Purpose or Case Report: Nephrolithiasis, once considered an adult condition, is now increasingly prevalent in pediatric populations, leading to flank pain, hydronephrosis, and potential renal failure. Traditional imaging modalities for diagnosing pediatric nephrolithiasis, such as ultrasound and CT, are evolving, with newer protocols (e.g., ultra-low dose CT with tin filtration) being developed. The aim of this study was to design and validate an ex vivo porcine model to simulate pediatric renal stones, providing a substrate for the advancement of imaging techniques in renal stone detection and characterization.
Methods & Materials: Grocery-grade porcine kidneys were selected to mimic pediatric renal parenchyma. Spherical surrogates, created by cutting a B-complex vitamin pill (Nature Made Nutritional Products, West Hills, CA) into varying diameters (1 mm, 2 mm, 3 mm, 4 mm, and 8 mm), were used to simulate renal stones. These were inserted into the porcine kidneys to create a model. The model underwent concurrent CT and ultrasound imaging to assess its suitability for renal stone research. Key imaging features, including echogenicity and attenuation, were compared to pediatric renal stones.
Results: The porcine kidney parenchyma exhibited echogenicity similar to that of pediatric kidneys. Surrogate stones demonstrated typical sonographic features of real pediatric renal stones, including acoustic shadowing and the twinkle artifact. CT imaging revealed attenuation values of 55±5 HU for the porcine parenchyma and 513±39 HU for the surrogate stones, closely matching pediatric values (39±29 HU and 552±294 HU, respectively, based on a cohort of 17 children aged 4-16 years with renal stones). The correlation between the spatial locations and sizes of the surrogate stones was consistent across both ultrasound and CT modalities
Conclusions: This ex vivo porcine model provides a cost-effective, ethically sound alternative for renal stone imaging research. It offers imaging fidelity comparable to in vivo models while avoiding limitations such as radiation concerns and maintenance challenges. The model’s simplicity, ease of construction, and disposable nature make it an invaluable tool for the development and optimization of innovative imaging techniques in pediatric nephrolithiasis