Department of Imaging (Division of Nuclear Medicine), Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.
J Cardiovasc Comput Tomogr. 2011 May-Jun;5(3):149-57. doi: 10.1016/j.jcct.2011.01.011. Epub 2011 Jan 28.
Electrocardiographic (ECG)-based tube current modulation during cardiac CT reduces radiation exposure but significantly increases noise in parts of the cardiac cycle where tube current is minimized.
We evaluated the effect of maximal ECG-based tube current reduction on left ventricular (LV) regional wall motion assessment and ejection fraction (EF) by comparing low-radiation helical dual-source CT (DSCT) to 2-dimensional transthoracic echocardiography (2D-TTE).
We studied 83 consecutive patients (15 with prior myocardial infarction) who underwent helically acquired DSCT coronary angiography with maximal ECG-based tube current modulation (low-radiation helical DSCT) and 2D-TTE within a 6-month period (median, 1 day), without any change in clinical status between the studies. In all patients, full tube current was applied only at 70% of the R-R interval, with minimal tube current (4% of maximum) in all other parts of the cardiac cycle. Reduced tube voltage (100 kVp) was combined with the maximal dose modulation in 34 patients. DSCT datasets were evaluated by a blinded, experienced cardiologist. Regional wall motion was assessed with the standard 17-segment model, with each segment scored as normal, hypokinetic, akinetic, and dyskinetic.
Mean effective radiation dose for the low-radiation helical DSCT was 5.2 ± 1.7 mSv. Regional wall motion was evaluable in all segments on low-radiation helical DSCT. There was excellent agreement of wall motion scoring by low-radiation helical DSCT and 2D-TTE in 1382 of 1411 segments (98%; Cohen's κ value 0.83; 95% confidence interval, 0.76-0.89; P < 0.0001). Mean LVEF was 67.6% ± 10.3% on low-radiation helical DSCT and 61.8% ± 10.3% on 2D-TTE (P < 0.0001).
Low-radiation dose helical coronary CT angiography with maximal ECG-based tube current modulation is comparable to 2D-TTE for regional wall motion and EF assessment.
心电图（ECG）引导的心脏 CT 管电流调制可降低辐射剂量，但会显著增加管电流最小化时心脏周期某些部位的噪声。
通过比较低辐射螺旋双源 CT（DSCT）与二维经胸超声心动图（2D-TTE），评估最大程度基于 ECG 的管电流减少对左心室（LV）局部壁运动评估和射血分数（EF）的影响。
我们研究了 83 例连续患者（15 例有心肌梗死病史），这些患者在 6 个月内（中位数为 1 天）接受了螺旋采集的 DSCT 冠状动脉造影，最大程度地基于 ECG 的管电流调制（低辐射螺旋 DSCT）和 2D-TTE，在两次研究之间没有任何临床状态的变化。在所有患者中，仅在 70%的 R-R 间隔应用全管电流，而在心脏周期的所有其他部分应用最小管电流（最大管电流的 4%）。在 34 例患者中，降低管电压（100 kVp）与最大剂量调制相结合。由一位经验丰富的盲法心脏病专家评估 DSCT 数据集。使用标准的 17 节段模型评估局部壁运动，每个节段评为正常、运动减退、无运动和运动不良。
低辐射螺旋 DSCT 的平均有效辐射剂量为 5.2 ± 1.7 mSv。低辐射螺旋 DSCT 可评估所有节段的局部壁运动。低辐射螺旋 DSCT 和 2D-TTE 在 1411 个节段中的 1382 个节段（98%；Cohen's κ 值为 0.83；95%置信区间为 0.76-0.89；P < 0.0001）的壁运动评分具有极好的一致性。低辐射螺旋 DSCT 的平均 LVEF 为 67.6%±10.3%，2D-TTE 的平均 LVEF 为 61.8%±10.3%（P < 0.0001）。
最大程度基于 ECG 的管电流调制的低辐射剂量螺旋冠状动脉 CT 血管造影与二维 TTE 相比，可用于局部壁运动和 EF 评估。
