A preliminary study on the combination of high iodine flow rate and high noise index in reducing the radiation dose of CT angiography for head and neck / 中国医学装备

ABSTRACT

Objective:To carry out preliminarily study on the combination of high iodine flow rate (IDR) and high noise index (NI) in reducing radiation dose of CT angiography (CTA) for head and neck.Methods:A total of 120patients with lesions on head and neck who underwent head and neck CTA in the hospital were divided into high IDR combined with high NI group (high IDR+NI group, 50 cases) , middle IDR combined with middle NI group (middle IDR+NI group, 40 cases) and low IDR combined with low NI group (low IDR+NI group, 30 cases) according to the random number table method.The scanned images were reconstructed by the iterative reorganization algorithm (ASiR) 2.0.The CT values of head and neck, signal to noise ratio (SNR) , contrast noise ratio (CNR) of all images in three groups were analyzed objectively and scored subjectively.And the CT dose index (CTDI) , dose length product (DLP) , effective radiation dose (ED) of the iodine intake and radiation dose were recorded.Results:The differences of CT value of ascending aorta, upper common carotid artery or lower internal carotid artery among the three groups were no significant, respectively.The SNR and CNR in high IDR+NI group were significantly higher than those in middle IDR+NI group and low IDR+NI group (F=47.908, F=52.525, P<0.05) , respectively.And there was no significant difference in subjective scores among the three groups.The differences of CTDI, DLP and ED in high IDR+NI group were significantly lower than those in middle IDR+NI group and low IDR+NI group (F=224.861, F=199.610, F=412.443, P<0.05) , respectively.Conclusion:The combination of high IDR and high NI for patients who undergoes head and neck CT can reduce the radiation dose when ensure the image quality, and it is worthy in clinical application.