title: Grading of small hepatocellular carcinomas (≤2 cm): correlation between histology, T2 and diffusion-weighted imaging.
abstract: OBJECTIVE
  To evaluate the capacity of diffusion-weighted imaging (DWI) to determine the histological grade of small-sized hepatocellular carcinomas (HCCs) in liver cirrhosis in comparison with T2 weighted imaging.
  
  
  METHODS
  51 cirrhotic patients with 63 histologically proven HCCs ≤2 cm underwent abdominal MRI, including DWI (b-values 50, 400 and 800 s mm(-2)) and T2 weighted sequences. HCCs were classified into well-differentiated HCCs (n = 37) and moderately differentiated HCCs (n = 26). Relative contrast ratios (RCRs) between the lesions and the surrounding liver were performed and compared between the two groups for T2 weighted images, each b-value and apparent diffusion coefficients (ADCs). A receiver operating characteristic (ROC) analysis was performed to compare RCRs in T2 and diffusion-weighted images.
  
  
  RESULTS
  We found significant differences in RCRs between well-differentiated vs moderately differentiated HCCs for b = 50, 400 and 800 s mm(-2) and T2 weighted images (1.35 ± 0.36 vs 1.86 ± 0.62; 1.35 ± 0.38 vs 1.82 ± 0.60; 1.27 ± 0.30 vs 1.74 ± 0.53; 1.14 ± 0.18 vs 1.43 ± 0.28, respectively; p < 0.001), whereas no significant differences were observed in ADC and ADC RCR (1.05 ± 0.19 vs 0.99 ± 0.15 and 1.1 ± 0.22 vs 1.09 ± 0.23; p = 0.16 and p = 0.82, respectively). No significant difference was found in the areas under the ROC curve for RCRs of T2 weighted images and every DWI b-value (p = 0.18).
  
  
  CONCLUSIONS
  The RCR measurement performed in DWI 50, 400 and 800 b-values and T2 demonstrated a significant difference between well-differentiated and moderately differentiated small-sized HCCs. Furthermore, no difference was shown by using either ADC or ADC RCR.
  
  
  CONCLUSIONS
  DWI with RCR measurement may be a valuable tool for non-invasively predicting the histological grade of small HCCs.
authors.affiliation: 1 Department of Radiology, Desgenettes Military Teaching Hospital, Lyon, France.
authors.forename: F
authors.initials: F
authors.lastname: Le Moigne
authors.forename: L
authors.initials: L
authors.lastname: Boussel
authors.forename: A
authors.initials: A
authors.lastname: Haquin
authors.forename: B
authors.initials: B
authors.lastname: Bancel
authors.forename: C
authors.initials: C
authors.lastname: Ducerf
authors.forename: Y
authors.initials: Y
authors.lastname: Berthezène
authors.forename: A
authors.initials: A
authors.lastname: Rode
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000150:complications / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008103:Liver Cirrhosis / Q000150:complications / Q000473:pathology; D008113:Liver Neoplasms / Q000150:complications / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012680:Sensitivity and Specificity