R₁ dispersion contrast at high field with fast field-cycling MRI.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Physics
• Biomedical Engineering

Background:

• Contrast agents with strong R1 dispersion enhance target-specific MRI contrast.
• Utilizing R1 field dependence necessitates adapting MRI scanners for fast field-cycling (FFC).

Purpose of the Study:

• To present the first implementation and validation of FFC-MRI at a clinical 3 Tesla field strength.
• To demonstrate the capability of generating R1 dispersion contrast at high field with suppressed background signal.

Main Methods:

• An insert coil was added to a conventional MRI system to achieve a field-cycling range of ±100 mT around the nominal B0 field.
• System validation was performed using iron oxide magnetic nanoparticles and compared with FFC-NMR relaxometry.
• Proof-of-principle R1 dispersion imaging was conducted.

Main Results:

• Successful implementation and validation of FFC-MRI at 3T.
• Demonstrated R1 dispersion imaging and contrast generation with suppressed background signal.
• The system effectively investigated MRI contrast agents with strong R1 dispersion.

Conclusions:

• The presented hardware setup enables FFC-MRI at 3T for investigating R1 dispersion contrast agents.
• This advancement facilitates the development of novel MRI contrast agents with enhanced specificity at clinical field strengths.