基于质子MRSI的肌细胞内脂测量技术的原理、现状及展望

The principle, present and prospect of IMCL measurement based on ^1H MRSI technology

胰岛素抵抗作为诱发糖尿病的主要原因可能早在糖尿病发病十多年前就已经出现.及早发现胰岛素抵抗对于糖尿病的早期预防、诊断、治疗有着至关重要的意义.研究发现,人类小腿肌肉细胞内脂质(intramyocellular lipid,IMCL)的含量与胰岛素抵抗和代谢障碍有着密切而又复杂的关联.因此,准确测量IMCL对于Ⅱ型糖尿病乃至多种精神疾病具有重要的研究意义.然而,目前测量IMCL的"金标准"是创伤性的活检技术,不适于大规模的基础研究和长期的临床应用.基于质子磁共振波谱成像(1H magnetic resonance spectrosocpic imaging,1H MRSI)的IMCL测量技术提供了一种无辐射、无创伤、高精度的检测方法,有望成为明晰IMCL含量与胰岛素抵抗,以及胰岛素抵抗与Ⅱ型糖尿病关系的重要技术并在临床上应用.本文基于1H MRSI的IMCL含量测量技术,阐述并总结了其发展历程,从小腿内部生理结构特征、肌纤维方向、脂肪分布、精确量化IMCL含量等方面指出目前该技术面临的挑战和最新的解决思路.本文特别探讨了多模态磁共振成像(magnetic resonance imaging,MRI)技术以及面向参数估计的磁共振指纹技术MRF(magnetic resonance fingerprinting)等新技术与质子磁共振波谱成像技术的结合,希望为IMCL高精度测量提供更加多样化、多维度、多尺度的可能和途径.

It has been found that,as a main mechanism for diabetes,insulin resistance may have appeared more than a decade before the onset of diabetes.Therefore,early detection of insulin resistance has vital significance for the early prevention,diagnosis,and treatment of diabetes.The content of intramyocellular lipid(IMCL)in human calf muscle has close and complex relationship with insulin resistance and metabolic disorders and,therefore,is associated with type 2 diabetes mellitus and even a variety of mental diseases.However,the current"gold standard"for IMCL measurement is the invasive biopsy technology,which is not suitable for large-scale basic research and long-term clinical applications.IMCL measurement technology based on proton magnetic resonance spectroscopy and spectroscopic imaging(1 H MRSI)provides a radiation-free,non-invasive,and high-precision detection method.More than this,1 H MRSI has been expected to clarify the relationship between IMCL content and insulin resistance,as well as the relationship between insulin resistance and type 2 diabetes mellitus,and has the potential to be applied in clinical practice.This paper describes and summarizes the technical development of1 H MRSI-based IMCL content measurement.It also points out the challenges and the latest solutions of this technique from the aspects of physiological and structural characteristics of calves,muscle fiber direction,the bulk fat distribution,and the demand for precise quantification of IMCL content.In addition to reviewing the latest technical solutions to these problems,we particularly discuss the combination of1 H MRSI with some new technologies such as multi-mode magnetic resonance imaging(MRI)and magnetic resonance fingerprinting spectroscopy(MRFS),which will synergically provide more diversified,multi-dimensional and multi-scale measurement method for high-precision measurement of IMCL.