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| Application of virtual unenhanced imaging of dual-source CT in small intestine lesions |
| WANG Jun, LI Hui, LIU Yan, WANG Jia |
| Radiographic Center, the People’s Hospital of Xinjiang Uygur Autonomous Region, Urumqi 830001, China |
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Abstract Objective: To explore the application of dual-source CT virtual scan in the small intestine. Methods: Thirty-five patients underwent small intestine radiography with dual source CT, a total of three scans, namely conventional unenhanced, arterial and venous phase. The virtual unenhanced images were obtained and compared with the real images in arterial and venous phase. The subjective score of image quality was evaluated by two doctors using double-blind method, the objective score of image quality was to select the region of interest in the images of three sequences, to record the average CT values of lesions, liver, muscle and fat of virtual unenhanced and real images in arterial and venous phase, and the noise generated by the machine, lesion-noise ratio(SNR) and contrast-noise ratio(CNR). At the same time, the total radiation dose of three phase scans and the total radiation dose of arterial and venous enhancement after the removal of the unenhanced dose were recorded. ANOVA was used to compare the average CT values of the images of two groups, SNR and CNR. Two independent samples t-test was used to analyze radiation dose. Results: In 35 patients, there were 16 males, and 19 females, aged 27~83 years old, which had no obvious abnormalities in 16 cases, chronic colitis in 3 cases, 4 cases of intestinal obstruction, 2 cases of tumor resection, intestinal polyp in 3 cases, 2 cases of lipoma, 3 cases of colon cancer, 1 case of mesenteric fibroma, ileocecal tumor in 1 case. Using SPSS 21.0 software for statistical analysis, the CT values of lesions, fat, muscle of virtrual non-contrasted(VNC) were less than the those of true non-contrasted(TNC), the difference was statistically significant, while the CT value of VNC of liver was greater than that of TNC, the difference was statistically significant. Virtual unenhanced SD was lower than the real plain, and SNR, CNR were higher than those of the real plain, the difference was not statistically significant. The subjective scores of the three images could meet the diagnostic requirements, although virtual unenhanced subjective rating was lower than that of real plain, but the difference was not statistically significant, high-quality image rate of 71.8%. The dual-energy two phases radiation dose was less than 24.8% of the conventional three phases radiation dose. Conclusions: In the examination of patients with small bowel radiography, the dual-energy CT VNC images can be used as a benchmark for the density measurement and an alternative for the traditional plain, eliminating the conventional pre-enhancement scan, greatly reducing the patient’s radiation dose.
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Received: 20 July 2016
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