Cerebral Hemodynamic Changes During Cardiac Surgery: A Feasibility MR Study in Piglets

Area of Science:

• Biomedical Engineering
• Neuroscience
• Pediatric Cardiology

Background:

• Congenital heart disease necessitates surgical intervention, often involving cardiopulmonary bypass (CPB).
• Infants undergoing CPB face increased risk of white matter injury, impacting neurodevelopment, with unclear mechanisms.
• Conventional heart-lung machines (HLMs) interfere with MR imaging, hindering in vivo studies of brain changes during CPB.

Purpose of the Study:

• To develop and evaluate an MR-conditional HLM for simultaneous MR imaging and CPB in a preclinical model.
• To assess the feasibility of monitoring cerebral perfusion and metabolism during CPB within an MR scanner.

Main Methods:

• An MR-conditional HLM, including a roller pump, was developed and tested.
• Piglets underwent CPB inside an MR scanner, with cooling, rewarming, and carotid clamping.
• In vivo MR imaging (flow, diffusion, perfusion, metabolism) was performed during CPB.

Main Results:

• The MR-conditional HLM operated effectively inside the scanner without compromising imaging or pump function.
• Key brain structures were visualized without artifacts, and monitoring signals remained stable.
• MR scans indicated flow-related changes and increased lactate, suggesting metabolic stress under hypoperfusion.

Conclusions:

• Performing CPB within an MR scanner using an MR-conditional HLM is technically feasible.
• This platform enables mechanistic studies of brain injury during CPB in large-animal models.
• Future applications include identifying early markers of cerebral vulnerability and developing neuroprotective strategies.