Department of Radiology, Yonsei University College of Medicine, Gangnam Severance Hospital, 211 Eonjuro, Gangnam-gu, Seoul 135-720, Republic of Korea.
AJR Am J Roentgenol. 2012 Jul;199(1):96-102. doi: 10.2214/AJR.11.7450.
The objective of our study was to investigate the feasibility of an 80-kVp protocol using a moderate-concentration contrast medium (CM) for CT angiography of the renal arteries by comparison with a conventional 120-kVp protocol using a high-concentration CM.
Attenuation values and signal-to-noise ratios (SNRs) were determined in a phantom for the 120-kVp protocol with a high-concentration CM and the 80-kVp protocol with a moderate-concentration CM. In addition, 50 patients were prospectively enrolled in the study: 25 were scanned with 120 kVp and 200 effective mAs (mAs(eff)) after the administration of 110 mL of high-concentration CM (370 mg I/mL), and the other 25 were scanned with 80 kVp and 585 mAs(eff) after the administration of 110 mL of moderate-concentration CM (300 mg I/mL). Images of the two groups were compared in terms of arterial attenuation, SNR, contrast-to-noise ratio (CNR), and subjective degree of arterial enhancement and image quality.
The mean attenuation of the main renal artery was significantly higher (p < 0.001) in the 80-kVp group who received moderate-concentration CM (mean ± SD, 370.0 ± 65.0 HU) than in the 120-kVp group who received high-concentration CM (269.9 ± 27.8 HU) without significant differences in SNR and CNR values. The 80-kVp protocol had significantly higher quality scores for arterial enhancement, sharpness of the artery, and overall diagnostic quality compared with the 120-kVp protocol. The effective dose of the 80-kVp protocol (4.5 mSv) was 8.2% lower than that of the 120-kVp protocol (4.9 mSv).
The use of 80 kVp with moderate-concentration CM could improve arterial enhancement and provide superior image quality with a smaller amount of iodine and a lower radiation dose.
本研究旨在通过比较使用高浓度对比剂（CM）的 120kVp 协议和使用中浓度 CM 的 80kVp 协议，探讨在肾动脉 CT 血管造影中使用 80kVp 协议的可行性。
在体模中对 120kVp 协议高浓度 CM 和 80kVp 协议中浓度 CM 进行衰减值和信噪比（SNR）测定。此外，前瞻性纳入 50 例患者：25 例采用 120kVp 扫描，200 有效毫安秒（mAs(eff))，注射 110ml 高浓度 CM（370mgI/mL）；25 例采用 80kVp 扫描，585mAs(eff)，注射 110ml 中浓度 CM（300mgI/mL）。比较两组动脉强化的衰减值、SNR、对比噪声比（CNR）、主观动脉强化程度和图像质量。
接受中浓度 CM 的 80kVp 组主肾动脉的平均衰减值明显较高（p<0.001）（均值±标准差，370.0±65.0HU），而接受高浓度 CM 的 120kVp 组为 269.9±27.8HU，SNR 和 CNR 值无显著差异。80kVp 组的动脉强化、动脉锐利度和整体诊断质量的评分明显高于 120kVp 组。80kVp 组的有效剂量（4.5mSv）比 120kVp 组（4.9mSv）低 8.2%。
使用 80kVp 和中浓度 CM 可以提高动脉强化效果，降低碘用量和辐射剂量，同时提供更好的图像质量。
