Multiparametric cardiac MRI in the diagnosis of transplant rejection in patients after orthotopic heart transplantation
摘要
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 methodsThe 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.
ResultsDuring 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.
ConclusionNoninvasive cardiac MRI, particularly T2-mapping, may help assess the risk of cardiac graft rejection and complement biopsy-based surveillance in HTx recipients.
Key Points