title: Assessment of hepatic fatty infiltration using spectral computed tomography imaging: a pilot study.
abstract: OBJECTIVE
  The objective of this study was to investigate the feasibility of using monochromatic spectral computed tomography (CT) imaging to assess fatty infiltration in liver.
  
  
  METHODS
  With spectral CT imaging, phantoms with known fat concentrations were studied for scanning parameter optimization, then 52 patients enrolled into 4 groups (healthy, mild, moderate, and severe fatty infiltration) received abdominal scanning. Based on reconstructed monochromatic images, hepatic attenuation was analyzed, and dual-energy subtraction imaging (DESI) was created for quantifying fat infiltration.
  
  
  RESULTS
  Corresponding to various hepatic fat infiltrations, 4 characteristic CT attenuation curve patterns were described. In DESI images, only fat and fatty components appeared bright. For livers without abnormal fat deposition, isolated bright pixels were visualized (% area = 0.5% ± 0.3%). With hepatic fat accumulation increasing, more bright pixels appeared in subtraction images with percentages of total liver area involved in 2.5%, 6.7%, and 13.4% of mild, moderate, and severe fat infiltration cases, respectively (P < 0.05). The corresponding CT values were as follows: 1.33, 2.53, 8.69, and 16.4 Hounsfield units (P < 0.01), which correlated with the % DESI area values (r = 0.9811).
  
  
  CONCLUSIONS
  Spectral CT imaging is a promising method to quantitatively assess hepatic fat content and fatty infiltration with advantages compared with conventional CT imaging.
authors.affiliation: Departments of Radiation Oncology and Radiology, Fudan University, Huadong Hospital, Shanghai, China. zhengxp@fudan.edu.cn
authors.forename: Xiangpeng
authors.initials: X
authors.lastname: Zheng
authors.forename: Yanping
authors.initials: Y
authors.lastname: Ren
authors.forename: William T
authors.initials: WT
authors.lastname: Phillips
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Meifang
authors.initials: M
authors.lastname: Song
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Hua
authors.forename: Guozhen
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D005234:Fatty Liver / Q000000981:diagnostic imaging* / Q000473:pathology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D010865:Pilot Projects; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*