title: Comparative accuracy of CT, dual-echo MRI and MR spectroscopy for preoperative liver fat quantification in living related liver donors.
abstract: BACKGROUND
  It is of significant importance to assess the extent of hepatic steatosis in living donor liver transplant (LDLT) surgery to ensure optimum graft regeneration as well as donor safety.
  
  
  OBJECTIVE
  To establish the accuracy of non-invasive imaging methods including computed tomography (CT), dual-echo in- and opposed-phase magnetic resonance imaging (MRI), and MR spectroscopy (MRS) for quantification of liver fat content (FC) in prospective LDLT donors with histopathology as reference standard.
  
  
  METHODS
  This retrospective study was conducted at our institution on LDLT donors being assessed for biliary and vascular anatomy depiction by Magnetic Resonance Cholangiopancreatography (MRCP) and CT scan, respectively, between July 2013 and October 2014.
  
  
  METHODS
  Liver FC was measured in 73 donors by dual-echoT1 MRI and MRS. Of these, CT liver attenuation index (LAI) values were available in 62 patients.
  
  
  METHODS
  CT and MRI FC were correlated with histopathological reference standard using Spearman correlation coefficient. Sensitivity, specificity, positive predictive value, negative predicative value, and positive and negative likelihood ratios with 95% confidence intervals were obtained.
  
  
  RESULTS
  CT LAI, dual-echo MRI, and MRS correlated well with the histopathology results (r = 0.713, 0.871, and 0.882, respectively). An accuracy of 95% and 96% was obtained for dual-echo MRI and MRS in FC estimation with their sensitivity being 97% and 94%, respectively. False-positive rate, positive predictive value (PPV), and negative predicative value (NPV) were 0.08, 0.92, and 0.97, respectively, for dual-echo MRI and 0.03, 0.97, and 0.95, respectively, for MRS. CT LAI method of fat estimation has a sensitivity, specificity, PPV, and NPV of 73%, 77.7%, 70.4%, and 80%, respectively.
  
  
  CONCLUSIONS
  Dual-echo MRI, MRS, and CT LAI are accurate measures to quantify the degree of hepatic steatosis in LDLT donors, thus reducing the need for invasive liver biopsy and its associated complications. Dual-echo MRI and MRS results correlate better with histological results in the study, as compared to CT LAI method for fat quantification.
authors.affiliation: Department of Radiology, Indraprastha Apollo Hospital, Delhi, India.
authors.forename: Ruchi
authors.initials: R
authors.lastname: Rastogi
authors.affiliation: Department of Surgery, Indraprastha Apollo Hospital, Delhi, India.
authors.forename: Subhash
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Department of Radiology, Indraprastha Apollo Hospital, Delhi, India.
authors.forename: Bhavya
authors.initials: B
authors.lastname: Garg
authors.affiliation: Department of Radiology, Indraprastha Apollo Hospital, Delhi, India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Vohra
authors.affiliation: Department of Gastroenerology, Indraprastha Apollo Hospital, Delhi, India.
authors.forename: Manav
authors.initials: M
authors.lastname: Wadhawan
authors.affiliation: Department of Radiology, Indraprastha Apollo Hospital, Delhi, India.
authors.forename: Harsh
authors.initials: H
authors.lastname: Rastogi
keywords: Computed tomography liver attenuation index; MR spectroscopy; dual-echo magnetic resonance imaging; hepatic steatosis; liver fat quantification; living donor liver transplantation