Detection of coronary artery stenosis with sub-milliSievert radiation dose by prospectively ECG-triggered high-pitch spiral CT angiography and iterative reconstruction.
Level 3 - non-randomized controlled study
Prospective consecutive diagnostic cohort study validating an imaging protocol against a reference standard.
PubMed 23807568 · doi:10.1007/s00330-013-2920-0
What was done
Forty consecutive patients (mean age 52.9 ± 8.7 years; 30 men) underwent dual-source coronary CT angiography (cCTA) using prospectively ECG-triggered high-pitch spiral acquisition with the tube current-time product set to 50% of standard-of-care CT examinations. Images were reconstructed with sinogram-affirmed iterative reconstruction. Diagnostic performance for identifying ≥50% coronary stenosis was evaluated against catheter coronary angiography as the reference standard.
What was found
Coronary CT angiography was successfully completed in all 40 patients. Of 601 assessable coronary segments, 543 (90.3%) achieved diagnostic image quality. For detecting ≥50% stenosis, per-patient sensitivity was 95.7% (95% CI, 76.0–99.8%) and specificity was 94.1% (95% CI, 69.2–99.7%), with an area under the receiver-operating characteristic curve (AUC) of 0.949. Per-vessel sensitivity was 89.5% (95% CI, 77.8–95.6%) and specificity was 93.2% (95% CI, 86.0–97.0%), with an AUC of 0.913. Mean effective radiation dose was 0.58 ± 0.17 mSv and mean size-specific dose estimate was 3.14 ± 1.15 mGy.
Why it matters
The study shows that prospectively ECG-triggered high-pitch spiral coronary CT angiography combined with iterative reconstruction can maintain high diagnostic accuracy for coronary stenosis while keeping radiation exposure under 1 mSv.
Limits
The study is limited by a small sample size (n = 40) and a male-predominant population (75%). Nearly 10% of coronary segments (58/601) had non-diagnostic image quality. The abstract does not provide details on blinding, patient heart rate eligibility, or BMI restrictions.
Cited by
- supports Coronary CT angiograms exposed patients to around 20 millisieverts of radiation 20 years ago, whereas modern CTAs deliver less than 1 millisievert.