High-pitch dual-source CT in prospectively electrocardiogram-triggered spiral double scanning mode for diagnosing coronary artery patency

Objective: To assess the image quality, diagnostic accuracy and effective radiation dose of prospectively ECG- triggered high-pitch spiral double scanning (Double Flash) mode of computed tomography coronary angiography (CTCA) using dual-source CT for the diagnosis of significant coronary stenoses.

Methods: Patients underwent both CTCA in Double Flash mode and conventional coronary angiography (CAG) and were divided into two groups according to heart rate (HR), namely group A with HR <65/min (62 cases) and group B with HR between 65 and 80/min (52 cases). All the coronary segments were evaluated by two blinded and independent observers for image quality on a four-point scale and for the presence of significant coronary stenoses (defined as a diameter narrowing exceeding 50%). CAG served as the reference standard for analyzing the diagnostic accuracy of Double Flash mode images on the level of both patients and vessels. Radiation dose values were calculated using the dose-length product.

Results: A total of 114 patients were enrolled and 1725 vessel segments were displayed. In terms of image quality, the diagnosable segments accounted for 98.5% (919/933) in group A and 97.3% (770/792) in group B. In the per-patient analysis, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 100%, 90.5%, 88.2%, 100% and 96.7% in group A and were 100%, 88.5%, 94.5%, 100% and 96.2% in group B, respectively. The mean effective radiation dose was 1.63∓0.52 mSv.

Conclusions: Double Flash spiral protocol of dual-source CTCA can acquire good image quality and yield high diagnostic accuracy for assessment of coronary artery stenoses at a low radiation dose in patients with HR between 65 and 80/min.