Extracellular volume fraction by cardiac computed tomography (ECV_CT): opportunities and challenges for clinical...

Area of Science:

• Cardiovascular Imaging
• Radiology
• Medical Physics

Background:

• Cardiac computed tomography (CT)-derived extracellular volume (ECV_CT) quantifies myocardial interstitial expansion.
• It serves as a CT marker for focal and diffuse fibrosis and amyloid infiltration.

Purpose of the Study:

• To evaluate ECV_CT as a non-invasive imaging biomarker.
• To explore its potential in various cardiac conditions and compare it with existing methods.

Main Methods:

• ECV_CT calculation using single-energy or spectral CT (including photon-counting CT).
• Quantification involves contrast distribution in the extracellular space, adjusted for hematocrit.
• Comparison with cardiac magnetic resonance (CMR)-derived ECV and histological collagen volume fraction.

Main Results:

• ECV_CT correlates well with CMR-derived ECV and histological findings across disease cohorts.
• It adds myocardial tissue characterization to existing CT examinations.
• Potential applications include opportunistic screening for amyloidosis and risk stratification.

Conclusions:

• ECV_CT is a promising, accessible imaging biomarker for myocardial fibrosis and infiltration.
• Standardization of protocols, validation, and consensus guidance are crucial for clinical adoption.
• Further multicentre studies are needed to establish reference ranges and diagnostic thresholds.