ConSept法和SAX法测量非缺血性扩张型心肌病心肌初始T_(1)值的对比分析

Comparative study on native T_(1) value of myocardium between using ConSept and SAX approaches in non-ischemic dilated cardiomyopathy

目的:纵向弛豫时间定量成像(T_(1) mapping)可以无创性定量心肌初始纵向弛豫时间(T_(1)值),在钆延时强化灶(late gadolinium enhancement,LGE)基础上提供更多的心肌纤维化信息。但传统的测量T_(1)值的方法由于感兴趣区(regions of interest,ROI)需包括短轴全部心肌(the whole short axis,SAX),操作复杂且耗时,因而限制了其在临床上的应用。本研究拟对比中间层间隔壁(conservatively within the midventricular septum,ConSept)法和SAX法获得的初始T_(1)值诊断心肌弥漫性病变的能力。方法:回顾性收集中南大学湘雅医院采用3.0T心脏磁共振扫描的38例非缺血性扩张型心肌病(non-ischemic dilated cardiomyopathy,NIDCM)患者和27例健康对照者。根据NIDCM患者是否存在LGE分为LGE阳性组和LGE阴性组。将ROI分别放置在ConSept或SAX进行初始T_(1)值测量,比较两种方法区分病变心肌和健康心肌的能力以及两种方法测得的心肌初始T_(1)值的差别。结果:NIDCM组采用ConSept或SAX法测得的初始T_(1)值均明显高于对照组(均P<0.001),LGE阳性组的初始T_(1)值均大于LGE阴性组(均P<0.05)。ConSept法和SAX法测得的中间层T_(1)值与基底层、心尖层T_(1)值无明显差别(均P>0.05),具有非常好的一致性[(concordance correlation coefficient,CCC)=0.954]。结论:与SAX法相比,ConSept法是一种等效且更简便的测量心肌初始T_(1)值的方法,适合在临床工作中使用。

Objective:T_(1) mapping can noninvasively quantify the native longitudinal relaxation time(T_(1) value)of myocardium and provide more information on myocardial fibrosis based on late gadolinium enhancement(LGE).However,the traditional approach of measuring T_(1) value limits the popularization and application of this technology in clinic because the whole short axis(SAX)of myocardium is required in the regions of interest(ROI).This study aims to evaluate the diagnostic ability of native T_(1) value obtained by comparison between the midventricular septum(ConSept)and SAX approaches in diffuse myocardial lesions.Methods:Retrospective analysis was performed on 38 patients with non-ischemic dilated cardiomyopathy(NIDCM)and 27 healthy controls who underwent T_(1) mapping and gadolinium delayed enhancement(LGE)scanning on a 3.0T cardiac magnetic resonance(CMR)in Xiangya Hospital of Central South University.Patients with NIDCM were divided into a LGE positive group and a LGE negative group according to the presence or absence of LGE.The native T_(1) value was measured by the ROI placed in the ConSept and SAX,respectively.The ability to distinguish the impaired myocardium from the healthy myocardium and the native T_(1) values of the myocardium measured by the 2 approaches were compared between the NIDCM group and the control group.Results:The native T_(1) values of NIDCM group using ConSept or SAX approach were significantly higher than those in the control group(all P<0.001),and the native T_(1) values in the LGE positive group were greater than those in the LGE negative group(all P<0.05).There was no significant difference in T_(1) value of middle,basal,and apical layer between the ConSept approach and SAX approach(all P>0.05).ConSept and SAX approaches had a good consistency[concordance correlation coefficient(CCC)=0.954].Conclusion:Comparing to the SAX approach,ConSept approach is a simple and equivalent method to measure the native T_(1) value of myocardium and is suitable for clinical application.