Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Neuropsychiatry

Objectives: The current study aimed to assess the role of DTI parameters (fractional anisotropy (FA) and apparent diffusion coefficient (ADC)) in diagnosing DPN. Patients and Methods: A total of 30 patients with diabetes mellitus complaining of neuropathy symptoms (12 males and 18 females, age (50.90 ± 9.18 years) and 15 healthy control subjects (10 males and 5 females), age (45.67 ± 7.77 years) were included in the study. Patients underwent evaluation for DPN using clinical scores (NDS, NIS-LL and DNEs) and all subjects underwent evaluation by NCS (upper and lower limbs) and DTI of the both median nerves by 1.5 T MR scanner. Results: Statistically significant difference was found between controls{u2018} and patient s{u2018} groups in FA of distal segment and FA of whole median nerve (P. value 0.016 and 0.024 respectively) being lower in patients{u2018} group, while regarding ADC there was a significant difference in both proximal and lower segments and the whole median nerve (P. value 0.027, 0.000 and 0.019 respectively) being higher in patients{u2018} group. Refining our results we found the best values can be obtained by measuring the distal segment of median nerve. Statistically significant correlation was found between FA of distal segment of median nerve and the NDS (r = -0.518, P = 0.003) and DNEs (r = -0.521, P = 0.003). Meanwhile, the distal segment ADC had statistically significant correlation with the all clinical scores used, NDS (r = 0.482, P= 0.007), NIS-LL (r = 0.524, P= 0.003) and DNEs (r= 0.459, P= 0.01). In addition, FA of distal segment was statistically correlated with sensory amplitude and motor CV of the median nerve (r= 0.257, P= 0.048 and r=0.299, P=0.020 respectively), furthermore, the ADC of distal segment was statistically highly correlated with sensory amplitude (P= 0.032). The best cut-off value of the FA of the distal segment was 0.45 with (87%) sensitivity and (80%) specificity, while the cut-off value of the ADC of distal segment was 1.217 with sensitivity and specificity of (80%). Conclusions: Our results suggest that the DTI assessment of peripheral nerves using 1.5T MR scanner can provide a useful noninvasive information in patients with DPN.

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