Schuknecht B
Institute of Neuroradiology, University Hospital of Zurich, Klinik Bethanien, Toblerstr 51, 8044 Zürich, Switzerland.
Neuroradiology. 2004 Dec;46 Suppl 2:s208-13. doi: 10.1007/s00234-004-1334-8.
Continuous evolution of multi row CT is increasingly making CT angiography a viable imaging modality for assessment of the supraaortic and intracranial vessels as an anatomically and functionally coherent vascular system. Extended non-invasive examinations with reduced contrast volume have become feasible with the availability of 16 and 64 row MDCT scanners. Prerequisites to obtain high resolution CT angiographies of the head and neck vessels with superior detail include the administration of low contrast volume, high contrast density (400 mg I/ml) contrast media, adequate timing and data acquisition, optimal flow rate (4 ml/s) and saline flushing. Non-invasiveness, delineation of vessel calcification, virtual independence from hemodynamic conditions, and the ability to provide quantification without needing to correct for magnification are all attributes that favour CT angiography over digital subtraction angiography and to some extent even magnetic resonance angiography as an alternative non-invasive technique. CT angiography is established as a modality of choice for the assessment of patients with acute stroke and chronic steno-occlusive disease. CT angiography may indicate the presence of extra- or intracranial acute vessel occlusion and dissection, predisposing atherosclerotic steno-occlusive disease and thus indicate thrombo-embolism or local appositional thrombosis as the principle pathogenic factor. CT angiography is used to assess anatomy, and to depict the presence, location and extent of calcified and non-calcified plaque as a cause of high grade stenosis. Despite relatively limited sensitivity CT angiography is indicated for suspected or confirmed aneurysms that demand further verification of their presence, geometry, or relationship to parent artery branches and osseous anatomic landmarks. Low volume high density contrast media have substantially increased the ability of CT angiography to depict small aneurysms, small branches, and collateral vessels, and to recognize the residual lumen in vessels with high grade stenosis or conditions such as dissection or pseudo-occlusion. Superior detail high resolution CT angiography is thus a viable alternative to DSA, relegating the latter technique to endovascular treatment applications only.
多层CT的不断发展，越来越使CT血管造影成为评估主动脉弓和颅内血管这一解剖和功能上连贯的血管系统的一种可行的成像方式。随着16排和64排MDCT扫描仪的出现，使用较少对比剂体积的扩展无创检查已变得可行。获得具有卓越细节的头颈部血管高分辨率CT血管造影的先决条件包括使用低对比剂体积、高对比剂密度（400 mg I/ml）的对比剂、适当的时机和数据采集、最佳流速（4 ml/s）以及生理盐水冲洗。无创性、血管钙化描绘、基本不受血流动力学条件影响以及无需校正放大倍数即可进行量化分析的能力，这些都是CT血管造影相对于数字减影血管造影甚至在一定程度上相对于磁共振血管造影作为一种替代性无创技术所具有的优势。CT血管造影已成为评估急性中风和慢性狭窄闭塞性疾病患者时的首选方式。CT血管造影可能显示颅外或颅内急性血管闭塞和夹层形成，提示动脉粥样硬化性狭窄闭塞性疾病，并因此表明血栓栓塞或局部贴壁血栓形成是主要致病因素。CT血管造影用于评估解剖结构，并描绘钙化和非钙化斑块的存在、位置和范围，这些斑块是导致高度狭窄的原因。尽管敏感性相对有限，但对于需要进一步确认其存在、形态或与母动脉分支及骨性解剖标志关系的疑似或确诊动脉瘤，CT血管造影仍有应用价值。低体积高密度对比剂显著提高了CT血管造影描绘小动脉瘤、小分支和侧支血管以及识别高度狭窄血管或夹层或假性闭塞等情况下残余管腔的能力。因此，卓越细节的高分辨率CT血管造影是数字减影血管造影的一种可行替代方法，使后者仅用于血管内治疗应用中。
