Characterization of urinary stone composition by use of third-generation dual-source dual-energy CT with increased spectral separation

Xinhui Duan, Zhoubo Li, Lifeng Yu, Shuai Leng, Ahmed F. Halaweish, Joel G. Fletcher, Cynthia H. McCollough

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


OBJECTIVE. The purpose of this phantom study was to determine the utility of a thirdgeneration dual-source CT scanner with increased dual-energy spectral separation in differentiating urinary stone composition. MATERIALS AND METHODS. Eighty-seven urinary stones from humans were scanned in 35-, 40-, 45-, and 50-cm wide anthropomorphic phantoms with a third-generation dual-source scanner (system A) with a high-energy beam of 150 kV plus 0.6-mm tin filtration (Sn). The low-energy data were acquired at 70, 80, 90, and 100 kV. A second-generation dualsource scanner (system B) was used to acquire data at 140 kV plus 0.4-mm Sn for the highenergy and 80 or 100 kV for the low-energy images. Volume CT dose index was matched for a given phantom size. CT number ratios were calculated and used to differentiate uric acid from non-uric acid stones and oxalate from apatite stones in an ROC analysis. RESULTS. The area under the curve (AUC) of the ROC curve for uric acid versus non- uric acid stones increased for large phantoms. For example, for imaging of the 45-cm wide phantom with system A at the 100-and 150-kV Sn low-and high-energy combination, the AUC was 0.99, whereas for system B at the 100-and 140-kV Sn combination, the AUC was 0.86. At each phantom size and for all energy combinations, the AUC values for oxalate versus apatite stones were higher for system A than they were for any energy combination for system B. CONCLUSION. Compared with use of second-generation dual-source CT, use of thirdgeneration dual-source CT at the energy combination of 100 and 150 kV Sn improved classification of urinary stones across a wide range of phantom sizes and increased the ability to differentiate oxalate from apatite stones.

Original languageEnglish (US)
Pages (from-to)1203-1207
Number of pages5
JournalAmerican Journal of Roentgenology
Issue number6
StatePublished - Dec 2015


  • CT
  • Dual-energy CT
  • Phantom
  • Spectral separation
  • Urinary stones

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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