Skip Navigation LinksHome > January/February 2013 - Volume 37 - Issue 1 > Determination of Renal Stone Composition in Phantom and Pati...
Journal of Computer Assisted Tomography:
doi: 10.1097/RCT.0b013e3182720f66
Abdominal Imaging

Determination of Renal Stone Composition in Phantom and Patients Using Single-Source Dual-Energy Computed Tomography

Kulkarni, Naveen M. MD; Eisner, Brian H. MD; Pinho, Daniella F. MD; Joshi, Mukta C. MS; Kambadakone, Avinash R. MD, FRCR; Sahani, Dushyant V. MD

Collapse Box

Abstract

Purpose: This study aimed to characterize the urinary tract stones in phantom and patients using single-source dual-energy computed tomography.

Materials and Methods: Twenty stones of pure crystalline composition (uric acid [UA], struvite, cystine, and calcium oxalate monohydrate) were assessed in a phantom and 11 patients (age 39–67 years) with urinary tract stones were evaluated. An initial low-dose unenhanced CT (tube potential, 120 kilovolts [peak]; milliampere range, 150–450; noise index, 26; section thickness, 5 mm) followed by a targeted dual-energy computed tomography acquisition on a single-source dual-energy computed tomography (Discovery CT 750 HDCT, GE) was performed. Uric acid and non-UA stones were defined using a 2-material decomposition (material density–iodine/water) algorithm. The stone effective atomic number (Zeff) was used to subclassify non-UA stones. The stone attenuation (Hounsfield unit) was also studied to determine its performance in predicting the composition. Ex vivo chemical analysis of the stone served as a criterion standard.

Results: Of the 59 verified stones (phantom, 20; patients, 39; mean size, 6 mm), there were 16 UA and 43 non-UA type. The material density images were 100% sensitive and accurate in detecting UA and non-UA stones. The Zeff accurately stratified struvite, cystine, and calcium (calcium oxalate monohydrate) stones in the phantom. In patients, Zeff identified 83% of calcium stones (n = 24), and in stones of mixed type, it resembled dominant composition. The Hounsfield unit measurements alone were 71% sensitive and 69% accurate in detecting the UA stones.

Conclusions: Single-source dual-energy computed tomography can accurately predict UA and non-UA stone composition in vitro and in vivo. Substratification of non-UA stones of pure composition can be made in vitro and in vivo. In stones of mixed composition, the Zeff values reflect the dominant composition.

© 2013 Lippincott Williams & Wilkins, Inc.

  

Login

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.