双源CT前瞻性心电门控技术在中心静脉血管成像中的应用价值

目的：探讨前瞻性心电门控技术在中心静脉CT血管成像（CTV）中的应用价值。方法：连续选取2016年7月至2020年1月在丽水市中心医院用西门子第3代双源Force CT行中心静脉CTV检查的患者60例，随机分为2组，每组30例，均采用120 kV管电压，有效管电流100 mAs，开启Care Dose 4D技术，准直宽度192×0.6 mm。常规组采用常规扫描模式，螺距0.8，转速0.5 s/圈。前瞻性心电门控组转速0.25 s/圈，当心率≤70次/min时，采用60%～70%时相触发扫描，当心率＞70次/min时，采用30%～45%时相触发扫描，并由系统自动重建最佳时相图像。比较两组的有效辐射剂量（ED）、扫描时间、中心静脉的图像质量。结果：常规组和前瞻性心电门控组的年龄、性别、心率、BMI、扫描长度差异无统计学意义（P ＞0.05）。常规组的扫描时间（3.29±0.41）s，明显少于前瞻性心电门控组的扫描时间（9.91±0.95）s，差异有统计学意义（P ＜0.05）。常规组DLP为（234.26±26.52）mGy·cm，CTDIvol为（9.27±0.88）mGy，ED为（3.98±0.45）mSv；前瞻性心电门控组的DLP为（233.01±25.89）mGy·cm，CTDIvol为（9.24±0.97）mGy，ED为（3.96±0.44）mSv，差异均无统计学意义（P ＞0.05）。比较2组患者共420段的中心静脉图像质量，前瞻性心电门控组上腔静脉、左头臂静脉、右头臂静脉的图像质量评分显著高于常规组（P ＜0.05），而2组的左锁骨下静脉、右锁骨下静脉、左颈静脉、右颈静脉的图像质量评分均较好，差异无统计学意义（P ＞0.05）。结论：应用前瞻性心电门控技术可显著提高中心静脉CTV中上腔静脉段及左、右头臂静脉段图像质量。

The value of dual-source CT prospective ECG-gated technique in central venous angiography

Objective: To evaluate the value of prospective ECG-gated technique in central venous angiography. Methods: Sixty patients who underwent central venous CTV with Siemens third-generation dualsource Force CT in our hospital from July 2016 to January 2020 were randomly divided into two groups of 30 and were treated with 120 kV tube voltage, an effective tube current of 100 mAs and Care Dose 4D technology with a collimation width of 192×0.6 mm. The conventional scanning mode was used in the routine group, with pitch 0.8 and rotational speed 0.5 s/circle. The prospective ECG-gated group rotational speed 0.25 s/circle, when the heart rate was less than 70 beats/min, the scan was triggered by 60%-70% phase; when the heart rate was more than 70 beats/min, the scan was triggered by 30%-45% phase; and the best phase image was automatically reconstructed by the system. The (ED), scanning time of the effective radiation dose, and the image quality of the central vein were compared between the two groups. Results: There was no significant difference in age, sex,heart rate, BMI, and scan length between the routine group and the prospective ECG-gated group (P>0.05). The scanning time in the routine group (3.29±0.41)s was significantly less than that in the prospective ECG-gated group (9.91±0.95)s, and there was significant difference between the two groups (P<0.05). The DLP (mGy·cm),CTDIvol (mGy), and ED (mSv) of the routine group were 234.26±26.52, 9.27±0.88, and 3.98±0.45 respectively.There was no significant difference in DLP, CTDIvol, and ED between the prospective ECG-gated group and the prospective ECG-gated group (233.01±25.89, 9.24±0.97 and 3.96±0.44, respectively) (P>0.05). Nonparametric test was used to compare the image quality of 420 segments of the central vein between the two groups. The image quality scores of superior vena cava, left brachiocephalic vein and right brachiocephalic vein in the prospective ECG-gated group were significantly higher than those in the routine group (P<0.05). The image quality scores of the left subclavian vein, right subclavian vein, left jugular vein and right jugular vein were better in the two groups, but there was no significant difference between the two groups (P>0.05). Conclusion: The prospective ECG-gated technique is superior to conventional spiral CT scan in the examination of central venous vessels,which is worthy of clinical application.