Estimation of Split Renal Function With 99m Tc-DMSA SPECT: Comparison Between 3D Volumetric Assessment and 2D Coronal Projection Imaging.

Objective: Split renal function (SRF) can be estimated with ^99m Tc-labeled dimercaptosuccinic acid (DMSA) SPECT cortical renal scintigraphy on either 2D projected images or 3D images. The purpose of this study was to determine whether there is a significant difference between SRF values calculated with the 2D method and those calculated with the 3D method.
Materials and Methods: This retrospective study was performed with ^99m Tc-DMSA SPECT images of 316 patients (age range, 1-26 years). All images were reconstructed by filtered back projection. An automated computational method was developed to estimate SRF using both 2D projection images and direct 3D images. A paired t test was used to evaluate the difference between SRFs determined with the two methods and the association between the magnitude of the differences and kidney size, patient age, and SRF.
Results: There was strong correlation between SRFs estimated with the 2D and 3D methods (r = 0.94, p < 0.001). There was small significant difference (0.14% ± 0.86%, p = 0.003) in SRFs obtained with the two methods. The difference was clinically negligible and independent of renal length (p = 0.698), volume (p = 0.297), and patient age (p = 0.768) but was associated with SRF (p = 0.018).
Conclusion: For determination of split renal function, ^99m Tc-DMSA SPECT renal scintigraphy 2D coronal projection images perform as well as and are simpler to analyze than 3D images.