©2014 MFMER | slide-1 Case Based Examples of Dual Energy CT Evaluation of Urinary Calculi Maria A. Jepperson, M.D.; Joseph G. Cernigliaro, M.D.; El- Sayed H. Ibrahim, Ph.D; David D. Thiel, M.D.; William E. Haley, M.D.

©2014 MFMER | slide-2 Purpose To demonstrate the clinical utility of Dual-energy computed tomography (DECT) on stone management through a case series

©2014 MFMER | slide-3 Epidemiology/Treatment of Urinary Calculi The risk of urinary calculi in the United States is 13% for men and 7% for women; with a 50% lifetime recurrence risk Information from CT imaging: Stone size, location, skin-to-stone distance, hydronephrosis/inflammatory change Stone Composition: Dictates response to ESWL and medical dissolution therapy Treatment Based on: STONE COMPOSITION TREATMENT

©2014 MFMER | slide-4 Background DECT DECT is an emerging imaging modality with the unique capability of determining urinary stone composition as uric acid or non-uric acid with nearly 100% accuracy in stones greater than 3 mm Other than analysis of collected stone material, dual energy analysis is the only currently available non-invasive method for determining stone composition and is therefore able to benefit patients in preoperative treatment planning

©2014 MFMER | slide-5 Methods Case Selection Medical chart review was performed on patients undergoing evaluation with DECT for urinary calculi All imaging was performed using a dual source DECT scanner (Somatom Definition Flash CT scanner; Siemens, Forchheim, Germany) with our standard renal stone protocol, including data reconstruction Selected patients are described to illustrate the clinical utility of DECT

©2014 MFMER | slide-6 Case 1 Medical Therapy- Uric Acid Calculi Determination of uric acid calculus composition enables the patient to be treated medically and avoid stone surgery Initial axial DECT diagnostic and material specific images demonstrates a UA (red) composition calculus Follow-up exam performed 4 months later demonstrates resolution of the UA calculus after medical therapy (Urocrit)

©2014 MFMER | slide-7 Case 2 DECT vs. Radiographs Determination of non-UA calculi composition enables the patient to be treated with stone extraction and avoid delayed treatment Calculi were not visualized on the abdominal radiograph and were mistakenly thought to be uric acid composition The patient was initially treated medically until follow-up DECT imaging was performed- demonstrating non-UA calculi adjacent to bilateral ureteral stents Follow-up imaging after stone extraction demonstrates the patient to be stone free

©2014 MFMER | slide-8 Case 3 DECT and Ureteral Stents Ureteral stents and drainage tubes are also characterized by the dual energy algorithm DECT Stent Characteristics StentColor Bard InLay OptimaBlue Boston Scientific PercuflexRed Boston Scientific Polaris LoopRed Cook Universa FirmBlue Cook Universa AmplatzBlue GYRUS ACMI TelcoflexRed

©2014 MFMER | slide-9 Case 3 DECT and Ureteral Stents Residual stone fragment adjacent to the ureteral stent was thought to be very small and the decision was made to remove the stent After stent removal the patient experienced symptoms of renal colic and repeat imaging demonstrates the obstructing residual stone fragment. An intervention was needed to remove the residual fragment. Ureteral stents can cause camouflage of retained stone fragments

©2014 MFMER | slide-10 Case 4 DECT and Ureteral Stents Potential for DECT to provide for stent/stone color contrasting, thereby lessening the risk that retained stones will be camouflaged and missed following treatment. The uric acid calculus (red) is easily identified adjacent to the blue ureteral stent, preventing premature stent removal. The patient failed medical therapy and was subsequently treated with cystoscopy and stone extraction. Other examples of stent/stone contrast:

©2014 MFMER | slide-11 Conclusion The four presented case examples demonstrate the potential of DECT to impact urinary calculi diagnosis, treatment, and prevention. Further, DECT can create a clinically useful color contrast between stents and stones to improve the detection of residual stone fragments, thereby significantly impacting patient morbidity.

©2014 MFMER | slide-12 References 1.Jepperson MA, Thiel DD, Cernigliaro JG, et al. Determination of ureter stent appearance on dual-energy computed tomography scan. Urology 2012; 80: Boll DT, Patil NA, Paulson EK, et al. Renal stone assessment with dual-energy multidetector CT and advanced postprocessing techniques: Improved characterization of renal stone composition—pilot study. Radiology 2009; 250: Eiber M, Holzapfel K, Frimberger M, et al. Targeted dual-energy single-source CT for characterization of urinary calculi: experimental and clinical experience. Eur Radiol 2012; 22: Eliahou R, Hidas G, Duvdevani M, et al. Determination of renal stone composition with dual-energy computer tomography: an emerging application. Semin Ultrasound CT MR 2010; 31: Graser A, Johnson TRC, Bader M, et al. Dual energy CT characterization of urinary calculi: initial in vitro and clinical experience. Invest Radiol 2008; 43: Matlaga BR, Kawamoto S, Fishman E. Dual source computer tomography: a novel technique to determine stone composition. J Urol 2008; 5: Primak AN, Fletcher JG, Vriska TJ, et al. Noninvasive differentiation of uric acid versus non-uric acid kidney stones using dualenergy CT. Acad Radiol 2007; 14: Acar, C, Cal C. Impact of residual fragments following endourological treatments in renal stones. Adv Urol 2012; 2012: Cicerello E, Merlo F, Maccatrozzo L. Management of clinically insignificant residual fragments following shock wave lithotripsy. Adv Urol 2012; 2012: Demirbas M, Samli M, Karalar M, et al. Extracorporeal shockwave lithotripsy for ureteral stones: twelve years of experience with 2836 patients at a single center. Urol J 2012; 9: