Coronary Artery Disease: Sheth T

Chow BJ, Larose E, Bilodeau S, Ellins ML, Galiwango P, Kass M, Sheth T, Jassal DS, Kirkpatrick ID, Mancini GB, Mayo J, Abraham A, White J. · Department of Medicine, University of Ottawa Heart Institute, Ontario, Canada. · Can J Cardiol. · Pubmed #19279980 links to  free full text

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Sheth TN, Rybicki F, Sheth T, Yucel EK. · Division of Cardiovascular Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. · Can Assoc Radiol J. · Pubmed #15835587 No free full text.

This publication has no abstract.

Venkatesh V, Ellins ML, Yang S, Natarajan M, Amlani S, Sheth T. · Cardiac CT, Hamilton Health Sciences, Hamilton, Ontario, Canada. · Clin Radiol. · Pubmed #19185654 No free full text.

Abstract: AIM: The purpose of this study was to evaluate the improved assessment of coronary atherosclerotic plaque burden by measurement of non-calcified plaque in addition to calcified plaque using CT coronary angiography (CTA). MATERIALS AND METHODS: Low to intermediate-risk outpatients with suspected coronary artery disease were prospectively recruited. Patients underwent CTA and calcium scoring in addition to invasive angiography. The presence of plaque (calcified, non-calcified, and mixed) was analysed on a per segment basis (percentage of segments with disease) with stratification by calcium score (CS). RESULTS: Seventy-six patients were enrolled of whom 30 had a CS of 0, 26 had a CS of 1-200, and 20 had a CS of >200. One thousand, one hundred and two segments were analysed using CTA and invasive angiography. The prevalence of segments with calcified or mixed plaque was 3.1% (n=13) for a CS of 0, 15.1% (n=57) for a CS of 1-200, and 50% (n=142) for a CS of >200 (all p<0.0001). The proportion of segments with non-calcified plaque alone was low and similar among the three groups: 5.4% (n=23; CS=0), 8.2% (n=32; CS=1-200), and 8.6% (n=25; CS= >200), (CS=0 versus CS= >200; p=0.04, others p=ns). The relative increase in diseased segments by additional assessment of non-calcified plaque was greatest for patients with a CS of 0 (173%) versus a CS of 1-200 (55%), and a CS of >200 (17%). CONCLUSION: CTA offers increased relative incremental detection of non-calcified plaque, particularly in those with negative CS; however, the absolute detection of non-calcified plaque in those with negative CS is low. The prognostic significance of non-calcified plaque for the prediction of cardiac events, particularly in patients with low CS, requires continued study.

Sheth T, Amlani S, Ellins ML, Mehta S, Velianou J, Cappelli G, Yang S, Natarajan M. · Cardiac CT, Hamilton General Hospital, Hamilton, Ontario, Canada. · Am Heart J. · Pubmed #18440342 No free full text.

Abstract: BACKGROUND: It is unclear if computed tomographic coronary angiography (CTA), an evolving technique for the evaluation of coronary artery disease (CAD), can identify patients with high-risk coronary anatomy. METHODS: Among patients referred for invasive angiography at Hamilton Health Sciences (Hamilton, Ontario, Canada), those with an intermediate pretest probability (25%-60% likelihood of a significant stenosis) were prospectively identified using a multivariate risk score and were studied on a 64-detector Toshiba Aquilion scanner (Toshiba Medical Systems, Tokyo, Japan) before invasive angiography. Patients with high-risk anatomy (left main, 3-vessel CAD, or 2-vessel CAD involving the proximal left anterior descending artery) or at least 1 significant stenosis were identified on CTA and invasive angiography, and the results of these modalities were compared on a per patient basis. RESULTS: Eighty patients were enrolled in the study (mean age 56 +/- 9 years, male-female ratio 43:37). Nondiagnostic scan results were obtained in 5 patients (6%). By CTA, 13 patients had high-risk anatomy and 31 patients had at least 1 significant stenosis. For the per patient detection of high-risk anatomy, CTA had 100% sensitivity (95% CI 69%-100%), 95% specificity (95% CI 86%-95%), a positive likelihood ratio of 18.0 (95% CI 6.4-50.3), and a negative likelihood ratio of 0.05 (95% CI 0-0.072). Revascularization was performed in 100% of patients with high-risk anatomy on CTA, 83% with at least 1 significant stenosis on CTA, and 0% without a significant stenosis on CTA. CONCLUSION: In appropriately selected patients, CTA is a highly sensitive and specific technique for the detection of high-risk anatomy and maybe a valuable method for noninvasive risk stratification.

