Chan K M John, Wage Ricardo, Symmonds Karen, Rahman-Haley Shelley, Mohiaddin Raad H, Firmin David N, Pepper John R, Pennell Dudley J, Kilner Philip J
Cardiovascular Magnetic Resonance Unit, Royal Brompton and Harefield NHS Trust, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
J Cardiovasc Magn Reson. 2008 Dec 22;10(1):61. doi: 10.1186/1532-429X-10-61.
Cardiovascular magnetic resonance (CMR) is increasingly used to assess patients with mitral regurgitation. Its advantages include quantitative determination of ventricular volumes and function and the mitral regurgitant fraction, and in ischemic mitral regurgitation, regional myocardial function and viability. In addition to these, identification of leaflet prolapse or restriction is necessary when valve repair is contemplated. We describe a systematic approach to the evaluation of mitral regurgitation using CMR which we have used in 149 patients with varying etiologies and severity of regurgitation over a 15 month period. Following standard ventricular cine acquisitions, including 2, 3 and 4 chamber long axis views and a short axis stack for biventricular function, we image movements of all parts of the mitral leaflets using a contiguous stack of oblique long axis cines aligned orthogonal to the central part of the line of coaptation. The 8-10 slices in the stack, orientated approximately parallel to a 3-chamber view, are acquired sequentially from the superior (antero-lateral) mitral commissure to the inferior (postero-medial) commissure, visualising each apposing pair of anterior and posterior leaflet scallops in turn (A1-P1, A2-P2 and A3-P3). We use balanced steady state free precession imaging at 1.5 Tesla, slice thickness 5 mm, with no inter-slice gaps. Where the para-commissural coaptation lines curve relative to the central region, two further oblique cines are acquired orthogonal to the line of coaptation adjacent to each commissure. To quantify mitral regurgitation, we use phase contrast velocity mapping to measure aortic outflow, subtracting this from the left ventricular stroke volume to calculate the mitral regurgitant volume which, when divided by the left ventricular stroke volume, gives the mitral regurgitant fraction. In patients with ischemic mitral regurgitation, we further assess regional left ventricular function and, with late gadolinium enhancement, myocardial viability. Comprehensive assessment of mitral regurgitation using CMR is feasible and enables determination of mitral regurgitation severity, associated leaflet prolapse or restriction, ventricular function and viability in a single examination and is now routinely performed at our centre. The mitral valve stack of images is particularly useful and easy to acquire.
心血管磁共振成像（CMR）越来越多地用于评估二尖瓣反流患者。其优势包括定量测定心室容积和功能以及二尖瓣反流分数，对于缺血性二尖瓣反流，还可评估局部心肌功能和存活情况。除此之外，在考虑瓣膜修复时，识别瓣叶脱垂或受限情况很有必要。我们描述了一种使用CMR评估二尖瓣反流的系统方法，在15个月期间，我们已将此方法应用于149例病因和反流严重程度各异的患者。在进行标准的心室电影采集后，包括二腔、三腔和四腔长轴视图以及用于双心室功能的短轴堆栈，我们使用与瓣叶贴合线中心部分正交的连续倾斜长轴电影堆栈来成像二尖瓣叶各部分的运动。堆栈中的8 - 10个层面，大致平行于三腔视图方向，从二尖瓣上（前外侧）联合依次采集至下（后内侧）联合，依次显示每对相邻的前叶和后叶扇贝（A1 - P1、A2 - P2和A3 - P3）。我们在1.5特斯拉场强下使用平衡稳态自由进动成像，层厚5毫米，层间无间隙。在瓣叶联合旁贴合线相对于中心区域弯曲的部位，与每个联合相邻的贴合线正交方向再采集另外两个倾斜电影。为了量化二尖瓣反流，我们使用相位对比速度成像来测量主动脉流出量，从左心室搏出量中减去该值以计算二尖瓣反流容积，二尖瓣反流容积除以左心室搏出量即得到二尖瓣反流分数。对于缺血性二尖瓣反流患者，我们进一步评估局部左心室功能，并通过延迟钆增强评估心肌存活情况。使用CMR对二尖瓣反流进行综合评估是可行的，能够在一次检查中确定二尖瓣反流严重程度、相关瓣叶脱垂或受限情况、心室功能和存活情况，目前在我们中心已成为常规检查。二尖瓣图像堆栈特别有用且易于获取。
