Adding T1 Mapping and Extracellular Volume Fraction for Myocardial Fibrosis Assessment: Implications for Cardiovascular Risk Assessment

Abstract

“T1 mapping” and “ECV mapping” techniques offer clinicians and researchers new opportunities to quantify important changes in the human myocardium such as myocardial fibrosis. These cardiovascular magnetic resonance (CMR) techniques employ “native T1” (i.e., without administration of contrast) and “extracellular volume fraction (ECV) measures.” These novel parameters can facilitate diagnosis of disease as well as associated prognosis since these quantitative measures depict the disease severity spectrum beyond its mere presence or absence. As such, these tools may enable the clinician to identify vulnerable patients and potentially improve outcomes by individualizing therapy and thus match the right treatment to the right patient. Clinicians now can possess new tools to detect focal and diffuse derangements in myocardial structure occurring in cardiac disease that can be otherwise difficult to detect. Fundamentally, increased ECV generally reflects expansion of the interstitial compartment (which includes the myocardial vasculature), whereas native T1 alterations may occur with processes affecting the myocyte or interstitium or both. These measurements complement the traditional functional and geometric surrogates of vulnerability such as left ventricular ejection fraction and volumes and mass. Increased understanding of the role of the interstitium in pathophysiology may facilitate new paradigms of cardiac vulnerability. Various aspects of T1 mapping and ECV have been reviewed in several previous publications.