Phase-based fast 3D high-resolution quantitative T₂ MRI in 7 T human brain imaging.

Area of Science:

• Medical Imaging
• Biophysics
• Radiology

Background:

• Quantitative T2 mapping is crucial for personalized medicine and disease progression monitoring.
• Ultra-high-field (UHF) MRI (≥7 Tesla) offers higher spatial resolution but faces challenges like increased power deposition and RF field inhomogeneity.
• Existing T2-weighted imaging provides only qualitative data, limiting diagnostic precision.

Purpose of the Study:

• To extend a novel phase-based T2 mapping technique to UHF MRI.
• To achieve fast, quantitative, high-resolution 3D T2 mapping at 7 Tesla.
• To address RF field inhomogeneity and power deposition challenges inherent in UHF MRI.

Main Methods:

• Utilized a phase-based T2 mapping approach with fast steady-state acquisitions.
• Employed low flip angle pulses and controlled RF pulse phase increments in gradient echo sequences.
• Simultaneously extracted T2 and RF field maps from signal phase, validated with a 3D head phantom.

Main Results:

• Successfully implemented fast quantitative high-resolution 3D T2 mapping at 7 Tesla.
• Overcame key UHF challenges including RF field inhomogeneity using low flip angles.
• Acquired whole-brain images with submillimeter resolution without specialized transmit coils.

Conclusions:

• The developed method enables efficient and quantitative high-resolution 3D T2 mapping at 7 Tesla.
• This technique addresses major UHF MRI limitations, enhancing its clinical applicability.
• Promotes the use of UHF MRI for advanced diagnostics and personalized medicine.