Homeostasis of the body weight is maintaining by the interactions between the different sections of the brain and peripheral tissues. Diffusion weighted magnetic resonance imaging (DWI) is a method that investigates the microscopic motion of the water particules in tissues and also depends on measurement of the signal variations in tissues which is connected with the kinetic energy of the molecules called; molecular diffusion. The purpose of this work was to detect brain diffusion abnormalities in obese patients by DWI.
Method: Eighty one obese patients (68 obese (group 1),13 morbid obese (group 2)) and 29 healty control were included. ADC (Appearance Diffusion Coefficience) values were measured with DWI in the hyppocampus, corpus amygdala, insular cortex, orbifrontal cortex,middle temporal cortex and cerebellum, and compared with healty controls.
Results: The ADC values obtained from hypothalamus, hippocampal gyrus, amygdala, insula, cerebellum and midbrain were significantly increased in patients compared to controls.There were statistically significant differences for ADC values that obtained from insula between group 1 (obesity, n: 68) and controls.There were statistically significant differences for ADC values that obtained from insula, thalamus, hippocampal gyrus, orbitofrontal cortex, midbrain, and occipital cortex between group 2 (morbid obesity, n: 13) and controls. The ADC values were significantly increased in group 2. The ADC values obtained from orbitofrontal and occipital cortex were significantly increased in group 2 (n:13) compared to group 1 subjects.The body weight were positively correlated with hippocampal gyrus, insula, orbitofrontal and middle temporal cortex ADC values. The BMI were positively correlated with amygdala, insula, orbitofrontal and middle temporal cortex ADC values.
Conclusion: Increased ADC values in the hypothalamus, hippocampal gyrus, amygdala, insula, cerebellum and midbrain. suggest development of the extracellular water accumulation similar to vasogenic edema in these location.
Key Words: Obesity, Diffusion magnetic resonance imaging.