Category: New Technology: Stones

MP22-15 - Efficacy of Single-source Rapid kv-Switching Dual-energy CT for Characterization of Non-uric Acid Renal Stones: a Prospective Ex-vivo Study Using Anthropomorphic Phantom

Sat, Sep 22
2:00 PM - 4:00 PM

Introduction & Objective :

To investigate the accuracy of rapid kV-switching single-source dual-energy computer tomography for prediction of classes of non-uric acid stones.


Methods :

Non-uric-acid renal stones retrieved via percutaneous nephrolithotomy were prospectively collected between January 2017 and February 2018 in a single institution. Only stones >5mm and with pure composition (i.e. >80% composed of one element) were studied. Stone composition was determined using Fourier Transform Infrared Spectroscopy. The stones were scanned in 32 cm-wide anthropomorphic whole body phantom in a location mimicking the kidneys. Image acquisition was performed using a single-source rapid-kVp switching CT scanner. The effective atomic number (Zeff) and the attenuation (HU) at 40 kev, 70 kev, and 140 kev virtual monochromatic sets of images were extracted by placing a ROI at the largest cross-sectional areas. Ratios between the attenuations at different energy levels were calculated. Mean values of different stone classes were compared using ANOVA and student t-test. Difference between the actual class of stone and the predicted class of stone based on vendor-recommended Zeff thresholds were assessed. A p-value


Results :

The final study sample included 31 stones from 31 patients consisting of 2 (6%) struvite, 4 (13%) cystein and 25 (81%) calcium-based pure stones. The mean size of the stones was 9.9 ± 2.4 mm. The mean Zeff of the stones was 12.0±0.41 for calcium-based, 10.1 ± 0.14 for struvite, and 9.9 ± 0.57 for cystein stones which were statistically different (p


Conclusions :

Zeff has superior performance to HU and attenuation ratios for differentiation of different classes of non-uric-acid stones.

Roberto Cannella

research fellow
University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania

Roberto Cannella, MD is a research fellow at the Department of Radiology in the University of Pittsburgh/UPMC. Dr. Cannella is involved in research studes centred on dual-energy CT on renal stones and hepatobiliary topis.

Mohammed Shahait

Fellow
Division of Urology, University of Pennsylvania
Philadelphia, Pennsylvania

Advanced Robotic Urology, University of Pennsylvania.
Interested in outcome research, new imaging modalities

Alessandro Furlan

Assistant Professor
Department of Radiology, University of Pittsburgh School of Medicine
Pittsburgh, Pennsylvania

Joel Bigley

Pittsburgh, Pennsylvania

Michelle Semins

Endourology Faculty
UPMC
Pittsburgh, Pennsylvania

Timothy Averch

Chief, Division of Urology
Palmetto Health - University of South Carolina
University of South Carolina
Columbia, South Carolina

Amir Borhani

Pittsburgh, Pennsylvania