动态增强MRI评估糖尿病足足底软组织血流灌注情况

Dynamic contrast enhanced MRI in evaluating soft tissue blood flow perfusion of sole in diabetic foot

目的:初步探讨动态增强MRI评估糖尿病足病患者足底软组织血流灌注的技术方法及应用价值,并分析糖尿病足软组织微循环的病变特征。方法:26例单侧足发病(湿性坏疽12例,干性坏疽4例,混合性坏疽6例,缺血高危足4例)的糖尿病足患者,运用2D FLASH序列行双侧足底软组织单层动态增强MRI检查,对比分析双足动态增强曲线类型及相关指标参数(开始强化时间、强化峰值、10 s及30 s信号改变率)特点及差异。结果:26例患者均顺利完成检查。4种类型糖尿病足双侧动态增强曲线参数(开始强化时间、强化峰值、10 s及30 s信号改变率)的比值(患侧足/非患侧足),湿性坏疽分别为0.97±0.08,1.55±0.66,1.77±0.78和1.21±0.43;混合性坏疽分别为0.98±0.10,1.23±0.37,2.14±1.44和1.54±0.59;干性坏疽分别为1.04±0.06,0.74±0.02,0.62±0.07和0.66±0.02;高危足分别为0.96±0.06,0.88±0.10,0.85±0.11和0.79±0.08。湿性坏疽与混合性坏疽的患侧足强化峰值、10 s及30 s信号改变率较非患侧高,而干性坏疽及高危足的这3项参数值较非患侧低;动态增强曲线类型分布及开始强化时间在患侧足与非患侧足之间均无明显差异。结论:DCE MRI能够评估糖尿病足病足底软组织血流灌注水平,湿性坏疽与混合坏疽患侧足的灌注状况有高于非患侧足的趋势,干性坏疽及缺血性高危足与之相反。

Objective：To study the feasibility and the clinical application of dynamic contrast enhanced MRI（DCE MRI） in the evaluation of soft tissue blood flow perfusion of sole and to analyze the characteristics of the micro-circulation of soft tissue perfusion in diabetic foot.Methods： 26 patients with diabetic foot having single foot involvement including humid gangrene（n=12）,dry gangrene（n=4）,mixed gangrene（n=6） and high risk ischemic foot（n=4）.DCE MRI was performed on bilateral feet with 2D FLASH sequence and single layer of soft tissue of sole were studied.The types of enhancing curve and correlated parameters（initial time of enhancement,peak value of enhancement and the changing rates of signal intensity at 10s and 30s） were calculated and analyzed.Results：All of 26 cases underwent MR examination successfully.The above-mentioned DCE MRI parameters in these 4 types of diabetic foot were displayed.The ratios of these parameters of the affected foot to that of unaffected foot were as follows：For the foot with humid gangrene,which was 0.97±0.08,1.55±0.66,1.77±0.78,1.21±0.43 respectively;for the foot with mixed gangrene was 0.98±0.10,1.23±0.37,2.14±1.44,1.54±0.59 respectively;for the foot with dry gangrene was 1.04± 0.06,0.74±0.02,0.62±0.07,0.66±0.02 respectively;and for the high risk foot was 0.96±0.06,0.88±0.10,0.85±0.11,0.79±0.08,respectively.The peak value of enhancement and the changing rate of signal intensity on 10s and 30s on the affected foot of humid gangrene and mixed gangrene were higher than that of unaffected foot,whereas,they were lower than the unaffected foot in patients with dry gangrene and high risk foot.However,in all types of diabetic foot,there was no significant difference between the enhanced curve patterns and the initial time enhancement.Conclusion：The patterns of blood flow perfusion of soft tissue of sole in diabetic foot could be evaluated by DCE MRI.Foot with humid or mixed gangrene showed a trend towards higher perfusion level than the unaffected foot,while it was just the reverse in foot with dry gangrene or high risk foot.