Inter-study variability in left ventricular mass measurement. Comparison between M-mode echography and MRI.

Area of Science:

• Cardiovascular Imaging
• Medical Diagnostics
• Biomedical Engineering

Background:

• Accurate assessment of left ventricular mass (LVM) is crucial for diagnosing and managing cardiovascular diseases.
• M-mode echocardiography is a common method for LVM assessment, but its reproducibility can be variable.
• Magnetic Resonance Imaging (MRI) offers advanced imaging capabilities for cardiac evaluation.

Purpose of the Study:

• To compare the inter-observer and inter-study variability of M-mode echocardiography and MRI in assessing left ventricular mass.
• To determine which imaging modality provides more reproducible measurements of left ventricular mass.

Main Methods:

• Twenty patients without coronary artery disease underwent two M-mode echocardiography and two MRI examinations within four days.
• Examinations were performed by different, blinded operators using standardized protocols (Devereux's method for echo, multislice spin-echo for MRI).
• Left ventricular mass was calculated using established formulas and planimetry for MRI.

Main Results:

• MRI demonstrated significantly lower inter-study variability (6.75 +/- 3.8%) compared to M-mode echocardiography (11 +/- 6.4%, P = 0.0021).
• The 95th percentile variability threshold was 13.5% for MRI versus 21.5% for echocardiography.
• MRI measurements showed higher correlation (r=0.96) with lower standard error of estimate (SEE=11.2 g) than echocardiography (r=0.89, SEE=22.7 g).

Conclusions:

• MRI is a significantly more reproducible imaging tool for evaluating left ventricular mass than M-mode echocardiography.
• The higher reproducibility of MRI allows for a reduced sample size needed to detect significant changes in LVM in clinical studies.
• MRI's enhanced precision in LVM assessment has practical implications for the efficiency and design of cardiovascular research.