# Parallel Excitation Methods for High Field MRI

> **NIH NIH R01** · MASSACHUSETTS GENERAL HOSPITAL · 2020 · $543,076

## Abstract

Abstract
 High field MRI (3T, 7T and above) offers many potential advantages to clinical and scientific
studies, including increased sensitivity and improved image contrast creating the potential for
improved characterization of biological function and anatomy in health and disease. Parallel
transmission (pTx) uses multiple excitation coils driven by independent RF pulse waveforms to
subdivide the transmit field into multiple spatial regions each controlled by a separate transmit
channel. Increasing the number of spatially distinct transmit elements and using temporally
distinct RF pulse waveforms creates spatial degrees of freedom that allow the spatial pattern of
the array to be exploited in the excitation process. Previous pTx work by ourselves and others
has concentrated on the potential to utilize this additional flexibility to move beyond the uniform
slice-select excitation and reduced SAR levels compared to birdcage type excitation. In the
current proposal, we propose a program of translational bioengineering development to widely
impact 3T clinical imaging and facilitate the advance of 7T clinical imaging by developing and
validating individualized medicine to MRI RF safety. We undertake the development of
methods to model the electromagnetics of the individual patient while he or she is in the
scanner to more accurately assess SAR and temperature safety metrics. This addresses a
longstanding weakness in MRI safety whereby current state-of-the-art applies E&M calculations
performed on a supine male body model to, for example, a pregnant patient lying on her side.
We also extend our individualized fast calculations to other unique configurations, such as
quickly identifying metal implants in a pre-scan and including them in the individuals SAR and
Temperature modeling. Successful implementation of such methods potentially allow us to
expand the quality of clinical imaging by providing more slices, higher flip angles, or shorter TR
periods in a wide range of clinical protocols.

## Key facts

- **NIH application ID:** 9954020
- **Project number:** 5R01EB006847-12
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Lawrence L Wald
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $543,076
- **Award type:** 5
- **Project period:** 2007-09-15 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9954020

## Citation

> US National Institutes of Health, RePORTER application 9954020, Parallel Excitation Methods for High Field MRI (5R01EB006847-12). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9954020. Licensed CC0.

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