Coronary angiography with 64-section CT provides diagnostic image quality within a wide range of heart rates. Reducing average heart rate and heart rate variability is beneficial for reducing artifacts.

Functionally relevant coronary artery disease: comparison of 64-section CT angiography with myocardial perfusion SPECT Gaemperli, O; Schepis, T; Valenta, I; Koepfli, P; Husmann, L; Scheffel, H; Leschka, S; Eberli, F R; Luscher, T F; Alkadhi, H; Kaufmann, P A Gaemperli, O; Schepis, T; Valenta, I; Koepfli, P; Husmann, L; Scheffel, H; Leschka, S; Eberli, F R; Luscher, T F; Alkadhi, H; Kaufmann, P A (2008 Functionally relevant coronary artery disease: comparison of 64-section CT angiography with myocardial perfusion SPECT Abstract PURPOSE: To prospectively determine the accuracy of 64-section computed tomographic (CT) angiography for the depiction of coronary artery disease (CAD) that induces perfusion defects at myocardial perfusion imaging with single photon emission computed tomography (SPECT), by using myocardial perfusion imaging as the reference standard. MATERIALS AND METHODS: All patients gave written informed consent after the study details, including radiation exposure, were explained. The study protocol was approved by the local institutional review board. In patients referred for elective conventional coronary angiography, an additional 64-section CT angiography study and a myocardial perfusion imaging study (1-day adenosine stress-rest protocol) with technetium 99m-tetrofosmin SPECT were performed before conventional angiography. Coronary artery diameter narrowing of 50% or greater at CT angiography was defined as stenosis and was compared with the myocardial perfusion imaging findings. Quantitative coronary angiography served as a reference standard for CT angiography. RESULTS: A total of 1093 coronary segments in 310 coronary arteries in 78 patients (mean age, 65 years +/-9 [standard deviation]; 35 women) were analyzed. CT angiography revealed stenoses in 137 segments (13%) corresponding to 91 arteries (29%) in 46 patients (59%). SPECT revealed 14 reversible, 13 fixed, and six partially reversible defects in 31 patients (40%). Sensitivity, specificity, and negative and positive predictive values, respectively, of CT angiography in the detection of reversible myocardial perfusion imaging defects were 95%, 53%, 94%, and 58% on a per-patient basis and 95%, 75%, 96%, and 72% on a per-artery basis. Agreement between CT and conventional angiography was very good (96% and kappa = 0.92 for patient-based analysis, 93% and kappa = 0.84 for vessel-based analysis). CONCLUSION: Sixty-four-section CT angiography can help rule out hemodynamically relevant CAD in patients with intermediate to high pretest likelihood, although an abnormal CT angiography study is a poor predictor of ischemia. Purpose:To prospectively determine the accuracy of 64-section computed tomographic (CT) angiography for the depiction of coronary artery disease (CAD) that induces perfusion defects at myocardial perfusion imaging with single photon emission computed tomography (SPECT), by using myocardial perfusion imaging as the reference standard. Materials and Methods:All patients gave written informed consent after the study details, includi...

The depiction rate of MB is greater with 64-section CT coronary angiography than with conventional coronary angiography. The degree of systolic compression of MB significantly correlates with tunneled segment depth but not length.

The reconstruction intervals providing best image quality for non-invasive coronary angiography with 64-slice computed tomography (CT) were evaluated. Contrastenhanced, retrospectively electrocardiography (ECG)-gated 64-slice CT coronary angiography was performed in 80 patients (47 male, 33 female; mean age 62.1±10.6 years). Thirteen data sets were reconstructed in 5% increments from 20 to 80% of the R-R interval. Depending on the average heart rate during scanning, patients were grouped as <65 bpm (n=49) and ≥65 bpm (n=31). Two blinded and independent readers assessed the image quality of each coronary segment with a diameter ≥1.5 mm using the following scores: 1, no motion artifacts; 2, minor artifacts; 3, moderate artifacts; 4, severe artifacts; and 5, not evaluative. The average heart rate was 63.3±13.1 bpm (range 38-102). Acceptable image quality (scores 1-3) was achieved in 99.1% of all coronary segments (1,162/1,172; mean image quality score 1.55±0.77) in the best reconstruction interval. Best image quality was found at 60% and 65% of the R-R interval for all patients and for each heart rate subgroup, whereas motion artifacts occurred significantly more often (P<0.01) at other reconstruction intervals. At heart rates <65 bpm, acceptable image quality was found in all coronary segments at 60%. At heart rates ≥65 bpm, the whole coronary artery tree could be visualized with acceptable image quality in 87% (27/31) of the patients at 60%, while ten segments in four patients were rated as non-diagnostic (scores 4-5) at any reconstruction interval. In conclusion, 64-slice CT coronary angiography provides best overall image quality in mid-diastole. At heart rates <65 bpm, diagnostic image quality of all coronary segments can be obtained at a single reconstruction interval of 60%.

Background-Although no data exist on the effect of altitude exposure on coronary flow reserve (CFR), patients with coronary artery disease (CAD) are advised not to exceed moderate altitudes of Ϸ2500 m above sea level. We studied the influence of altitude on myocardial blood flow (MBF) in controls and CAD patients. Methods and Results-In 10 healthy controls and 8 patients with CAD, MBF was measured by positron emission tomography and 15 O-labeled water at rest, during adenosine stress, and after supine bicycle exercise. This protocol was repeated during inhalation of a hypoxic gas mixture corresponding to an altitude of 4500 m (controls) and 2500 m (CAD). Workload was targeted to comparable heart rate-blood pressure products at normoxia and hypoxia. Resting MBF increased significantly in controls at 4500 m (ϩ24%, PϽ0.01) and in CAD patients at 2500 m (ϩ24%, PϽ0.05). Altitude had no influence on adenosine-induced hyperemia and CFR. Exercise-induced hyperemia increased significantly in controls (ϩ38%, PϽ0.01) at 4500 m (despite a reduction in workload, Ϫ28%, PϽ0.0001) but not in CAD patients at 2500 m (moderate decrease in workload, Ϫ11%, PϽ0.05). Exercise-induced reserve was preserved in controls (ϩ10%, PϭNS) but decreased in CAD patients (Ϫ18%, PϽ0.005). Conclusions-At 2500 m altitude, there is a significant decrease in exercise-induced reserve in CAD patients, indicating that compensatory mechanisms might be exhausted even at moderate altitudes, whereas healthy controls have preserved reserve up to 4500 m. Thus, patients with CAD and impaired CFR should be cautious when performing physical exercise even at moderate altitude.