Clinical recommendations for cardiovascular magnetic resonance mapping of T1, T2, T2* and extracellular volume: A consensus statement by the Society for Cardiovascular Magnetic Resonance (SCMR) endorsed by the European Association for Cardiovascular Imaging (EACVI)

Abstract

Parametric mapping techniques provide a non-invasive tool for quantifying tissue alterations in myocardial disease in those eligible for cardiovascular magnetic resonance (CMR). Parametric mapping with CMR now permits the routine spatial visualization and quantification of changes in myocardial composition based on changes in T1, T2, and T2*(star) relaxation times and extracellular volume (ECV). These changes include specific disease pathways related to mainly intracellular disturbances of the cardiomyocyte (e.g., iron overload, or glycosphingolipid accumulation in Anderson-Fabry disease); extracellular disturbances in the myocardial interstitium (e.g., myocardial fibrosis or cardiac amyloidosis from accumulation of collagen or amyloid proteins, respectively); or both (myocardial edema with increased intracellular and/or extracellular water). Parametric mapping promises improvements in patient care through advances in quantitative diagnostics, inter- and intra-patient comparability, and relatedly improvements in treatment. There is a multitude of technical approaches and potential applications. This document provides a summary of the existing evidence for the clinical value of parametric mapping in the heart as of mid 2017, and gives recommendations for practical use in different clinical scenarios for scientists, clinicians, and CMR manufacturers.

Fig. 1

Typical appearance of T1, T2, T2*, and ECV maps in healthy subjects and in patients with myocardial disease. Arrows denote relative change in respective parametric maps. Courtesy of P.K

Fig. 2

General imaging protocol for myocardial tissue characterization including parametric mapping. The choice of components depends on the clinical scenario (see Tables 2 and 4). For slice orientations see Table 4. STIR = Short TI inversion recovery. 1: Should be obtained immediately before the scan if possible, otherwise within 24 h of scanning. Not necessary if synthetic ECV available. 3: Search tool for focal myocardial edema. Dispensable if high-quality T1 and/or T2 mapping is performed with full LV coverage. 3&5: Not necessary in non-acute disease. 6: Not necessary if iron is not of interest. 7–9: Not necessary if both focal and diffuse myocardial fibrosis are not of interest

Fig. 3

Alterations of T1 and ECV in different myocardial diseases (reproduced with permission from [193]). T1 values refer to MOLLI-based techniques at 1.5 T

Fig. 4

Roadmap for developing biomarkers derived from parametric mapping