Kuehne Titus, Saeed Maythem, Moore Phillip, Gleason Kelly, Reddy Gautham, Teitel David, Higgins Charles B
Department of Radiology, Division of Pediatric Cardiology, University of California San Francisco, 505 Parnassus Ave, L308, San Francisco, CA 94143-0628, USA.
Radiology. 2002 May;223(2):439-45. doi: 10.1148/radiol.2232010975.
To compare the effects of various stents on magnetic resonance (MR) imaging flow volume measurements and to determine the value of a blood-pool MR imaging contrast medium in assessment of vascular stents.
In 11 pigs, six nitinol stents (Memotherm), four platinum stents (NuMed), and one elgiloy stent (Wallstent) were placed in the main pulmonary artery under x-ray fluoroscopic guidance. MR imaging was performed 3 months after stent placement before and after injection of NC100150 contrast medium. Blood flow volumes were assessed with velocity-encoded cine MR imaging through and next to the stent. The signal-to-noise ratio and width of susceptibility artifacts of the stents also were determined. Measurements were analyzed with the paired Student t test and Bland-Altman test, where appropriate.
Blood flow volumes measured through the nitinol and platinum stents disclosed no significant difference between velocity-encoded cine MR imaging measurements through and next to the stent. On cine MR images, small susceptibility artifacts were observed around the nitinol and platinum stents. Signal-to-noise ratio in the stent lumen was reduced in nitinol and platinum stents when compared with that next to the stent. The elgiloy stent produced severe susceptibility artifacts, making measurement of flow volumes impossible. NC100150 injection caused no significant effect on flow volume measurements. It improved the signal-to-noise ratio of the pulmonary arterial lumen outside and, to a lesser extent, inside the stent.
Assessment of morphology and flow volumes through nitinol and platinum stents is feasible with MR imaging. Blood-pool contrast media provide persistent signal enhancement in the pulmonary artery and, to a lesser extent, in the lumina of nitinol and platinum stents.
比较各种支架对磁共振（MR）成像血流量测量的影响，并确定血池MR成像造影剂在评估血管支架中的价值。
在11头猪中，于X线透视引导下将6个镍钛合金支架（Memotherm）、4个铂支架（NuMed）和1个埃尔吉洛伊耐蚀合金支架（Wallstent）置入主肺动脉。在支架置入3个月后，于注射NC100150造影剂前后进行MR成像。通过支架及支架旁的速度编码电影MR成像评估血流量。还测定了支架的信噪比和磁化率伪影宽度。在适当情况下，采用配对学生t检验和布兰德-奥特曼检验对测量结果进行分析。
通过镍钛合金和铂支架测量的血流量显示，通过支架及支架旁的速度编码电影MR成像测量结果之间无显著差异。在电影MR图像上，在镍钛合金和铂支架周围观察到小的磁化率伪影。与支架旁相比，镍钛合金和铂支架内的支架腔信噪比降低。埃尔吉洛伊耐蚀合金支架产生严重的磁化率伪影，使得血流量测量无法进行。注射NC100150对血流量测量无显著影响。它提高了支架外肺动脉腔以及在较小程度上支架内肺动脉腔的信噪比。
利用MR成像评估镍钛合金和铂支架的形态及血流量是可行的。血池造影剂在肺动脉中提供持续的信号增强，在较小程度上也在镍钛合金和铂支架腔内提供信号增强。
