Venous oxygenation measurements in the upper arm: reproducibility and sensitivity to a physical challenge

Motivation: TRUST estimates blood oxygenation in the superior sagittal sinus via T2 decay fitting. However, validating the calibration curve —derived from ex-vivo tests on healthy and specific patient samples —is challenging due to the inability to directly sample blood from the sinus. Goal(s): The goal is to adapt TRUST for T2b arm measurements that can be compared with cephalic vein blood samples. Approach: TRUST was adapted to the arm veins, allowing for direct comparison with venous blood samples and tracking oxygenation dynamics during exercise. Results: The modified TRUST sequence successfully measured venous blood T2 in the upper arm, enabling disease-specific calibration curves through direct blood correlation. Impact: The optimized TRUST sequence enables fast-T2b measurements in upper arm veins, allowing accurate, disease-specific venous calibration curves via a-posteriori blood characteristic correlation. This may improve oxygenation assessment using TRUST in various patient groups, providing a tool to investigate pathological mechanisms.