弥散峰度成像评价慢性肾小球肾炎患者肾功能及病理损伤程度

Diffusion kurtosis imaging for evaluation on renal function and pathological damage degree in patients with chronic glomerular nephritis

目的观察弥散峰度成像(DKI)评估慢性肾小球肾炎(CGN)患者肾功能及病理损伤程度的价值。方法对46例经肾活检确诊的CGN患者[27例慢性肾脏病(CKD)1~2级(CGN轻度损伤组)、19例CKD 3~4级(CGN中重度损伤组)]及19名健康志愿者(对照组)采集肾DKI,比较3组间肾皮、髓质平均弥散峰度(MK)和平均弥散系数(MD)的差异,以及各组内肾皮质与髓质MK和MD的差异,分析CGN患者肾脏MK和MD与肾功能指标[估算肾小球滤过率(eGFR)和胱抑素C]及肾脏损伤病理积分的相关性;绘制受试者工作特征(ROC)曲线,计算曲线下面积(AUC),评估肾脏MK及MD鉴别不同程度损伤CGN的效能。结果随肾损伤程度加重,肾皮髓质MK均升高、MD均降低(P均<0.01)。各组内肾皮质MD均高于、MK均低于髓质(P均<0.01)。肾脏MK与胱抑素C及肾脏损伤病理积分呈正相关、与eGFR呈负相关(P均<0.05),肾脏MD与胱抑素C及肾脏损伤病理积分呈负相关、与eGFR呈正相关(P均<0.05)。肾脏皮髓质MK和MD鉴别轻度与中重度损伤CGN的AUC为0.731~0.840。结论DKI能无创、定量评估CGN患者肾功能和病理损伤程度。

Objective To observe the value of diffusion kurtosis imaging(DKI)for evaluation on renal function and pathological damage degree in patients with chronic glomerular nephritis(CGN).Methods Kidney DKI was collected from 46 patients with CGN confirmed by renal biopsy pathology(27 patients with chronic kidney disease[CKD]grade 1—2[CGN mild damage group]and 19 patients with CKD grade 3—4[CGN moderate-severe damage group])and 19 healthy volunteers(control group).The mean kurtosis(MK)and mean diffusion coefficient(MD)of renal cortex and medulla were compared among 3 groups,also within each group.The correlations of renal MK and MD with renal function indexes(estimated glomerular filtration rate[eGFR]and cystatin C)and pathological score of renal damage in CGN patients were analyzed.Receiver operating characteristic(ROC)curves were drawn,and the areas under the curves(AUC)were calculated to evaluate the efficacy of renal MK and MD for differentiating CGN patients with different damage degrees.Results With the severity of kidney injury,MK of renal cortex and medulla increased while MD decreased(all P<0.01).MD of renal cortex was higher than that of medulla,and MK of renal cortex was lower than that of medulla within each group(all P<0.01).Renal MK were positively correlated with cystatin C and pathological score of renal damage,negatively correlated with eGFR(all P<0.05),while renal MD were negatively correlated with cystatin C and pathological score of renal damage,positively correlated with eGFR(all P<0.05).AUC of MK and MD of renal cortex and medulla for differentiating mild damage and moderate-severe damage CGN patients were 0.731—0.840.Conclusion DKI could be used to noninvasively and quantitatively evaluate renal function and renal pathological damage degree in CGN patients.