Computed tomography coronary angiography can accurately quantify coronary luminal area and plaque volume compared to invasive intravascular ultrasound

Abstract

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511 Comparison of radiation doses between coronary CT and catheter coronary angiography: an update K. Leong ∗ , J. Vazirani, P. Einsiedel, C. Hacking, N. Better, R. Gurvitch, C. Neal, D. Ecclestone, F. Langenberg, E. Lui, S. Joshi The Royal Melbourne Hospital, VIC, Australia Background: Much attention has been paid to radiation exposure with CT coronary angiography (CTCA) but less to the dose associated with invasive catheter angiography (CA). Methods: Radiation doses were reviewed from consecutive CTCA and diagnostic CA studies (100 CTCA, 400 CA) from January 2014. CT and CA studies for bypass graft or non-coronary indications were excluded. Effective radiation doses were estimated from the dose-length product and the dose-area product using the respective chest conversion coefficients (0.014 mSv/mGy x cm and 0.20 mSv/Gy x cm2 ). CTCA was performed on a 128 detector row dual source scanner. Doses were then compared with 2012 when a 1st generation dual source CT scanner was in use. Results: The median effective dose for CTCA was 2.0 mSv (IQR 1.3 to 3.6) vs 9.2 mSv (IQR 6.3 to 12.8) for CA, p < 0.001. The majority of CTCA patients (87/100) underwent calcium scoring with a median additional dose of 0.7 mSv. In patients weighing < 80kg, the median CTCA dose was 1.6 mSv vs 7.0 for CA (p < 0.001). Compared with 2012, CTCA radiation doses have reduced from 5.2 mSv to 2.0 mSv (p < 0.001) while there has been no significant change in CA doses (9.1 vs 9.2 mSv, p = NS). Conclusion: At our institution, radiation exposure associated with CTCA is several-fold less than that with CA. With new hardware, CTCA doses have halved since 2012 while there has been no significant change in CA over the same period. http://dx.doi.org/10.1016/j.hlc.2015.06.514 512 Computed tomography coronary angiography can accurately quantify coronary luminal area and plaque volume compared to invasive intravascular ultrasound R. Munnur 1,∗ , J. Andrews 2 , S. Nicholls 2 , Y. Kataoka 2 , Y. Malaiapan 1 , B. Ko 1 , J. Cameron 1 , I. Meredith 1 , S. Seneviratne 1 , D. Wong 1 1 MonashHEART,

Victoria, Australia Australian Health & Medical Research Institute, University of Adelaide, SA, Australia

2 South

Aim: To assess the accuracy of Computed-TomographyCoronary-Angiography (CTCA) derived quantitative plaque analysis using Intravascular-Ultrasound (IVUS) as reference standard.

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Methods: Patients who underwent IVUS and CTCA within a 3-month period at MonashHEART between October-2008 and December-2013 were retrospectively studied. Core-lab analysis was performed on all IVUS and CTCA datasets. CT images were analysed using SurePlaque-software. Luminal (LCSA), vessel-cross-sectional-area (VCSA) and plaque volume (PV), defined as (VCSA-LCSA)/VCSA were manually quantified on IVUS and CTCA at 0.5mm cross-sections on all interrogated vessels. Bland-Altman analysis was performed to assess the agreement of measurements between IVUS and CTCA. Data is expressed as mean ± standard error of mean (SEM), and two-tailed p<0.05 was accepted as significant. Results: Thirty-two vessels (23 patients), including 513 cross-sections were analysed (left-main n=9, left-anteriordescending n=16, left-circumflex n=4 and right-coronaryartery n=3). Un-interpretable-segments, segments without fiduciary-points and seven patients with poor CT images were excluded. There was no significant mean difference in LCSA (0.08 ± 0.08mm2 , p=0.33), VSCA (0.06 ± 0.12 mm2 , p=0.65 or PV (0.03±0.06mm3 , p=0.64) as quantified by IVUS and CTCA. The agreement between IVUS and CTCA for PV was better in non-calcified vessels (0.12 ± 0.07mm3 ) compared to calcified vessels (0.19 ± 0.9mm3 ). There was no significant difference in per-patient total-atheroma-volume measured on IVUS and CTCA (3.4 ± 2.1mm3 , p=0.12). Conclusion: Quantification of coronary-luminal-area and plaque volume using CTCA is highly accurate when compared with IVUS. Observed difference in plaque volumes was lower in non-calcified plaque. CTCA has the potential to accurately monitor coronary plaque progression and regression non-invasively. http://dx.doi.org/10.1016/j.hlc.2015.06.515 513 Coronary graft aneurysm causing dynamic pulmonary artery compression S. Gutman ∗ , J. Gutman, D. Mooney, J. Vrazas St. Vincent’s Hospital Melbourne, VIC, Australia A 77 year-old man presented with dyspnoea. A left sternal edge systolic ejection murmur was noted. He underwent coronary artery bypass grafting with a vein graft(SVG) to the LAD 34 years prior, complicated by graft degeneration 10 years later, necessitating repeat surgery (LIMA to LAD). A rest/exercise echocardiogram demonstrated normal rest and exercise left ventricular function with no ischaemia demonstrated. The right ventricle(RV) was mildly dilated at rest with mild systolic impairment and further dilatation and hypokinesis with exercise. The resting RV systolic pressure was 50 mmHg + right atrial pressure(RAP), increasing to 100 mmHg + RAP with exercise, falling to 60 mmHg + RAP post exercise. The PA systolic pressure gradients at rest and exercise were 50mmHg and 95mmHg respectively. Invasive investigations revealed a PA gradient 20 mmHg, RV systolic pressure 40 mmHg, PA pressure 20/4 mmHg and a large, partially thrombosed aneurysm of the original vein graft. The LIMA graft to the LAD was patent. Computed tomography (figure) confirmed a 6.3 cm graft