Stress T1 Mapping and Quantitative Perfusion Cardiovascular Magnetic Resonance in Patients with Suspected Obstructive Coronary Artery Disease.

Abstract

Aims: T1 mapping reactivity (ΔT1) has been proposed as a novel contrast-free technique to detect obstructive coronary artery disease (CAD). The aims of the study are: 1) to compare the cardiovascular magnetic resonance (CMR)-derived ΔT1 with quantitative perfusion (QP CMR) measures; 2) to assess the influence of sex and comorbidities on ΔT1; and 3) to assess the diagnostic accuracy of ΔT1 to detect obstructive CAD diagnosed with the invasive coronary angiography (ICA) and/or fractional flow reserve.

Methods and results: This study retrospectively analyzed 51 patients with suspected obstructive CAD who underwent CMR including rest and adenosine stress first-pass perfusion and native T1 mapping (MOLLI). A moderate correlation was found between pooled rest and stress native T1 mapping and MBF (Pearson's r=0.476; p<0.001). When stratified by MPR, ischemic myocardium had significantly lower stress T1 mapping values (p<0.001) and ΔT1 (p=0.005) vs. nonischemic myocardium. Male sex and history of diabetes were independently associated with lower ΔT1. The optimal cut-off value of Δ T1 to detect impaired MPR on a per-vessel basis was ≤5.4%, with an AUC of 0.662 (95% CI: 0.563-0.752, p=0.003), sensitivity of 84% (95% CI: 67-95) and specificity of 46% (95% CI: 34-58). When validated against ICA, stress T1 and Δ T1 did not reach statistical significance in detecting obstructive CAD.

Conclusion: ΔT1 is significantly influenced by sex and comorbidities and has poor diagnostic accuracy for detecting myocardial ischemia. Therefore, the clinical utility of ΔT1 in a real-world cohort of patients to detect obstructive CAD is limited.