title: Influence of technical parameters on epicardial fat volume quantification at cardiac CT.
abstract: OBJECTIVE
  To systematically analyze the influence of technical parameters on quantification of epicardial fat volume (EATV) at cardiac CT.
  
  
  METHODS
  153 routine cardiac CT data sets were analyzed using three-dimensional pericardial border delineation. Three image series were reconstructed per patient: (a) CTAD: coronary CT angiography (CTA), diastolic phase; (b) CTAS: coronary CTA, systolic phase; (c) CaScD: non-contrast CT, diastolic phase. EATV was calculated using three different upper thresholds (-15HU, -30 HU, -45HU). Repeated measures ANOVA, Spearman's rho, and Bland Altman plots were used.
  
  
  RESULTS
  Mean EATV differed between all three image series at a -30HU threshold (CTAD 87.2 ± 38.5 ml, CTAS 90.9 ± 37.7 ml, CaScD 130.7 ± 49.5 ml, P<0.001). EATV of diastolic and systolic CTA reconstructions did not differ significantly (P=0.225). Mean EATV for contrast enhanced CTA at a -15HU threshold (CTAD15 102.4 ± 43.6 ml, CTAS15 105.3 ± 42.3 ml) could be approximated most closely by non-contrast CT at -45HU threshold (CaScD45 105.3 ± 40.8 ml). The correlation was excellent: CTAS15-CTAD15, rho=0.943; CTAD15-CaScD45, rho=0.905; CTAS15-CaScD45, rho=0.924; each P<0.001). Bias values from Bland Altman Analysis were: CTAS15-CTAD15, 4.9%; CTAD15-CaScD45, -4.3%; CTAS15-CaScD45, 0.6%.
  
  
  CONCLUSIONS
  Measured EATV can differ substantially between contrast enhanced and non-contrast CT studies, which can be reconciled by threshold modification. Heart cycle phase does not significantly influence EATV measurements.
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany.
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Bucher
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA. Electronic address: schoepf@musc.edu.
authors.forename: U
authors.initials: U
authors.lastname: Joseph Schoepf
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Aleksander W
authors.initials: AW
authors.lastname: Krazinski
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Silverman
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: James V
authors.initials: JV
authors.lastname: Spearman
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza" - Polo Pontino, Latina, Italy.
authors.forename: Carlo N
authors.initials: CN
authors.lastname: De Cecco
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany.
authors.forename: Felix G
authors.initials: FG
authors.lastname: Meinel
authors.affiliation: Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Vogl
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany.
authors.forename: Lucas L
authors.initials: LL
authors.lastname: Geyer
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging / Q000473:pathology*; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000473:pathology*; D003971:Diastole; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000000981:diagnostic imaging / Q000473:pathology*; D013599:Systole; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Cardiac computed tomography; Cardiovascular disease; Epicardial adipose tissue; Risk assessment; Software tool