Stefanie Fiechter1, Elio Geissbühler1, Alexandrine Bähler2, Verena Obmann2, Susan Meierhans1, Aris K Exadaktylos3, Andreas Christe2, George N Thalmann1, Beat Roth4,5. 1. Department of Urology, University of Bern, 3010, Bern, Switzerland. 2. Department of Radiology, University of Bern, Bern, Switzerland. 3. Department of Emergency Medicine, University of Bern, Bern, Switzerland. 4. Department of Urology, University of Bern, 3010, Bern, Switzerland. urology.berne@insel.ch. 5. Department of Urology, University Hospital of Lausanne (CHUV), University of Lausanne, Lausanne, Switzerland. urology.berne@insel.ch.
Abstract
PURPOSE: Digital low-dosage, linear slot scanning radiography (Lodox®) is an imaging modality that can emit down to one-tenth the radiation of conventional X-ray systems. We prospectively evaluated Lodox® as a diagnostic imaging modality in patients with ureterolithiasis. METHODS: Conventional kidney-ureter-bladder (KUB) X-ray and Lodox® were performed in 41 patients presenting with acute flank pain due to unilateral ureteral stone confirmed by computed tomography. KUB X-ray and Lodox® images were then reviewed by four blinded readers (urology expert/resident, radiology expert/resident). Identification rates were compared using Pearson's Chi square test. The impact of different parameters on stone identification by Lodox® was evaluated using logistic regression and generalized linear mixed models. Inter-reader agreement was tested using Cohen's kappa coefficient. RESULTS: Median stone size was 5 mm (range 2-12), median stone density was 800 HU (range 200-1500). The identification rates of the urology expert were 68% for KUB X-ray and 90% for Lodox® (p = 0.014), and for all four readers 61% for KUB X-ray and 62% for Lodox® (p = 0.8). Radiation exposure for KUB X-ray and Lodox® was 0.45 mSv (SD ± 0.64) and 0.027 mSv (SD ± 0.038), respectively. Multivariable analyses showed an association between stone identification by Lodox® and stone size (p < 0.001), stone density (p = 0.005), lower body mass index (p = 0.005), and reader (p < 0.001). CONCLUSIONS: The high identification rates and low radiation doses of Lodox® make it a promising imaging modality for the diagnosis of ureteral stones. Further validation in larger cohorts, including performance evaluation for renal stones, is warranted. TRIAL REGISTRATION: http://www.controlled-trails.com/ISRCTN12915426.
PURPOSE: Digital low-dosage, linear slot scanning radiography (Lodox®) is an imaging modality that can emit down to one-tenth the radiation of conventional X-ray systems. We prospectively evaluated Lodox® as a diagnostic imaging modality in patients with ureterolithiasis. METHODS: Conventional kidney-ureter-bladder (KUB) X-ray and Lodox® were performed in 41 patients presenting with acute flank pain due to unilateral ureteral stone confirmed by computed tomography. KUB X-ray and Lodox® images were then reviewed by four blinded readers (urology expert/resident, radiology expert/resident). Identification rates were compared using Pearson's Chi square test. The impact of different parameters on stone identification by Lodox® was evaluated using logistic regression and generalized linear mixed models. Inter-reader agreement was tested using Cohen's kappa coefficient. RESULTS: Median stone size was 5 mm (range 2-12), median stone density was 800 HU (range 200-1500). The identification rates of the urology expert were 68% for KUB X-ray and 90% for Lodox® (p = 0.014), and for all four readers 61% for KUB X-ray and 62% for Lodox® (p = 0.8). Radiation exposure for KUB X-ray and Lodox® was 0.45 mSv (SD ± 0.64) and 0.027 mSv (SD ± 0.038), respectively. Multivariable analyses showed an association between stone identification by Lodox® and stone size (p < 0.001), stone density (p = 0.005), lower body mass index (p = 0.005), and reader (p < 0.001). CONCLUSIONS: The high identification rates and low radiation doses of Lodox® make it a promising imaging modality for the diagnosis of ureteral stones. Further validation in larger cohorts, including performance evaluation for renal stones, is warranted. TRIAL REGISTRATION: http://www.controlled-trails.com/ISRCTN12915426.