title: Detection of significant stenosis in the left anterior descending artery by 'virtual myocardial perfusion' bolus tracking, 320 slice computed tomography.
abstract: OBJECTIVE
  We used bolus-tracking CT-images, which are usually used only to detect contrast-material in target organs for optimal-starting of acquisition, as virtual first pass myocardial perfusion images.
  
  
  METHODS
  Retrospective-analysis of 14 patients (10 male, 63 ± 10 years) diagnosed with ≥ 75% stenosis confined to left-anterior-descending-artery (LAD) (7 patients, Group-1) or insignificant stenosis of any coronary artery (7 patients Group-2) diagnosed using invasive-coronary-angiograms (ICA) and enhanced 320-slice-CT within 3-months and without incident between examinations. Bolus-tracking CT-images were acquired at mid-level left-ventricle (LV) until CT-attenuation of descending-aorta increased to 200 HU. We measured CT-attenuation (HU) in the LV anterior-wall (AW), the basal inter-ventricular-septum (BIVS), and LV basal lateral-wall (BLW) in end-systole using both bolus-tracking images and routine, enhanced, early-phase CT-images.
  
  
  RESULTS
  In the bolus-tracking images, the Group-1 LV AW, BIVS, BLW CT-attenuation and ratio of LV AW CT attenuation to the average of BIVS and BLW were 36 ± 7HU, 62 ± 11HU, 58 ± 25HU, and 0.6 ± 0.1 respectively. In Group-2, they were 53 ± 14HU, 56 ± 9HU, 54 ± 15HU, and 1.0 ± 0.3 respectively. LV AW CT attenuation and the ratio of LV AW CT values to the average of BIVS and BLW, were significantly lower in Group-1 (both P < 0.05). These values were not significant using routine, enhanced, early-phase CT-images.
  
  
  CONCLUSIONS
  Bolus-tracking CT-images may be useful to detect the LAD-confined stenosis that cannot be detected using routine, enhanced, early-phase CT-images. This can be achieved by measuring the local-reduction in CT-attenuation of the LV AW compared with the average of those of the BIVS and BLW and without the need for drugs, exercise or additional radiation-exposure.
authors.affiliation: Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takaoka
authors.affiliation: Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan. Electronic address: nobusada@w8.dion.ne.jp.
authors.forename: Nobusada
authors.initials: N
authors.lastname: Funabashi
authors.affiliation: Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan.
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Fujimoto
authors.affiliation: Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kobayashi
mesh_terms: D000368:Aged; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D010865:Pilot Projects; D012189:Retrospective Studies; D014584:User-Computer Interface
keywords: 320 Slice Computed Tomography; Left Anterior Descending Artery; Significant stenosis; Virtual myocardial perfusion bolus tracking