An optical fiber-based gating device for prospective mouse cardiac MRI

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Optical Sensing

Background:

• Prospective synchronization in MRI requires monitoring respiratory and cardiac motion.
• Conventional methods like ECG and air pressure sensors have limitations, especially in small animals, due to MRI interference and bulkiness.
• A compact, simultaneous respiratory and cardiac monitoring device is needed for enhanced MRI sensitivity and reduced artifacts.

Purpose of the Study:

• To develop and assess a novel fiber-optic-based device for simultaneous respiratory and cardiac monitoring in small animal MRI.
• To evaluate the device's suitability for prospective triggering and physiological monitoring.
• To compare the performance of the optical device against conventional ECG and pressure sensors.

Main Methods:

• A fiber-optic transmit-receive pair was developed for sensing physiological motion.
• The device was tested on mice (n=10) for dual cardiac and respiratory synchronization.
• Experiments involved comparing prospective triggering using the optical signal, ECG, and pressure sensor, as well as comparing prospective vs. retrospective triggering.

Main Results:

• The fiber-optic signal was unaffected by radiofrequency pulses and magnetic field gradients.
• Mice heart MR images showed low motion artifacts across all tested sensors.
• No significant signal-to-noise ratio (SNR) differences were observed between imaging series.
• The optical device performed comparably to ECG and pressure sensors but with reduced bulk.

Conclusions:

• The fiber-optic device is suitable for prospective triggering in cardiac MRI of small animals.
• It offers a robust, compact, and MRI-compatible alternative to conventional sensors.
• This technology is particularly advantageous for small animal MRI in confined spaces or with dedicated cardiac coils.