title: Comparison of apparent diffusion coefficient calculation between two-point and multipoint B value analyses in prostate cancer and benign prostate tissue at 3 T: preliminary experience.
abstract: OBJECTIVE
  The purpose of this study was to prospectively evaluate the reliability and variability of apparent diffusion coefficient (ADC) calculations between two-point and multipoint b value analyses in prostate cancer and benign prostate tissue.
  
  
  METHODS
  Forty-eight consecutive patients with suspected prostate cancer underwent diffusion-weighted MRI (DWI) at 3 T followed by surgery. DWI was examined under different b values. ADC maps were generated by two different methods: two-point b values (0 and 1000 s/mm(2)) and multipoint b values (0, 100, 300, 700, and 1000 s/mm(2)). Two independent readers measured ADC in the cancers, benign peripheral zone and transition zone, and obturator internus muscle. Statistical analyses were performed using the intraclass correlation coefficient (ICC), correlation of variation (CV), Bland-Altman test, and paired Student t test.
  
  
  RESULTS
  The intermethod ADC calculation revealed excellent reliability for all tissues in both readers: cancer (ICC = 0.979-0.981), transition zone (0.989-0.993), peripheral zone (0.990-0.994), and obturator internus muscle (0.967-0.975). In both readers, the variability of the intermethod ADC calculation was 2.90-3.09% CV in cancer, 1.16-1.48% CV in the transition zone, 1.03-1.29% CV in the peripheral zone, and 2.44-2.62% CV in the obturator internus muscle. For interreader variability, the CVs of ADC calculation for two-point versus multipoint b value analyses in all tissues were 7.21-9.65% versus 7.18-9.01%.
  
  
  CONCLUSIONS
  For estimating ADC values on 3-T DWI of the prostate, two-point b value analysis seems to present excellent correlation with multipoint b value analysis, with little error in accuracy.
authors.affiliation: 1 Department of Radiology and Center for Imaging Science, Samsung Medical Center, 50 Ilwon-dong, Gangnam-gu, Seoul, Korea 135-710.
authors.forename: Sung Yoon
authors.initials: SY
authors.lastname: Park
authors.forename: Chan Kyo
authors.initials: CK
authors.lastname: Kim
authors.forename: Byung Kwan
authors.initials: BK
authors.lastname: Park
authors.forename: Ghee Young
authors.initials: GY
authors.lastname: Kwon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009716:Numerical Analysis, Computer-Assisted; D010865:Pilot Projects; D011471:Prostatic Neoplasms / Q000145:classification / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: apparent diffusion coefficient (ADC); comparative study; diffusion-weighted MRI (DWI); prostate