Iles Leah, Pfluger Heinz, Phrommintikul Arintaya, Cherayath Joshi, Aksit Pelin, Gupta Sandeep N, Kaye David M, Taylor Andrew J
Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Australia.
J Am Coll Cardiol. 2008 Nov 4;52(19):1574-80. doi: 10.1016/j.jacc.2008.06.049.
The purpose of this study was to investigate a noninvasive method for quantifying diffuse myocardial fibrosis with cardiac magnetic resonance imaging (CMRI).
Diffuse myocardial fibrosis is a fundamental process in pathologic remodeling in cardiomyopathy and is postulated to cause increased cardiac stiffness and poor clinical outcomes. Although regional fibrosis is easily imaged with cardiac magnetic resonance, there is currently no noninvasive method for quantifying diffuse myocardial fibrosis.
We performed CMRI on 45 subjects (25 patients with heart failure, 20 control patients), on a clinical 1.5-T CMRI scanner. A prototype T(1) mapping sequence was used to calculate the post-contrast myocardial T(1) time as an index of diffuse fibrosis; regional fibrosis was identified by delayed contrast enhancement. Regional and global systolic function was assessed by cine CMRI in standard short- and long-axis planes, with echocardiography used to evaluate diastology. An additional 9 subjects underwent CMRI and endomyocardial biopsy for histologic correlation.
Post-contrast myocardial T(1) times correlated histologically with fibrosis (R = -0.7, p = 0.03) and were shorter in heart failure subjects than controls (383 +/- 17 ms vs. 564 +/- 23 ms, p < 0.0001). The T(1) time of heart failure myocardium was shorter than that in controls even when excluding areas of regional fibrosis (429 +/- 22 ms vs. 564 +/- 23 ms, p < 0.0001). The post-contrast myocardial T(1) time shortened as diastolic function worsened (562 +/- 24 ms in normal diastolic function vs. 423 +/- 33 ms in impaired diastolic function vs. 368 +/- 20 ms in restrictive function, p < 0.001).
Contrast-enhanced CMRI T(1) mapping identifies changes in myocardial T(1) times in heart failure, which appear to reflect diffuse fibrosis.
本研究旨在探讨一种利用心脏磁共振成像（CMRI）定量评估弥漫性心肌纤维化的非侵入性方法。
弥漫性心肌纤维化是心肌病病理重塑的一个基本过程，据推测会导致心脏僵硬度增加和临床预后不良。虽然利用心脏磁共振成像可以很容易地对局部纤维化进行成像，但目前尚无定量评估弥漫性心肌纤维化的非侵入性方法。
我们在一台临床1.5-T心脏磁共振成像扫描仪上，对45名受试者（25名心力衰竭患者和20名对照患者）进行了CMRI检查。使用一种原型T(1)映射序列计算造影剂注射后心肌的T(1)时间，以此作为弥漫性纤维化的指标；通过延迟强化来识别局部纤维化。在标准短轴和长轴平面上，利用电影CMRI评估局部和整体收缩功能，并用超声心动图评估舒张功能。另外9名受试者接受了CMRI检查和心内膜心肌活检以进行组织学相关性分析。
造影剂注射后心肌的T(1)时间与纤维化在组织学上具有相关性（R = -0.7，p = 0.03），且心力衰竭受试者的T(1)时间比对照组短（383±17毫秒对564±23毫秒，p < 0.0001）。即使排除局部纤维化区域，心力衰竭心肌的T(1)时间仍比对照组短（429±22毫秒对564±23毫秒，p < 0.0001）。随着舒张功能恶化，造影剂注射后心肌的T(1)时间缩短（舒张功能正常时为562±24毫秒，舒张功能受损时为423±33毫秒，限制性舒张功能时为368±20毫秒，p < 0.001）。
对比增强CMRI的T(1)映射可识别心力衰竭患者心肌T(1)时间的变化，这似乎反映了弥漫性纤维化。
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