title: Added value of arterial enhancement fraction color maps for the characterization of small hepatic low-attenuating lesions in patients with colorectal cancer.
abstract: OBJECTIVE
  To assess the added value of arterial enhancement fraction (AEF) color maps for the differentiation of small metastases from hepatic benign lesions.
  
  
  METHODS
  We retrospectively analyzed 46 patients with colorectal cancer who underwent multiphasic liver CT imaging and had low-attenuating liver lesions smaller than 3 cm (123 total lesions; metastasis: benign = 32:91). AEF color maps of the liver were created from multiphasic liver CT images using dedicated software. Two radiologists independently reviewed multiphasic CT image sets alone and in combination with image sets with AEF color maps using a five-point scale. The additional diagnostic value of the color maps was assessed by means of receiver-operating characteristic (ROC) analysis.
  
  
  RESULTS
  The area under the ROC curve (Az) increased when multiphasic CT images were combined with AEF color map analysis as compared with evaluation based only on multiphasic CT images (from 0.698 to 0.897 for reader 1, and from 0.825 to 0.945 for reader 2; P < 0.001 and 0.002, respectively). The increase Az was especially significant for lesions less than 1 cm (from 0.702 to 0.888 for reader 1, and from 0.768 to 0.958 for reader 2; P = 0.001 and P = 0.001, respectively). The mean AEF of tumor-adjacent parenchyma (35.07 ± 27.2) was significantly higher than that of tumor-free liver parenchyma (27.3 ± 20.6) (P = 0.04).
  
  
  CONCLUSIONS
  AEF color mapping can improve the diagnostic performance for small hepatic metastases from colorectal cancer and may allow for the elimination of additional examinations.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Mina
authors.initials: M
authors.lastname: Park
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Yong Eun
authors.initials: YE
authors.lastname: Chung
authors.affiliation: Department of Radiology, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea.
authors.forename: Kyung Ah
authors.initials: KA
authors.lastname: Kim
authors.affiliation: Department of Radiology, Konyang University College of Medicine, Daejon, Korea.
authors.forename: Woo-Suk
authors.initials: WS
authors.lastname: Chung
authors.affiliation: Biostatistics Collaboration Unit, Medical Research Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Biostatistics Collaboration Unit, Medical Research Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyung Hwa
authors.initials: KH
authors.lastname: Han
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Ki Whang
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods*