title: Histogram analysis of gadoxetic acid-enhanced MRI for quantitative hepatic fibrosis measurement.
abstract: OBJECTIVE
  The diagnosis and monitoring of liver fibrosis is an important clinical issue; however, this is usually achieved by invasive methods such as biopsy. We aimed to determine whether histogram analysis of hepatobiliary phase images of gadoxetic acid-enhanced magnetic resonance imaging (MRI) can provide non-invasive quantitative measurement of liver fibrosis.
  
  
  METHODS
  This retrospective study was approved by the institutional ethics committee, and a waiver of informed consent was obtained. Hepatobiliary phase images of preoperative gadoxetic acid-enhanced MRI studies of 105 patients (69 males, 36 females; age 56.1±12.2) with pathologically documented liver fibrosis grades were analyzed. Fibrosis staging was F0/F1/F2/F3/F4 (METAVIR system) for 11/20/13/15/46 patients, respectively. Four regions-of-interest (ROI, each about 2 cm2) were placed on predetermined locations of representative images. The measured signal intensity of pixels in each ROI was used to calculate corrected coefficient of variation (cCV), skewness, and kurtosis. An average value of each parameter was calculated for comparison. Statistical analysis was performed by ANOVA, receiver operating characteristic (ROC) curve analysis, and linear regression.
  
  
  RESULTS
  The cCV showed statistically significant differences among pathological fibrosis grades (P<0.001) whereas skewness and kurtosis did not. Univariable linear regression analysis suggested cCV to be a meaningful parameter in predicting the fibrosis grade (P<0.001, β = 0.40 and standard error  = 0.06). For discriminating F0-3 from F4, the area under ROC score was 0.857, standard deviation 0.036, 95% confidence interval 0.785-0.928.
  
  
  CONCLUSIONS
  Histogram analysis of hepatobiliary phase images of gadoxetic acid-enhanced MRI can provide non-invasive quantitative measurements of hepatic fibrosis.
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Honsoul
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Pathology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eun Kyung
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Pathology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Young Nyun
authors.initials: YN
authors.lastname: Park
authors.affiliation: Department of Nuclear Medicine, Radiology and Psychiatry, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Hae-Jeong
authors.initials: HJ
authors.lastname: Park
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Choi
mesh_terms: D000328:Adult; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D008103:Liver Cirrhosis / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA