迭代模型重建与 iDose4 混合迭代重建在 头颈部低剂量 CT 血管成像中的应用比较.

Objective To compare the application of iterative model reconstruction (IMR) and iDose4 hybrid iterative reconstruction technique in head and neck CT angiography (CTA) with low radiation dose and low iodine intake. Methods 60 patients with body mass index ≤30 kg/m² underwent head and neck CTA in our hospital from January to May 2024. The patients were divided into control group (30) and experimental group (30). The CTA in the control group was performed with 120 kV, 150 mAs, 50 mL contrast medium injected at the rate of 5 mL/s and iDose4 compared to CTA of the experimental group (100 kV, 100 mAs, 30 mL, 3 mL/s) with iDose4 or IMR. The CT values, standard deviation (SD), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the left common carotid artery, internal carotid artery, and M1 segment of the middle cerebral artery, the volume CT dose index and dose-length product and the effective dose were compared between the control and experimental groups. Image quality was scored subjectively by two radiologists. The independent sample t test was used to compare the radiation dose. The CT values, SD, SNR, CNR, and image quality score were analyzed using ANOVA or Welch's test. Pairwise comparisons were performed using LSD-t test or Tamhane's T2. Results There was no significant difference (P>0.05) in the blood vessel image quality scores, SD, SNR, CNR between IMR and control groups whereas the image quality scores, SNR and CNR of blood vessels in iDose4 group were significantly lower than those in the IMR and control groups (P<0.05). The CT values of the corresponding vessels in the control group were significantly higher than those in the iDose4 and IMR groups (P<0.05). The effective dose of the experimental group (1.62± 0.08) decreased by 57.41% compared with the control group (0.69±0.33) while the iodine intake of the contrast agent decreased by 40%. Conclusion In head and neck CTA, the application of low tube voltage, low tube current, low injection dose and low injection flow rate combined with IMR technology can significantly reduce the radiation dose and iodine intake of patients while ensuring image quality. IMR technique is better than iDose4 in reducing image noise and improving image SNR and CNR. [ABSTRACT FROM AUTHOR]