Han Yuchi, Peters Dana C, Salton Carol J, Bzymek Dorota, Nezafat Reza, Goddu Beth, Kissinger Kraig V, Zimetbaum Peter J, Manning Warren J, Yeon Susan B
Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA.
JACC Cardiovasc Imaging. 2008 May;1(3):294-303. doi: 10.1016/j.jcmg.2008.01.013.
This study sought to develop cardiovascular magnetic resonance (CMR) diagnostic criteria for mitral valve prolapse (MVP) using echocardiography as the gold standard and to characterize MVP using cine CMR and late gadolinium enhancement (LGE)-CMR.
Mitral valve prolapse is a common valvular heart disease with significant complications. Cardiovascular magnetic resonance is a valuable imaging tool for assessing ventricular function, quantifying regurgitant lesions, and identifying fibrosis, but its potential role in evaluating MVP has not been defined.
To develop CMR diagnostic criteria for MVP, characterize mitral valve morphology, we analyzed transthoracic echocardiography and cine CMR images from 25 MVP patients and 25 control subjects. Leaflet thickness, length, mitral annular diameters, and prolapsed distance were measured. Two- and three-dimensional LGE-CMR images were obtained in 16 MVP and 10 control patients to identify myocardial regions of fibrosis in MVP.
We found that a 2-mm threshold for leaflet excursion into the left atrium in the left ventricular outflow tract long-axis view yielded 100% sensitivity and 100% specificity for CMR using transthoracic echocardiography as the clinical gold standard. Compared with control subjects, CMR identified MVP patients as having thicker (3.2 +/- 0.1 mm vs. 2.3 +/- 0.1 mm) and longer (10.5 +/- 0.5 mm/m(2) vs. 7.1 +/- 0.3 mm/m(2)) indexed posterior leaflets and larger indexed mitral annular diameters (27.8 +/- 0.7 mm/m(2) vs. 21.5 +/- 0.5 mm/m(2) for long axis and 22.9 +/-0.7 mm/m(2) vs. 17.8 +/- 0.6 mm/m(2) for short axis). In addition, we identified focal regions of LGE in the papillary muscles suggestive of fibrosis in 10 (63%) of 16 MVP patients and in 0 of 10 control subjects. Papillary muscle LGE was associated with the presence of complex ventricular arrhythmias in MVP patients.
Cardiovascular magnetic resonance image can identify MVP by the same echocardiographic criteria and can identify myocardial fibrosis involving the papillary muscle in MVP patients. Hyperenhancement of papillary muscles on LGE is often present in a subgroup of patients with complex ventricular arrhythmias.
本研究旨在以超声心动图作为金标准，制定二尖瓣脱垂（MVP）的心血管磁共振（CMR）诊断标准，并通过电影CMR和延迟钆增强（LGE）-CMR对MVP进行特征描述。
二尖瓣脱垂是一种常见的瓣膜性心脏病，可引发严重并发症。心血管磁共振是评估心室功能、量化反流病变及识别纤维化的重要成像工具，但其在评估MVP中的潜在作用尚未明确。
为制定MVP的CMR诊断标准并描述二尖瓣形态，我们分析了25例MVP患者和25例对照者的经胸超声心动图和电影CMR图像。测量瓣叶厚度、长度、二尖瓣环直径及脱垂距离。对16例MVP患者和10例对照患者进行二维和三维LGE-CMR成像，以识别MVP患者心肌纤维化区域。
我们发现，以经胸超声心动图作为临床金标准时，在左心室流出道长轴视图中瓣叶突入左心房2mm的阈值对CMR的敏感性和特异性均为100%。与对照者相比，CMR显示MVP患者的后叶厚度（3.2±0.1mm对2.3±0.1mm）和长度（10.5±0.5mm/m²对7.1±0.3mm/m²）更大，二尖瓣环直径指数更大（长轴为27.8±0.7mm/m²对21.5±0.5mm/m²，短轴为22.9±0.7mm/m²对17.8±0.6mm/m²）。此外，我们在16例MVP患者中的10例（63%）及10例对照者中的0例乳头肌中发现了提示纤维化的LGE局灶区域。乳头肌LGE与MVP患者复杂室性心律失常的存在相关。
心血管磁共振成像可依据相同的超声心动图标准识别MVP，并可识别MVP患者累及乳头肌的心肌纤维化。LGE上乳头肌的强化增强常见于有复杂室性心律失常的患者亚组中。
