Department of Radiology, Shengjing Hospital of China, Medical University, 36 Sanhao Street, 110004, Shenyang, Liaoning Province, People's Republic of China.
Int J Cardiovasc Imaging. 2012 Jan;28(1):153-62. doi: 10.1007/s10554-010-9760-7. Epub 2010 Dec 14.
To compare image quality and radiation dose estimates for coronary computed tomography angiography (CCTA) obtained with a prospectively gated transaxial (PGT) CT technique and a retrospectively gated helical (RGH) CT technique using a 256-slice multidetector CT (MDCT) scanner and establish an upper limit of heart rate to achieve reliable diagnostic image quality using PGT. 200 patients (135 males, 65 females) with suspected coronary artery disease (CAD) underwent CCTA on a 256-slice MDCT scanner. The PGT patients were enrolled prospectively from January to June, 2009. For each PGT patient, we found the paired ones in retrospective-gating patients database and randomly selected one patient in these match cases and built up the RGH group. Image quality for all coronary segments was assessed and compared between the two groups using a 4-point scale (1: non-diagnostic; 4: excellent). Effective radiation doses were also compared. The average heart rate ± standard deviation (HR ± SD) between the two groups was not significantly different (PGT: 64.6 ± 12.9 bpm, range 45-97 bpm; RGH: 66.7 ± 10.9 bpm, range 48-97 bpm, P = 0.22). A receiver-operating characteristic (ROC) analysis determined a cutoff HR of 75 bpm up to which diagnostic image quality could be achieved using the PGT technique (P < 0.001). There were no significant differences in assessable coronary segments between the two groups for HR ≤ 75 bpm (PGT: 99.9% [961 of 962 segments]; RGH: 99.8% [1038 of 1040 segments]; P = 1.0). At HR > 75 bpm, the performance of the PGT technique was affected, resulting in a moderate reduction of percentage assessable coronary segments using this approach (PGT: 95.5% [323 of 338 segments]; RGH: 98.5% [261 of 265 segments]; P = 0.04). The mean estimated effective radiation dose for the PGT group was 3.0 ± 0.7 mSv, representing reduction of 73% compared to that of the RGH group (11.1 ± 1.6 mSv) (P < 0.001). Prospectively-gated axial coronary computed tomography using a 256-slice multidetector CT scanner with a 270 ms tube rotation time enables a significant reduction in effective radiation dose while simultaneously providing image quality comparable to the retrospectively gated helical technique. Our experience demonstrates the applicability of this technique over a wider range of heart rates (up to 75 bpm) than previously reported.
比较前瞻性门控轴位（PGT）CT 技术和回顾性门控螺旋（RGH）CT 技术在 256 层多排 CT（MDCT）扫描仪上获得的冠状动脉 CT 血管造影（CCTA）的图像质量和辐射剂量估计，并确定使用 PGT 获得可靠诊断图像质量的最高心率上限。200 名疑似冠心病（CAD）患者（男性 135 名，女性 65 名）在 256 层 MDCT 扫描仪上进行了 CCTA。PGT 患者前瞻性纳入 2009 年 1 月至 6 月，为每位 PGT 患者在回顾性门控患者数据库中找到配对患者，并在这些匹配病例中随机选择一位患者建立 RGH 组。使用 4 分制（1：非诊断；4：优秀）评估和比较两组的所有冠状动脉节段的图像质量。还比较了两组的有效辐射剂量。两组间平均心率±标准差（HR±SD）无显著差异（PGT：64.6±12.9bpm，范围 45-97bpm；RGH：66.7±10.9bpm，范围 48-97bpm，P=0.22）。受试者工作特征（ROC）分析确定了 75bpm 的 HR 截止值，在此截止值以下，使用 PGT 技术可获得诊断图像质量（P<0.001）。在 HR≤75bpm 时，两组间可评估的冠状动脉节段无显著差异（PGT：99.9%[961 个/962 个节段]；RGH：99.8%[1038 个/1040 个节段]；P=1.0）。在 HR>75bpm 时，PGT 技术的性能受到影响，导致使用该方法可评估的冠状动脉节段百分比适度降低（PGT：95.5%[323 个/338 个节段]；RGH：98.5%[261 个/265 个节段]；P=0.04）。PGT 组的平均有效辐射剂量估计值为 3.0±0.7mSv，与 RGH 组（11.1±1.6mSv）相比，降低了 73%（P<0.001）。使用 256 层多排 CT 扫描仪进行前瞻性轴位冠状动脉 CT 检查，管旋转时间为 270ms，可显著降低有效辐射剂量，同时提供与回顾性门控螺旋技术相当的图像质量。我们的经验表明，与以前报道的相比，这种技术在更广泛的心率范围内（高达 75bpm）具有适用性。
