Objective The degree of subclinical coronary atherosclerosis in HIV-infected patients is unknown. We investigated the degree of subclinical atherosclerosis and the relationship of traditional and nontraditional risk factors to early atherosclerotic disease using coronary computed tomography angiography. Design and methods Seventy-eight HIV-infected men (age 46.5 ± 6.5 years and duration of HIV 13.5 ± 6.1 years, CD4 T lymphocytes 523 ± 282; 81% undetectable viral load), and 32 HIV-negative men (age 45.4 ± 7.2 years) with similar demographic and coronary artery disease (CAD) risk factors, without history or symptoms of CAD, were prospectively recruited. 64-slice multidetector row computed tomography coronary angiography was performed to determine prevalence of coronary atherosclerosis, coronary stenosis, and quantitative plaque burden. Results HIV-infected men demonstrated higher prevalence of coronary atherosclerosis than non-HIV-infected men (59 vs. 34%; P = 0.02), higher coronary plaque volume [55.9 (0–207.7); median (IQR) vs. 0 (0–80.5) μl; P = 0.02], greater number of coronary segments with plaque [1 (0–3) vs. 0 (0–1) segments; P = 0.03], and higher prevalence of Agatston calcium score more than 0 (46 vs. 25%, P = 0.04), despite similar Framingham 10-year risk for myocardial infarction, family history of CAD, and smoking status. Among HIV-infected patients, Framingham score, total cholesterol, low-density lipoprotein, CD4/CD8 ratio, and monocyte chemoattractant protein 1 were significantly associated with plaque burden. Duration of HIV infection was significantly associated with plaque volume (P = 0.002) and segments with plaque (P = 0.0009) and these relationships remained significant after adjustment for age, traditional risk factors, or duration of antiretroviral therapy. A total of 6.5% (95% confidence interval 2–15%) of our study population demonstrated angiographic evidence of obstructive CAD (>70% luminal narrowing) as compared with 0% in controls. Conclusion Young, asymptomatic, HIV-infected men with long-standing HIV disease demonstrate an increased prevalence and degree of coronary atherosclerosis compared with non-HIV-infected patients. Both traditional and nontraditional risk factors contribute to atherosclerotic disease in HIV-infected patients.

Adenosine stress CT can identify stress-induced myocardial perfusion defects with diagnostic accuracy comparable to SPECT, with similar radiation dose and with the advantage of providing information on coronary stenosis.

Purpose:First, to assess the feasibility of a protocol involving stressinduced perfusion evaluated at computed tomography (CT) combined with cardiac CT angiography in a single examination and second, to assess the incremental value of perfusion imaging over cardiac CT angio graphy in a dual-source technique for the detection of obstructive coronary artery disease (CAD) in a high-risk population. Materials and Methods:Institutional review board approval and informed patient consent were obtained before patient enrollment in the study. The study was HIPAA compliant. Thirty-fi ve patients at high risk for CAD were prospectively enrolled for evaluation of the feasibility of CT perfusion imaging. All patients underwent retrospectively electrocardiographically gated (helical) adenosine stress CT perfusion imaging followed by prospectively electrocardiographically gated (axial) rest myocardial CT perfusion imaging. Analysis was performed in three steps: (a) Coronary arterial stenoses were scored for severity and reader confi dence at cardiac CT angiography, (b) myocardial perfusion defects were identifi ed and scored for severity and reversibility at CT perfusion imaging, and (c) coronary stenosis severity was reclassifi ed according to perfusion fi ndings at combined cardiac CT angiography and CT perfusion imaging. The sensitivity, specifi city, negative predictive value (NPV), and positive predictive value (PPV) of cardiac CT angiography before and after CT perfusion analysis were calculated. Results:With use of a reference standard of greater than 50% stenosis at invasive angiography, all parameters of diagnostic accuracy increased after CT perfusion analysis: Sensitivity increased from 83% to 91%; specifi city, from 71% to 91%; PPV, from 66% to 86%; and NPV, from 87% to 93%. The area under the receiver operating characteristic curve increased signifi cantly, from 0.77 to 0.90 ( P , .005). Conclusion:A combination protocol involving adenosine perfusion CT imaging and cardiac CT angiography in a dual-source technique is feasible, and CT perfusion adds incremental value to cardiac CT angiography in the detection of signifi cant CAD.q RSNA, 2010

