title: Transluminal attenuation gradient in coronary computed tomography angiography for determining stenosis severity of calcified coronary artery: a primary study with dual-source CT.
abstract: OBJECTIVE
  To evaluate the diagnostic accuracy of transluminal attenuation gradient (TAG) for stenosis severity of calcified lesions assessed by coronary computed tomography angiography (CCTA).
  
  
  METHODS
  One hundred seven patients who underwent CCTA and coronary angiography (CAG) were enrolled. TAGs of 309 major epicardial coronary arteries were measured. The impact of plaque composition, Agatston scores, and lesion length ratio on TAG were analyzed. Diagnostic performance vs. CAG of TAG, CCTA, and combined TAG/CCTA were evaluated, and incremental value of TAG for reclassification of CCTA stenosis severity in calcified lesions was also analyzed.
  
  
  RESULTS
  TAG decreased consistently with stenosis severity. TAG was significantly lower in coronary arteries with calcification scores >300 and lesion length ratios >2/3. TAG improved diagnostic accuracy of CCTA (c-statistic =0.982 vs. 0.942, P = 0.0001) in calcified lesions, and the sensitivity, specificity, positive, and negative predictive values of TAG cutoff ≤ -11.33 were 72 %, 91 %, 88 %, and 78 %, respectively. The addition of TAG to CCTA resulted in significant reclassification (NRI =0.093, P = 0.022) in calcified vessels.
  
  
  CONCLUSIONS
  Measurement of TAG may improve diagnostic performance and reclassification of CCTA in coronary stenosis caused by calcified lesions.
  
  
  CONCLUSIONS
  • TAG decreased as calcification scores and lesion length increased. • TAG markedly improved the diagnostic performance of CCTA for calcified lesions. • TAG improved reclassification of coronary artery stenosis severity in CCTA.
authors.affiliation: Department of Radiology, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, 710032, Shaanxi Province, China, zhengmw2007@163.com.
authors.forename: Minwen
authors.initials: M
authors.lastname: Zheng
authors.forename: Mengqi
authors.initials: M
authors.lastname: Wei
authors.forename: Didi
authors.initials: D
authors.lastname: Wen
authors.forename: Hongliang
authors.initials: H
authors.lastname: Zhao
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Jiayi
authors.initials: J
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Li
mesh_terms: D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*; D061205:Vascular Calcification / Q000000981:diagnostic imaging*