0; range, 0-6) (P = .002).
  
  
  CONCLUSIONS
  3D dual-echo T2*-weighted imaging at 7T results in better and more reliable detection of microbleeds compared with 3D T2*-weighted imaging at 1.5T.
authors.affiliation: Department of Radiology, University Medical Center Utrecht, the Netherlands. m.conijn@umcutrecht.nl
authors.forename: M M A
authors.initials: MM
authors.lastname: Conijn
authors.forename: M I
authors.initials: MI
authors.lastname: Geerlings
authors.forename: G-J
authors.initials: GJ
authors.lastname: Biessels
authors.forename: T
authors.initials: T
authors.lastname: Takahara
authors.forename: T D
authors.initials: TD
authors.lastname: Witkamp
authors.forename: J J M
authors.initials: JJ
authors.lastname: Zwanenburg
authors.forename: P R
authors.initials: PR
authors.lastname: Luijten
authors.forename: J
authors.initials: J
authors.lastname: Hendrikse
mesh_terms: D000544:Alzheimer Disease / Q000150:complications* / Q000175:diagnosis*; D002543:Cerebral Hemorrhage / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity