[Show abstract][Hide abstract]ABSTRACT: Patients with mildly abnormal or equivocal results on myocardial perfusion imaging (MPI) typically undergo diagnostic angiography or receive medical management for coronary artery disease. Catheterization is often required for either appropriate diagnosis or management. With its very high negative predictive rate, coronary computed tomographic angiography (CCTA) has great potential to rule out clinically significant coronary artery disease in this setting. The aim of this study was to analyze the clinical utility and cost implications of CCTA before invasive angiography in patients with abnormal or equivocal results on MPI. Consecutive patients referred by their physicians to our center with abnormal or equivocal results on MPI were reviewed. Patients with histories of myocardial infarction or of revascularization (coronary artery bypass grafting or percutaneous coronary intervention) were excluded. All patients underwent CCTA. Of 241 participants, only 66 (27%) of the studies with abnormal or equivocal nuclear findings revealed obstructive disease on CCTA (>50% stenosis). Fifty-five of 241 patients had normal coronary arteries, 97 patients had nonsignificant disease (<30%), and 23 patients had mild disease (30% to 50% stenosis) on CCTA, leading to diagnoses of noncardiac chest pain. Selective catheterization (for >50% stenosis on CCTA) demonstrated an average cost reduction of $1,295 per patient. Sensitivity analysis revealed cost savings to be preserved even if up to 70% of the patient cohort underwent catheterization after CCTA and across a wide range of procedural costs. In conclusion, CCTA after equivocal or mild or moderate abnormal MPI findings results in significant cost savings and a robust reduction in the need for cardiac catheterization and excludes obstructive coronary artery disease in almost 75% of patients.
Full-text · Article · Jan 2012 · The American journal of cardiology
[Show abstract][Hide abstract]ABSTRACT: Multidetector computed tomographic angiography (MDCTA) has emerged as a promising noninvasive tool to rule out significant coronary artery disease (CAD). In addition, MDCTA also provides additional information about atherosclerotic plaque composition. In this study, we aim to assess whether differences in plaque composition exist across patients with varying degree of stenotic CAD disease.
Four hundred and sixteen patients with chest pain or shortness of breath thought to be related to CAD (64% males, mean age: 61+/-13 years), with 61 (15%) reporting type 2 diabetes mellitus, who underwent contrast-enhanced MDCTA were studied. Enrolled patients had an intermediate pretest probability of obstructive disease.
Overall 51 patients (12%) had normal coronaries without evidence of plaque. In the remaining 365 patients, 45 (12%) and 83 (23%) were found to have stenosis 50-70% and at least 70% in at-least one coronary artery segment, respectively. Those with a higher degree of stenotic CAD showed significantly more coronary segments with exclusively calcified and mixed plaques. With increasing severity of CAD (<50 vs. 50-70% vs. >70% stenosis), the overall proportion of plaque burden was more likely to be mixed (18 vs. 38% vs. 44%) in nature as well less likely to be exclusively noncalcified (39 vs. 20 vs. 16%). Only two of 108 (2%) patients without any underlying calcification had significant CAD (stenosis> or =50%).
Significant differences in plaque composition according to severity of CAD were observed in our study. Individuals with a higher likelihood of stenotic CAD were more likely to have higher underlying burden of exclusively calcified and mixed plaque. These findings should stimulate further investigations to assess the prognostic value of plaque according to their underlying composition.
[Show abstract][Hide abstract]ABSTRACT: To date, sparse data are available with regard to gender differences in plaque morphology and composition. The aim of the present report was to assess the differences in coronary plaque burden and composition in a noninvasive manner between women and men using multidetector computed tomographic angiography. The study population consisted of 416 patients (61 +/- 13 years), with 148 women (36%). A stenosis of >or=70% in at least one coronary segment was found in 11% of women compared to 25% of men (p <0.0001). Overall, women presented with a significantly lower mean number of segments containing calcified plaques (1.43 +/- 2.04 vs 2.25 +/- 2.30, p = 0.004) and mixed plaques (1.67 +/- 1.23 vs 2.25 +/- 2.30, p = 0.05). No such relation was seen with noncalcified plaques (0.72 +/- 1.01 vs 0.86 +/- 1.06, p = 0.21). In addition, the assessment of the overall proportion of the composition of plaque burden revealed relatively more noncalcified (40% vs 28%), less calcified (38% vs 43%), and mixed (23% vs 28%) plaques in women than in men (p <0.0001). On multivariate analysis of the total plaque burden, the women had a 19% (95% confidence interval 11% to 28%, p <0.0001) greater relative distribution of plaque that was noncalcified compared to the men, and the overall plaque burden was less likely to be calcified (p = 0.006) or mixed (p = 0.019). Similar results were seen in younger and older subjects. In conclusion, gender differences exist, not only in the atherosclerotic disease burden, but also in the underlying plaque composition. Women tended to have more exclusively noncalcified plaque and were less likely to have calcified or mixed plaques compared to men. Future studies are needed to elucidate whether these underlying differences in plaque composition might explain the reduced risk of cardiac events in women.
