Efficacy of Multi-Detector Computed Tomography for the Diagnosis of Medullary Sponge Kidney

Abstract

Objective: To expand the diagnostic armamentarium for medullary sponge kidney (MSK), we evaluate the use of high-resolution multidetector computed tomography (MDCT) for MSK diagnosis and compare to the standard intravenous urography (IVU). Despite a significant prevalence amongst stone formers, diagnosis of this well described condition has declined. IVU, the gold standard in MSK diagnosis, has largely been replaced by CT, which has previously been shown unable to demonstrate signs of MSK. Methods and Materials: Patients with known history of MSK based on IVU underwent limited MDCT urogram. Control group patients, without MSK, also had MDCT urograms performed for other clinically indicated conditions. Studies were scored by board-certified radiologists on a 0-2 scale based on the likelihood of MSK. IVU studies, when available, were similarly graded. Results: MDCT was diagnostic of MSK in 9 out of the 10 patients with known history of MSK. No false positives were present in our series. The one case of MSK not detected on MDCT was graded as a “1” on its respective IVU. Sensitivity and specificity were 90 and 100%, respectively, when compared with IVU. Conclusion: Concordance with IVU findings, despite a small reduction in sensitivity, indicates MDCT to be a suitable, and more readily available replacement for IVU in the diagnosis of MSK.

Ultrasound to address medullary sponge kidney: a retrospective study

“…Finally, we lacked the IVU studies to confirm the diagnosis reported on medical records. Nevertheless, the review of CT images, available for 7 patients, by our expert radiologist, detected typical features of MSK in one patient according to what was reported in the studies by Koraishy [15] and Gaunay [16] and confirm the presence of cysts and calcifications in the other cases strengthening our diagnosis. So, we believe that a thorough differential diagnosis and a critical appraisal of both clinical findings, history, biochemical analysis and imaging studies, can help make the diagnosis of MSK with good accuracy even in the absence of the gold standard imaging technique.…”

“…Finally, we lacked the IVU studies to confirm the diagnosis reported on medical records. Nevertheless, the review of CT images, available for 7 patients, by our expert radiologist, detected typical features of MSK in one patient according to what was reported in the studies by Koraishy [ 15 ] and Gaunay [ 16 ] and confirm the presence of cysts and calcifications in the other cases strengthening our diagnosis.…”

“…The second is a trial that compared IVU and multidetector CTU for diagnosis of MSK in 10 patients. It demonstrated that multidetector CTU had a sensitivity of 90% and a specificity of 100% when compared with IVU [16]. However, the routine use of this imaging technique has some limitations in patients and in particular in renal ones.…”

“…Finally, it cannot be repeated frequently as a follow-up imaging method, due to a substantial patient exposure to radiations [8]. The previous cited studies, proposing multidetector CTU, lacked considerations about patients renal function as a possible limitation in using contrast media and only one of them reflected about the opportunity to use dose reduction protocol to limit patients radiation exposures [15,16]. In contrast with CT use, we found that there was an extensive use of US imaging in our patients, in most cases with a dedicated operator.…”

<p>Medullary Sponge Kidney: Current Perspectives</p>

“…The incidence of MSK is similar worldwide compared to the United States 4. Since MSK is associated with renal and urinary tract stone formation, it is hypothesized that up to 20% of patients with calcified renal stones will have the disease 4,13. Though MSK may have a sporadic prevalence of 5/10,000 to 5/100,000 according to Geavlete et al, other sources state that the epidemiology of MSK is difficult to predict.…”