Can spleen T1 mapping be used as a marker of adequate adenosine response in stress perfusion CMR?

Motivation: There is limited existing data regarding T1 mapping as a method for assessing splenic switch-off. Goal(s): To further investigate quantitative T1 mapping for splenic switch-off assessment as a marker of adequate response to adenosine in stress in CMR perfusion studies for improving test accuracy and mitigating the occurrence of false-negatives. Approach: Prospective CMR with first-pass perfusion and T1 mapping at rest and stress in 59 patients at 1.5T. Results: Splenic T1 values decreased from rest to stress in patients with switch-off. T1 mapping detected splenic switch-off in a clinical population with a specificity of 75% and sensitivity of 80% (ΔT1 threshold of -5.5ms). Impact: This study suggest that splenic T1 changes can detect splenic switch-off during adenosine stress CMR, potentially enabling real-time stress adequacy assessment. However, it raises questions about adenosine's effects on splenic perfusion and the link of splenic switch-off to myocardial response.