Hähnel Stefan, Trossbach Manuel, Braun Cora, Heiland Sabine, Knauth Michael, Sartor Klaus, Hartmann Marius
Division of Neuroradiology, Department of Neurology, University of Heidelberg Medical Center, Germany.
AJNR Am J Neuroradiol. 2003 Sep;24(8):1512-6.
Our purpose was to evaluate whether CT angiography is a suitable alternative to conventional angiography in the evaluation of small-vessel stents for intracranial angioplasty.
CT angiographic appearances of 23 stents of different designs and sizes (2.0, 3.0, and 4.0 mm) were investigated after they were filled with a solution of 0.9% NaCl or diluted contrast medium. For each stent, artificial lumen narrowing (ALN) was measured, and the difference in the number of pixels with a Hounsfield value below 200 HU between the two filling states, DIFF(HU<200), was calculated to provide an objective indicator of the size of the evaluable stent diameter.
With a window width of 1500 HU at a window level of 400 HU, ALN ranged from 66.8% to 97.7% in the group of 2.0-mm stents and from 38.6% to 66.8% in the groups of 3.0- and 4.0-mm stents. For the 2.0-mm stents, DIFF(HU<200) was zero. In the groups of 3.0- and 4.0-mm stents, DIFF(HU<200) ranged from 0.3 to 6.7, corresponding to a diameter of 0.13-3.0 mm, when the pixel size was presupposed to be 0.449 mm.
CT angiographic evaluation of small-vessel patency after stent placement is considerably impaired by ALN. Stent manufacturers should be aware of potential artifacts caused by their stents during noninvasive diagnostic studies such as CT angiography.
我们的目的是评估在颅内血管成形术中小血管支架的评估中，CT血管造影是否是传统血管造影的合适替代方法。
在23个不同设计和尺寸（2.0、3.0和4.0毫米）的支架填充0.9%氯化钠溶液或稀释造影剂后，研究其CT血管造影表现。对于每个支架，测量人工管腔狭窄（ALN），并计算两种填充状态下Hounsfield值低于200 HU的像素数量差异DIFF(HU<200)，以提供可评估支架直径大小的客观指标。
在窗宽1500 HU、窗位400 HU时，2.0毫米支架组的ALN范围为66.8%至97.7%，3.0毫米和4.0毫米支架组的ALN范围为38.6%至66.8%。对于2.0毫米支架，DIFF(HU<200)为零。在3.0毫米和4.0毫米支架组中，当预设像素大小为0.449毫米时，DIFF(HU<200)范围为0.3至6.7，对应直径为0.13至3.0毫米。
支架置入后小血管通畅性的CT血管造影评估因ALN而受到显著损害。支架制造商应意识到其支架在CT血管造影等非侵入性诊断研究过程中可能产生的伪影。
