Using deep learning methods to shorten acquisition time in children's renal cortical imaging

PurposeThis study evaluates the capability of diffusion-based generative models to reconstruct diagnostic-quality renal cortical images from reduced-acquisition-time pediatric 99mTc-DMSA scintigraphy. Materials and MethodsA prospective study was conducted on 99mTc-DMSA scintigraphic data from consecutive pediatric patients with suspected urinary tract infections (UTIs) acquired between November 2023 and October 2024. A diffusion model SR3 was trained to reconstruct standard-quality images from simulated reduced-count data. Performance was benchmarked against U-Net, U2-Net, Restormer, and a Poisson-based variant of SR3 (PoissonSR3). Quantitative assessment employed peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), Frechet inception distance (FID), and learned perceptual image patch similarity (LPIPS). Renal contrast and anatomic fidelity were assessed using the target-to-background ratio (TBR) and the Dice similarity coefficient respectively. Wilcoxon signed-rank tests were used for statistical analysis. ResultsThe training cohort comprised 94 participants (mean age 5.16{+/-}3.90 years; 48 male) with corresponding Poisson-downsampled images, while the test cohort included 36 patients (mean age 6.39{+/-}3.16 years; 14 male). SR3 outperformed all models, achieving the highest PSNR (30.976{+/-}2.863, P<.001), SSIM (0.760{+/-}0.064, P<.001), FID (25.687{+/-}16.223, P<.001), and LPIPS (0.055{+/-}0.022, P<.001). Further, SR3 maintained excellent renal contrast (TBR: left kidney 7.333{+/-}2.176; right kidney 7.156{+/-}1.808) and anatomical consistency (Dice coefficient: left kidney 0.749{+/-}0.200; right kidney 0.745{+/-}0.176), representing significant improvements over the fast scan (all P < .001). While Restormer, U-Net, and PoissonSR3 showed statistically significant improvements across all metrics, U2-Net exhibited limited improvement restricted to SSIM and left kidney TBR (P < .001). ConclusionSR3 enables high-quality reconstruction of 99mTc-DMSA images from 4-fold accelerated acquisitions, demonstrating potential for substantial reduction in imaging duration while preserving both diagnostic image quality and renal anatomical integrity.