Changes in brain metabolism after ECT–Positron emission tomography in the assessment of changes in glucose metabolism subsequent to electroconvulsive therapy — Lessons, limitations and future applications

BackgroundElectroconvulsive therapy (ECT) has been used as an effective treatment option in severe and treatment resistant cases of depression for decades. However the mode of action of ECT is still not fully understood. Advances in neuroimaging created new possibilities to understand the functional changes of the human brain.MethodsLiterature review of studies assessing possible changes in cerebral glucose metabolism pre- and post-ECT by PET, identified by PubMed.ResultsStudies were limited by small sample size, inhomogeneous study population with uni- and bipolar depressive patients and methodological inconsistencies. Despite considerable variance, reduction in glucose metabolism after ECT in bilateral anterior and posterior frontal areas represented the most consistent findings.ConclusionsFuture research into this issue should include larger and more consistent cohorts of patients. Assessing clinical improvement of depression after ECT should allow to correlate changes in brain glucose metabolism with functional scores. Follow up PET scans after six or twelve months should be performed to test if changes in brain metabolism are persistent.