The Study of Low-dose Computed Tomography with Iterative Reconstruction in Neck

Objective: Exploring the application value of iterative reconstruction algorithm in neck low-dose computed tomography (CT). Methods: 172 patients undergoing CT examination on a 640-slice CT system for suspected neck diseases, were randomly divided into routine-dose (86 cases, 125 m As) and low-dose (86 cases, 40-110 m As) groups, with using conventional filtered back projection construction and Auto-m A adaptive iterative dose reduction construction with three dimensional processing technology respectively. Mean attenuation values and standard deviation (SD) were measured and recorded on the level of mandible and mediastinum, image quality was assessed objectively at the level of mandible and superior mediastinum and by two independent readers using a four-point scale. The image quality and radiation dose were compared using with independent sample test and wilcoxon rank sum test. Results: On the level of mandible, the internal jugular vein (IJV) noise in low-dose group was significantly higher than that in routine-dose group (<i<P</i<<0.05), while there was not significantly different in noise, signal-to-noise-ratio (SNR), contrast-to-noise ratio (CNR) of sternocleidomastoid muscle (SCM) and background noise between the two groups (<i<P</i<<0.05). On the level of mediastinum, the noise in low-dose group was lower than that in routine-dose group (<i<P</i<<0.05), while the SNR was higher (<i<P</i<<0.05). There was not significant difference in CNR between the two groups (<i<P</i<<0.05). The agreement of the routine-dose and low-dose image quality was good. Both readers graded the similar score on the level of mandible for overall image quality (<i<P</i<<0.05), but the low-dose group graded higher score than routine-dose on the level of mediastinum (<i<P</i<<0.05). Comparing to the routine-dose group, the CT dose index (CTDIvol) and effective dose (ED) in low-dose group reduced about 63.34% and 63.16%. Conclusion: Low-dose CT with AIDR3 D can provide high quality image with the reduction of radiation dose, and it has application value in low-dose CT of neck.