Ferrero A, Gutjahr R, Halaweish AF, Leng S, McCollough CH. Characterization of Urinary Stone Composition by Use of Whole-body, Photon-counting Detector CT.
Acad Radiol 2018;
25:1270-1276. [PMID:
29454545 DOI:
10.1016/j.acra.2018.01.007]
[Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 01/02/2018] [Accepted: 01/02/2018] [Indexed: 10/18/2022]
Abstract
RATIONAL AND OBJECTIVES
This study aims to investigate the performance of a whole-body, photon-counting detector (PCD) computed tomography (CT) system in differentiating urinary stone composition.
MATERIALS AND METHODS
Eighty-seven human urinary stones with pure mineral composition were placed in four anthropomorphic water phantoms (35-50 cm lateral dimension) and scanned on a PCD-CT system at 100, 120, and 140 kV. For each phantom size, tube current was selected to match CTDIvol (volume CT dose index) to our clinical practice. Energy thresholds at [25, 65], [25, 70], and [25, 75] keV for 100, 120, and 140 kV, respectively, were used to generate dual-energy images. Each stone was automatically segmented using in-house software; CT number ratios were calculated and used to differentiate stone types in a receiver operating characteristic (ROC) analysis. A comparison with second- and third-generation dual-source, dual-energy CT scanners with conventional energy integrating detectors (EIDs) was performed under matching conditions.
RESULTS
For all investigated settings and smaller phantoms, perfect separation between uric acid and non-uric acid stones was achieved (area under the ROC curve [AUC] = 1). For smaller phantoms, performance in differentiation of calcium oxalate and apatite stones was also similar between the three scanners: for the 35-cm phantom size, AUC values of 0.76, 0.79, and 0.80 were recorded for the second- and third-generation EID-CT and for the PCD-CT, respectively. For larger phantoms, PCD-CT and the third-generation EID-CT outperformed the second-generation EID-CT for both differentiation tasks: for a 50-cm phantom size and a uric acid/non-uric acid differentiating task, AUC values of 0.63, 0.95, and 0.99 were recorded for the second- and third-generation EID-CT and for the PCD-CT, respectively.
CONCLUSION
PCD-CT provides comparable performance to state-of-the-art EID-CT in differentiating urinary stone composition.
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