Full-text · Article · Feb 2010 · The American journal of cardiology
[Show abstract][Hide abstract]ABSTRACT: This is a 77-year-old diabetic woman with history of claudication (Rutherford Category 2). Due to fear of underestimating disease with ankle-brachial index in a person with diabetes and advancing age, a CT angiogram was performed. The right common iliac artery had aneurysmal disease (3.4 cm) and a thrombus of right internal iliac artery. There was also a 40% stenosis of right external iliac artery and a left subtotal internal iliac stenosis at the origin. Given it's non-invasive nature and high diagnostic accuracy, CTA is poised to become the noninvasive test of choice in patients with suspected PAD or in patients at risk for obstructive vascular disease.
No preview · Article · Nov 2009 · Catheterization and Cardiovascular Interventions
[Show abstract][Hide abstract]ABSTRACT: Thoracic aortic aneurysm (TAA) is an increasingly frequent and potentially life-threatening medical diagnosis. TAA is defined as a localized dilatation of the aorta to more than 50% of baseline. Patients are most commonly asymptomatic at the time of diagnosis. Diagnosis is made incidentally on chest radiography or echocardiography. Diagnosis is then confirmed by echocardiography, left ventricular angiography, cardiac computed tomography or cardiac magnetic resonance. Cardiac computed tomography angiography (CTA) is an excellent imaging modality for this purpose as it allows simultaneous analysis of the coronary artery tree, which is useful in determining the most suitable procedure for each patient.
Full-text · Article · Aug 2009 · Clinical Cardiology
[Show abstract][Hide abstract]ABSTRACT: Type 2 diabetes mellitus (DM) is associated with a higher risk of cardiovascular disease and atherosclerotic burden. However little data exists in regards to plaque distribution and plaque composition in these patients. To assess for differences in the coronary plaques burden and composition among symptomatic patients with and without type 2 DM using multidetector computed tomography angiography (MDCTA). The 416 symptomatic patients (64% males, mean age: 61 +/- 13 years) with 61 (15%) reporting type 2 DM, who underwent contrast-enhanced MDCTA were studied. Enrolled patients had an intermediate to high pre-test probability of obstructive coronary artery disease. Multivariate analysis was used to correct for differences in age and gender. Patients with type 2 DM were more likely to have significant stenosis >or=70% in at least one coronary segments (33% in type 2 DM vs. 18% in non diabetic, P = 0.013), whereas 11% of both type 2 DM and non diabetics had stenosis of 50-70% (P = NS). Also type 2 DM patients had a higher number of coronary segments with mixed plaques compared to nondiabetic patients (1.67 +/- 2.01 vs. 1.23 +/- 1.61, P = 0.05), whereas no such differences were observed for non-calcified or calcified plaques. Nearly half (43%) of type 2 DM had coronary artery calcium scores (CACS) >or=400 vs. 29% in non diabetic patients (P = 0.03). Patients with type 2 DM tend to have atherosclerotic plaques which are more likely to be mixed in nature. Future studies need to elucidate the prognostic value of differences in plaque characteristics observed according to type 2 diabetic status.
