Influence of heart rate on vessel visibility in noninvasive coronary angiography using new multislice computed tomography - Experience in 94 patients

Objectives: Initial reports indicate that coronary artery lesions might be visualized with high sensitivity and specificity by the use or recently introduced multislice computed tomography (MSCT). Current CT technology offers a temporal resolution of 250 ms. In case of heart rates (HRs) > 65 beats/min (bpm), however, the reconstruction software switches from a single-phase algorithm (using data front one heart cycle only) to a biphase algorithm using image data of two consecutive heart cycles, improving temporal resolution to down to 125 ms. Thus, it was the aim of the present study to evaluate the influence of the patients' (pts) HR on image quality expressed by vessel segment visibility. Methods and results: MSCT scans (Somatom VZ) were performed in 94 pts. Ten coronary segments were analyzed in each patient with regard to image quality (RCA: segments [sgts] 1-4, LMS: sgt 5, LAD: sgts 5-8. LCX: sgts 11, 12). A total of 697 of 940 (74.1%) sgts were accurately visualizable (RCA: 244/376 [64.9%], LMS: 94/94 [100%], LAD: 232/283 (82.3%), LCX: 146/188 [77.7%]). beta-Blocker therapy had a significant influence on mean HR (65 pts on beta-blocker, HR 65.1 +/- 10.7 bpm vs. 29 pts, HR 71.6 +/- 12.2 bpm, P < .01). A significant inverse correlation between HR and segmental visibility was found (r = -.48, P < .0001), with best visibility in pts with lower HRs (n = 14 pts with 10 analyzable sgts, HR 60 +/- 10.1 vs. n = 8 pis with 4 analyzable sgts, HR 79.9 +/- 6.9, P < .0001). Conclusions: Our results indicate that vessel visibility is highly dependent on the pts FIR. Best vessel visibility was found in pis with HR < 65 bpm with single-phase image reconstruction. Thus, it appears to be advisable to evaluate, and if needed, to lower the pis HRs before undergoing MSCT coronary angiography in order to achieve best image quality. (C) 2002 Elsevier Science Inc. All rights reserved.