Association of Preoperative Posterior Cingulate Cortex Microstructural Damage With Postoperative Delirium.

Area of Science:

• Neuroscience
• Geriatric Medicine
• Radiology

Background:

• Postoperative delirium is a common complication in older adults.
• It increases the risk of long-term cognitive decline, Alzheimer's disease (AD), and related dementias (ADRD).
• The neurological basis for this increased risk remains unclear.

Purpose of the Study:

• To investigate brain microstructural abnormalities linked to postoperative delirium and cognitive function in older adults.
• To explore the relationship between these abnormalities and attention/concentration performance.
• To determine if these abnormalities correlate with Alzheimer's disease biomarkers.

Main Methods:

• Analysis of pre- and post-operative Neurite Orientation Dispersion and Density Imaging (NODDI) MRI data.
• Focus on the posterior cingulate cortex (PCC) in 110 patients aged ≥60 years undergoing non-cardiac/non-intracranial surgery.
• Comparison of patients who developed delirium versus those who did not.

Main Results:

• Increased free water (FISO) and decreased neurite density index (NDI) and orientation dispersion index (ODI) in the dorsal PCC were observed before surgery in patients who later developed delirium.
• Preoperative dorsal PCC NDI and ODI were positively associated with preoperative attention/concentration performance.
• These diffusion metrics did not correlate with cerebrospinal fluid amyloid beta (Aβ) levels.

Conclusions:

• Preoperative latent brain abnormalities in the dorsal PCC may predispose individuals to attention deficits and postoperative delirium.
• These microstructural changes in the PCC are not significantly associated with CSF Aβ levels.
• Microstructural vulnerability in the PCC may explain the link between attention deficits and increased delirium risk in older surgical patients.