Real-time cardiac MRI without triggering, gating, or breath holding

Area of Science:

• Cardiovascular Imaging
• Magnetic Resonance Imaging (MRI)
• Small Animal Models

Background:

• Real-time cardiac MRI is challenging in rats due to high heart rates (330 bpm) and respiratory motion.
• Existing methods like Electrocardiogram (ECG) triggered, respiratory gated cine imaging have limitations in temporal and spatial resolution for rat studies.

Purpose of the Study:

• To develop and validate a dynamic imaging method for real-time cardiac MRI in rats.
• To assess the feasibility of this method for anatomical and perfusion imaging of transplanted rat hearts.

Main Methods:

• Utilized a dynamic imaging method based on Partially Separable Function (PSF) theory.
• Employed an acceleration factor of 256 for rapid data acquisition.
• Achieved 200 microm in-plane resolution and 17.2 msec temporal resolution.

Main Results:

• Successfully overcame challenges of high heart rate and respiratory motion in rats.
• Demonstrated improved spatial resolution (2x) compared to conventional ECG-triggered cine imaging.
• Achieved reduced acquisition time (3x) enabling efficient studies.

Conclusions:

• The PSF-based dynamic imaging method is effective for real-time cardiac MRI in rats.
• This technique facilitates detailed anatomical and perfusion assessment of transplanted rat hearts.
• Offers significant improvements in spatial resolution and acquisition speed for small animal cardiac imaging.