# Angular Dependency of T1 Relaxation Time in Cerebral White Matter in Ultrahigh Field MRI

> **NIH NIH R03** · UNIVERSITY OF MINNESOTA · 2020 · $77,000

## Abstract

PROJECT SUMMARY
Contrast in magnetic resonance imaging (MRI) scans of the brain are influenced by complex
interactions between water, brain macromolecules and microstructural compenents. The
most commonly used MR relaxation-based contrasts change with magnetic field strength,
because both T1 and T2 MR relaxation times are field dependent. At higher fields inherent
tissue-specific factors, such as bulk magnetic susceptibility due to tissue microstructure
and/or biochemical making, affect relaxation thereby influencing MRI contrast. For efficient
and adequate use of MR images in neuroscientific research and clinical diagnosis, it is
pivotal to understand effects of tissue-related factors on relaxation-based contrasts at clinical
(such as 3 Tesla=T) and ultrahigh field (UHF, 7T or above) MRI.
The thrust of the proposal is to study the angular dependency of T1 relaxation in human
white matter (WM) at 3T and 7T. Our goal is to gain understanding of effects of MR-visible
water on the angular dependency of T1 relaxation in WM. Experiments are designed to
study the role of the magnetic field strength, axonal diameter and magnetization transfer in
the fiber-to-field dependency of MR-visible water and T1 relaxation time. MRI data will be
acquired from healthy adult participants at 3T and 7T. The specific aims of the project are as
follows: AIM 1: to measure the amplitude of the angular dependency of MR-visible water and
T1 relaxation time in WM and study its relationship with WM tracts axonal microstructure,
such as axonal diameter. AIM 2: to study the magnetic field dependency of the amplitude of
MR-visible water and T1 relaxation in WM. AIM3: to study the effects of magnetization
transfer on the amplitude of the angular dependency of MR-visible water and T1 relaxation
time in WM at 3T and 7T.
The project adds to our long-term pursuit to advance understanding of biophysical
underpinnings of MR contrasts in brain images. Our overarching goal is to improve
delineation of tissue morphology by MRI for imaging of normal brain and its disorders in
modern neuroimaging.

## Key facts

- **NIH application ID:** 9983056
- **Project number:** 5R03EB027873-02
- **Recipient organization:** UNIVERSITY OF MINNESOTA
- **Principal Investigator:** MICHAEL GARWOOD
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $77,000
- **Award type:** 5
- **Project period:** 2019-08-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9983056

## Citation

> US National Institutes of Health, RePORTER application 9983056, Angular Dependency of T1 Relaxation Time in Cerebral White Matter in Ultrahigh Field MRI (5R03EB027873-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9983056. Licensed CC0.

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