Reducing radiation dose in the diagnosis of pulmonary embolism using adaptive statistical iterative reconstruction and lower tube potential in computed tomography.

Objectives: To assess the impact of ASIR (adaptive statistical iterative reconstruction) and lower tube potential on dose reduction and image quality in chest computed tomography angiographies (CTAs) of patients with pulmonary embolism.

Materials And Methods: CT data from 44 patients with pulmonary embolism were acquired using different protocols-Group A: 120 kV, filtered back projection, n = 12; Group B: 120 kV, 40 % ASIR, n = 12; Group C: 100 kV, 40 % ASIR, n = 12 and Group D: 80 kV, 40 % ASIR, n = 8. Normalised effective dose was calculated; image quality was assessed quantitatively and qualitatively.

Results: Normalised effective dose in Group B was 33.8 % lower than in Group A (p = 0.014) and 54.4 % lower in Group C than in Group A (p < 0.001). Group A, B and C did not show significant differences in qualitative or quantitative analysis of image quality. Group D showed significantly higher noise levels in qualitative and quantitative analysis, significantly more artefacts and decreased overall diagnosability. Best results, considering dose reduction and image quality, were achieved in Group C.

Conclusions: The combination of ASIR and lower tube potential is an option to reduce radiation without significant worsening of image quality in the diagnosis of pulmonary embolism.

Key Points: • Iterative algorithms and lowering of tube potential reduce radiation without compromising interpretability • 40 % ASIR and 100 kV tube potential led to a 54.4 % dose reduction • 40 % ASIR and 80 kV tube potential led to significantly worse image quality.