Effects of reconstruction technique on the quality of abdominal CT angiography: A comparison between forward projected model-based iterative reconstruction solution (FIRST) and conventional reconstruction methods.

Purpose: This study aimed to compare the quality of abdominal CT angiography (CTA) images obtained using conventional reconstruction algorithms with those obtained using a novel iterative algorithm (forward projected model-based iterative reconstruction solution, FIRST) for evaluating arteries in the abdomen.

Materials And Methods: Abdominal CTA images from 60 patients (M:F = 27:33; mean age, 62.4 ± 16.7 years) were reconstructed using three algorithms - filtered back projection (FBP), adaptive iterative dose reduction 3D (AIDR 3D), and FIRST. Image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in the abdominal aorta, celiac trunk, superior mesenteric, renal, and right hepatic arteries were objectively evaluated via region-of-interest analysis and compared using the one-way analysis of variance test. Two radiologists independently scored and selected the best (score 3), second best (score 2), and the worst (score 1) images based on the visual image quality of peripheral arteries. Wilcoxon signed rank test was used for comparing image quality scores.

Results: FIRST and AIDR 3D significantly reduced image noise compared with FBP (P < 0.001). SNR and CNR were significantly higher with AIDR 3D and FIRST than with FBP reconstruction (P < 0.001), with FIRST displaying the highest CNR (14.31 ± 4.17) for the right hepatic artery than the other two methods (P < 0.05). Both radiologists scored FIRST images as having the best image quality among the three methods for peripheral abdominal artery evaluation (3.0 ± 0.0, P < 0.001).

Conclusion: FIRST reconstruction yielded superior abdominal CTA images as compared with FBP or AIDR 3D reconstruction.