Fast SSFP gradient echo sequence for simultaneous acquisitions of FID and echo signals

Area of Science:

• Magnetic Resonance Imaging
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Fast gradient echo imaging sequences with small flip angles and short repetition times are common in NMR.
• Decreasing repetition times (TR) comparable to spin-spin relaxation time (T2) can induce residual phase coherency, forming a T2-weighted signal similar to spin-echo.
• This T2-weighting effect has not been exploited in conventional fast gradient echo imaging.

Purpose of the Study:

• To propose and validate a new fast imaging technique enabling simultaneous acquisition of both Free Induction Decay (FID) and echo signals.
• To investigate the weighting properties (T1 vs. T2) of the simultaneously acquired FID and echo signals.
• To determine optimal flip angles for maximizing signal and contrast in the proposed fast SSFP imaging sequence.

Main Methods:

• Development of a novel fast steady-state free precession (SSFP) imaging sequence.
• Simultaneous acquisition of FID and echo signals within the proposed SSFP sequence.
• Experimental validation of the technique and analysis of signal weighting and contrast properties.

Main Results:

• The proposed technique successfully enables simultaneous acquisition of FID and echo signals.
• Experimental results demonstrate that the FID signal is T1-weighted.
• The echo signal acquired simultaneously is strongly T2-weighted.

Conclusions:

• The novel fast SSFP technique allows for simultaneous acquisition of T1-weighted FID and T2-weighted echo signals.
• This method offers a new approach to fast NMR imaging by leveraging residual phase coherency.
• Further studies can explore optimal flip angles for specific contrast enhancement in various applications.