Pilot Tone-Triggered MRI for Quantitative Assessment of Cardiac Function, Motion, and Structure

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Biomedical Engineering

Background:

• Electrocardiogram (ECG) triggering is standard for cardiac MRI, but signal interference can occur.
• Pilot tone (PT) is an alternative triggering method for cardiac MRI acquisition.

Purpose of the Study:

• To evaluate the agreement between cardiac functional and structural indices derived from PT-triggered and ECG-triggered MRI sequences.
• To test the hypothesis that PT triggering provides comparable results to ECG triggering in cardiac MRI.

Main Methods:

• Cardiac MRI was performed on 16 healthy volunteers using both PT and ECG triggering.
• Cine MRI, T1, and T2 mapping were acquired.
• Quantitative measurements included ventricular volumes, ejection fraction, longitudinal strain, and T1/T2 values.
• Agreement was assessed using interclass correlation coefficient, coefficient of variation, and Bland-Altman plots.

Main Results:

• No significant differences were found in cardiac indices between PT and ECG triggering.
• Good agreement and low variation were observed for most measured parameters.
• Interclass correlation coefficients ranged from 0.73 to 0.98, with coefficients of variation from 1.4% to 22.6%.

Conclusions:

• Pilot tone-triggered MRI yields comparable results to ECG-triggered MRI for cardiac function, motion, and structure.
• PT triggering shows potential as a backup for ECG gating in cardiovascular MRI.