Comparative analysis of two kinds of virtual unenhanced technique of spectral CT and routine plain CT in thorax / 中国医学影像技术

ABSTRACT

Objective: To investigate image quality of virtual unenhanced images (VUE) and material suppressed iodine images (MSI) compared with true unenhanced images (TUE), and to explore the application value of virtual unenhanced technique in chest CT scanning. Methods: Forty patients underwent conventional unenhanced CT and contrast-enhanced CT with spectral imaging mode, and dual-phase enhanced scanning with GSI Assist mode was performed. VUE based on initial data and MSI based on contrast-enhanced images during arterial phase (AP) and venous phase (VP) were generated, respectively. CT values and standard (SD), CNR of thoracic aorta, pulmonary artery, erector spinae muscle and fat and qualitative visual parameters (image quality as graded on a 5-point scale) were compared. Statistical analysis was performed with One-way ANOVA, Mann-Whitney U test and Kruskal-Wallis H tests. Results: CT value of pulmonary artery and thoracic aorta in AP-MSI were significantly different with those in TUE (both P0.05). Compared with TUE, qualitative visual parameters had no difference with VP-VUE (all P>0.005), which were lower in AP-VUE, AP-MSI and VP-MSI (all P<0.005). The radiation dose reduced by 19.29% with VUE compared with TUE. Conclusion: Using VUE could acquire better image quality than MSI with reducing radiation dose. VP-VUE has similar image quality to TUE, which has potential to replace TUE.