title: Differentiation of small hepatic hemangioma from small hepatocellular carcinoma: recently introduced spectral CT method.
abstract: OBJECTIVE
  To investigate the usefulness of computed tomographic (CT) spectral imaging parameters in differentiating small (≤3 cm) hepatic hemangioma (HH) from small hepatocellular carcinoma (HCC), with or without cirrhosis, during the late arterial phase (AP) and portal venous phase (PVP).
  
  
  METHODS
  This prospective study was institutional review board approved, and written informed consent was obtained from all patients. The authors examined 49 patients (39 men, 10 women; 65 lesions) with CT spectral imaging during the AP and the PVP. Twenty-one patients had HH; nine, HCC with cirrhosis; and 19, HCC without cirrhosis. Iodine concentrations were derived from iodine-based material-decomposition CT images and normalized to the iodine concentration in the aorta. The difference in iodine concentration between the AP and PVP (ie, iodine concentration difference [ICD]) and the lesion-to-normal parenchyma ratio (LNR) were calculated. Two readers qualitatively assessed lesion types on the basis of conventional CT characteristics. Sensitivity and specificity were compared between the qualitative and quantitative studies. The two-sample t test was performed to compare quantitative parameters between HH and HCC.
  
  
  RESULTS
  Normalized iodine concentrations (NICs) and LNRs in patients with HH differed significantly from those in patients with HCC and cirrhosis and those in patients with HCC without cirrhosis: Mean NICs were 0.47 mg/mL ± 0.24 (standard deviation) versus 0.23 mg/mL ± 0.10 and 0.23 mg/mL ± 0.08, respectively, during the AP and 0.83 mg/mL ± 0.38 versus 0.47 mg/mL ± 0.86 and 0.52 mg/mL ± 0.11, respectively, during the PVP. Mean LNRs were 5.87 ± 3.36 versus 2.56 ± 1.10 and 2.29 ± 0.87, respectively, during the AP and 2.01 ± 1.33 versus 0.96 ± 0.16 and 0.93 ± 0.26, respectively, during the PVP. The mean ICD for the HH group (1.37 mg/mL ± 0.84) was significantly higher than the mean ICDs for the HCC-cirrhosis (0.33 mg/mL ± 0.29) (P < .001) and HCC-no cirrhosis (0.82 mg/mL ± 0.99) (P = .03) groups. The combination of NIC and LNR had higher sensitivity and specificity compared with those of conventional qualitative CT image analysis during individual and combined phases.
  
  
  CONCLUSIONS
  Use of spectral CT with fast tube voltage switching may increase the sensitivity for differentiating small hemangiomas from small HCCs in two-phase scanning.
authors.affiliation: Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197 Ruijin Er Rd, Shanghai, China 200025.
authors.forename: Peijie
authors.initials: P
authors.lastname: Lv
authors.forename: Xiao Zhu
authors.initials: XZ
authors.lastname: Lin
authors.forename: Jianying
authors.initials: J
authors.lastname: Li
authors.forename: Weixia
authors.initials: W
authors.lastname: Li
authors.forename: Kemin
authors.initials: K
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media; D003937:Diagnosis, Differential; D004998:Ethiodized Oil; D005260:Female; D006391:Hemangioma / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging / Q000473:pathology; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D004998:Ethiodized Oil