Ultra-low radiation dose CT angiography of the lower extremity using the iterative model reconstruction (IMR) algorithm. Issue 11 (November 2018)

• Record Type: Journal Article
• Authors: Qian, W.-L.; Zhou, D.-J.; Jiang, Y.; Feng, C.; Chen, Q.; Wang, H.; Zhang, J.-B.; XU, J.-M.
• Is Part Of: Clinical radiology. Volume 73:Issue 11(2018)
• Page Start: 985.e13
• Page End: 985.e19
• Publication Date: 2018-11
• Subjects: Medical radiology -- Periodicals; Radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiology -- Periodicals; Societies, Medical -- Periodicals; Medical radiology; Radiotherapy; Electronic journals; Periodicals; 616.0757
• DOI: 10.1016/j.crad.2018.08.001
• Languages: English
• ISSNs: 0009-9260

Abstract

Abstract : Aim: To investigate the image quality of lower-extremity computed tomography (CT) angiography (CTA) with ultra-low radiation dose using the iterative model reconstruction (IMR) algorithm. Materials and methods: Lower-extremity CTA was acquired using a 256-multidetector CT system from 90 patients assigned into three groups: (1) the routine dose (RD) group: 120 kVp, automatic tube current modulation (ACTM) with an image quality index of 12, and filtered back projection (FBP); (2) the low-dose (LD) group: 80 kVp, ACTM with an image quality index of 1, and IMR; and (3) the ultra-low dose (ULD) group: 80 kVp, 20 mAs, and IMR. CT attenuation, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of the lower-extremity arteries were calculated. Subjective image quality of lower-extremity segments was assessed. Effective radiation dose was recorded. Results: The radiation dose was reduced by 91.4% and 67.3% in the ULD group (0.15±0.02 mSv) compared to the RD group (1.86±0.51 mSv) and the LD group (0.49±0.08 mSv; both p< 0.05). Higher CT attenuation, SNR, CNR, and lower image noise were obtained in the ULD group and the LD group compared to the RD group (all p< 0.05). Better subjective image quality in lower leg segments was obtained in the ULD group and the LD group compared to the RD group (all p< 0.05). No difference was found between the ULD and LD groups in both objective and subjective image quality (all p> 0.05). Conclusion: By using IMR during lower-extremity CTA, the radiation dose is reduced by up to 91.4% without compromising image quality. Highlights: Iterative model reconstruction (IMR) is the latest advancement in the field of reconstruction techniques. We investigated the feasibility of lower extremity CT angiography (CTA) with ultra-low radiation dose using IMR. Our ultra-low dose CTA protocol allows for reducing 91.4% radiation dose meanwhile without compromising image quality.