Jansen O, Braks E, Hähnel S, Schramm T, Sartor K
Abteilung Neuroradiologie, Ruprecht-Karls-Universität Heidelberg.
Rofo. 1998 Aug;169(2):175-81.
To examine in a model and in clinical practice whether CT angiography (CTA) is suitable to determine the size of intracranial aneurysms.
For an aneurysm model the contrast medium-filled balloon of an occlusion catheter was used. At different levels of filling images were obtained by both CTA and digital subtraction angiography (DSA). In the CT image the size of the simulated aneurysm was calculated from the CTA data at the workstation while from the DSA images it was performed by the DSA system with the use of both an external reference structure (two-ring method) and a stereotactic system (ANGIOLOG). In 7 patients, the size of the aneurysm was determined by CTA and DSA prior to aneurysm occlusion by means of guglielmi detachable coils (GDC therapy).
On the basis of 2 D reconstructions of the CT average size deviations in the XY plane of 1.6% and on the Z axis of 3.2% were determined. These errors increased to 3.4% (XY plane) and 5.6% (Z axis) with 3 D reconstructions. By use of the two-ring model, DSA gave an average size deviation of 3% while with the stereotactic system (ANGIOLOG) it was as high as 11%. In 6 of the 7 patients, the appropriate spiral size was chosen primarily after CTA measurements.
CTA enables the reliable determination of the size of an intracranial arterial aneurysm and in individual cases can give a better representation of an anatomic situation at the base of an aneurysm than DSA. Thus, CTA imaging of an aneurysm prior to GDC therapy is useful.
在模型和临床实践中检验CT血管造影（CTA）是否适合用于确定颅内动脉瘤的大小。
对于动脉瘤模型，使用封堵导管中充满造影剂的球囊。在不同充盈水平下，通过CTA和数字减影血管造影（DSA）获取图像。在CT图像中，在工作站根据CTA数据计算模拟动脉瘤的大小，而在DSA图像中，通过DSA系统使用外部参考结构（双环法）和立体定向系统（ANGIOLOG）来计算。在7例患者中，在通过 Guglielmi 可脱卸弹簧圈（GDC治疗）进行动脉瘤封堵之前，通过CTA和DSA确定动脉瘤的大小。
基于CT的二维重建，确定在XY平面的平均尺寸偏差为1.6%，在Z轴为3.2%。三维重建时，这些误差增加到3.4%（XY平面）和5.6%（Z轴）。使用双环模型时，DSA的平均尺寸偏差为3%，而使用立体定向系统（ANGIOLOG）时高达11%。在7例患者中的6例中，主要在CTA测量后选择了合适的弹簧圈尺寸。
CTA能够可靠地确定颅内动脉动脉瘤的大小，在个别情况下，与DSA相比，能更好地显示动脉瘤底部的解剖情况。因此，在GDC治疗前对动脉瘤进行CTA成像很有用。
