Exploring Postoperative Cognitive Dysfunction and Delirium in Noncardiac Surgery Using MRI: A Systematic Review

Area of Science:

• Neuroscience
• Radiology
• Geriatric Medicine

Background:

• Postoperative cognitive dysfunction (POCD) and postoperative delirium (POD) are significant risks for surgical patients, leading to adverse outcomes and socioeconomic burdens.
• Magnetic resonance imaging (MRI) provides valuable insights into brain structure and function, crucial for understanding the neurological underpinnings of POCD and POD.

Purpose of the Study:

• To systematically review and synthesize findings from MRI studies investigating the relationship between brain changes and POCD/POD in surgical patients.
• To identify potential neuroimaging biomarkers associated with the development of cognitive impairment and delirium after surgery.

Main Methods:

• Systematic literature searches were performed in PubMed, EMBASE, and PsycINFO databases.
• Included studies focused on surgical patients diagnosed with POCD (via cognitive testing) or POD (via Confusion Assessment Method) who underwent MRI.
• Data from ten eligible studies involving 269 surgical patients, 36 patient controls, and 55 healthy controls were analyzed.

Main Results:

• Preliminary findings suggest an association between reduced thalamic and hippocampal volumes and decreased cerebral blood flow with POCD.
• Evidence indicates that pre-existing and postoperative white matter abnormalities may be linked to POD.
• The current evidence base is considered weak, necessitating further investigation.

Conclusions:

• MRI may offer potential markers for identifying patients at risk of or experiencing POCD and POD.
• Further robust MRI studies are required to validate these preliminary associations and enhance our understanding of the neurobiology of postoperative cognitive complications.
• These findings underscore the importance of neuroimaging in the perioperative care pathway.