Assessment of Splenic Switch‐Off With Arterial Spin Labeling in Adenosine Perfusion Cardiac MRI

• Published in: Journal of magnetic resonance imaging Vol. 58; no. 1; pp. 147 - 156
• Main Authors: Aramendía‐Vidaurreta, Verónica, Solis‐Barquero, Sergio M., Ezponda, Ana, Vidorreta, Marta, Echeverria‐Chasco, Rebeca, Pascual, Marina, Bastarrika, Gorka, Fernández‐Seara, María A.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.07.2023; Wiley Subscription Services, Inc
• Subjects: Adenosine; Adequacy; arterial spin labeling; Blood flow; Cardiovascular disease; Coronary artery disease; Data acquisition; Delay; Feasibility studies; Field strength; Heart diseases; Image acquisition; Ischemia; Labeling; Magnetic resonance imaging; Medical imaging; Perfusion; Population studies; Spin labeling; Spleen; splenic switch‐off; Statistical analysis; Statistical models; Statistical tests; Stress; stress cardiac MRI; Transit time; adenosine; splenic switch-off; arterial spin labeling; stress cardiac MRI
• ISSN: 1053-1807; 1522-2586; 1522-2586
• DOI: 10.1002/jmri.28460

Background In patients with suspected coronary artery disease (CAD), myocardial perfusion is assessed under rest and pharmacological stress to identify ischemia. Splenic switch‐off, defined as the stress to rest splenic perfusion attenuation in response to adenosine, has been proposed as an indicator of stress adequacy. Its occurrence has been previously assessed in first‐pass perfusion images, but the use of noncontrast techniques would be highly beneficial. Purpose To explore the ability of pseudo‐continuous arterial spin labeling (PCASL) to identify splenic switch‐off in patients with suspected CAD. Study Type Prospective. Population Five healthy volunteers (age 24.8 ± 3.8 years) and 32 patients (age 66.4 ± 8.2 years) with suspected CAD. Field strength/Sequence A 1.5‐T/PCASL (spin‐echo) and first‐pass imaging (gradient‐echo). Assessment In healthy subjects, multi‐delay PCASL data (500–2000 msec) were acquired to quantify splenic blood flow (SBF) and determine the adequate postlabeling delay (PLD) for single‐delay acquisitions (PLD > arterial transit time). In patients, single‐delay PCASL (1200 msec) and first‐pass perfusion images were acquired under rest and adenosine conditions. PCASL data were used to compute SBF maps and SBF stress‐to‐rest ratios. Three observers classified patients into “switch‐off” and “failed switch‐off” groups by visually comparing rest‐stress perfusion data acquired with PCASL and first‐pass, independently. First‐pass categories were used as reference to evaluate the accuracy of quantitative classification. Statistical Tests Wilcoxon signed‐rank, Pearson correlation, kappa, percentage agreement, Generalized Linear Mixed Model, Mann–Whitney, Pearson Chi‐squared, receiver operating characteristic, area‐under‐the‐curve (AUC) and confusion matrix. Significance: P value < 0.05. Results A total of 27 patients (84.4%) experienced splenic switch‐off according to first‐pass categories. Comparison of PCASL‐derived SBF maps during stress and rest allowed assessment of splenic switch‐off, reflected in a reduction of SBF values during stress. SBF stress‐to‐rest ratios showed a 97% accuracy (sensitivity = 80%, specificity = 100%, AUC = 85.2%). Data Conclusion This study could demonstrate the feasibility of PCASL to identify splenic switch‐off during adenosine perfusion MRI, both by qualitative and quantitative assessments. Evidence Level 2 Technical Efficacy 2