Pulse Sequences

RF Pulse Sequences

MR Physicist Amaresh Konar Shridhar can work with new researchers to design or refine their pulse sequences. We offer a wide range of radiofrequency pulse sequences for researchers to choose from for functional, structural, and diffusion imaging. We are also constantly working on developing and acquiring more sequences to better fit the needs of our researchers, so please reach out to us if there is something here you don’t see or something you’d like to collaborate on. Below is a selection of the most commonly used sequences

 

The most commonly utilized structural sequences include T1-weighted (T1w) Magnetization-Prepared Rapid Acquisition Gradient Echo (MPRAGE), T2-weighted (T2w) Turbo Spin Echo (TSE) or Fast Spin Echo (FSE), and Fluid-Attenuated Inversion Recovery (FLAIR). Additionally, we employ third-party developed sequences like T1 and T2w vNav as needed based on the specific study requirements.

 

Our most common sequences used for functional imaging are:

  • Siemens product BOLD sequences
  • Multiband/Multi-slice (MB/SMS) imaging using Siemens, CMRR, or MGH sequences, which can be combined with in-plane acceleration for additional spatial or temporal resolution
  • Multi-echo imaging using the CMRR sequence, which can be combined with MB imaging.

 

Further details about our multi-band and multi-echo capabilities:

Siemens SMS BOLD. This FDA-approved Siemens product sequences utilize Simultaneous Multi-Slice (SMS) technology to reduce exam times by up to 46% and enhance temporal resolution for BOLD fMRI. SMS can be combined with conventional parallel imaging for additional scan time reductions. As a Siemens product, it offers optimized image reconstruction and support from the Siemens application team. This sequence is recommended when FDA approval is required. Learn more.

CMRR Multi-band Multi-echo (MBME) Sequence, with multi-echo Capability: The CMMR multi-band can be combined with multi-echo imaging. ME sequences are used to acquire volumes at multiple TEs, which can to compensate for T2* variations and dropout. This can enhance BOLD contrast-to-noise ratio (CNR), especially in regions close to sinuses (medial prefrontal cortex, medial temporal lobe)

MGH (ABCD) Simultaneous Multi-Slice excitation (SMS) Sequence. Features blipped-CAIPI for reduced cross-slice signal contamination and combined slice and in-plane acceleration, LeakBlock reconstruction for improved image quality.

GRE Field Map Sequence: Comprises two magnitude images and a phase difference image for field map calculation.

CMRR SE Field Map Sequences (AP and PA): Opposite phase-encoded sequences for accurate field mapping. Also called a “top up” scan.

  • Ultrashort echo time sequences
  • Diffusion imaging
  • MR Spectroscopy targeting multiple nuclei, arterial
  • Neuromelanin-sensitive sequences

 

Before starting a study, we suggest users meet with our MR Physicist Amaresh to discuss sequence choice and optimization.