Assessment of sub-clinical acute cellular rejection after heart transplantation: comparison of cardiac magnetic resonance imaging and endomyocardial biopsy

Abstract

Objective: Comparing the diagnostic value of multi-sequential cardiac magnetic resonance imaging (CMR) with endomyocardial biopsy (EMB) for sub-clinical cardiac allograft rejection.

Methods: One hundred and forty-six examinations in 73 patients (mean age 53 ± 12 years, 58 men) were performed using a 1.5 Tesla system and compared to EMB. Examinations included a STIR (short tau inversion recovery) sequence for calculation of edema ratio (ER), a T1-weighted spin-echo sequence for assessment of global relative enhancement (gRE), and inversion-recovery sequences to visualize late gadolinium enhancement (LGE). Histological grade ≥1B was considered relevant rejection.

Results: One hundred and twenty-seven (127/146 = 87 %) EMBs demonstrated no or mild signs of rejection (grades ≤1A) and 19/146 (13 %) a relevant rejection (grade ≥1B). Sensitivity, specificity, positive predictive, and negative predictive values were as follows: ER: 63 %, 78 %, 30 %, and 93 %; gRE: 63 %, 70 %, 24 %, and 93 %; LGE: 68 %, 36 %, 13 %, and 87 %; with the combination of ER and gRE with at least one out of two positive: 84 %, 57 %, 23 %, and 96 %. ROC analysis revealed an area under the curve of 0.724 for ER and 0.659 for gRE.

Conclusion: CMR parameters for myocarditis are useful to detect sub-clinical acute cellular rejection after heart transplantation. Comparable results to myocarditis can be achieved with a combination of parameters.

Key points: • Magnetic resonance imaging is useful for the assessment of cardiac allograft rejection. • CMR has a high negative predictive value for exclusion of allograft rejection. • Diagnostic performance is not yet good enough to replace endomyocardial biopsy.

Fig. 1

Short-axis STIR image with ROIs drawn in the myocardium and skeletal muscle. Edema Ratio (ER) is 3.0

Fig. 2

Transverse T1-weighted TSE sequence before (a) and after contrast injection (b) with ROIs drawn in the myocardium and skeletal muscle. Global relative enhancement (gRE) is 3.0

Fig. 3

Receiver operator characteristic (ROC) analysis for the CMR parameters ER (a) and gRE (b) for the diagnosis of therapeutically relevant rejection (grade ≥ 1B) as compared to the results of EMB demonstrate good results for both parameters with an area under the curve (AUC) of 0.724 for the ER (a) and 0.659 for the gRE (b)

Fig. 4

The box-plots of the ER (a) and gRE (b) in patients with histological grade 0 and 1A (n = 127) vs. patients with grade 1B or higher (n = 19) demonstrated with statistically significant differences (*p < 0.05)