The value of virtual monoenergetic images based on dual-layer spectral detector CT for demonstrating superior thyroid artery / 实用放射学杂志

ABSTRACT

Objective To explore the optimal virtual monoenergetic image of superior thyroid artery(STA)based on dual-layer spectral detector CT,and to optimize the image quality of STA.Methods A total of 100 patients who underwent dual-phase neck enhanced spectral CT scan were selected retrospectively.The 120 kVp conventional images and the 40-70 keV(interval of 10 keV)virtual monoenergetic images in the arterial phase were analyzed.The CT values,background noise,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)of blood vessels and surrounding tissues were analyzed in the five groups of images,and the image quality was scored.Results In monoenergetic image groups,the CT values,SNR and CNR of STA increased with the monoenergetic level decreased,and the highest values were found when the monoenergetic level was 40 keV,which was significantly higher than those in the 120 kVp conventional image group(P＜0.05).The background noise increased with the monoenergetic level decreased,and reached the maximum at 40 keV,but it was still lower than that in the 120 kVp conventional image group,and the difference was statistically significant(P＜0.001).The subjective score of 40 keV image was significantly better than that of 120 kVp conventional image group(P＜0.001).In the evaluation of the origin of the STA in 100 patients,a total of 200 STA were shown,69％of which originated from the external carotid artery.Conclusion The image quality of the STA on the 40 keV monoenergetic image is significantly higher than that on the conventional image,which has obvious advantages in evaluating the anatomy of the STA.