title: High-flow haemangiomas versus hypervascular hepatocellular carcinoma showing "pseudo-washout" on gadoxetic acid-enhanced hepatic MRI: value of diffusion-weighted imaging in the differential diagnosis of small lesions.
abstract: OBJECTIVE
  To validate the usefulness of diffusion-weighted imaging (DWI) in the differentiation of high-flow haemangiomas showing pseudo-washout appearance on gadoxetic acid-enhanced hepatic MRI from small hypervascular hepatocellular carcinomas (HCCs).
  
  
  METHODS
  DWI (b=50, 800 s/mm2) with apparent diffusion coefficient (ADC) maps for 50 haemangiomas (6.4±2.9 mm) showing intense enhancement on arterial dominant phase imaging and hypointensity on transitional and/or hepatobiliary phase imaging during gadoxetic acid-enhanced MRI were retrospectively analysed and compared with that of 113 hypervascular HCCs (12.8±3.7 mm). In addition to measurement of mean ADC values on DWI and contrast-to-noise ratio (CNR) on corresponding T2-weighted imaging, qualitative analysis of DWI was performed for each lesion by two independent observers using a five-point scale.
  
  
  RESULTS
  Both of mean ADC value (1.902 versus 0.997×10-3mm2/s) and mean CNR (119.2 versus 36.9) for haemangioma were significantly larger than for HCC (p<0.001). On receiver operating characteristic (ROC) analysis, an area under the curve (AUC) of 0.995 for ADC values was significantly larger than 0.915 for CNRs (p=0.002). When the ADC value of 1.327×10-3mm2/s was used as the threshold for the diagnosis of haemangioma, the sensitivity and specificity were 98% and 97.3%, respectively. The mean sensitivity and specificity of qualitative analysis for the differentiation of haemangioma from HCC were 92% and 99.1%, respectively.
  
  
  CONCLUSIONS
  For high-flow small haemangiomas showing pseudo-washout appearance during gadoxetic acid-enhanced hepatic MRI, high b-factor DWI including an ADC map may provide additional information to enhance the confidence to exclude small hypervascular HCCs.
authors: Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-Ro, Gangnam-Gu, Seoul 06273, South Korea; Department of Radiology, Daerim St Mary's Hospital, 657 Siheung-Daero, Yeongdeungpo-Gu, Seoul 07442, South Korea.
authors: S J
authors: SJ
authors: Nam
authors: Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-Ro, Gangnam-Gu, Seoul 06273, South Korea. Electronic address: yjsrad97@yuhs.ac.
authors: J-S
authors: JS
authors: Yu
authors: Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-Ro, Gangnam-Gu, Seoul 06273, South Korea.
authors: E-S
authors: ES
authors: Cho
authors: Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-Ro, Gangnam-Gu, Seoul 06273, South Korea.
authors: J H
authors: JH
authors: Kim
authors: Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-Ro, Gangnam-Gu, Seoul 06273, South Korea.
authors: J-J
authors: JJ
authors: Chung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA; D006391:Hemangioma / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging / Q000473:pathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA