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.

中文翻译：

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新西兰兔头颈部 CT 血管造影影像质量和剂量评估。

背景：虽然计算机断层扫描 (CT) 是诊断血管疾病的一种强大的诊断成像方式，但由于高辐射剂量，它对人类健康存在一定风险。因此，CT 供应商开发了低剂量计算机断层扫描 (LDCT)，旨在解决这个问题。如今，LDCT已逐渐成为CT检查的主流。目的：本研究旨在评估 LDCTA 在动物模型中的可行性，并比较两种临床扫描仪的成像特征和剂量。方法：使用256层和64层CT扫描仪对22张新西兰兔头颈部注射造影剂前后的CTA图像进行扫描。256 片和 64 片 CTA 中使用的管电压分别为 70 kVp 和 80 kVp。比较了在这两种扫描仪中从 CTA 获得的定量图像指数和辐射剂量。结果：与 64 层 CT 扫描仪相比，在 256 层 CT 扫描仪上的多平面重建 (MPR) CTA 中可以看到更多的颈部动脉血管。注射造影剂后，所有观察到的颈部动脉血管在 256 层 CTA 中的 CT 数均高于 64 层 CTA。这两种扫描仪之间的 CTA 图像的对比噪声 (CNR) 没有显着差异。256 层 CTA 的 CT 剂量指数 (CTDI) 和剂量长度乘积 (DLP) 低于 64 层 CTA。结论：兔 70 或 80 kVp 的低剂量 CTA 在 256 层或 64 层 CT 扫描仪中是可行的。256 层 CTA 的辐射剂量远低于 64 层 CTA，SNR 和 CNR 相当。