Evaluation of a super-resolution deep learning reconstruction algorithm in abdominal CT imaging-A qualitative and quantitative performance analysis.

BACKGROUND

A super-resolution deep learning (DL) image reconstruction algorithm (Precise Image Quality Engine (PIQE)) was originally designed for cardiac CT, but is now available for abdominal CT.

PURPOSE: To examine objective and subjective image quality (IQ) improvements PIQE compared to Advanced Intelligent Clear-IQ Engine (AiCE) in abdominal CT.

METHODS

A retrospective analysis was conducted on 69 adult patient routine contrast enhanced abdominopelvic CT exams on a single Aquilion ONE/INSIGHT CT system (Canon Medical Systems, Otawara Japan). Images were reconstructed using PIQE (strength level L1 and L2) and AiCE (L1- the institutional standard). Four blinded radiologists assessed image noise, image contrast, small structure visibility, image sharpness, artifacts, and overall image preference with Likert scales. Reader agreement was assessed with Krippendorff's alpha. Circular regions of interest were placed on five slices on the left and right liver, portal vein, aorta, subcutaneous fat, and bilateral psoas muscles. CT number, noise, signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs) were determined. All significant differences between reconstructions were assessed via the Friedman test with post-hoc Dunn-Sidak corrections.

RESULTS

Reader agreement was fair ( α ¯ = 0.20 $\bar{\alpha}=0.20$ ). PIQE L2 was preferred for image contrast and image noise and PIQE L1 was preferred for image sharpness (p < 0.05). CT numbers were significantly different between AiCE L1 and PIQE (p < 0.05) and noise was statistically lowest in PIQE L2 compared to AiCE L1 (p < 0.05). SNR and CNR differences were statistically significant (p < 0.003), with PIQE L2 demonstrating the highest SNR and CNR.

CONCLUSION

The best subjective IQ metrics for image contrast, image noise, and image sharpness were obtained with PIQE. The best objective IQ metrics (SNR and CNR) were obtained with PIQE L2. This work supports improved image contrast and decreased noise when using PIQE as compared to AiCE.