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Diagnostic Efficiency of Split-Bolus Dual-Energy Computed Tomography for Patients With Suspected Urinary Stones

Yeo, Yu Jin MD*; Kim, See Hyung MD*; Kim, Mi Jeong MD*; Kim, Young Hwan MD*; Cho, Seung Hyun MD; Lee, Eun Joo MD

Journal of Computer Assisted Tomography: January/February 2015 - Volume 39 - Issue 1 - p 25–31
doi: 10.1097/RCT.0000000000000151
Abdominal Imaging

Objective The objective of this study was to evaluate the efficiency of virtual noncontrast image (VNCI) generated from dual-energy split-bolus computed tomographic urography (DE-SBCTU) for urinary stones detection.

Methods Three hundred fifty-six patients underwent true noncontrast image (TNCI) and DE-SBCTU. Two radiologists evaluated opacification scores of DE-SBCTU as well as iodine subtractions and image noise on VNCI. Diagnostic performance of the VNCI was evaluated using TNCI as a reference standard, according to diameter and image quality. The results were compared between patient groups with body mass index of less than 25 and 25 kg/m2 or greater.

Results Agreements for opacification, iodine subtraction, and image noise between the radiologists were excellent, and there were no significant difference in the 2 patients groups. A total of 499 stones were detected on VNCI, with a sensitivity and diagnostic accuracy of 95.1% (468/492) and 92.9% (499/537). Mean (SD) diameter was significantly smaller on VNCI (3.6 [2.3] mm) than on TNCI (4.4 [2.0] mm) (P = 0.01). The stone diameter with false interpretation was less than 4 mm in 48 of 51 patients. The diameter and image quality on VNCI had no significant difference between the 2 patients groups.

Conclusions Virtual noncontrast image displays high accuracy for detecting urinary stones, regardless of body mass index.

From the *Department of Radiology, Dongsan Hospital, Keimyung University; †Department of Radiology, Kyungpook National University Hospital; and ‡Department of Radiology, Yeungnam University Hospital, Daegu, South Korea.

Received for publication April 27, 2014; accepted August 28, 2014.

Reprints: See Hyung Kim, MD, Department of Radiology, Dongsan Hospital, Keimyung University, 56 Dalsungro, Jung-gu, Daegu 700-712, South Korea (e-mail:

The authors declare no conflict of interest.

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