Lysann Hildebrand MD, Presenter: Nothing to Disclose

Clara Frank, Abstract Co-Author: Nothing to Disclose

Matthias Gutberlet MD, PhD, Abstract Co-Author: Nothing to Disclose

To evaluate if cardiovascular magnetic resonance (CMR) is a suitable method for identifying subclinical acute cellular rejection (ACR) requiring treatment in patients post heart transplantation (HTX), using T1- and T2-Mapping techniques as compared to conventional CMR techniques for inflammation assessment using endomyocardial biopsy (EMB) as the standard of reference.

Thirty-five CMRs were performed in 20 patients (mean age 53±11 years, 24male) using a 1.5T scanner compared to EMB. The CMR protocol included a T2w STIR-sequence to calculate the myocardial edema ratio (ER), a T1w spinecho and inversion recovery sequence for global relative (gRE) and late gadolinium enhancement (LGE), as well as a modified Look-Locker inversion-recovery (MOLLI) sequence before and 15 minutes after administration of 0.1 mmol/kg/body weight of Gadobutrol (Gadovist, Bayer HealthCare Pharmaceuticals, Berlin, Germany) i.v. for T1-quantification and a free-breathing, navigator-gated multi-echo sequence for T2-quantification. T1- pre- and postcontrast, T2- and ECV-maps were calculated with the software (cvi42, Calgary, Canada).

No or a mild ACR (ISHLT <1B) was revealed in 20/35, ACR requiring treatment in 15/35 EMBs. The area-under-the-curve (AUC) of the receiver operating characteristic (ROC) analysis were only 0,54 for the ER and 0.52 for gRE, but 0.65 for native T1-Mapping, 0.66 for ECV, 0.73 for T2-Mapping and 0.78 for postcontrast T1-Mapping. Similar to myocarditis the best cut-off values for ER were ≥2 and for gRE ≥4.5. The best sensitivity and specificity (%) could be achieved with T2-Mapping using a cut off 65ms (73/75), for T1-Mapping postcontrast using a cut off of 342ms (73/70) and for ECV with a cut off of 42 (67/70), respectively. Native T1-Mapping using a cut off of 1060 ms achieved a very high sensitivity (87%) but only low specificity (45%).

Especially T2- and T1-Mapping postcontrast as well as ECV quantification seem to be promising tools to identify subclinical ACR in patients after HTx, better than the calculation of the ER and gRE. This may help to potentially reduce, if not eliminate, the need for EMB in these patients.

In patients post HTX, CMR using T1- and T2-Mapping techniques is a suitable method for identifying subclinical ACR requiring treatment.

Hildebrand, L, Frank, C, Gutberlet, M, T1-, T2-Mapping and Extracellular Volume Quantification for the Diagnosis of Subclinical Acute Cellular Rejection in Patients after Heart Transplantation Using Magnetic Resonance Imaging.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14017549.html