title: Evaluation of malignant and benign renal lesions using diffusion-weighted MRI with multiple b values.
abstract: BACKGROUND
  Limited data are available regarding the use of diffusion-weighted (DW) magnetic resonance imaging (MRI) with multiple b values for characterization of renal lesions.
  
  
  OBJECTIVE
  To demonstrate and compare the diagnostic performance of DW-MRI with multiple b values for renal lesion characterization.
  
  
  METHODS
  Sixty-three lesions (36 malignant, 27 benign) in 60 consecutive patients (48 men, 12 women; age 60 ± 12.5 years) with solid/cystic renal lesion diagnosed after MRI were included prospectively. Single-shot echo-planar DW abdominal MRI (1.5T) was obtained using seven b values with eight apparent diffusion coefficient (ADC) maps. Contrast-to-noise ratios (CNRs), signal intensities, lesion ADCs, and lesion/normal parenchyma ADC ratios were analyzed. Receiver-operating characteristic analysis was performed.
  
  
  RESULTS
  The mean signal intensities of malignant lesions (at b0, 50, and 200s/mm(2)) were significantly lower than those of benign lesions (P < 0.05). The mean ADC values at all b value combinations of malignant lesions were significantly lower than those of benign lesions (P < 0.000), excluding the ADC value at b50 s/mm(2). ADC with all b values could better distinguish between benign and malignant lesions. A 1.35 × 10(-3) mm(2)/s threshold ADC value permitted this distinction with 85.2% sensitivity and 65.6% specificity. The lesion/normal parenchyma ADC ratio was more effective than the lesion ADC.
  
  
  CONCLUSIONS
  In addition to the ADC value, the signal intensity curve on DW images using multiple b values could be helpful for differentiation of malignant and benign renal lesions.
authors.affiliation: Faculty of Medicine, Department of Radiology, Baskent University, Ankara, Turkey.
authors.forename: Gurcan
authors.initials: G
authors.lastname: Erbay
authors.forename: Zafer
authors.initials: Z
authors.lastname: Koc
authors.forename: Elif
authors.initials: E
authors.lastname: Karadeli
authors.forename: Baris
authors.initials: B
authors.lastname: Kuzgunbay
authors.forename: M Resit
authors.initials: MR
authors.lastname: Goren
authors.forename: Nebil
authors.initials: N
authors.lastname: Bal
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007668:Kidney / Q000473:pathology; D007674:Kidney Diseases / Q000473:pathology*; D007680:Kidney Neoplasms / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D003287:Contrast Media