Use of Multiplied, Added, Subtracted and/or FiTted Inversion Recovery (MASTIR) pulse sequences

Area of Science:

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

Background:

• Conventional inversion recovery (IR) sequences have limitations in optimizing contrast and suppressing unwanted signals.
• There is a need for advanced MRI techniques that offer greater flexibility in tissue characterization and signal manipulation.

Purpose of the Study:

• To describe the Multiplied, Added, Subtracted and/or fiTted Inversion Recovery (MASTIR) pulse sequences.
• To outline the uses and applications of MASTIR sequences for enhancing image contrast and demonstrating specific tissues and fluids.

Main Methods:

• Combining two or more IR images of different types using multiplication, addition, subtraction, and/or fitting.
• Utilizing a formalism of pulse sequences as tissue property filters with univariate and multivariate models.
• Employing techniques such as echo subtraction, diffusion subtraction, Magnetization Transfer (MT), and susceptibility weighting.
• Incorporating phase images and phase-sensitive reconstructions.
• Utilizing the Double Echo Sliding IR (DESIRE) sequence for a wide range of inversion times (TIs).

Main Results:

• MASTIR sequences provide a range of options for increasing image contrast and suppressing unwanted signals.
• Subtraction of IR images can yield high T1-dependent contrast and positive contrast enhancement.
• Additional contrast can be achieved by incorporating T2, diffusion, MT, and susceptibility information.
• Selective imaging of lipid and water components, as well as ultrashort and short T2 tissue components, is possible.
• Phase-sensitive and magnitude image manipulation allows for signal suppression and contrast enhancement.
• Demonstrated utility in various applications including brain, cartilage, multiple sclerosis, Alzheimer's disease, and peripheral nerve imaging.

Conclusions:

• MASTIR sequences offer a versatile platform for advanced MRI, enabling tailored contrast generation and signal suppression.
• These sequences allow for the selective visualization of specific tissue and fluid components.
• MASTIR techniques hold significant potential for improving diagnostic capabilities in various neurological and musculoskeletal conditions.