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

Purpose This study evaluates the capability of diffusion-based generative models to reconstruct diagnostic-quality renal cortical images from reduced-acquisition-time pediatric 99mTc-DMSA scintigraphy.

A 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), Fréchet 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.

The 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).

SR3 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. Competing Interest Statement Author C. G. works for RadioDynamic Medical. Authors B. P., N.G. are the stockholders of RadioDynamic Medical. Funding Statement This study was funded by Natural Science Foundation of Xiamen 3502Z202373090. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Ethics Committee of Xin Hua Hospital Affiliated to Shanghai Jiaotong University School of Medicine gave ethical Approval No. XHEC-D-2025-116 for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes Clinical Trial Registration: Ethics Committee of Xin Hua Hospital Affiliated to Shanghai Jiaotong University School of Medicine No. XHEC-D-2025-116 Data Availability All data produced in the present study are available upon reasonable request to the authors.