Background <p>Diffusion tensor imaging (DTI) is a precise and recent imaging technique used to detect the microstructural changes of the brain using multiple measures with the most commonly used one is the fractional anisotropy (FA). In patients with Parkinson disease (PD), such changes could help in better understanding of the disease process, demonstrating distribution of the disease within the brain, and also help in diagnosis and follow-up of Parkinson’s disease patients. The aim of the study was to investigate the role of DTI in detection of microstructural changes in different gray and white matter regions of the brain using FA values in patients with PD compared to healthy controls and proving the reliability of using DTI as a biomarker in PD.</p> Results <p>This study was a case control study and included 40 cases (20 patients and 20 age and gender matched healthy controls) underwent MRI with diffusion tensor imaging. The FA values of the corpus callosum, caudate nucleus, putamen, thalamus and substantia nigra on the right and the left sides in the patients and in the control group were measured. Variable alterations of fractional anisotropy of the body of corpus callosum, putamen, thalamus and substantia nigra was found in patients with Parkinson’s disease compared to healthy controls. Cutoff fractional anisotropy value of 0.64 in the body of corpus callosum predicted Parkinson’s disease by sensitivity 80% and specificity 60%. Also, there was asymmetry of anisotropy between the right and left putamina and thalami in the patients group.</p> Conclusions <p>Diffusion tensor imaging can detect microstructural changes of the brain in patients with Parkinson disease that are beyond conventional MRI capabilities. Such changes could help in better understanding of the disease process, demonstrating distribution of the disease within the brain and also help in diagnosis and follow-up of Parkinson’s disease patients.</p>