The 7TBRP routinely collects a plethora of different sequence types for 7T neuroimaging studies. While we do have many standard sequences, others can be optimized based on PI request and study needs. Neuroimaging studies are performed utilizing the Tac Family of RF head coil systems and the RAPIDBiomed 1H/31P dual-tuned RF head coil, as needed.
Structural Sequences
T1w MPRAGE
Frequently collected at 0.75mm isotropic resolution, we have many other variations, based on resolution and acquisition time needs, optimized for our RF head coil systems.
T1w MP2RAGE
Using a double inversion technique at 0.55mm isotropic resolution, the MP2RAGE is an extremely versatile sequence. Offering both 3D high resolution T1 weighted images great for white and grey matter morphology, the sequence also boasts several outputs to allow for further analyses such as T1 Maps, and individual single inversions to aid in skull stripping.
T2w SPACE
The T2w 3D SPACE is optimized at 0.6mm isotropic resolution. SPACE is another versatile sequences that can either be optimized to provide excellent grey to white matter delineation, or to highlight enlarged perivascular spaces (ePVS). SPACE is a great T2w sequence for morphology and quantification of tissues/structures, including the hippocampus.
T2w FLAIR
Great for identifying white matter hyperintensities or lesions, especially those from multiple sclerosis (MS) or strokes – we have both 2D and 3D FLAIR sequences tailored for excellent performance and quality at 7T. FLAIR has similar qualities of other T2w sequences, with the added benefit of attenuating the CSF, giving it a dark appearance in contrast with the expected bright white on T2 weighted imaging, giving better contrast and quantification of lesions. We most often acquire a 2D T2w FLAIR at 0.75x0.75x1.5 mm3.
SWI/GRE
Susceptibility Weighted Imaging, or SWI is a robust and multifaceted modality. Most uniquely at 7T, a "blooming" effect takes place on extremely small (~50um) venules allowing for histology like visualization of these tiny venous structures. The SWI sequence can be optimized in a plethora of different options, including bipolar and monopolar, and can be used to assess microbleeds or for T2* and QSM mapping. We use both standard GRE for SWI and ASPIRE CLEAR SWI and have optimized resolutions from 0.55 isotropic all the way to 0.2 in-plane resolution.
T1w 2D TSE
Most commonly used for hippocampal subfield segmentation the T2w 2D TSE sequence is optimized at 0.375x0.375x1.5mm3, collected coronally, we can vary the number of slices to either collect whole brain TSE, or only acquire the hippocampus, allowing for a short, high resolution option for segmenting the brain's memory center.
Functional and Diffusion Images
BOLD Echo Planer Imaging
Using Echo Planer Imaging (EPI) to map blood oxygen level dependencies (BOLD) signal, investigators can map the inner workings of the brain, both at rest and during tasks with functional stimulation via audio or visual presentations. Many of our EPI studies utilize 2mm isotropic resolution with 1 second or 700 ms TRs, though the 7TBRP has implemented protocols for even higher resolution EPI such as 1.5, 1.25, 1.0, and stunning 0.8mm isotropic resolution.
Diffusion Weighted Imaging
Duffusion Weighted Imaging (DWI) and Diffusion Tensor Imaging (DTI) can be utilized for a wide array of brain metrics, including fiber tracking, FA maps, and NODDI. We optimized many advanced diffusion sequence, especially those with multi-shell and high b-values, with custom designed diffusion vectors to achieve high quality DWI.
CSF Flow
CSF Flow imaging utilizes fast echo planer imaging to rapidly image volumes of the brain in quick succession, allowing the pusatility of the cerebrospinal fluid to be visualized, in correlating with physiological measures, we can derive further analysis of things like xyz.
Pseudo-Continuous Arterial Spin Labeling
pCASL is a form of Arterial Spin Labeling (ASL) where RF is used to "tag" blood in the neck and measure as it perfuses in the brain. With this technique we can achieve perfusion weighted imaging, and quantify Cerebral Blood Flow (CBF) in the brain.
MR Angiography
Time of Flight
The TOF sequence allows us to use the inflow effect to visualize blood flow against a saturated dark background, making arteries stand out. The increased sensitivity possible at 7T allows for these arterioles to be traced throughout the brain at 0.5mm or 0.38mm isotropic resolutions.
Magnetic Resonance Spectroscopy (MRS)
1H Single Voxel Spectroscopy (SVS)
Utilizing sequences including STEAM, Single Voxel Spectroscopy (SVS) can be achieved with excellent spectral quality. Commonly used for regions such as Prefrontal Cortex (PFC), Dorsal Lateral Prefrontal Cortex (DLPFC), Left and Right Amygdala, and Left and Right Hippocampus allowing for quantification of various metabolites in the region of interest.
Whole-Brain 31P MRS
Commonly used for bioenergetics, 31P MRS has a broad range of utility that includes both physcial and psychiatric conditions.
1H 2D and 3D MRS
Capitalizing on Concentric Ring Trajectories (CRT) for improved acquisition timing and SNR gains, 2D and 3D MRS can give larger coverage for MRS than SVS, while keeping imaging times low.