Cardiovasc Imaging Asia.  2022 Jul;6(3):88-95. 10.22468/cvia.2022.00024.

Splenic T1-Mapping for Predicting Adenosine Stress Adequacy in Cardiac Magnetic Resonance Myocardial Perfusion Imaging: A Validation and Reproducibility Study

• Wan FFy
• Yeung CMm
• Yam Pk
• Ng Pp
• Chow BCk
• Chiang JB
• Lee JCy
• Cheung KKy
• Ng My

• KMID: 2532342
• DOI: http://doi.org/10.22468/cvia.2022.00024

Abstract

Objective
Splenic switch-off (SSO) sign has been utilized as a surrogate marker of adequate stress but can only be assessed after first-pass perfusion imaging. A study previously reported that drop in T1 _spleen ≥30 ms during adenosine infusion predicts presence of SSO, but this finding has not been externally validated. This study aimed to prospectively validate whether drop in T1 _spleen ≥30 ms is a reliable marker of SSO and hence adequate stress, and to assess reproducibility of T1 _spleen measurements.
Materials and Methods
Data of fifty consecutive patients undergoing stress cardiac magnetic resonance were prospectively collected. Native T1-maps were acquired at rest and at 2.5 min after adenosine infusion in short axis slices, followed by perfusion images at 3 min. To measure T1 _spleen pre- and post-adenosine infusion, regions of interest were manually placed to include most splenic tissue. Adenosine stress adequacy was evaluated by visual SSO assessment and semi-quantitative splenic perfusion analysis.
Results
A significant association was found between a drop in T1 _spleen of ≥30 ms and SSO response (p<0.001). There was excellent correlation between SSO response and semiquantitative perfusion change in _spleen (rho=0.847, p<0.001). Inter-observer and intra-observer agreement for measurement of ΔT1 _spleen values were excellent, with intra-class correlation coefficients of 0.987 and 0.995, respectively. By receiver-operating characteristic analysis, the optimal cut-off value of ΔT1 _spleen for predicting presence of SSO was -28 ms, with area under the curve=0.76 (p=0.002).
Conclusion
Splenic T1-mapping is accurate and reproducible for predicting SSO, potentially allowing optimization of adenosine dosage for adequate stress.

Keyword

Magnetic resonance; Heart; Adenosine; Perfusion