Peripheral and central olfactory measurements in Chronic Obstructive Pulmonary Disease patients

Abstract

OBJECTIVES. We investigated peripheric and central olfactory pathways on MRI in Chronic Obstructive Pulmonary Disease (COPD) patients and the relationship between olfactory measurements of COPD patients and thorax CT images of emphysema classification in them. MATERIAL AND METHODS. In this retrospective study, cranial MRI of 42 adult patients with COPD and 42 healthy adults without COPD were included. In both groups, peripheral (olfactory bulb (OB) volume and olfactory sulcus (OS) depth) and central olfactory areas (insular gyrus and corpus amygdala areas) were evaluated. We classified thorax CT findings according to emphysema by size as 1 to 4. RESULTS. In the present study, left OB volume of the COPD group was significantly lower than that in the control group (p<0.05). On the right side, there were no significant differences between OB volumes of the COPD and control groups. Although right OB volume values were found to decrease proportionally, they were not found to be statistically significant. Also, insular gyrus and corpus amygdala areas of the COPD group were significantly lower than those in the control group, bilaterally (p<0.05). OS depths of the COPD group were significantly higher than those in the control group, bilaterally (p<0.05). In males, the right OB volume values were higher than those in females (p<0.05). CONCLUSION. In COPD patients, left OB volumes decrease and OS depths increase bilaterally, and central areas decrease bilaterally, regardless of the thoracic emphysema classification. It may be related to hypoxemia that causes airway inflammation; inflammatory mediators may be harmful to the olfactory neuroepithelium.