Department of Radiology, Harbin Medical University, Harbin, China.
Minerva Med. 2011 Aug;102(4):249-59.
The aim of this study was the comparison of image quality, diagnostic accuracy and radiation dose of ECG-gated volume scan mode of 320-detector row CT with 64-detector row CT.
A hundred and twenty patients receiving coronary artery CT angiography (CTA) were divided into two groups. Sixty patients in Group A underwent 64-detector row CTA; for the remainder, Group B, 320-detector row CT was used. Conventional coronary angiography was then performed in all patients. In Group B, patients with a pulse <65 beat/min underwent a prospective ECG-gated volume scan using a 70-80% R-R phase window and 1-beat, whereas a 30-80% R-R phase window, 2-beat CT was performed in patients with a pulse >65 beat/min.
In Group A, 247 vessels and 920 segments were assessed; in Group B, 242 and 906. In 320-detector row CTA, the coronary stenosis diagnosis' specificities were 98%, 96%, and 95% at the segmental, vessel, and patient levels, respectively (98%, 94%, and 92% in 64-detector row CTA); the negative predictive values were 99%, 98%, and 100% (98%, 97%, and 95% in 64-detector row CTA). There was no significant difference in specificity or negative predictive values between the groups. The average effective radiation dose in Group B was lower than in Group A (P<0.001). In Group B, the dose for 48 patients with 70-80% R-R phase window, 1-beat scan, was lower than for the remaining 12 patients (30-80% R-R phase window, 2-beat) (P<0.001).
The 320-detector CT reduces the radiation exposure by approximately 80% compared with 64-detector CT, with similar diagnostic accuracy and image quality.
本研究旨在比较 320 层与 64 层螺旋 CT 心电门控容积扫描模式的图像质量、诊断准确性和辐射剂量。
将 120 例行冠状动脉 CT 血管造影（CTA）的患者分为两组。A 组 60 例行 64 层 CTA，B 组 60 例行 320 层 CT。所有患者均进行常规冠状动脉造影。B 组中，脉搏<65 次/分的患者采用 70-80%R-R 时相窗和 1 个心动周期的前瞻性心电门控容积扫描，脉搏>65 次/分的患者采用 30-80%R-R 时相窗和 2 个心动周期的 CT。
A 组中 247 支血管和 920 个节段得到评估，B 组中 242 支血管和 906 个节段得到评估。320 层 CT 冠状动脉狭窄诊断的特异性在节段、血管和患者水平分别为 98%、96%和 95%（64 层 CTA 分别为 98%、94%和 92%），阴性预测值分别为 99%、98%和 100%（64 层 CTA 分别为 98%、97%和 95%）。两组间的特异性或阴性预测值无显著差异。B 组的平均有效辐射剂量低于 A 组（P<0.001）。在 B 组中，采用 70-80%R-R 时相窗、1 个心动周期扫描的 48 例患者的剂量低于采用 30-80%R-R 时相窗、2 个心动周期扫描的 12 例患者（P<0.001）。
与 64 层 CT 相比，320 层 CT 可将辐射暴露量降低约 80%，而诊断准确性和图像质量相似。
