title: Multiphasic MDCT enhancement pattern of hepatocellular carcinoma smaller than 3 cm in diameter: tumor size and cellular differentiation.
abstract: OBJECTIVE
  The purpose of this study was to evaluate according to size and degree of cellular differentiation the multiphasic MDCT enhancement pattern of hepatocellular carcinoma (HCC) smaller than 3 cm in diameter in patients with cirrhosis.
  
  
  METHODS
  In 155 consecutively registered patients (126 men, 29 women; mean age, 58.4 years), 204 pathologically proven HCCs smaller than 3 cm were detected at multiphasic MDCT. Three radiologists in consensus classified the relative attenuation of the tumors compared with the surrounding liver parenchyma as hyperattenuation, isoattenuation, or hypoattenuation on biphasic (n = 86) and triphasic (n = 69) CT scans.
  
  
  RESULTS
  The prevalent enhancement patterns of HCC differed depending on tumor size. The prevalent pattern of HCC measuring 20-29 mm was arterial hyperattenuation with venous washout (47%, 47/101). The prevalent enhancement patterns of HCC smaller than 10 mm and HCC measuring 10-19 mm were isoattenuation during the arterial and portal venous phases (29%, 6/21) and hyperattenuation and isoattenuation during the arterial and portal venous phases (33%, 27/82). The typical HCC enhancement pattern (arterial hyperattenuation with venous washout) was identified in 48% (67/141) of the moderately and poorly differentiated HCCs and in 13% (8/63) of well-differentiated HCCs.
  
  
  CONCLUSIONS
  The prevalent enhancement patterns of HCC smaller than 3 cm on multiphasic MDCT scans differed depending on tumor size and cellular differentiation. HCCs smaller than 2 cm and well-differentiated HCCs frequently had atypical enhancement patterns.
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul, 110-744, Korea.
authors.forename: Soon Ho
authors.initials: SH
authors.lastname: Yoon
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Young Ho
authors.initials: YH
authors.lastname: So
authors.forename: Sung Hyun
authors.initials: SH
authors.lastname: Hong
authors.forename: Soo Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.forename: Byung Ihn
authors.initials: BI
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*