64排螺旋CT前瞻性心电门控扫描技术在先天性心脏病中的应用研究

The application study of scan technique of perspective ECG-gating of spiral CT with 64 slices in the CHD

目的:探讨64排螺旋CT前置门控扫描模式在成年先天性心脏病(CHD)患者扫描中取得满意图像和扫描参数的设定。方法:使用64排螺旋CT对医院收治的18例成年CHD患者进行扫描成像。对比剂团注流率4 ml/s,注射70 ml后继续注射20 ml生理盐水,继续注射15 ml对比剂,再跟踪注射25 ml生理盐水。采用前瞻性心电门控和对比剂智能跟踪方式进行扫描。感兴趣位置选在与气管分叉处同等高度的降主动脉,阈值为130 HU,采用阈值触发扫描方式。应用后处理工作站(Philips EBW)采用矢状位、冠状位和轴位的重建,并进行三维的多平面重建(MPR)、曲面重建(CPR)、最大密度投影(MIP)和容积再现(VR),观察患者心脏腔室和外周血管状况。结果:心脏各房、室结构清楚,与外周血管比邻关系清晰,可见主动脉瓣和房室间隔;经重建后的影像诊断结果与多普勒超声心动影像吻合。结论:利用64排螺旋CT前置门控扫描技术,有效降低辐射剂量时,可以得到符合诊断要求、有价值的心脏各房室和外周血管影像。在扫描中参数的配置准确恰当、对比剂的用量用法得当、扫描速度的快慢、扫描时间的长短以及触发阈值的设定均为获得高质量影像的关键因素。

Objective： To explore the setting of the scan mode of prospective electrocardiography（ECG）-gating of spiral CT with 64 slices for the adults with congenital heart disease（CHD） so as to obtain satisfying images and scanning parameters. Methods： 18 adults with CHD were scanned by using spiral CT with 64 slices. The flow rate of contrast agent was 4 m L/s, and 20 m L normal saline（NS） was injected after 70 m L contrast agent was injected, and then 15 m L contrast agent was injected following with NS, and 25 m L NS was used for tracing injection. The prospective ECG-gating and intelligence tracing of contrast agent were adopted to scan. The descending aorta that has same height with crotch of weasand should be chosen as interesting position, and the threshold value was 130 HU, the scan mode of triggering threshold was adopted in the research. The post processing workstation（Philips EBW） was applied to adopt reestablishment of sagittal view, coronal view and axial view, and to carry out reconstruction of 3 D multiplanar reformation（MPR）, curved planar reformation（CPR）, maximum intensity projection（MIP） and volume rendering（VR） so as to observe the situations of heart cavity and peripheral vessel of patients. Results： Each atrium and ventricle has clear construction, and the relationship with peripheral vessel was clearness, and the aortic valve and atrioventicular septum could be observed. And the diagnostic result by using reconstruction technique could be identical with image of Doppler echocardiography. Conclusion： The scan technique of perspective ECG-gating of spiral CT with 64 slices could obtain images, that conformed to requirement of diagnosis and had value, of each atrium, ventricle and peripheral vessel. In the scan, the accurate and suitable parameters, the appropriate dosage and usage of contrast agent, the scan speed, scan time and setting of triggering threshold were the key factors of obtaining image with high quality.