2型糖尿病患者肾脏脂肪定量测量:Dixon与HISTO MRS技术的比较

Quantitative measurement of renal fat in patients with type 2 diabetes mellitus:Comparison between Dixon and HISTO MRS techniques

目的比较基于六回波水脂分离(Dixon)和高速T2校正多回波磁共振波谱(high-speed T2-crrected multiecho magnetic resonance spectroscopic,HISTO MRS)技术脂肪定量指标在肾脏的一致性并探讨其对肾功能损害的预测能力,为2型糖尿病(type 2 diabetic mellitus,T2DM)患者肾脏脂毒性损害程度判定及治疗监测提供依据。材料与方法前瞻性纳入172名T2DM患者和55名健康受试者。所有受试者接受Dixon与HISTO MRS腹部3 T MRI检查,获得肾脏质子密度脂肪分数(proton density fat fraction,PDFF),分别记为D-PDFF和H-PDFF。使用组内相关系数评价两种技术的一致性;根据有无T2DM和肾小球滤过率(estimated glomerular filtration rate,eGFR)将所有受试者分为健康受试者、T2DM患者肾功能正常组(N-T2DM)、T2DM患者肾功能轻中度受损组(M-T2DM)、T2DM患者肾功能严重受损组(S-T2DM),并比较组间差异性;应用Pearson相关性分析和多元线性回归明确D-PDFF和H-PDFF是否为eGFR降低的独立危险因素。结果D-PDFF和H-PDFF的组内相关系数为0.185。校正混杂因素后,健康受试者和T2DM患者D-PDFF的差异有统计学意义(P<0.001),H-PDFF的差异无统计学意义(P>0.05)。校正后健康受试者与N-T2DM组、健康受试者与M-T2DM组、N-T2DM与M-T2DM组的D-PDFF的差异均有统计学意义(P均≤0.001);H-PDFF在各组间的差异均无统计学意义(P均>0.05)。在校正混杂因素后D-PDFF与eGFR的升高独立负相关(β=-0.168,P=0.016),是肾功能损害的独立危险因素。H-PDFF值与eGFR无相关性(β=-0.008,P=0.918)。结论两种MRI脂肪定量测量技术在肾脏的一致性差,基于Dixon的PDFF更能反映T2DM患者肾脏脂肪沉积增加和肾功能损害,可能更适用于T2DM患者的肾脏脂肪沉积监测。

Objective:To compare the concordance of renal fat quantification measures based on the six-echo water-fat separation(Dixon)and high-speed T2-corrected multiecho magnetic resonance spectroscopic(HISTO MRS)techniques,and to investigate their predictive ability for renal function impairment.Provide a basis for determining the extent of renal lipotoxicity in patients with type 2 diabetes mellitus(T2DM)and for monitoring treatment efficacy.Materials and Methods:This prospective study enrolled 172 patients with T2DM and 55 healthy subjects.Renal proton density fat fraction(PDFF)was obtained through abdominal 3 T MRI using Dixon and HISTO MRS techniques,recorded as D-PDFF and H-PDFF.The intraclass correlation coefficient was used to evaluate the consistency between the two techniques within the same group.The subjects were divided into healthy subjects,normal renal function group in T2DM patients(N-T2DM),mild to moderate renal function impairment group in T2DM patients(M-T2DM),and severe renal function impairment group in T2DM patients(S-T2DM)based on the presence or absence of T2DM and estimated glomerular filtration rate(eGFR),and inter-group differences were compared.Pearson correlation and multiple linear regression analyses were performed to investigate whether D-PDFF and H-PDFF are independent risk factors for decreased eGFR.Results:The interclass correlation coefficient was 0.185 for D-PDFF and H-PDFF.After adjusting for confounding factors,the difference in D-PDFF between healthy participants and T2DM patients was statistically significant(P<0.001),while the difference in H-PDFF was not statistically significant(P>0.05).After adjustment,the differences in D-PDFF between the healthy participant group and the N-T2DM group,the healthy participant group and the M-T2DM group,and the N-T2DM group and the M-T2DM group were all statistically significant(all P≤0.001).The differences in H-PDFF among the groups were not statistically significant(all P>0.05).D-PDFF was independently and negatively associated with increased eGFR(β=-0.168,P=0.016)after correction for confounders and was identified as an independent risk factor for renal impairment.H-PDFF values did not correlate with eGFR(β=-0.008,P=0.918).Conclusions:The two magnetic resonance fat quantification techniques are poorly concordant in the kidney.Dixon-based PDFF is more responsive to increased renal ectopic fat accumulation(RELA)and renal function impairment in patients with T2DM than HISTO MRS-based PDFF.Therefore,Dixon-based PDFF may be a more suitable method for monitoring RELA in patients with T2DM.