Low-Dose CT Coronary Angiography in the Step-and-Shoot Mode: Diagnostic Performance
Hans Scheffel 1, Hatem Alkadhi 1*, Sebastian Leschka 2, Andre Plass 3, Lotus Desbiolles 1, Ivo Guber 3, Tobias Krauss 1, Juerg Gruenenfelder 3, Michele Genoni 3, Thomas F Luescher 4, Borut Marincek 1 and Paul Stolzmann 1
1 Institute of Diagnostic Radiology, Switzerland
2 University Hospital Zurich, Switzerland
3 Clinic for Cardiovascular Surgery, Switzerland
4 Cardiovascular Center, Switzerland
* To whom correspondence should be addressed. E-mail: hatem.alkadhi{at}usz.ch.
Accepted 20 May 2008
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Objective
We investigated the performance of low-dose dual-source computed tomography (DSCT) coronary angiography in the step-and-shoot (SAS) mode for the diagnosis of significant coronary artery stenoses in comparison with conventional coronary angiography (CCA).
Design, Setting and Patients
Prospective, single-center study conducted in a referral center enrolling 120 patients (71 males, age 68±9 years, BMI 26.2±3.2 kg/m2). All study participants underwent DSCT in the SAS mode and CCA within 14 days. Twenty-seven patients were given IV beta-blockers for heart rate reduction prior to CT. Patients were excluded if a target heart rate >70 bpm could not be achieved by beta-blockers or when the patients were in non-sinus rhythm. Two blinded readers independently evaluated coronary artery segments for assessability and for the presence of significant (>50%) stenoses. Sensitivity, specificity, negative (NPV) and positive predictive value (PPV) were determined with CCA being the standard of reference. Radiation dose values were calculated.
Results
DSCT coronary angiography in the SAS mode was successfully performed in all 120 patients. Mean heart rate during scanning was 59±6bpm (range 44-69bpm). 1773/1803 coronary segments (98%) were depicted with a diagnostic image quality in 109/120 patients (91%). The overall patient-based sensitivity, specificity, PPV, and NPV for the diagnosis of significant stenoses were 100%, 93%, 94%, and 100%. The mean effective dose of the CT protocol was 2.5±0.8mSv (range 1.2-4.4mSv).
Conclusions
DSCT coronary angiography in the SAS mode allows in selected patients with a regular heart rate for the accurate diagnosis of significant coronary stenoses at a low radiation dose.
