title: Comparison of acquired diffusion weighted imaging and computed diffusion weighted imaging for detection of hepatic metastases.
abstract: OBJECTIVE
  To compare the accuracy of acquired diffusion weighted imaging (DWI) (b=1000 s/mm(2)) with that of computed DWI (b=1000 s/mm(2)) for the detection of hepatic metastases.
  
  
  METHODS
  Two hundred and sixty patients underwent abdominal magnetic resonance imaging (MRI) at 3.0 T for the evaluation of hepatic metastasis, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), heavily T2WI, DWI with b-values of 0, 500, 1000 s/mm(2), and three-dimensional dynamic contrast-enhanced MRI with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), and 190 patients were included in the final study. Computed DWI (=1000 s/mm(2)) was synthesized from lower b-values (b=0 and 500 s/mm(2)). Two groups were assigned and compared: group A (acquired DWI) and group B (computed DWI). Diagnostic performance using each imaging set was evaluated by receiver operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  A total of 76 hepatic metastases were confirmed. The area under the ROC curve (Az) of group A was larger than that of group B (Observer 1; 0.919-0.915, Observer 2; 0.926-0.901), but there were no significant differences (observer 1, P=0.500; observer 2, P=0.190). There were 5 metastases visualized in group A, but these were difficult to detect in group B. However, there were 2 metastases that were better visualized in group B than in group A.
  
  
  CONCLUSIONS
  There were no significant differences between acquired DWI and computed DWI in the detection of hepatic metastasis.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Japan. hshimizu@kuhp.kyoto-u.ac.jp
authors.forename: Hironori
authors.initials: H
authors.lastname: Shimizu
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Isoda
authors.forename: Koji
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Seiya
authors.initials: S
authors.lastname: Kawahara
authors.forename: Akihiro
authors.initials: A
authors.lastname: Furuta
authors.forename: Toshiya
authors.initials: T
authors.lastname: Shibata
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007564:Japan / Q000453:epidemiology; D008113:Liver Neoplasms / Q000453:epidemiology* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity