Prospective Randomized Trial On RadiaTion Dose Estimates Of CT AngIOgraphy In PatieNts Scanned With A Sequential Scan Protocol

Overview

The objective of this study is to compare radiation dose of a standard spiral scan with the a new sequential scan protocol. We hypothesize that the sequential scan protocol is associated with a reduction in dose estimates of at least 20%, while the diagnostic image quality is not inferior. Secondary endpoints of the study include quantitative image quality parameters, diagnostic accuracy for spiral versus sequential studies compared to invasive angiography in patients who underwent subsequent invasive coronary angiography.

All patients scheduled for a coronary CT scan are screened for inclusion and exclusion criteria. Patients are included if they have stable sinus rhythm (heart rate \<75 bpm for dual source CT and \<65 bpm for 64-slice CT). Informed signed consent is obtained from these patients and the CT scan is prepared. After topogram scan and the native scan for Ca-Scoring, patients are randomized in two groups with the use of sealed envelopes. After that contrast-enhanced coronary CT angiography is performed with the standard spiral protocol or with the sequential protocol. The CT examination is evaluated by two experienced investigators on a per-vessel basis and all results and study-related data are collected in a dedicated database. For assessment of image quality, a previously established 4-point score system is used and quantitative image quality parameters are measured. A 30 day follow-up after the CT examination aims to evaluate if patients underwent invasive coronary angiography or were scheduled for a myocardial stress / perfusion test (such as stress-echocardiography, myocardial scintigraphy or stress perfusion imaging by MRI).