Computed tomography angiography for suspected pulmonary embolism: comparison of 2 adaptive statistical iterative reconstruction blends to filtered back-projection alone.

Objective: The objective of this study was to analyze pulmonary computed tomography angiography image quality and pulmonary embolism (PE) depiction comparing 2 blends of adaptive statistical iterative reconstruction (ASIR) to filtered back-projection alone.

Methods: Seventy-nine consecutive patients (49 women, 30 men; 52 ± 18 years) underwent pulmonary computed tomography angiography (120 kVp, 100-600 mA) reconstructed with filtered back-projection alone (ASIR0), 30% ASIR (ASIR30), and 50% ASIR (ASIR50) for this institutional review board-approved study. Two radiologists independently assessed PE depiction and vascular characterization, which was correlated with body mass index.

Results: Twelve patients (15%) had PE. No difference in PE depiction (P = 0.536), pulmonary arterial attenuation (P = 0.22-0.99), or subjective vascular characterization score (P = 0.58-.016) was observed for either blend. ASIR30 and ASIR50 achieved higher signal-to-noise ratio (P = 0.001-0.003). Body mass index inversely correlated with vascular characterization scores (P < 0.001).

Conclusions: ASIR0, ASIR30, and ASIR50 accurately depict PE using the imaging parameters described. ASIR30 and ASIR50 improve objective image quality without altering subjective vascular characterization scores particularly when body mass index was less than 30 kg/m.