Kuehne Titus, Saeed Maythem, Higgins Charles B, Gleason Kelly, Krombach Gabriele A, Weber Oliver M, Martin Alastair J, Turner Daniel, Teitel David, Moore Phillip
Department of Radiology, University of California San Francisco, 505 Parnassus Ave, L308, San Francisco, CA 94143-0628, USA.
Radiology. 2003 Feb;226(2):475-81. doi: 10.1148/radiol.2262011639.
To assess the feasibility of using magnetic resonance (MR) imaging to guide stent deployment in the pulmonary valve and artery and evaluate, after stent deployment, the position and morphology of and blood flow through the stent.
Angiography and 1.5-T MR imaging were performed in a dual-imaging suite. Nitinol stents were placed in the pulmonary valve and main pulmonary artery in five pigs by using MR imaging guidance. For interactive MR imaging monitoring of catheter manipulation and stent delivery, balanced fast field-echo and T1-weighted turbo field-echo sequences were used. Visualization of the delivery system was based on T2* (with air as the contrast material) or T1 (with gadodiamide as the contrast material). After stent deployment, the position and morphology of and flow through the stent were verified with multiphase multisection balanced fast field-echo and velocity-encoded cine MR imaging. Findings at angiography and postmortem examination also helped verify stent placement. The paired Student t test was used for data analysis.
The stent was successfully deployed in all animals. The stent was placed distal to the pulmonary valve in four animals and across the pulmonary valve in one animal. The position and morphology of the stent were clearly depicted on balanced fast field-echo images. In the animal with the stent placed across the pulmonary valve, the pulmonary regurgitant fraction was 37%; this was not seen in the animals with stents placed distal to the pulmonary valve. No complication (eg, stent migration, intramural injury, or vascular perforation) was noted during the intervention. Findings at angiography and postmortem examination confirmed the position of the stents.
MR imaging has the potential to guide stent placement in the pulmonary valve or artery and to evaluate flow volume within the stent lumen after the intervention.
评估使用磁共振（MR）成像引导肺动脉瓣和动脉内支架置入的可行性，并在支架置入后评估支架的位置、形态及通过支架的血流情况。
在双成像套件中进行血管造影和1.5-T MR成像。通过MR成像引导，将镍钛合金支架置入5只猪的肺动脉瓣和主肺动脉内。为对导管操作和支架输送进行交互式MR成像监测，使用了平衡快速场回波和T1加权涡轮场回波序列。输送系统的可视化基于T2*（以空气作为对比剂）或T1（以钆双胺作为对比剂）。支架置入后，通过多期多层面平衡快速场回波和速度编码电影MR成像来验证支架的位置、形态及血流情况。血管造影和尸检结果也有助于验证支架的放置位置。采用配对学生t检验进行数据分析。
所有动物的支架均成功置入。4只动物的支架置于肺动脉瓣远端，1只动物的支架横跨肺动脉瓣。支架的位置和形态在平衡快速场回波图像上清晰显示。在支架横跨肺动脉瓣的动物中，肺动脉反流分数为37%；而在支架置于肺动脉瓣远端的动物中未观察到这种情况。干预过程中未发现并发症（如支架移位、壁内损伤或血管穿孔）。血管造影和尸检结果证实了支架的位置。
MR成像有潜力引导肺动脉瓣或动脉内支架置入，并在干预后评估支架腔内的血流量。
