title: Dual-Energy CT for Patients Suspected of Having Liver Iron Overload: Can Virtual Iron Content Imaging Accurately Quantify Liver Iron Content?
abstract: OBJECTIVE
  To prospectively assess the feasibility of using virtual iron content (VIC) imaging at dual-energy computed tomography (CT) to evaluate the liver iron content (LIC) in patients suspected of having liver iron overload and to compare the LIC grading performance of VIC imaging and magnetic resonance (MR) imaging.
  
  
  METHODS
  This study was approved by the institutional review board, and informed consent was obtained from all patients. Fifty-six patients suspected of having liver iron overload (serum ferritin concentrations >500 μg/L) underwent unenhanced dual-energy CT and MR imaging of the liver. MR imaging-measured LICs were obtained in 34 of the 56 patients. VIC images were generated with dual-energy analysis. R2* and MR-measured LIC were obtained with gradient-echo and spin-echo sequences, respectively. Correlations between CT and MR measurements were analyzed. The diagnostic performance of VIC and R2* in the differentiation of different LIC thresholds were evaluated with receiver operating characteristic (ROC) analysis.
  
  
  RESULTS
  Hepatic VIC showed significant correlation with R2* and MR-measured LIC (r = 0.885 and 0.871, respectively; P < .0001). To differentiate among different LIC thresholds of 1.8, 3.2, 7.0, and 15.0 mg of iron per gram of dry tissue, the corresponding optimal cutoff values for VIC were 2.50, 5.13, 8.93, and 17.97 HU, respectively. At a LIC threshold of 7.0 mg of iron per gram of dry tissue or higher, 100% sensitivity (15 of 15 patients) and 100% specificity (19 of 19 patients) were obtained for VIC. There was no significant difference between VIC and R2* (area under the ROC curve, 0.964 vs 0.993, respectively; P = .299) in grading LIC levels at a LIC threshold of 3.2 mg of iron per gram of dry tissue or higher. Conclusion Hepatic VIC is a potential index for accurately evaluating and grading clinically significant liver iron accumulation, with a diagnostic performance similar to that of MR imaging.
authors.affiliation: From the Departments of Radiology (X.F.L., X.Q.X., Y.Y., H.Z., W.M.C., F.H.Y.) and Hematology (S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai 200025, China; Siemens Shanghai Medical Equipment, Shanghai, China (Y.J.); and Siemens AG, Healthcare Sector, Forchheim, Germany (B.S.).
authors.forename: Xian Fu
authors.initials: XF
authors.lastname: Luo
authors.affiliation: From the Departments of Radiology (X.F.L., X.Q.X., Y.Y., H.Z., W.M.C., F.H.Y.) and Hematology (S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai 200025, China; Siemens Shanghai Medical Equipment, Shanghai, China (Y.J.); and Siemens AG, Healthcare Sector, Forchheim, Germany (B.S.).
authors.forename: Xue Qian
authors.initials: XQ
authors.lastname: Xie
authors.affiliation: From the Departments of Radiology (X.F.L., X.Q.X., Y.Y., H.Z., W.M.C., F.H.Y.) and Hematology (S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai 200025, China; Siemens Shanghai Medical Equipment, Shanghai, China (Y.J.); and Siemens AG, Healthcare Sector, Forchheim, Germany (B.S.).
authors.forename: Shu
authors.initials: S
authors.lastname: Cheng
authors.affiliation: From the Departments of Radiology (X.F.L., X.Q.X., Y.Y., H.Z., W.M.C., F.H.Y.) and Hematology (S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai 200025, China; Siemens Shanghai Medical Equipment, Shanghai, China (Y.J.); and Siemens AG, Healthcare Sector, Forchheim, Germany (B.S.).
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: From the Departments of Radiology (X.F.L., X.Q.X., Y.Y., H.Z., W.M.C., F.H.Y.) and Hematology (S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai 200025, China; Siemens Shanghai Medical Equipment, Shanghai, China (Y.J.); and Siemens AG, Healthcare Sector, Forchheim, Germany (B.S.).
authors.forename: Jing
authors.initials: J
authors.lastname: Yan
authors.affiliation: From the Departments of Radiology (X.F.L., X.Q.X., Y.Y., H.Z., W.M.C., F.H.Y.) and Hematology (S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai 200025, China; Siemens Shanghai Medical Equipment, Shanghai, China (Y.J.); and Siemens AG, Healthcare Sector, Forchheim, Germany (B.S.).
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: From the Departments of Radiology (X.F.L., X.Q.X., Y.Y., H.Z., W.M.C., F.H.Y.) and Hematology (S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai 200025, China; Siemens Shanghai Medical Equipment, Shanghai, China (Y.J.); and Siemens AG, Healthcare Sector, Forchheim, Germany (B.S.).
authors.forename: Wei Min
authors.initials: WM
authors.lastname: Chai
authors.affiliation: From the Departments of Radiology (X.F.L., X.Q.X., Y.Y., H.Z., W.M.C., F.H.Y.) and Hematology (S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai 200025, China; Siemens Shanghai Medical Equipment, Shanghai, China (Y.J.); and Siemens AG, Healthcare Sector, Forchheim, Germany (B.S.).
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmidt
authors.affiliation: From the Departments of Radiology (X.F.L., X.Q.X., Y.Y., H.Z., W.M.C., F.H.Y.) and Hematology (S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai 200025, China; Siemens Shanghai Medical Equipment, Shanghai, China (Y.J.); and Siemens AG, Healthcare Sector, Forchheim, Germany (B.S.).
authors.forename: Fu Hua
authors.initials: FH
authors.lastname: Yan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000068598:Data Accuracy; D005260:Female; D006801:Humans; D007501:Iron / Q000032:analysis*; D019190:Iron Overload / Q000175:diagnosis*; D008099:Liver / Q000737:chemistry*; D008107:Liver Diseases / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D007501:Iron