Keywords:
Cardiac, Cardiovascular system, Vascular, CT, CT-Angiography, Contrast agent-intravenous
Authors:
A. Gennarelli, A. Di Sibio, M. Perri, F. Di Stasio, V. Felli, M. Di Luzio, A. V. Giordano, E. Di Cesare, C. Masciocchi; L'Aquila/IT
DOI:
10.1594/ecr2013/C-0788
Methods and Materials
47 patients with a history of bypass graft surgery and at least one IMA (Internal Mammary Artery) graft,
for a total of 108 CABG (66 arterial and 42 venous),
underwent coronary CT angiography using a 640-slices CT scanner with prospective gating and step-and-shot protocol with Adaptive Iterative Dose Reduction (AIDR) system 3D,
from January until September 2012.
Exclusion criteria were previous allergic reaction to iodine contrast medium and renal failure (creatinine ≥ 1.5mg/ dl).
All patients that presented heart rate > 65bpm received,
prior the exam,
an intravenous bolus of beta-blocker (5–15 mL); were excluded all patients that presented heart rate > 65bpm after beta-blocker bolus.
In addition,
sublingual nitroglycerin (5 mg) was administered 5 min before the CTA investigation.
A slice thickness of 0.50 mm was obtained and the reconstruction interval was set to 0.25 mm; obtained images were transferred to a dedicated workstation (Vitrea).
In conjunction with axial source images,
three-dimensional volume-rendered images,
multiplanar reformation images and maximum intensity projection images were generated to better demonstrate the relationships between graft anastomoses and individual grafts.
For every patient was calculated the effective dose with a dose-length product (DLP) conversion factor of 0.014 mSv/(mGy × cm).
Image quality was evaluated by two radiologists experienced in the field of MDCT based coronary angiography using a 4 scores grading system: score 1 (absence of motion artefacts),
score 2 (presence of mild artefacts),
score 3 (presence of moderate artefacts) and score 4 (presence of severe artefacts).
Median score of both radiologist and inter-rater reliability (k coefficient) were assessed.