Yu Jin Yeo1, See Hyung Kim, Mi Jeong Kim, Young Hwan Kim, Seung Hyun Cho, Eun Joo Lee. 1. 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.
Abstract
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.
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.