Assessment of image quality and dose in contrast-enhanced head and neck CT angiography of New Zealand rabbit

Article type: Research Article

Authors: Hsiao, Chia-Chi^a | Chen, Po-Chou^b | Kuo, Pei-Chi^b | Ho, Chih-Hao^c | Jao, Jo-Chi^{d; *}

Affiliations: [a] Department of Radiology, Kaohsiung Veterans General Hospital, Taiwan, R.O.C | [b] Department of Biomedical Engineering, I-Shou University, Taiwan, R.O.C | [c] Department of Medical Imaging, Taipei City Hospital (Yangming Branch), Taiwan, R.O.C | [d] Department of Medical Imaging and Radiological Sciences, College of Health Sciences, Kaohsiung Medical University, Taiwan, R.O.C

Correspondence: [*] Corresponding author: Jo-Chi Jao, Ph.D. (80708) No. 100, Shih-Chuan 1st Rd., Sanmin Dist., Kaohsiung City, Taiwan, R.O.C. Tel.: +886 7 3121101 ext. 2356 14; Fax: +886 7 3113449; E-mail: jochja@kmu.edu.tw.

Abstract: BACKGROUND:Although computed tomography (CT) is a powerful diagnostic imaging modality for diagnosing vascular diseases, it is some what risky to human health due to the high radiation dosage. Thus, CT vendors have developed low dose computed tomography (LDCT) aiming to solve this problem. Nowadays, LDCT has gradually become a main stream of CT examination. OBJECTIVE:This study aimed to assess the feasibility of LDCTAin an animal model and compare the imaging features and doses in two clinical scanners. METHODS:Twenty-two New Zealand rabbit head and neck CTA images pre- and post-contrast agent injection were performed using256-sliceand 64-slice CT scanners. The tube voltages used in the 256-slice and the 64-slice CTA were 70 kVp and 80 kVp, respectively. Quantitative images indices and radiation doses obtained from CTA in these two scanners were compared. RESULTS:More neck arterial vessels could be visualized in multi-planar reconstruction (MPR) CTA on the 256-slice CT scanner than on the 64-slice CT scanner. After contrast agent injection, all observed neck arterial vessels had higher CT numbers in 256-slice CTA than in 64-slice CTA. There was no significant difference in contrast-to-noise (CNR) of CTA images between these two scanners. CT dose index (CTDI) and dose length product (DLP) for the 256-slice CTA were lower than those for the 64-slice CTA. CONCLUSIONS:Low dose CTA of rabbits with 70 or 80 kVp is feasible in a 256-slice or a 64-slice CT scanner. The radiation dose from the 256-slice CTA was much lower than that from the 64-slice CTA with comparable SNR and CNR. The technique can be further applied in longitudinal monitoring of an animal stroke model in the future.

Keywords: Low dose computed tomography angiography, 256-slice CTA, 64-slice CTA, New Zealand rabbit model, CT number, signal-to-noise ratio, contrast-to-noise ratio

DOI: 10.3233/XST-200669

Journal: Journal of X-Ray Science and Technology, vol. 28, no. 4, pp. 739-750, 2020