Diagnostic accuracy of Tc-99m DMSA scintigraphy and renal ultrasonography for detecting renal scarring and relative function in patients with spinal dysraphism.

AIMS: To study additional benefits of performing Tc-99m dimercaptosuccinic acid (Tc-99m-DMSA) scintigraphy as part of the follow-up of adults with spinal dysraphism (SD), compared with ultrasonography, with regard to finding renal scarring and difference in split renal function.

METHODS

Between January 2011 and April 2013 every patient visiting our specialized outpatient clinic for adults with SD was invited to undergo both renal ultrasonography and Tc-99m-DMSA scintigraphy. Outcomes of both modalities were compared, with focus on renal scarring. The relation between renal scarring and hypertension was also assessed.

RESULTS

In total, 122 patients (with 242 renal units) underwent both renal scintigraphy and ultrasonography. More scars were seen on DMSA scintigraphy than on ultrasonography: 45.9% vs. 10.3% of renal units; P < 0.001. Renal scarring seen on DMSA was associated with the presence of hypertension (P = 0.049) whereas scarring seen on ultrasonography was not (P = 0.10). If ultrasonography was difficult to interpret, many more scars were missed on ultrasonography (78.9%) compared with easily interpretable ultrasonographic images (30.6%; P < 0.001).

CONCLUSIONS

In adults with SD, ultrasonography is of value to diagnose dilatation and stones of the upper urinary tract; however, compared with DMSA renography, renal scars are often missed, especially when the ultrasound is difficult to interpret.