Analysis of factors affecting the detection of urinary stone using virtual unenhanced images derived from dual-energy CTU
- VernacularTitle:影响能谱CTU虚拟平扫尿路结石检出的因素分析
- Author:
Yannan CHENG
1
;
Yanan LI
1
;
Jingtao SUN
1
;
Qian TIAN
1
;
Jian YANG
2
;
Wei TONG
1
;
Jian YANG
1
;
Jianxin GUO
1
Author Information
- Publication Type:Journal Article
- Keywords: dual-energy spectral computed tomography urography (CTU); urinary stone; virtual unenhanced (VUE) image; detection; Logistic regression
- From: Journal of Xi'an Jiaotong University(Medical Sciences) 2024;45(4):535-541
- CountryChina
- Language:Chinese
- Abstract: 【Objective】 To evaluate the factors affecting urinary stone detection rate using virtual unenhanced (VUE) images obtained from triphasic dual-energy CT urography (DECTU) based on Logistic regression analysis. 【Methods】 For this study, 150 patients who had suspected urinary stone and underwent triphasic DECTU were included. The true unenhanced (TUE) images were reconstructed as 120 kVp-like images, and VUE images at the portal venous phase [VUE(VP)] and excretory phase [VUE(EP)] were obtained using iodine removal technique from portal venous and excretory phase DECTU images, respectively. Two readers independently evaluated the above three types of images, and recorded the number of urinary stones, their anatomical locations, and whether there was residual iodine on the VUE images. Stone size and CT number were recorded only on the TUE images. Stone size, CT number, anatomical location, and iodine contrast agent were included in univariate and multivariate Logistic regression analyses to evaluate the factors affecting urinary stone detection rate using VUE images. Thresholds for detecting urinary stones on VUE images were determined using receiver operating characteristics (ROC) analysis. 【Results】 We detected 304 stones on TUE images, while the detection rates were 92.4% and 71.4% when using VUE (VP) and VUE (EP) images, respectively. Stone size and CT number were important factors influencing urinary stone detection rate using VUE (VP) and VUE (EP) images (P<0.01). The area under curve (AUC) of using stone size and CT number for detecting stones using the VUE (VP) images was up to 0.96, and as threshold values, stones with size larger than 3.52 mm and CT number greater than 469 HU were found to have high accuracy. However, the AUC decreased to 0.88 when we combined stone size, CT number and anatomical location using the VUE (EP) images. In addition, different contrast agents did not affect the detection rate of stones on the VUE (EP) images (P=0.57). The stone detection rate in the kidney was significantly lower than those on the VUE (EP) images (P<0.001). 【Conclusion】 VUE (VP) images provide better stone detection. Stone size and CT number have significant impacts on the stone detection rate using VUE images. The lower stone detection rate in the kidney on the VUE (EP) images is related to the residual iodine.
