Neuroimaging after critical illness: implications for neurorehabilitation outcome

Survivors of critical illness frequently have severe and long-lasting cognitive impairments and psychiatric disorders, which adversely affect functional outcomes including return to work, and quality of life. While data regarding cognitive outcomes has increased over the last 15 years, neuroimaging data in medical and surgical critical populations is extremely limited. The abrupt development of new significant cognitive impairments after critical illness along with abnormalities on neuroimaging suggest that critical illness results in new acquired brain injury, similar to that observed in other acquired brain injuries. Abnormalities on neuroimaging including cortical and subcortical lesions, brain atrophy, and white matter hyperintensities (WMH) which occur in widely distributed brain regions. Patients admitted to neurorehabilitation who received critical care related to their primary diagnosis may have sustained neurological injury from the nonspecific effects of their critical illness and as demonstrated in this review, generalized, non-specific neuroimaging findings may be observed and quantified. Given the high prevalence rate of cognitive impairments in this population, neuroimaging is important to help elucidate neuropathology of critical illness acquired brain injury and may be beneficial in guiding rehabilitation outcomes in this population.