Assessment of Pelviureteric Junction Obstruction by Diffusion and Perfusion Parameters on Three Tesla MRI in Comparison with Diuretic Renography

Background: Pelviureteric junction (PUJ) obstruction is a common cause of neonatal and antenatal hydronephrosis, often diagnosed in childhood, but can also affect adults. Diagnosis involves various imaging modalities, with magnetic resonance imaging (MRI) offering high-resolution, non-invasive assessment. Diffusion-weighted MRI (DW-MRI) and dynamic contrast-enhanced (DCE) MRI are advanced techniques that provide functional imaging, while diuretic renography is the established method for evaluating obstruction. This study aims to evaluate the effectiveness of DW-MRI and DCE-MRI parameters compared to diuretic renography in assessing PUJ obstruction. Methods: Thirty patients diagnosed with PUJ obstruction were included in this cross-sectional study conducted at the Urology and Nephrology Center, Mansoura University, Egypt, from October 2023 to September 2024. All patients underwent MRI, including DW-MRI and DCE-MRI, alongside diuretic renography. Results: Significant differences were found between obstructive and non-obstructive groups in diuretic renography, with higher T1/2 and lower glomerular filtration rate (GFR) in obstructive cases (P ≤ 0.001). Apparent diffusion coefficient (ADC) values from DW-MRI significantly differed between groups (P < 0.001). A ROC curve analysis showed that ADC had a sensitivity of 77.8% and specificity of 52.2% for predicting obstruction at a cutoff of 2.17. Conclusion: DW-MRI provides significant functional data that correlates with diuretic renography parameters, demonstrating its potential as a reliable alternative for assessing PUJ obstruction.