MPRAGE/3D FGRE/3D FAST SPGR/3D TFE/3D FAST FE

MPRAGE, or Magnetization Prepared Rapid Gradient Echo Imaging, is a prominent 3D gradient echo (GRE) MRI technique, especially in neuroimaging. It intricately melds an inversion recovery (IR) sequence with a rapid gradient echo acquisition, creating detailed volumetric images.

MPRAGE MRI Physics

MPRAGE is essentially a modified TurboFLASH technique that integrates magnetization-prepared inversion pulses. It begins with a 180-degree inversion pulse, followed by a GRE imaging sequence in a steady state that employs rewinder gradients. To generate 3D images, a secondary phase encoding step is applied in the slice-select direction. Each preparatory pulse yields only one segment or partition of a 3D data record. Following signal acquisition, all rows within a 3D partition introduce a delay time known as TD, which is necessary to prevent saturation effects.

MPRAGE sequences find widespread use in high-resolution 3D isotropic brain imaging. In comparison to T1-weighted spin echo (SE) sequences, MPRAGE offers superior image quality and enhanced contrast differentiation between gray matter and white matter. This makes it a valuable tool in clinical neuroimaging for diagnosing and studying various neurological conditions.

MPRAGE MRI Image Appearance

T1 SE and MPRAGE sequences appear similar. The only noticeable difference is that MPRAGE sequences exhibit better contrast between gray and white matter. MPRAGE sequences produce high-resolution 3D isotropic images, enabling multiplanar reconstruction after image acquisition.

MPRAGE MRI Applications

Neuroimaging: MPRAGE is often the sequence of choice for brain imaging, offering high-resolution 3D images. It’s particularly useful for volumetric analysis.
Pre-surgical Planning: Its detailed images can assist surgeons in planning procedures, especially for brain surgeries.

Tissues and their MPRANGE appearance

Fat: Bright
Muscles: Intermediate
CSF: Dark
White Matter: Bright.
Gray Matter: Intermediate.
Bone: Dark (low signal).
Bone Marrow: Variable but often bright.
Blood Vessels: Mostly Dark, Depending on flow characteristics, can be bright or dark.
Pituitary Gland: Intermediate. Choroid Plexus: Intermediate..
Cerebellum (consists of both white and gray matter): Gray matter darker than white matter.
Brain Stem: Intermediate to bright.
Sinuses: Dark (filled with air).
Thalamus: Darker than white matter.
Putamen: Darker than white matter.
Pineal Gland: Intermediate.
Hippocampus: Darker than white matter.
Corpus Callosum: Intermediate to bright.
Caudate Nucleus: Darker than white matter.

Use

Pathological appearance on MPRAGE

Pathological processes often result in elevated tissue water content, leading to signal attenuation on MPRAGE-weighted images, resulting in a dark appearance of these pathologies. Conversely, vascular lesions exhibit brightness in Post-Gadolinium DTPA MPRAGE scans.