Image quality of ultra-low radiation exposure coronary CT angiography with an effective dose <0.1 mSv using high-pitch spiral acquisition and raw data-based iterative reconstruction

We evaluated the potential of prospectively ECG-triggered high-pitch spiral acquisition with low tube voltage and current in combination with iterative reconstruction to achieve coronary CT angiography with sufficient image quality at an effective dose below 0.1 mSv.Contrast-enhanced coronary dual source CT angiography (2 x 128 x 0.6 mm, 80 kV, 50 mAs) in prospectively ECG-triggered high-pitch spiral acquisition mode was performed in 21 consecutive individuals (body weight < 100 kg, heart rate a parts per thousand currency sign60/min). Images were reconstructed with raw data-based filtered back projection (FBP) and iterative reconstruction (IR). Image quality was assessed on a 4-point scale (1 = no artefacts, 4 = unevaluable).Mean effective dose was 0.06 +/- 0.01 mSv. Image noise was significantly reduced in IR (128.9 +/- 46.6 vs. 158.2 +/- 44.7 HU). The mean image quality score was lower for IR (1.9 +/- 1.1 vs. 2.2 +/- 1.0, P < 0.0001). Of 292 coronary segments, 55 in FBP and 40 in IR (P = 0.12) were graded "unevaluable". In patients with a body weight a parts per thousand currency sign75 kg, both in FBP and in IR, the rates of fully evaluable segments were significantly higher in comparison to patients > 75 kg.Coronary CT angiography with an estimated effective dose < 0.1 mSv may provide sufficient image quality in selected patients through the combination of high-pitch spiral acquisition and raw data-based iterative reconstruction.