Sustainable four-dimensional cardiac CT: Minimizing data storage via reduced matrix size with optimized reconstruction.

Introduction: The increasing volume of four-dimensional cardiac CT data complicates transcatheter aortic valve repair (TAVR) planning, particularly regarding data storage. This study evaluates a modified 256 × 256 reconstruction method for TAVR-CT that reduces storage requirements while maintaining aortic valve measurement accuracy.

Methods: A retrospective analysis was performed on 75 TAVR-CT scans obtained using the dual-source energy-integrating detector CT. The modified 256 × 256 reconstruction used a sharper Bv44 kernel (iterative construction strength 4) and narrowed the field of view to 80 %. We assessed virtual basal ring (BR) areas using reference 512 × 512, standard 256 × 256, and modified 256 × 256 images. Five technologists-three from the CT team and two from the interventional radiology (IR) team-manually evaluated the BR areas. The measurements were averaged within each team. The intraclass correlation coefficient (ICC), bias, and consistency in device selection were assessed.

Results: Among 75 patients (48 women, median age 85), the mean BR area was 416.2 ± 77.9 mm. The mean bias between the modified 256 × 256 and reference 512 × 512 images was -2.5 mm (95 % CI: -5.2 to 0.3), significantly smaller (P = 0.04) than the bias between standard 256 × 256 and reference (4.1 mm, 95 % CI: 0.7 to 7.5). BR measurements demonstrated excellent reproducibility (ICC = 0.996-0.997), with limits of agreement (LOA) for the modified 256 × 256 ranging from -13.0 to 12.2 mm for the IR team and -14.5 to 11.6 mm for the CT team, comparable to the inter-team LOA of -18.1 to 13.1 mm. Valve selection consistency was 95 % (Cohen's Kappa = 0.92).

Conclusion: The modified 256 × 256 reconstruction method effectively preserved BR measurements and valve selection reliability.

Implications For Practice: The proposed 256 × 256 method could cut data storage while ensuring accurate valve selection.