Prediction of split renal function and obstruction with magnetic resonance urography in comparison with dynamic renal...

Magnetic resonance urography (MRU) examinations allow the assessment of kidney functions through recently developed image post-processing techniques, in addition to providing detailed visualization of urinary system anatomy. MRU and MAG3 scintigraphy were compared in terms of functional evaluation.

Dynamic contrast-enhanced MRU images of 76 children who had previously undergone MAG3 scintigraphy examinations were evaluated. Morphological parameters, volumetric split renal functions (SRF), and renal transit times (RTT) were calculated from the dynamic MRU phases using the CHOP-fMRU software. Results were compared with the half-time (T1/2) and SRF values obtained from MAG3 scintigraphy. Student's t-test and Mann-Whitney U test were used to compare quantitative variables, and Pearson correlation analysis was performed. ROC analysis was performed to reveal the prediction of obstruction by MRU-based quantitative parameters.

The ages of included patients ranged from 1 to 216 months (median: 59.50 months, IQR = 4.1-179.5 months). Statistically significant positive correlations (r > 0.9, p = 0.001) were found between SRFs of the right and left kidneys, measured by MRU and scintigraphy. When the cut-off value was set to 11.5 min for RTT, the sensitivity, specificity, positive and negative predictive values, and accuracy of RTT were found to be 94%, 86%, 90%, 88%, and 88%, respectively.

MRU could be an invaluable tool in the assessment of renal functions. Its diagnostic accuracy in detecting the level and extent of obstruction is comparable to that of MAG3 scintigraphy. Despite the lack of extensive comparative data, the potential benefits of MRU justify the need for further studies.