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
Authors:
Michael Lell, Mohamed Marwan, Tiziano Schepis, Tobias Pflederer, Katharina Anders, Thomas Flohr, Thomas Allmendinger, Willi Kalender, Dirk Ertel, Carsten Thierfelder, Axel Kuettner, Dieter Ropers, Werner G. Daniel, Stephan Achenbach
Published in:
European Radiology
|
Issue 11/2009
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Abstract
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.