PD51-10 OVERUTILIZATION OF CT IMAGING IN PATIENTS WITH KNOWN URINARY TRACT CALCULI

Abstract

INTRODUCTION AND OBJECTIVES: Nephrolithiasis is an increasingly common disease process often requiring extensive followup and care with significant economic ramifications. Computed tomography (CT) remains the preferred initial diagnostic modality due to its excellent sensitivity and specificity for stone disease. Medical expulsive therapy is a reasonable course of treatment for many patients but often results in a protracted clinical course. Concern regarding overutilization of CT with respect to increased radiation exposure and health care costs has been expressed. We sought to identify patients with known urinary tract calculi who undergo additional CT imaging between initial diagnosis and stone passage or intervention to determine if their management is altered by the additional imaging study. METHODS: Retrospective chart review of all urinary stone patients (by ICD-9 code) between January 2009 and January 2012 was performed. We identified those patients who had repeat CT imaging performed within six weeks of the initial urinary stone diagnosis for the same indication. Charts were examined to determine if additional information was gained through repeat CT imaging and if the repeat CT scan altered course of stone management. RESULTS: 1119 patients were identified. 128 patients (11%) met inclusion criteria with repeat CT scan. Repeat CT scan (within 6 weeks of initial diagnosis) resulted in a change in planned management in 9/128 patients (7%). Average additional radiation dose per patient was 36.9 mSv. Thirty-six patients underwent CT imaging for flank pain even after a ureteral stent had previously been placed. CONCLUSIONS: Many patients undergo unnecessary repeat CT imaging for kidney stones leading to increased cost and radiation exposure. Only 7% of patients who underwent repeat CT imaging had an alteration in the previously planned management for known kidney stones. Repeat imaging with CT is rarely necessary in the short-term management of nephrolithiasis. Following a diagnosis of nephrolithiasis, additional follow-up information and progress may be acquired through physical exam, laboratory values, and possibly ultrasound examination limiting cost and cumulative radiation exposure.