Hydraulic In Vitro Characterization of MR-Conditional Blood Pumps.

BACKGROUND

Many cardiac surgical procedures use cardiopulmonary bypass (CPB), which in neonates requires the heart-lung machine (HLM) to be positioned close to the patient due to their small circulating blood volume. The absence of an MR-compatible blood pump to be used in CPB remains a key challenge for studying perioperative brain injury mechanisms in this high-risk group. This study aims to take the first step toward MR-conditional HLMs by developing hardware, verifying pump hydraulics, and ensuring MR compatibility.

METHODS

This study presents three MR-conditional blood pump prototypes: a roller pump, a non-occlusive roller pump, and a centrifugal pump. MR compatibility was assessed by monitoring for imaging interference during scanning. Hydraulic performance was evaluated with pressure-flow diagrams using a mock circulation test bench.

RESULTS

None of the prototypes interfered with MR imaging, and although SNR was reduced by -8.43% ± 7.96%, image quality remained sufficient for reliable assessment of relevant brain regions. Roller and non-occlusive pumps maintained stable flow across pressure heads, with reductions of -4.46 ± 8.02 and -119.33 ± 18.22 mL/min, respectively. The centrifugal pump exhibited pressure-dependent performance (slope -2.21 ± 0.45 mmHg/[L/min]). All pumps generated non-pulsatile flow (SHE < 1000 erg/cm3).

CONCLUSION

All three pumps meet basic MR-conditionality and flow requirements, supporting their potential for use in MRI-guided studies during neonatal cardiac surgery.