van Gorp Maarten J, van der Graaf Yolanda, de Mol Bas A J M, Bakker Chris J G, Witkamp Theo D, Ramos Lino M P, Mali Willem P T M
Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Heidelberglaan 100, PO Box 85500, Room D01.335, 3508 GA Utrecht, the Netherlands.
Radiology. 2004 Mar;230(3):709-14. doi: 10.1148/radiol.2303021619. Epub 2004 Jan 22.
To assess the relationship between heart valve history and susceptibility artifacts at magnetic resonance (MR) imaging of the brain in patients with Björk-Shiley convexoconcave (BSCC) valves.
MR images of the brain were obtained in 58 patients with prosthetic heart valves: 20 patients had BSCC valve replacements, and 38 had other types of heart valves. Two experienced neuroradiologists determined the presence or absence of susceptibility artifacts in a consensus reading. Artifacts were defined as characteristic black spots that were visible on T2*-weighted gradient-echo MR images. The statuses of the 20 explanted BSCC valves-specifically, whether they were intact or had an outlet strut fracture (OSF) or a single-leg fracture (SLF)-had been determined earlier. Number of artifacts seen at brain MR imaging was correlated with explanted valve status, and differences were analyzed with nonparametric statistical tests.
Significantly more patients with BSCC valves (17 [85%] of 20 patients) than patients with other types of prosthetic valves (18 [47%] of 38 patients) had susceptibility artifacts at MR imaging (P =.005). BSCC valve OSFs were associated with a significantly higher number of artifacts than were intact BSCC valves (P =.01). No significant relationship between SLF and number of artifacts was observed.
Susceptibility artifacts at brain MR imaging are not restricted to patients with BSCC valves. These artifacts can be seen on images obtained in patients with various other types of fractured and intact prosthetic heart valves.
评估接受比约克-希利凸凹型（BSCC）瓣膜置换术的患者，其心脏瓣膜病史与脑部磁共振（MR）成像时的磁化率伪影之间的关系。
对58例人工心脏瓣膜置换患者进行脑部MR成像：20例患者接受了BSCC瓣膜置换，38例患者接受了其他类型的心脏瓣膜置换。由两名经验丰富的神经放射科医生通过共同阅片确定是否存在磁化率伪影。伪影定义为在T2*加权梯度回波MR图像上可见的特征性黑点。之前已确定20个取出的BSCC瓣膜的状态，具体而言，它们是否完整、是否存在出口支柱骨折（OSF）或单腿骨折（SLF）。将脑部MR成像中观察到的伪影数量与取出瓣膜的状态进行关联，并使用非参数统计检验分析差异。
接受BSCC瓣膜置换的患者（20例中的17例[85%]）在MR成像时出现磁化率伪影的比例显著高于接受其他类型人工瓣膜置换的患者（38例中的18例[47%]）（P = 0.005）。与完整的BSCC瓣膜相比，BSCC瓣膜的OSF与显著更多的伪影相关（P = 0.01）。未观察到SLF与伪影数量之间存在显著关系。
脑部MR成像时的磁化率伪影并不局限于接受BSCC瓣膜置换的患者。在接受各种其他类型破裂和完整人工心脏瓣膜置换的患者所获得的图像上也可看到这些伪影。
