Application value of noise index-based tube current modulation technology combined with forward projected model-based iterative reconstruction solution in low iodine contrast agent CT pulmonary angiography among the elderly patients
10.3760/cma.j.issn.0254-9026.2025.05.002
- VernacularTitle:结合噪声指数的自动管电流调制技术联合全模型迭代重建算法在老年人低碘对比剂CT肺动脉血管成像中的应用
- Author:
Xiaotong LIU
1
;
Jing WANG
;
Xiaomao XU
;
Tao GU
Author Information
1. 北京医院放射科 国家老年医学中心 中国医学科学院老年医学研究院，北京 100730
- Publication Type:Journal Article
- Keywords:
Pulmonary embolism;
Angiography;
Iodine contrast medium;
Model-based iterative reconstruction
- From:
Chinese Journal of Geriatrics
2025;44(5):577-583
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the effects of low tube voltage, automatic tube current modulation technology combined with noise index(NI), and forward projected model-based iterative reconstruction solution(FIRST)on radiation dose and image quality in low iodine contrast agent CT pulmonary angiography(CTPA)among elderly patients.Methods:This retrospective study continuously collected imaging and clinical data from elderly patients suspected of having acute pulmonary embolism (APE)who underwent low-iodine contrast CTPA at the emergency department and inpatient department of Beijing Hospital from February 2022 to July 2023.A total of 80 patients were included in the study.Based on the reconstruction algorithm utilized during the CTPA examination, the patients were divided into two groups: the adaptive iterative dose reduction using three-dimensional processing(AIDR 3D)group and the FIRST group, with 40 cases in each group.We measured the average CT value and noise value of the pulmonary artery at various positions in both groups on axial images, calculated the signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR), and recorded the average tube current and effective radiation dose for both patient groups.Two observers independently performed subjective scoring on the display of the pulmonary artery in each group using a blind method.Results:There were no statistically significant differences in age, body mass index (BMI), gender, and the extent of pulmonary embolism between the AIDR 3D group and the FIRST group (all P>0.05).In comparison to the AIDR 3D group, the FIRST group exhibited a significantly lower tube current[(220.2±84.5) mA vs.(264.1±81.2) mA, t=0.463, P=0.020], resulting in an effective radiation dose reduction of 15.7%[(1.39±0.49) mSv vs.(1.65±0.41) mSv, t=0.072, P=0.043].No statistically significant differences were observed in the mean CT values, noise values, and SNR values of the main pulmonary artery, left and right pulmonary trunks, and lobar and segmental pulmonary arteries between the AIDR 3D group and the FIRST group (all P>0.05).The CNR of the AIDR 3D group was lower than that of the FIRST group in both the left and right segmental pulmonary arteries( Z=-2.473, -1.973; P=0.013, 0.049), while no significant differences were found in the other pulmonary arteries(all P>0.05).In patients with normal BMI, the FIRST group demonstrated higher CNR values in both the left and right segmental pulmonary arteries compared to the AIDR 3D group( Z=-2.008, -2.662, P=0.046, 0.007), whereas the improvement in CNR was not significant in overweight and obese patients(all P>0.05).The two radiologists provided consistent subjective evaluations in scoring(Kappa=0.744, P<0.001), and there was no statistically significant difference in subjective scores between the AIDR 3D group and the FIRST group ( χ2=0.346, P=0.770). Conclusions:The imaging technique that integrates automatic tube current modulation technology with NI, the FIRST reconstruction algorithm, and a low tube voltage of 100 kVp effectively ensures image quality by providing clear visualization of pulmonary arteries at all levels.Moreover, it reduces radiation dose during low-iodine contrast agent CTPA examinations in elderly patients with APE.
