# Stretchable Coils for Low-Field, Portable MRI

> **NIH NIH R21** · MASSACHUSETTS GENERAL HOSPITAL · 2024 · $208,750

## Abstract

Project Summary/Abstract
 The widespread availability of portable Magnetic Resonance Imaging (MRI) scanners that can be
transported to the bedside could have a tremendous impact for critical care and general clinical care in low-
resource settings. To achieve truly portable, point-of-care operation, a low magnetic field strength (<0.1 T) is
considered a prerequisite for both size requirements and safety considerations. However, the main limitation of
low-field MRI is the associated low signal-to-noise (SNR) ratio. The low SNR of these systems results in
significantly inferior image quality compared to conventional MRI. While high SNR is not always necessary to
detect pathology, there may be a high risk of missed findings and misdiagnosis. This is a significant issue that
currently defrays the use of low-field MRI and could ultimately limit the widescale adoption and scale-up of
portable accessible MRI technology.
 One non-invasive method for improving the sensitivity of the MR measurement, is to maximize the receiver
coil sensitivity. Our proposal attempts to achieve this with stretchable receiver caps for brain imaging. The
stretchable coils will adapt to each subject to provide the highest filling factor for the coil and attempt to achieve
body-noise dominance. Instead of using a lossy stretchable conductor, we will use flexible, strategically draped
litz wire on a stretchable cap to construct the single channel receiver coil. The inductance of the coil will
change with each subject due to the change-able diameter and shape. Therefore, we will implement an
external tuning and matching box for “autotuning” the coil. The autotuning system will make use of a compact
PC-controlled vector network analyzer (VNA) to monitor the S-parameters of the coil and output appropriate
voltages to voltage-controlled capacitors (varactor diodes) for adjustable tuning/matching. Our end goal is to
create the optimal brain imaging coil for each individual subject (through adapting the shape and
tuning/matching) with the ultimate goal of improving portable MRI image quality and clinical utility.

## Key facts

- **NIH application ID:** 10906177
- **Project number:** 5R21EB034865-02
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Clarissa Zimmerman Cooley
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $208,750
- **Award type:** 5
- **Project period:** 2023-08-15 → 2026-07-21

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10906177

## Citation

> US National Institutes of Health, RePORTER application 10906177, Stretchable Coils for Low-Field, Portable MRI (5R21EB034865-02). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10906177. Licensed CC0.

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