Login to Access Video or Poster Abstract: MP18-16
Sources of Funding: Funding support was provided by the NIH P20-DK-100863 (TC, MLS) and NIH R21-DK-109433 (TC)

Introduction

A discrepancy often exists between urologists&[prime] and radiologists&[prime] estimation of a patient&[prime]s true stone burden. Current AUA guidelines recommend treatment based on stone size thresholds and therefore accurate stone measurements are critical in directing patients to the most appropriate surgery. With an increasing trend towards determining quality of care based on the amount of stone removed, accurate stone burden estimation is essential to defining operative success. This study aimed to compare the number, size, and location of stones recorded by urologists and radiologists, and determine what discrepancies exist and how these differences could impact stone management.

Methods

From October 2015 to August 2016, 371 new stone patients at University of California, San Francisco were prospectively enrolled into the Registry for Stones of the Kidney and Ureter (ReSKU^TM). Treating urologists personally reviewed all computed tomography (CT) imaging, recording stone number, location, and total stone burden. Stone burden was based on the largest aggregate linear dimension from axial and coronal views. A blinded, retrospective review of the corresponding radiologic reports for these patients was then performed, comparing how often these key attributes were mentioned. A report was categorized as unclear for each characteristic when it failed to specifically mention the number, location or total stone burden.

Results

A total of 219 patients had both CT images and a report available for review. With regard to stone number, 57/219 (26%) of reports were considered unclear. Radiologists reported significantly smaller stone burden than urologists for both single stones (8.8 ± 9.2 mm vs 10.7 ± 11.8 mm, p <0.001) and multiple stones (12.7 ± 10.0 mm vs 21.3 ± 20.3 mm, p <0.001, paired-sample t test). Of 300 stone-containing renal units, 90 (30%) had a radiology description that was either unclear or based on size discrepancy could have resulted in a potential change in surgical management (Table 2).

Conclusions

There is a statistically significant difference in the estimation of stone size between urologist and radiologist interpretation of CT scans. To optimize appropriate surgical selection and allow for quality outcomes measurements, urologists should perform their own imaging interpretation.

Funding

Funding support was provided by the NIH P20-DK-100863 (TC, MLS) and NIH R21-DK-109433 (TC)