Author(s): Achenbach S, Ropers U, Kuettner A, Anders K, Pflederer T,
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Abstract OBJECTIVES: The purpose of this study was to analyze the influence of a systematic approach to lower heart rate for coronary computed tomography (CT) angiography on diagnostic accuracy of 64-slice single- and dual-source CT. BACKGROUND: Coronary CT angiography is often impaired by motion artifacts, so that routine lowering of heart rate is usually recommended. This is often conceived as a major limitation of the technique. It is expected that higher temporal resolution, such as with dual-source 64-slice CT, would allow diagnostic imaging even without systematic pre-treatment for lowering the heart rate. METHODS: Two hundred patients with suspected coronary artery disease were first randomized to either 64-slice single-source CT (n = 100) or dual-source CT (n = 100) for contrast-enhanced coronary artery evaluation. In each group, patients were further randomized to either receive systematic heart rate control (oral and intravenous beta-blockade for a target heart rate < or =60 beats/min) or receive no premedication. Evaluability of datasets and diagnostic accuracy were compared between groups against the results obtained from invasive angiography. RESULTS: Systematic pre-treatment lowered heart rate during CT coronary angiography by 10 beats/min. Heart rate control significantly improved evaluability in single-source CT (93\% vs. 69\% on a per-patient basis, p = 0.005), whereas it did not in dual-source CT (96\% vs. 98\%). In evaluable patients, sensitivity to detect the presence of at least 1 coronary stenosis by single-source CT was 86\% and 79\%, respectively, with and without heart rate control (p = NS). For dual-source CT, it was 100\% and 95\%, respectively (p = NS). The rate of correctly classified patients, defined as evaluable and correct classification as to the presence or absence of at least 1 coronary artery stenosis, was significantly improved by heart rate control in single-source CT (78\% vs. 57\%, p = 0.04), whereas there was no such influence in dual-source CT (87\% vs. 93\%). CONCLUSIONS: Systematic heart rate control significantly improves image quality for coronary visualization by 64-slice single-source CT, whereas image quality and diagnostic accuracy remain unaffected in dual-source CT angiography. Improved temporal resolution obviates the need for heart rate control.
This article was published in JACC Cardiovasc Imaging
and referenced in Journal of Vascular Medicine & Surgery