Harrison M J, Johnson B A, Gardner G M, Welling B G
Division of Neurosurgery, David Grant United States Air Force Medical Center, Little Rock, Arkansas, USA.
Neurosurgery. 1997 May;40(5):947-55; discussion 955-7. doi: 10.1097/00006123-199705000-00014.
The goal was to assess the capability of magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) to replace catheter angiography in the evaluation of unruptured intracranial aneurysms.
A prospective evaluation of a 1-year period included all patients suspected of harboring unruptured intracranial aneurysms at a single institution. All patients underwent magnetic resonance imaging, MRA, and CTA, for comparison with intraoperative findings or results from catheter angiography. Both MRA and CTA now provide submillimeter resolution of vascular structures, with accurate detection of intracranial aneurysms of a diameter greater than or equal to 3 mm. This resolution calls into question the universal need for catheter angiography in the care of patients with suspected intracranial aneurysms. When the catheter angiography can be avoided, radiological costs can be reduced by as much as two-thirds while eliminating the risk of arterial injury and stroke.
Excellent visualization of the intracranial vasculature was provided by both MRA and CTA. No vascular lesion was detected at surgery or by formal angiography that was not visualized by noninvasive angiographic techniques. The three-dimensional anatomy of the aneurysm complex (unavailable with catheter angiography) was well depicted by both MRA and CTA. CTA was unique in its capacity to display the relationship of vascular structures to bone, information that is invaluable for planning operative strategies for lesions such as carotidophthalmic artery aneurysms. Additionally, acquisition of CTA images was very rapid, with a scanning time of less than 1 minute. Both MRA and CTA allowed for retrospective manipulation of data into an infinite number of views, including views that paralleled those encountered through the operative microscope. Additionally, both MRA and CTA can depict the internal anatomy of aneurysms, an ability not possessed by intra-arterial angiography. This ability alerts the surgeon to possible intraoperative risks, such as plaque in the lumen of an aneurysm or calcium within the walls of the arteries.
Both MRA and CTA provide several advantages over digital subtraction angiography, in addition to reduced costs and avoidance of arterial injury and stroke. These include retrospective manipulation of data in a 360-degree format, visualization of the internal anatomy of arteries and aneurysms, three-dimensional depiction of anatomy, and rapid data acquisition. Preliminary data and a review of the literature suggest that MRA, when used in concert with CTA, can replace catheter angiography in the assessment of select patients harboring unruptured intracranial aneurysms. Although no firm conclusions or generalizations can be drawn from this small cohort of patients, it is hoped that this report will stimulate interest and further study at other institutions.
评估磁共振血管造影（MRA）和计算机断层血管造影（CTA）在评估未破裂颅内动脉瘤时替代导管血管造影的能力。
对一家机构内1年期间所有疑似患有未破裂颅内动脉瘤的患者进行前瞻性评估。所有患者均接受磁共振成像、MRA和CTA检查，以便与术中发现或导管血管造影结果进行比较。如今，MRA和CTA均能提供亚毫米级的血管结构分辨率，可准确检测直径大于或等于3mm的颅内动脉瘤。这种分辨率让人质疑在疑似颅内动脉瘤患者的治疗中对导管血管造影的普遍需求。若能避免进行导管血管造影，放射学检查费用可降低多达三分之二，同时消除动脉损伤和中风的风险。
MRA和CTA均能出色地显示颅内血管系统。手术中或正式血管造影未发现无创血管造影技术未显示的血管病变。MRA和CTA均能很好地描绘动脉瘤复合体的三维解剖结构（导管血管造影无法提供）。CTA的独特之处在于能够显示血管结构与骨骼的关系，这一信息对于规划颈眼动脉瘤等病变的手术策略非常宝贵。此外，CTA图像的采集非常迅速，扫描时间不到1分钟。MRA和CTA都允许对数据进行回顾性处理，生成无数个视图，包括与手术显微镜所见平行的视图。此外，MRA和CTA都能描绘动脉瘤的内部解剖结构，这是动脉内血管造影所不具备的能力。这种能力可提醒外科医生注意可能的术中风险，如动脉瘤腔内的斑块或动脉壁内的钙化。
除了降低成本以及避免动脉损伤和中风外，MRA和CTA相对于数字减影血管造影还有几个优势。这些优势包括以360度格式对数据进行回顾性处理、显示动脉和动脉瘤的内部解剖结构、对解剖结构进行三维描绘以及快速采集数据。初步数据和文献综述表明，MRA与CTA联合使用时，可在评估部分患有未破裂颅内动脉瘤的患者时替代导管血管造影。尽管从这一小群患者中无法得出确凿的结论或进行概括，但希望本报告能激发其他机构的兴趣并促使其进一步研究。
