Interactive worksheet
Interactive worksheet
Clinical inputs
0/5 filled
Clinical contextWhy this tool matters and how to interpret it
Understand the result,
not just the number.
Extracellular Volume Fraction (ECV%) Calculator: Explanation and Clinical Context Extracellular Volume Fraction (ECV%) quantifies the proportion of myocardial tissue that is extracellular space, as derived from pre- and post-contrast T1 mapping in cardiac magnetic resonance imaging (CMR). It reflects interstitial expansion caused by fibrosis, edema, or infiltration. The ECV is calculated using native and post-contrast myocardial and blood T1 values, adjusted for the patient’s hematocrit.
This allows estimation of the myocardial interstitial volume independent of field strength and sequence type. Normal ECV values typically range from 25–30% in healthy myocardium. Elevated ECV (>30%) indicates diffuse myocardial fibrosis as seen in conditions such as hypertensive heart disease, dilated cardiomyopathy, amyloidosis, or post-infarction remodeling.
Clinically, ECV quantification improves risk prediction beyond late gadolinium enhancement (LGE), as it detects diffuse interstitial fibrosis not visible on LGE imaging. It is associated with adverse outcomes, impaired diastolic function, and progressive heart failure.
Evidence & references3 primary sources mapped
- Source 1
Kellman P, et al. "Extracellular volume fraction mapping in the myocardium, part 1: evaluation of an automated method." J Cardiovasc Magn Reson. 2012;14:63.
- Source 2
Sado DM, et al. "Quantification of diffuse myocardial fibrosis using T1 mapping (ECV): reference values and clinical correlations." J Cardiovasc Magn Reson. 2013;15:78.
- Source 3
Schelbert EB, et al. "Myocardial extracellular volume fraction measurement by magnetic resonance imaging and its association with left ventricular remodeling." Circulation. 2015;131(13):1249–1256.
Clinical discussionModerated, tool-specific conversation
Loading discussion…