High-pitch coronary CT angiography with third generation dual-source CT: limits of heart rate

Gordic, Sonja ; Husarik, Daniela ; Desbiolles, Lotus ; Leschka, Sebastian ; Frauenfelder, Thomas ; Alkadhi, Hatem

In: The International Journal of Cardiovascular Imaging, 2014, vol. 30, no. 6, p. 1173-1179

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    To determine the average heart rate (HR) and heart rate variability (HRV) required for diagnostic imaging of the coronary arteries in patients undergoing high-pitch CT-angiography (CTA) with third-generation dual-source CT. Fifty consecutive patients underwent CTA of the thoracic (n=8) and thoracoabdominal (n=42) aorta with third-generation dual-source 192-slice CT with prospective electrocardiography (ECG)-gating at a pitch of 3.2. No β-blockers were administered. Motion artifacts of coronary arteries were graded on a 4-point scale. Average HR and HRV were noted. The average HR was 66±11beats per minute (bpm) (range 45-96bpm); the HRV was 7.3±4.4bpm (range 3-20bpm). Interobserver agreement on grade of image quality for the 642 coronary segments evaluated by both observers was good (κ=0.71). Diagnostic image quality was found for 608 of the 642 segments (95%) in 43 of 50 patients (86%). In 14% of the patients, image quality was nondiagnostic for at least one segment. HR (p=0.001) was significantly higher in patients with at least one non-diagnostic segment compared to those without. There was no significant difference (p>0.05) in HRV between patients with nondiagnostic segments and those with diagnostic images of all segments. All patients with a HR<70bpm had diagnostic image quality in all coronary segments. The effective radiation dose and scan time for the heart were 0.4±0.1mSv and 0.17±0.02s, respectively. Third-generation dual-source 192-slice CT allows for coronary angiography in the prospectively ECG-gated high-pitch mode with diagnostic image quality at HR up to 70bpm. HRV is not significantly related to image quality of coronary CTA.