No preview · Article · Jul 2009 · The international journal of cardiovascular imaging
[Show abstract][Hide abstract]ABSTRACT: Current 64-multidetector Computed Tomographic scanners (MDCT) utilize retrospective overlapping helical acquisition (RS-OHA) which imparts a higher than desired radiation dose. Although the radiation burden of computed tomographic angiography (CTA) can be efficiently reduced by dose modulation and limiting field of view, a further decrease in radiation without compromising diagnostic image quality would be indeed very desirable. An alternative imaging mode is the axial prospective ECG-triggering acquisition (prospective gating). This study was done to compare the effective radiation dose and the image quality with two techniques to reduce radiation doses with CTA studies utilizing 64-MDCT scanners. The study included 149 consecutive patients (48 females and 101 males) 64-MDCT (mean age = 67 +/- 11 years, 72.2% male). Patients underwent CT coronary angiography using one of three algorithms: retrospective triggering with dose modulation; prospective triggering with padding (step and shoot acquisition with additional adjacent phases); and prospective triggering without padding (single phase acquisition only). Based on body habitus, two different voltages were utilized: 100 kVp (<85 kg) or 120 kVp (>85 kg). Radiation doses and image quality (signal to noise ratio) was measured for each patient, and compared between different acquisition protocols. The signal to-noise ratio of the ascending aorta (SNR-AA) was calculated from the mean pixel values of the contrast-filled left ventricular chamber divided by the standard deviation of these pixel values. Use of 100 kVp reduced radiation dose 41.5% using prospective triggering and 39.6% using retrospective imaging as compared to 120 kVp (P < 0.001). Use of prospective imaging reduced radiation exposure by 82.6% as compared to retrospective imaging (P < 0.001). Using both prospective imaging and 100 kVp without padding (single phase data, no other phases obtained), radiation dose was reduced by 90% (P < 0.001). In terms of image quality, the coefficient of variation of ascending aortic contrast enhancement between kVp of 120 and kVp of 100 was 6% (1.05, 95 CI 0.93-1.17), and 7.8% (0.9, 95% CI 0.7-1.2) at the pulmonary artery. The prospective ECG-Triggered acquisition and 100 kVp images were of diagnostic quality, allowing adequate assessment in all patients. CTA using PA and 100 kVp reduced the radiation dose by up to 90% without compromising the image quality.
Full-text · Article · Apr 2009 · The international journal of cardiovascular imaging
[Show abstract][Hide abstract]ABSTRACT: Because almost all data currently available with coronary calcium scanning are from electron beam tomography (EBT), we assessed whether scores obtained with 64-multidetector computed tomography (CT; MDCT) are similar. We evaluated the interscan variation in coronary artery calcium (CAC), Agatston score (AS), and volume score (VS) between EBT and 64-MDCT (VCT; GE, Milwaukee, Wis).
One hundred two patients (mean age, 61.1 years; 27 women) underwent dual CAC scanning with both EBT and 64-MDCT. The AS and VS were measured with the Aquarius workstation (TeraRecon, Inc, San Mateo, Calif). The correlation coefficient, Bland-Altman analysis, interscanner variation, and agreement in AS and VS scores between EBT and 64-MDCT were computed.
Interscan agreement for presence of CAC was 99%. Median values were 286 and 268 mm for AS and 243 and 213 mm for VS with EBT and 64-MDCT, respectively (P > 0.05). There was significant linear relationship between scores from the 2 scanners (R = 0.98 in AS and R = 0.99 in VS; P < 0.001). The interscanner variability between EBT and 64-MDCT was 20.9% and 17.6% in AS and VS, respectively (P = NS). Bland-Altman analysis demonstrated a mean difference in scores of 8.3% for AS and 7.8% by VS. When compared with EBT, there were larger and more prevalent motion artifacts (P < 0.001) and larger mean Hounsfield units using 64-MDCT (P < 0.001).
At CAC scanning, 64-MDCT and EBT were comparable in AS and VS. The interscan variability between scanners is similar to interscan variability of 2 calcium scores done on the same equipment. However, heart rate control was achieved for this study for calcium scores. Whether these results are repeatable without heart rate control needs to be further assessed.
No preview · Article · Feb 2009 · Journal of computer assisted tomography
[Show abstract][Hide abstract]ABSTRACT: Although left ventricular (LV) pseudoaneurysm is seen infrequently, it should be recognized and distinguished from the common type of left ventricular aneurysm. The diagnosis can be difficult and the lesions are prone to rupture, thus the condition is associated with a high rate of morbidity and mortality. LV pseudoaneurysms are the result of a contained rupture of the free wall of the myocardium, with the containment being provided by adherent pericardium or scar tissue. Among patients dying of infarction, 17% have been found to have ruptured the heart through the infarcted area. Rupture of the free wall is four to five times more common than septal rupture and is usually immediately fatal. We present images of a LV pseudoaneurysm in a patient with a past history of coronary bypass grafting who underwent computed tomographic angiography for evaluation of his bypass vessels.
Full-text · Article · Aug 2008 · The Journal of invasive cardiology