Objective:To explore the quantitative analysis value of diffusion tensor imaging (DTI) for early changes of calf muscle in type 2 diabetes mellitus (T2DM) patients without peripheral ischemia.Methods:From September 2018 to March 2019, 20 male T2DM patients (age: 45-64 years) without peripheral ischemia and 20 matched male healthy controls (age: 46-62 years) who performed lower limb DTI in Wuxi Second Hospital Affiliated to Nanjing Medical University were prospectively analyzed. Fractional anisotropy (FA), apparent diffusion coefficient (ADC) and λ 1, λ 2, λ 3 values of medial head of gastrocnemius (GM), lateral head of gastrocnemius (GL), tibialis anterior(TA) and soleus muscles(SOL) were measured respectively. The differences of DTI diffusion characteristics between 2 groups were compared by using independent-sample t test, and the correlation between FA, ADC and body mass index (BMI), fasting blood glucose (FBG), hemoglobin A 1c (HbA1c), high density lipoprotein (HDL), low density lipoprotein (LDL) and triglyceride (TG) were analyzed by Pearson correlation analysis. Results:The ADC of TA and SOL in T2DM group ((1.77±0.15) and (1.83±0.10)×10 -3 mm 2/s) was higher than that in control group ((1.66±0.11) and (1.75±0.16)×10 -3 mm 2/s); λ 1, λ 2, and λ 3 of TA in the T2DM group ((2.30±0.21), (1.63±0.17) and (1.38±0.13)×10 -3 mm 2/s) were higher than those in control group ((2.17±0.12), (1.51±0.13) and (1.31±0.12)×10 -3 mm 2/s); λ 2 and λ 3 of SOL were also higher than those in control group ((1.74±0.11) vs (1.64±0.18)×10 -3 mm 2/s and (1.53±0.12) vs (1.44±0.15)×10 -3 mm 2/s; t values: 2.65-3.91, all P<0.05). There were no significant correlations between FA, ADC and BMI, FBG, HbA1c, HDL, LDL and TG ( r values: from -0.15 to 0.08, all P>0.05). Conclusions:Quantitative parameters of DTI, especially ADC, can sensitively detect the microstructural changes of calf muscle in T2DM patients without peripheral ischemia. TA and SOL have high sensitivity to the diffusion of T2DM-related microstructural changes.