Imaging Phenotypes of Stress Based on Functional MRI

Abstract

Background: Stress is an adaptive response to daily challenges faced by the body to maintain its internal homeostasis. The pathophysiology of stress has been described based on the role of the sympatho-adrenergic system and the hypothalamic-pituitary- adrenal axis. Few studies have been done describing the role of functional MRI and PET to study the patterns of brain involvement in symptomatic patients. Methods: The author studied 50 post-acute covid-19 syndrome patients one year after the acute episodes along with 10 healthy control patients. Based on the patterns of stress on imaging the patients were phenotyped on the severity of the changes of stress into a classification system. Results: The results of the study showed a distinct temporal pattern of changes based on the severity of chronic stress. Class II and III Group patients on imaging formed the largest number 32(64%) and also showed good correlation with PCS-10 scores which were moderate in this group. The supra optic nucleus followed by para ventricular nuclei were the commonest affected during stress. The study showed that involvement of DMN and SALIEN was seen as the severity of stress progressed to a burn out stage IV which resulted in hypoactivation of all major networks and hypothalamic nuclei. Hippocampal and amygdala volumetric changes alongwith altered asymmetry was seen in class II-IV groups. Conclusion: The author concluded that functional MRI could detect the pattern of changes of stress and the findings not only can be helpful in the diagnosis but also in planning management of these patients.