extracellular volume
Also written as: ECV — extracellular volume
A cardiac MRI-derived parameter that quantifies myocardial fibrosis by measuring the proportion of extracellular space in the myocardium.
Full Definition
Extracellular volume (ECV) is a quantitative cardiac MRI parameter that represents the percentage of myocardial tissue occupied by the extracellular space, which includes both the intravascular and interstitial compartments. ECV is calculated using pre- and post-contrast T1 relaxation times of both myocardium and blood, along with the patient's hematocrit value. Elevated ECV values indicate expansion of the extracellular space, typically due to myocardial fibrosis, edema, or infiltrative processes. Normal ECV values are typically 20-30%, while values above 30% suggest pathological tissue changes. This technique has proven valuable in assessing various cardiomyopathies, monitoring treatment response, and providing prognostic information in heart failure patients.
Usage
Usage note: ECV is widely accepted abbreviation; requires hematocrit for accurate calculation.
In Context
- "The elevated extracellular volume of 38% suggested significant myocardial fibrosis in this patient with heart failure." — Cardiac MRI report
- "ECV mapping demonstrated diffuse fibrosis that was not apparent on late gadolinium enhancement imaging." — Cardiomyopathy evaluation report