title: Value of gadoxetic acid-enhanced and diffusion-weighted MR imaging in evaluation of hepatocellular carcinomas with atypical enhancement pattern on contrast-enhanced multiphasic MDCT in patients with chronic liver disease.
abstract: OBJECTIVE
  The purpose of this study was to investigate the value of enhancement kinetics and ancillary imaging findings on gadoxetic acid-enhanced and diffusion-weighted (DW) MR imaging for diagnosing hepatocellular carcinomas (HCCs) without the typical enhancement pattern on contrast-enhanced multiphasic MDCT in patients with chronic liver disease.
  
  
  METHODS
  Eighty-two surgically confirmed HCCs without the typical enhancement pattern (hypervascular in the arterial phase, followed by washout on the portal or equilibrium phases) on triple-phase MDCT were enrolled in this study. The patients were classified into four categories based on the CT density pattern of arterial and equilibrium phases (isodense-isodense, hypodense-hypodense, isodense-hypodense, and hyperdense-isodense) compared to liver parenchyma. Signal intensity of HCCs on T2-weighted images (T2WI), arterial phase, 3 min late-phase, hepatobiliary phase (HBP) and DW images with a b value of 800 s/mm2 were qualitatively evaluated, and ADC values were measured. Fisher's exact test and Chi-square test were used to compare the frequency and trend of hyperintensity on T2WI, hypointensity on HBP images, hyperintensity on DW images, and histopathologic grades between groups with different CT density patterns. Kruskal-Wallis test was used to compare the ADC value between groups.
  
  
  RESULTS
  Thirty and 52 HCCs were categorized as hypervascular (hyperdense-isodense) and non-hypervascular HCCs (3, isodense-isodense; 37, hypodense-hypodense; 12, isodense-hypodense), respectively. Most HCCs showed hyperintensity on T2WI (77/82, 93.9%) and DW images (81/82, 98.8%) and hypointensity on HBP images (80/82, 97.6%). Thirty-eight HCCs (38/82, 46.3%) showed typical HCC enhancement pattern on dynamic MR images. There were no significant differences in the frequency and trend of signal intensity on T2WI, HBP images, DW images, and histopathologic grades with regard to the four CT density patterns (p<0.05). No significant difference in mean ADC values between groups was identified (p<0.05).
  
  
  CONCLUSIONS
  Gadoxetic acid-enhanced and DW MR imaging can help diagnose HCCs with atypical enhancement patterns on multiphasic CT in patients with chronic liver disease.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, South Korea.
authors.forename: Hyun Su
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, South Korea. Electronic address: kshyun@skku.edu.
authors.forename: Seong Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, South Korea.
authors.forename: Tae Wook
authors.initials: TW
authors.lastname: Kang
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, South Korea.
authors.forename: Kyoung Doo
authors.initials: KD
authors.lastname: Song
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, South Korea.
authors.forename: Dongil
authors.initials: D
authors.lastname: Choi
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul 135-710, South Korea.
authors.forename: Cheol Keun
authors.initials: CK
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000473:pathology; D016009:Chi-Square Distribution; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D058625:End Stage Liver Disease / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA
keywords: Enhanced MRI; Gadoxetic acid; Hepatocellular carcinoma; MDCT