Eur Radiol. 2026 May 26. doi: 10.1007/s00330-026-12631-3. Online ahead of print.
ABSTRACT
OBJECTIVES: Heart transplantation (HTx) remains the main long-term treatment for end-stage heart failure. Due to the high risk of acute cellular rejection (ACR), HTx recipients undergo multiple endomyocardial biopsies to monitor graft tolerance. This prospective, single-center study evaluated quantitative magnetic resonance imaging (MRI), particularly T1- and T2-mapping, as noninvasive tools for rejection monitoring.
MATERIALS AND METHODS: The study included 17 adult HTx recipients (men, 88%; age, 53 ± 13 years) enrolled within 1 month after transplantation and 10 controls without structural heart disease. Htx recipients underwent 5 to 6 serial cardiac MRI scans with T1- and T2-mapping, coinciding with routine endomyocardial biopsies, to correlate imaging findings with histopathological evidence of ACR. Cardiac MRI relaxation times were compared based on the biopsy evidence of ACR.
RESULTS: During the 6-month follow-up, HTx recipients underwent 87 cardiac MRI scans, with 13 ACR episodes reported in 9 patients (53%). They had significantly higher T1- and T2-mapping values than controls. Cardiac biomarkers, NT-proBNP and troponin, did not differ between patients with or without ACR. Global T2-mapping and regional abnormalities, particularly in septal segments, identified rejection, with a cutoff of 51 ms showing high specificity (92%) but modest sensitivity (46%) for ACR. In contrast, T1-mapping values were elevated only in selected myocardial segments, showing a consistent inferoseptal pattern, without differences in global myocardial T1 values between ACR and non-ACR patients, limiting their usefulness for identifying ACR.
CONCLUSION: Noninvasive cardiac MRI, particularly T2-mapping, may help assess the risk of cardiac graft rejection and complement biopsy-based surveillance in HTx recipients.
KEY POINTS: Question Monitoring acute cellular rejection (ACR) after heart transplantation is crucial, but whether noninvasive imaging can safely reduce the number of endomyocardial biopsies is still debatable. Findings Multiparametric cardiac magnetic resonance combining T1- and T2-mapping may improve diagnostic assessment and support more targeted use of invasive endomyocardial biopsies. Clinical relevance T2-mapping appears to be a promising noninvasive biomarker for detecting ACR in heart transplant recipients within the 6 months post-surgery, whereas T1-mapping shows regional differences but lacks consistency across the myocardium, having limited diagnostic utility in detecting acute inflammatory changes.
PMID:42189216 | DOI:10.1007/s00330-026-12631-3