Background

Diabetic foot disease is associated with physiological and biomechanical abnormalities in the foot that increase risk for ulceration. The objective was to assess MRI changes in the composition of sub-calcaneal fat pad tissue and its association with plantar pressure during walking.

Methods

Fourteen people with diabetes and peripheral neuropathy and five age-matched healthy controls underwent T1-weighted sagittal plane spin-echo Dixon MRI of the rearfoot. Dixon Chemical Shift Imaging was used to create fat-only and water-only images from which the fat signal fraction in a defined ROI of the sub-calcaneal fat pad was calculated. Barefoot plantar pressure distribution during walking was assessed and associated with fat pad outcomes.

Findings

Mean ± SD fat signal fraction was significantly lower in the neuropathic subjects than in the healthy controls (0.55 ± 0.11 vs. 0.72 ± 0.03, p < 0.005), and was explained by a lowering in fat signal (R² 0.87), more than an increase in water signal (R² 0.32). Mean ± SD peak pressure at the heel was 391 ± 119 kPa for the neuropathic subjects and 325 ± 53 kPa for the healthy controls (non-significantly different). Fat signal fraction and peak pressure were significantly inversely correlated (r = −0.59, p < 0.01).

Interpretation

Dixon chemical shift MRI showed a reduced fat signal fraction in sub-calcaneal fat pad tissue in people with diabetic neuropathy. Both neuropathic and non-neuropathic factors may be attributed to this outcome. Fat pad function also seems to be compromised, as indicated by an associated increase in peak plantar pressures. This may increase risk for foot ulceration.

中文翻译：

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糖尿病神经病变患者跟骨下脂肪垫成分的变化及其与足底动态压力的关系

背景

糖尿病足病与足部的生理和生物力学异常相关，从而增加了溃疡的风险。目的是评估跟骨下脂肪垫组织组成的 MRI 变化及其与行走过程中足底压力的关系。

方法

14 名糖尿病和周围神经病变患者和 5 名年龄匹配的健康对照者接受了后足的 T1 加权矢状面自旋回波 Dixon MRI。Dixon Chemical Shift Imaging 用于创建仅含脂肪和仅含水的图像，从中计算出跟骨下脂肪垫定义的 ROI 中的脂肪信号分数。评估了步行期间的赤足足底压力分布，并将其与脂肪垫结果相关联。

发现

神经病变受试者的平均 ± SD 脂肪信号分数显着低于健康对照组（0.55 ± 0.11 对 0.72 ± 0.03，p  < 0.005），这可以通过脂肪信号降低来解释（R ² 0.87），超过水信号增加 (R ² 0.32)。神经病变受试者足跟处的平均 ± SD 峰值压力为 391 ± 119 kPa，健康对照组为 325 ± 53 kPa（无显着差异）。脂肪信号分数和峰值压力显着负相关（r  = -0.59，p  < 0.01）。

解释

Dixon 化学位移 MRI 显示糖尿病神经病变患者跟骨下脂肪垫组织中的脂肪信号分数降低。神经性和非神经性因素均可归因于这一结果。脂肪垫功能似乎也受到损害，如足底压力峰值的相关增加所示。这可能会增加足部溃疡的风险。