Diagnostic image quality of a comprehensive high-pitch dual-spiral cardiothoracic CT protocol in patients with undifferentiated acute chest pain

Objective: To evaluate diagnostic image quality of high-pitch dual source comprehensive cardiothoracic CT protocol in patients presenting with acute undifferentiated chest pain. Materials and methods: Consecutive symptomatic subjects (n = 51) with undifferentiated acute chest pain underwent ECG-synchronized high-pitch dual-spiral chest CT angiography (Definition Flash, Siemens Medical Solutions, 2 x 100 kVp or 2 x 120 kV if BMI > 30, collimation: 128 x 0.6 mm, pitch: 3.2). Independent investigators determined the image quality of each cardiac and pulmonary vessel segment, measured contrast-to-noise-ratio (CNR), and determined radiation exposure. In addition, the prevalence of CT findings (pulmonary embolism (PE), aortic dissection (AD) and significant coronary stenosis (>= 50%)) was determined. Univariate and multivariate analysis were performed to determine the subpopulation with highest diagnostic quality. Results: Among 51 subjects (66% male, average age: 63 +/- 15.8), the prevalence of positive CT findings was moderate (overall: 11.7%). Overall, image quality of the pulmonary, aortic and coronary vasculature was good (1.26 +/- 0.43 and CNR: 2.52) with an average radiation dose of 3.82 mSv and 3.2% of segments rated non-evaluable. The image quality was lowest in the coronary arteries (p = 0.02), depending on the heart rate (r = 0.52, p < 0.001). In subjects with a heart rate of = 65 bpm (n = 30) subjective image quality and CNR of the coronary arteries were higher (1.6 +/- 0.5 vs. 2.1 +/- 0.5, p = 0.03 and 1.21 +/- 0.3 vs. 1.02 +/- 0.3, p = 0.05) with only 1.5% segments classified as non-evaluable. Conclusion: High-pitch dual-spiral comprehensive cardiothoracic CT provides low radiation exposure with excellent image quality at heart rates = 65 bpm. In subjects with higher heart rates, image quality of the aortic and pulmonary vasculature remains excellent, while the assessment of the coronary arteries degrades substantially. (c) 2010 Elsevier Ireland Ltd. All rights reserved.