title: Influence of Coronary Artery Diameter on Intracoronary Transluminal Attenuation Gradient During CT Angiography.
abstract: The goal of this study was to assess the effect of coronary artery diameter on luminal attenuation and the correlation between the transluminal attenuation gradient (TAG) and transluminal diameter gradient (TDG) on computed tomography (CT) coronary angiography.
  
  
  
  Recent studies have reported promising results of TAG in detecting significant stenosis. However, because of the intrinsic nature of CT reconstruction algorithms, luminal attenuation may be affected by vessel diameter.
  
  
  
  In this 3-part study, phantom simulating vessels of various diameters immersed in different contrast mixtures were scanned, and intraluminal attenuations were measured. In addition, dynamic volume CT scanning was performed in 3 mongrel dogs (untreated, a stenosis model, and an occlusion model) using 320-row area detector computed tomography and intraluminal attenuations, and TAGs were calculated at each temporal scan and compared. In a separate clinical study, TAGs and TDGs of 152 coronary arteries from 62 patients who underwent 320-row area detector computed tomography coronary angiography and invasive angiography were measured and compared.
  
  
  
  Intraluminal attenuation of phantom vessels gradually decreased along with a decrease in diameter. Animal studies revealed that the peak attenuation of distal smaller coronary arteries did not reach that of proximal larger coronary arteries: 55.2% to 78.1% peak attenuation of proximal coronary arteries. No differences in TAG were found between stenotic and normal left circumflex arteries at temporal scans (all, p > 0.05). The clinical study demonstrated significant correlation between TAG and TDG (r = 0.580; p < 0.0001).
  
  
  
  Intraluminal attenuation was shown to decrease with diminution of vessel diameters. In addition, TAG exhibited a significant correlation with TDG, implying that TAG may be a secondary result because of differences in diameters.
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Eun-Ah
authors.initials: EA
authors.lastname: Park
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea. Electronic address: whal.lee@gmail.com.
authors.forename: Whal
authors.initials: W
authors.lastname: Lee
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Yeo Koon
authors.initials: YK
authors.lastname: Kim
authors.affiliation: Department of Thoracic Surgery, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Ho Young
authors.initials: HY
authors.lastname: Hwang
mesh_terms: D000465:Algorithms; D000818:Animals; D000072226:Computed Tomography Angiography / Q000295:instrumentation; D017023:Coronary Angiography / Q000295:instrumentation / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D004195:Disease Models, Animal; D004285:Dogs; D006801:Humans; D061330:Multidetector Computed Tomography; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies
keywords: 320-row area detector CT; coronary artery disease; coronary artery stenosis