title: Diffusion-weighted MRI and optimal b-value for characterization of liver lesions.
abstract: BACKGROUND
  Diffusion-weighted imaging (DWI) is commonly used to distinguish between benign and malignant liver lesions. However, different b-values are recommended.
  
  
  OBJECTIVE
  To determine the most suitable b-value in DWI for differentiation of benign and malignant liver lesions.
  
  
  METHODS
  A total of 124 lesions in 89 consecutive patients (43 men, 46 women; age, mean ± standard deviation, 58 ± 14 years) with a pathological or radiological diagnosis of malignant or benign focal liver lesions after magnetic resonance imaging (MRI) were included in this study. Routine abdominal MRI and DWI were performed using seven b-values (0, 50, 200, 400, 600, 800, 1000 s/mm(2)). Lesions were analyzed for benignity/malignity using apparent diffusion coefficient (ADC) values with 10 b-value combinations and by measuring the lesion/normal parenchyma ADC ratio.
  
  
  RESULTS
  Mean ADC values were significantly different between malignant and benign lesions for all b-value combinations (P=0.000). The best b-value combination was 0 and 800 (Az=0.935). Using lower b-values such as 0 and 50 together with higher b-values ≥ 600 s/mm(2) was beneficial (Az=0.928 and 0.927). Mean ADC values were approximately 13% (1-15%) higher in total when b=0 and b=50 s/mm(2) were included in multiple b-value combinations.
  
  
  CONCLUSIONS
  In DWI, we recommend the use of b-values of 0 and 800 s/mm(2) as two b-values, or b=0, 50, 600, 800, and 1000 s/mm(2) as multiple b-values for distinguishing between benign and malignant liver lesions. Mean ADC value is 13% higher in total by additional use of b=0 and b=50 s/mm(2) in multiple b-value combinations.
authors: Department of Radiology, Faculty of Medicine, Baskent University, Ankara, Turkey Present address: Radiology, Siirt Government Hospital, Ministry of Health, Siirt, Turkey.
authors: Bilal
authors: B
authors: Kaya
authors: Department of Radiology, Faculty of Medicine, Baskent University, Ankara, Turkey koczafer@gmail.com.
authors: Zafer
authors: Z
authors: Koc
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media
keywords:     b-value; Optimization; cholangiocellular cancer; diffusion-weighted imaging (DWI); focal lesions; hepatocellular cancer; liver; magnetic resonance imaging (MRI); metastasis