Visceral abdominal fat has been associated to cardiovascular risk factors and coronary artery disease (CAD). Computed tomography (CT) coronary angiography is an emerging technology allowing detection of both obstructive and nonobstructive CAD adding information to clinical risk stratification. The aim of this study was to evaluate the association between CAD and adiposity measurements assessed clinically and by CT. We prospectively evaluated 125 consecutive subjects (57% men, age 56.0+/-12 years) referred to perform CT angiography. Clinical and laboratory variables were determined and CT angiography and abdominal CT were performed in a 64-slice scanner. CAD was defined as any plaque calcified or not detected by CT angiography. Visceral and subcutaneous adiposity areas were determined at different intervertebral levels. CT angiography detected CAD in 70 (56%) subjects, and no association was found with usual anthropometric adiposity measurements (waist and hip circumferences and body mass index). Otherwise, CT visceral fat areas (VFA) were significantly related to CAD. VFA T12-L1 values > or =145cm(2) had an odds ratio of 2.85 (95% CI 1.30-6.26) and VFA L4-L5 > or =150cm(2) had a 2.87-fold (95% CI 1.31-6.30) CAD risk. The multivariate analysis determined age and VFA T12-L1 as the only independent variables associated to CAD. Visceral fat assessed by CT is an independent marker of CAD determined by CT angiography.

Summary Epicardial fat accumulation may have important clinical consequences, yet little is known regarding this depot in HIV patients. We compared epicardial fat volume in 78 HIV-infected men and 32 HIV-negative controls. Epicardial fat volume was higher in HIV than control subjects (p=0.04). In HIV patients, epicardial fat volume was strongly associated with visceral adipose tissue area (VAT)(ρ = 0.76, p<0.0001), fasting glucose (ρ = 0.41, p=0.001) and insulin (ρ = 0.44, p=0.0003). Relationships with glucose and insulin remained significant controlling for age, race, BMI, adiponectin, VAT, and antiretroviral therapy. Epicardial fat may be an important fat depot in HIV-infected patients.

Introduction-We have recently described a technique for assessing myocardial perfusion using adenosine-mediated stress imaging (CTP) with dual source computed tomography. SPECT myocardial perfusion imaging (SPECT-MPI) is a widely utilized and extensively validated method for assessing myocardial perfusion. The aim of this study was to determine the level of agreement between CTP and SPECT-MPI at rest and under stress on a per-segment, per-vessel, and per-patient basis.

The ability to simultaneously visualize both coronary atherosclerosis and myocardial perfusion may enable the assessment of the anatomical burden and physiological significance of coronary lesions in a single exam. In this paper we introduce a novel use of the dual source CT: pharmacologically induced stress myocardial perfusion imaging, (SP-DSCT). We describe an experimental protocol by which we used the DSCT to assess both stress and rest myocardial perfusion in order to identify areas of infarcted and ischemic myocardium. Based on our initial investigations, this protocol is feasible and can be used to identify hemodynamically significant stenosis. Nevertheless, further studies are required to determine the incremental value of this technique to traditional coronary CT angiography and/or nuclear stress myocardial perfusion imaging.

Elective vs non-elective radial artery grafts: comparing midterm results through 64-Slice Computed Tomography. Clinics. 2007; 62(6):725-30.BACKGROUND: Left internal thoracic artery to left anterior descending artery (LITA-LADA) grafting has become a fundamental part of the coronary artery bypass graft procedure (CABG). This grafting in turn has led to an increased use of other arterial conduits, of which the radial artery (RA) is most popular. Whether RA grafting can be used in the emergency patient is controversial. METHODS: 47 patients with critical stenosis (≥70%) in all target vessels underwent CABG with LITA and RA grafts from 1996 to 2003. Patients were divided into elective (23 patients) and non-elective groups (24 patients) with LITA and RA grafts per patient being similar in both groups. Of these 47 patients, 5 died from non-cardiac complications and 12 were unavailable. Thus, 30 patients (71% of survivors) were studied by multidetector computed tomography. A total of 36 LITA and 64 RA grafts were studied. RESULTS: The RA patency rate for elective and non-elective grafts were 82% (31/38) and 85% (22/26), respectively (p=0.75). The RA had a similar patency rate for all target vessels ranging from 73% to 100%. Only one patient had a redo CABG and 29 (97%) are free from angina or re-intervention. LITA-LADA had a 92% (11/12) and 100% (10/10) patency rate for elective and non-elective groups, respectively (p=0.37). The sequential LITA-diagonal-LADA in the elective group had a 50% (03/06) patency rate, which was significantly lower than the 100% (08/08) patency rate of the non-elective group (p=0.02). CONCLUSION: Radial Artery grafts can be used in both elective and non-elective patients with excellent results.