Jason Stockmann

• Massachusetts General Hospital

Despite their importance in shaping visual perception, functional connectivity between ocular dominance columns (ODCs), the building blocks of neuronal processing within the human primary visual cortex (V1), remains largely unknown. Using high-resolution functional MRI (fMRI), we localized ODCs and assessed their resting-state functional connectivi...

Purpose Introduce a unified acquisition and modeling strategy to simultaneously quantify magnetization transfer (MT), tissue susceptibility (χ$$ \chi $$) and T2*$$ {T}_2^{\ast } $$. Theory and Methods Magnetization transfer is induced through the application of off‐resonance irradiation between excitation and acquisition of an RF‐spoiled gradient‐...

To increase granularity in human neuroimaging science, we designed and built a next-generation 7 Tesla magnetic resonance imaging scanner to reach ultra-high resolution by implementing several advances in hardware. To improve spatial encoding and increase the image signal-to-noise ratio, we developed a head-only asymmetric gradient coil (200 mT m⁻¹...

The quality of cervical spinal cord images can be improved by the use of tailored radiofrequency (RF) coil solutions for ultrahigh field imaging; however, very few commercial and research 7-T RF coils currently exist for the spinal cord, and in particular, those with parallel transmission (pTx) capabilities. This work presents the design, testing,...

Purpose An MRI scanner is equipped with global shim systems for shimming one region of interest (ROI) only. However, it often fails to reach state‐of‐the‐art when shimming two isolated regions of interest simultaneously, even though the two‐area shimming can be essential in scan scenarios, such as bilateral breasts or dyadic brains. To address thes...

T1 relaxation times of the 14 T1 phantom spheres that make up the standard ISMRM/NIST system phantom are being reported at 7 T. T1 values of six out of the 14 T1 spheres at 7 T (with T1 > 270 ms) have been reported previously but to the best of our knowledge, not all the T1s of the 14 T1 spheres at 7 T have been reported before. Given the increasin...

Absolute concentration maps in mM unit of glutamine plus glutamate (GLX) and myo‐inositol (MI) in the five healthy subjects obtained from ERQ and IWQ methods. The corresponding high‐resolution MEMPRAGE image and CSF segmentation map down‐sampled to MRSI size are shown in the first and second columns, respectively BY Bijaya Thapa et al. (121‐133)

Purpose To introduce wave‐encoded acquisition and reconstruction techniques for highly accelerated EPI with reduced g‐factor penalty and image artifacts. Theory and Methods Wave‐EPI involves application of sinusoidal gradients during the EPI readout, which spreads the aliasing in all spatial directions, thereby taking better advantage of 3D coil s...

Purpose To extend the coverage of brain coil arrays to the neck and cervical–spine region to enable combined head and neck imaging at 7 Tesla (T) ultra‐high field MRI. Methods The coil array structures of a 64‐channel receive coil and a 16‐channel transmit coil were merged into one anatomically shaped close‐fitting housing. Transmit characteristic...

Object Improve shimming capabilities of ultra-high field systems, with addition of an accessible low-complexity B 0 shim array for head MRI at 7 T. Materials and methods An eight channel B 0 shim coil array was designed as a tradeoff between shimming improvement and construction complexity, to provide an easy to use shim array that can be employed...

Background Absolute quantification of metabolites in MR spectroscopic imaging (MRSI) requires a stable reference signal of known concentration. The Electronic REference To access In vivo Concentrations (ERETIC) has shown great promise but has not been applied in patients and 3D MRSI. ERETIC hardware has not been integrated with receive arrays due t...

Ultra-high field MRI at 7 T can produce much better visualization of sub-cortical structures compared to lower field, which can greatly help target verification as well as overall treatment monitoring for patients with deep brain stimulation (DBS) implants. However, use of 7 T MRI for such patients is currently contra-indicated by guidelines from t...

We introduce wave encoded acquisition and reconstruction techniques for highly accelerated echo planar imaging (EPI) with reduced g-factor penalty and image artifacts. Wave-EPI involves playing sinusoidal gradients during the EPI readout while employing interslice shifts as in blipped-CAIPI acquisitions. This spreads the aliasing in all spatial dir...

To enable concurrent non-invasive stimulation (TMS) and whole-head multimodal imaging (EEG-fMRI), we propose to apply Bexible RF coil technology to build a Erst-of-its-kind TMS compatible integrated multimodal imaging array, the “RF- EEG cap”. The proposed system allows unrestricted positioning of the TMS coil across the entire scalp. We built a 2-...

Purpose Brain imaging exams typically take 10‐20 min and involve multiple sequential acquisitions. A low‐distortion whole‐brain echo planar imaging (EPI)‐based approach was developed to efficiently encode multiple contrasts in one acquisition, allowing for calculation of quantitative parameter maps and synthetic contrast‐weighted images. Methods I...

Metabolic imaging of the human brain by in-vivo magnetic resonance spectroscopic imaging (MRSI) can non-invasively probe neurochemistry in healthy and disease conditions. MRSI at ultra-high field (≥ 7 T) provides increased sensitivity for fast high-resolution metabolic imaging, but comes with technical challenges due to non-uniform B0 field. Here,...

Using Singular Value Decomposition of optimal Stream Functions computed from a database of 100 B0 fieldmaps, a 13-channel cylindrical optimized Multi-Coil Array for shimming of the human brain is built and tested in an experimental setup for field measurement at 7T. Such measurements are compared to expected performances, serving as proof of concep...

Functional magnetic resonance imaging (fMRI) in monkeys is important for bridging the gap between invasive animal brain studies and non-invasive human brain studies. To resolve the finer functional structure of the monkey brain, ultra-high-field (UHF) MR is essential, and high-performance, close-fitting RF receive coils are typically desired to ful...

Purpose B1+ and T1 corrections and dynamic multicoil shimming approaches were proposed to improve the fidelity of high‐isotropic‐resolution generalized slice‐dithered enhanced resolution (gSlider) diffusion imaging. Methods An extended reconstruction incorporating B1+ inhomogeneity and T1 recovery information was developed to mitigate slab‐boundar...

Synopsis gSlider is an SNR-efficient simultaneous multi-slab acquisition that has shown great potential for high-resolution diffusion imaging (DI). In this work, approaches to improve the fidelity of gSlider are proposed. A modified reconstruction which incorporates B1 + inhomogeneity and T1 recovery information was developed and demonstrated to su...

Synopsis gSlider is an SNR-efficient simultaneous multi-slab acquisition that has shown great potential for high-resolution diffusion imaging (DI). In this work, approaches to improve the fidelity of gSlider are proposed. A modified reconstruction which incorporates B1 + inhomogeneity and T1 recovery information was developed and demonstrated to su...

gSlider is an SNR-efficient simultaneous multi-slab acquisition that has shown great potential for high-resolution diffusion imaging (DI). In this work, approaches to improve the fidelity of gSlider are proposed. A modified reconstruction which incorporates B1+ inhomogeneity and T1 recovery information was developed and demonstrated to successfully...

This article considers a new type of integrated multichannel Transcranial Magnetic Stimulator and Magnetic Resonance Imaging (TMS/MRI) system at 3T that is currently being designed. The system will enable unprecedented spatiotemporal control of the TMS-induced electric fields (Efields) with simultaneous rapid whole-head MRI acquisition to record th...

Integrated multichanel TMS system and MRI

Permanent magnet arrays offer several attributes attractive for the development of a low-cost portable MRI scanner for brain imaging. They offer the potential for a relatively lightweight, low to mid-field system with no cryogenics, a small fringe field, and no electrical power requirements or heat dissipation needs. The cylindrical Halbach array,...