多层螺旋CT血管成象评估透析患者血管通路

目的：应用多层螺旋CT血管成象(muhislice spiral computed tomographic angiography，MSCTA)三维重建技术检查维持性血液透析(MHD)患者血管通路狭窄情况，为手术修复和经皮经腔血管成形术(PTA)提供指导。方法：采用TOSHIBA16层螺旋CT，对19例临床拟为血管通路功能不良的MHD患者进行检查，采用对侧肢体外周静脉注射非离子型碘造影剂，注射速度3ml／s，造影剂总量50～100ml。注射后延时25～30s行多层螺旋CT扫描检查、采象，应用最大密度投影、容积成象和曲面重建技术对图象数据进行处理和三维重建。结果：MSCTA配合三维重建技术可获得空间分辨率很高的透析血管通路全景图，包括动脉流人道、吻合口和静脉流出道，血管走行情况和狭窄部位均获得清晰显示。检查发现内瘘吻合口狭窄4例；静脉流出道狭窄10例16个部位，其中4例形成明显静脉侧支循环；前臂内瘘局部扩张6例；锁骨下静脉狭窄3例；头静脉汇人锁骨下静脉处狭窄1例；上腔静脉狭窄1例。根据MSCTA的结果，对8例患者进行了动静脉内瘘手术修复，4例进行了数字减影血管造影(DSA)介导PTA，手术直视和DSA证实了MSCTA诊断的准确性，手术和PTA干预的短期效果令人满意。结论：MSCTA是一项评估透析血管通路的先进手段，具有无创伤、成象迅速、高清晰度等优点，能全面、准确地评估MHD患者内瘘情况，并为进一步治疗提供指导。

Multi-slice spiral computed tomographic angiography in evaluating the vascular access of hemodialysis

Objective:To evaluate multi-slice spiral computed tomographic angiography (MSCTA) in assessing stenosis of hemodialysis vascular accesses, and in guiding repairing operation or percutaneous transluminal angioplasty (PTA) of access. Methodology:TOSHIBA 16-slice spiral CT was used to examine 19 hemodialysis patients with various vascular access stenosis. Non-enhanced CT was performed first, followed by contrast material-enhanced CT angiography. Non-ionized iodine contrast material ( iohexol ) at the rate of 3 ml/sec (totally 50-100 ml) was injected in the other upper limb's peripheral vein. After 25-30 seconds ' delay, contrast-enhanced CT scan was initiated. The transverse source images were reformatted as maximum intensity projection (MIP), volume rendering (VR) and multiple/curved planar reconstruction (MPR or CPR) images with 10-mm section thickness and 9-mm overlap in the transverse, coronal, and sagittal planes. The angiographic studies were interpreted by 2 certificated radiologists with 10 years experience in MR and CT image interpretation. Results:Segments of vascular access lesions were clearly revealed. MIP, VR and MPR images displayed the AV fistula with the feeding artery, anastomoses and outflow tract up to the superior caval vein in every patient. The results showed 4 cases of anastomoses stenosis, 10 cases of outflow tract stenosis (total 16 stenosis segments were observed) with venous collateral circulation formed in 4 cases, 6 cases of outflow tract dilation, 3 cases of subclavian vein stenosis, 1 case of cephalic vein-subclavian vein joint stenosis and 1 case of superior caval vein stenosis. According to the results of MSCTA, AV fistula repairing surgery was done in 8 patients and percutaneous transluminal angioplasty (PTA) under the guide of digital subtraction angiography (DSA) was done in 4 patients. The results of MSCTA were confirmed by surgery or DSA in these 12 subjects. Conclusion:In our opinion, MSCTA is a good non-invasive diagnostic technique to detect various hemodialysis vascular access abnormalities. It could replace DSA in the initial imaging of hemodialysis vascular access and may provide important information for further AVF repairing operation or PTA.