MR Angiography, MR Imaging and Proton MR Spectroscopy In-Vivo Assessment of Skeletal Muscle Ischemia in Diabetic Rats

To prospectively evaluate the feasibility of using magnetic resonance (MR) techniques for in-vivo assessing a rat diabetic model of limb ischemia. Unilateral hind limb ischemia was induced by ligation of the iliac-femoral artery in male streptozotocin-treated and non-diabetic control rats. Four weeks after ligation, rats underwent MR Angiography (MRA), T1-weighted and Short Time Inversion Recovery (STIR) sequences and muscle Proton MR Spectroscopy (1H-MRS) on both hind limbs. After MR examinations, immunoblotting and immunofluorescence analysis were performed. MRA showed a signal void due to flow discontinuation distal to the artery ligation. T1-weighted and STIR images showed, respectively, the presence of tissue swelling (p = 0.018 for non-diabetic; p = 0.027 for diabetic rats) and signal hyperintensity in tissue affected by occlusion. Mean total creatine/water for the occluded limb was significantly lower than for the non-occluded limbs in both non-diabetic (5.46×10−4 vs 1.14×10−3, p = 0.028) and diabetic rats (1.37×10−4 vs 1.10×10−3; p = 0.018). MR Imaging and 1H-MRS changes were more pronounced in diabetic than in non-diabetic occluded limbs (p = 0.032). MR findings were confirmed by using histological findings. Combined MR techniques can be used to demonstrate the presence of structural and metabolic changes produced by iliac-femoral artery occlusion in rat diabetic model of limb ischemia.