磁共振检查在儿童心肌炎诊疗中的应用价值

Application of cardiovascular magnetic resonance in pedi⁃atric myocarditis

心肌炎是儿童非缺血性心肌病变中最常见的疾病,其主要病理生理改变为心肌水肿、心肌充血和毛细血管渗漏以及心肌坏死/纤维化。目前,心肌炎诊断金标准仍为心肌内膜活检,但由于其有创性和敏感度较低,在临床中并未广泛应用。心血管磁共振(CMR)作为一种新型的、无创的检查手段,对心肌炎的诊断及心肌改变的评估均具有较高的敏感度、特异度和准确度。T2W图像、早期钆强化(EGE)和晚期延迟钆强化(LGE)的T1W图像共同构成了反映心肌病理改变的重要参数,其联合应用不仅可早期准确诊断心肌炎,还有助于对心肌炎的分型、分期以及与缺血性心肌疾病的鉴别。另外,CMR还有助于心内膜活检的定位,提高后者的成功率。随着影像技术的提高,CMR还创新出组织T1值(native T1 mapping)、组织T2值(native T2 mapping)和计算得出的细胞外容积(extracellu⁃lar volume,ECV)等新参数,为心肌炎的诊断和病情评估开拓了新领域。

Myocarditis is the most common disease of the non-ischemic cardiomyopathies.The pathophysiologic chang⁃es of myocarditis include myocardial edema,hyperemia and capillary leakage as well as myocardial necrosis/fibrosis.Re⁃cently,the golden diagnostic criteria of myocarditis is still the endocardial biopsy(ECB).However,it is not used broadly in clinical practice due to its invasiveness and poor sensitivity.Cardiovascular magnetic resonance imaging(CMR)emerged as a new,non-invasive tool which has high sensitivity,speci⁃ficity and accuracy for diagnosis and evaluation of myocarditis in children.T2WI,early Ga enhancement(EGE)and late Ga enhancement(LGE)comprise the key parameters which re⁃flect the myocardial pathologies in myocarditis.The combined parameters can not only diagnose the myocarditis timely and accurately,but also contribute to the classification,staging and differing from ischemic cardiomyopathies.Furthermore,CMR is helpful for location of ECB to improve the success rate.With the development of CMR technique,the new sequences have been created,such as native T1/T2 mapping and extracellular volume(ECV),for initiating the new field for diagnosis and evaluation of pediatric myocarditis.