title: Diffusion-weighted single-shot echoplanar MR imaging for liver disease.
abstract: OBJECTIVE
  The aims of this study were to determine apparent diffusion coefficients (ADCs) of the abdominal organs and liver lesions, to determine the effect of the magnitude of b values on the ADCs, and to determine whether measured ADCs of liver tumors help differentiate benign from malignant lesions.
  
  
  METHODS
  Six healthy volunteers and 126 patients were examined with diffusion-weighted single-shot echo-planar imaging using multiple b values (maximum, 846 sec/mm2). The ADCs of the liver, spleen, kidney, 49 malignant liver lesions (33 hepatocellular carcinomas, 15 metastatic liver tumors, and one cholangiocellular carcinoma), and 30 benign lesions (17 cysts, 12 hemangiomas, and one angiomyolipoma) were calculated.
  
  
  RESULTS
  The ADCs of the abdominal organs and liver lesions showed smaller values when calculated with the greater maximum b values. The ADCs of the benign lesions calculated with all the b values of less than 850 sec/mm2 (2.49+/-1.39 x 10(-3) mm2/sec) were significantly (p = .0024) greater than those of the malignant lesions (1.01+/-0.38 x 10(-3) mm2/sec). When the maximum b value is 846 sec/mm2, use of a threshold ADC of 1.6 x 10(-3) mm2/sec would result in a sensitivity of 98% and a specificity of 80% for differentiation of malignant liver lesions from benign lesions.
  
  
  CONCLUSIONS
  Measurement of ADC has good potential for characterizing liver lesions, but the calculated ADCs could be affected by the magnitude of the maximum b value.
authors.affiliation: Department of Radiology, Osaka University Medical School, Suita City, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kim
authors.forename: T
authors.initials: T
authors.lastname: Murakami
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Hori
authors.forename: K
authors.initials: K
authors.lastname: Tsuda
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D017352:Echo-Planar Imaging / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016014:Linear Models; D008099:Liver / Q000473:pathology; D008107:Liver Diseases / Q000175:diagnosis*; D008113:Liver Neoplasms / Q000175:diagnosis / Q000556:secondary; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging / Q000706:statistics & numerical data; D018709:Statistics, Nonparametric; D014781:Viscera / Q000473:pathology