Burris Nicholas S, Hope Michael D
Department of Radiology and Biomedical Imaging, University of California, San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, California 94143-0628.
Department of Radiology and Biomedical Imaging, University of California, San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, California 94143-0628.
Acad Radiol. 2015 Jun;22(6):690-6. doi: 10.1016/j.acra.2015.01.010. Epub 2015 Mar 10.
Abnormal blood flow with bicuspid aortic valve (BAV) has been characterized with four-dimensional flow magnetic resonance imaging (MRI), but this approach is time consuming and requires technical expertise. We assess the relationship between different leaflets fusion patterns with BAV, eccentric systolic flow, and dilation patterns of the ascending aorta using two-dimensional (2D) phase-contrast (PC) MRI.
Fifty-nine patients with BAV who underwent cardiac MRI were identified; 47 had right-left (RL) aortic leaflet fusion and 12 had right-noncoronary (RN) fusion. Flow displacement was calculated, and patients with abnormal displacement (>0.1) were classified as either rightward or leftward. Patterns of aortopathy were determined (0-3), and correlation between leaflet fusion, flow direction, aortopathy type, and other clinical parameters was performed with Pearson correlation, the Fisher exact test and chi-square analysis.
Normal systolic flow was seen in 24% of cases and was significantly correlated with normal aortas (P = .011). Abnormal flow displacement with RL fusion was strongly associated with rightward deviation (36 of 37 cases), whereas RN fusion skewed leftward (seven of eight cases; P < .01). In patients with aortopathy, RL fusion was strongly associated with type 2 aortopathy and RN with type 3 aortopathy (P < .01).
Conventional PC MRI can identify abnormal systolic flow and differences in jet orientation with BAV. RL leaflet fusion is associated with rightward flow deviation and type 2 aortopathy, whereas RN fusion is linked to leftward deviation and type 3 aortopathy. The presence and direction of eccentric flow jets may help risk stratify these patients for valve-related aortic disease.
二维血流磁共振成像（MRI）已对二叶式主动脉瓣（BAV）的异常血流进行了特征描述，但这种方法耗时且需要专业技术知识。我们使用二维（2D）相位对比（PC）MRI评估BAV不同瓣叶融合模式、偏心收缩期血流与升主动脉扩张模式之间的关系。
确定了59例接受心脏MRI检查的BAV患者；47例为右-左（RL）主动脉瓣叶融合，12例为右-无冠状动脉（RN）融合。计算血流位移，位移异常（>0.1）的患者分为向右或向左。确定主动脉病变模式（0-3），并使用Pearson相关性分析、Fisher精确检验和卡方分析对瓣叶融合、血流方向、主动脉病变类型和其他临床参数之间的相关性进行分析。
24%的病例可见正常收缩期血流，且与正常主动脉显著相关（P = 0.011）。RL融合时的异常血流位移与向右偏移密切相关（37例中的36例），而RN融合时血流向左偏斜（8例中的7例；P < 0.01）。在患有主动脉病变的患者中，RL融合与2型主动脉病变密切相关，RN融合与3型主动脉病变密切相关（P < 0.01）。
传统的PC MRI可以识别BAV的异常收缩期血流和射流方向的差异。RL瓣叶融合与向右血流偏移和2型主动脉病变相关，而RN融合与向左偏移和3型主动脉病变相关。偏心血流射流的存在和方向可能有助于对这些患者进行与瓣膜相关的主动脉疾病的风险分层。
