The feasibility of Forward-projected model-based Iterative Reconstruction SoluTion (FIRST) for coronary 320-row computed tomography angiography: A pilot study.

BACKGROUND: We aimed to assess and compare the influence of Forward projected model-based Iterative Reconstruction SoluTion (FIRST), a recently introduced full iterative reconstruction method, on radiation doses and image quality with that of Adaptive Iterative Dose Reduction (AIDR) 3D for 320-row cardiac computed tomography (CT).

METHODS: A total of 184 patients subjected to single-beat reconstruction cardiac CT were retrospectively included. The first 89 patients received standard radiation doses; their data were reconstructed using AIDR 3D, whereas the last 95 patients received in average 20% reduction in tube current; their data were reconstructed using FIRST. Subjective image quality (blooming, image sharpness, image noise, and overall subjective image quality) were graded using 3-, 5-, 4-, and 4-point scales (0-2, 1-5, 1-4, and 1-4), respectively; for all items, the highest score indicated excellent image quality. Image noise and signal-to-noise ratios at proximal segments were analyzed as objective measures of image quality.

RESULTS: FIRST reconstruction allowed 28% dose reduction compared with AIDR 3D (1.88 vs. 2.61 mSv, p = 0.012) and yielded better subjective image quality in terms of blooming, image sharpness, image noise, and overall image quality (1.10 vs. 1.01, p = 0.0007; 3.02 vs. 2.74, p < 0.0001; 3.61 vs. 3.17, p < 0.0001; and 3.30 vs. 2.98, p < 0.0001, respectively). Although no significant difference was observed in image noise, the signal-to-noise ratio was significantly higher with FIRST (18.4 vs. 16.6, p = 0.0066).

CONCLUSIONS: FIRST allowed 28% dose reduction while improving image quality.