Sheth T, Dodd JD, Hoffmann U, Abbara S, Finn A, Gold HK, Brady TJ, Cury RC. · Cardiac MR-PET-CT Program, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA. · Catheter Cardiovasc Interv. · Pubmed #17421013 No free full text.

Abstract: BACKGROUND: We evaluated the assessability of contemporary stent platforms by 64-slice multi-detector computed tomography (MDCT). METHODS: Patients undergoing coronary stenting were included in a prospective protocol of MDCT imaging within 48 hr of stent implantation. MDCT data were acquired using a "Sensation 64" MDCT scanner (Siemens Medical Solutions, Forchheim, Germany). Stent assessability was assessed by two independent blinded observers and disagreement was resolved by a third observer. Assessability was defined at visualization of the in-stent lumen without influence of partial volume effects, beam hardening, motion, calcification, or contrast to noise limitations. RESULTS: Fifty four stents (Cypher n = 25, Vision/Minivision n = 19, Taxus Express n = 8, Liberte n = 1, Driver n = 1) in 44 patients were included in the study. The two independent observers classified 30 of 54 stents (56%) as assessable. Interobserver reproducibility was good with kappa = 0.66. Stent size was the most important determinant of assessability. Consistently assessable stents were 3.0 mm or larger (85%), whereas those under 3 mm were mostly nonassessable (26%). CONCLUSIONS: Contemporary stent designs evaluated on a 64-slice MDCT scanner showed artifact free assessability only in larger stents. Increase in spatial resolution of MDCT scanners or modifications in stent design will be necessary to noninvasive evaluate stents <3 mm in diameter, where in-stent restenosis is more frequent.

Butler J, Shapiro M, Reiber J, Sheth T, Ferencik M, Kurtz EG, Nichols J, Pena A, Cury RC, Brady TJ, Hoffmann U. · Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. · Am Heart J. · Pubmed #17307416 No free full text.

Abstract: BACKGROUND: The extent and nature of overall coronary artery disease (CAD), defined as the cumulative stenotic and nonstenotic, calcified and noncalcified atherosclerosis burden, are underestimated by invasive coronary angiography (ICA) and more accurately quantified with intravascular ultrasound. Multidetector row computed tomography (MDCT) is inferior to intravascular ultrasound but may constitute an attractive noninvasive alternative to assess overall CAD burden. METHODS: To compare ICA with MDCT for detection of CAD (defined as luminal narrowing of any degree or calcification by ICA and any atherosclerotic plaque detection by MDCT using the 17-segment model), we studied 37 patients (age, 63 +/- 11 years) who underwent both tests. RESULTS: A total of 508 of 586 (87%) segments were assessable, and CAD was detected in 121 of 508 (24%) segments by ICA versus 338 of 508 (67%) by MDCT (P < .01). Of the 121 segments positive for CAD by ICA, MDCT detected plaques in 117 segments (97%). In the 387 of 508 (76%) segments that were free of CAD by ICA, MDCT detected CAD in 221 (57%) segments. Overall, ICA detected CAD in only 20%, 48%, and 46% of segments with noncalcified, calcified, and mixed plaques, respectively, seen by MDCT (P = .01). Of the 221 segments negative for CAD by ICA, 119 (54%) were positively remodeled on MDCT. Overall correlation between ICA and MDCT for detection of CAD was poor (kappa = 0.25). CONCLUSIONS: Invasive coronary angiography and MDCT differ significantly in estimating the presence and nature of CAD. Multidetector row computed tomography may provide an attractive noninvasive alternative to ICA to assess the effects of medical therapy.