Published in:
01-11-2009 | Cardiac
Prospectively ECG-triggered high-pitch spiral acquisition for coronary CT angiography using dual source CT: technique and initial experience
Published in: European Radiology | Issue 11/2009
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Objective
We evaluated radiation exposure and image quality of a new coronary CT angiography protocol, high-pitch spiral acquisition, using dual source CT (DSCT).
Material and methods
Coronary CTA was performed in 25 consecutive patients with a stable heart rate of 60 bpm or less after premedication, using 2 × 128 0.6-mm sections, 38.4-mm collimation width and 0.28-s rotation time. Tube settings were 100 kV/320 mAs and 120 kV/400 mAs for patients below and above 100-kg weight, respectively. Data acquisition was prospectively ECG-triggered at 60% of the R–R interval using a pitch of 3.2 (3.4 for the last 10 patients). Images were reconstructed with 75-ms temporal resolution, 0.6-mm slice thickness and 0.3-mm increment. Image quality was evaluated using a four-point scale (1 = excellent, 4 = unevaluable).
Results
Mean range of data acquisition was 113 ± 22 mm, mean duration was 268 ± 23 ms. Of 363 coronary artery segments, 327 had an image quality score of 1, and only 2 segments were rated as “unevaluable”. Mean dose–length product (DLP) was 71 ± 23 mGy cm, mean effective dose was 1.0 ± 0.3 mSv (range 0.78–2.1 mSv). For 21 patients with a body weight below 100 kg, mean DLP was 63 ± 5 mGy cm (0.88 ± 0.07 mSv; range 0.78–0.97 mSv).
Conclusion
Prospectively ECG-triggered high-pitch spiral CT acquisition provides high and stable image quality at very low radiation dose.