# Zero Echo Time Imaging of Knee Joint

> **NIH NIH R21** · NEW YORK UNIVERSITY SCHOOL OF MEDICINE · 2021 · $217,027

## Abstract

PROJECT SUMMARY
Human knee joints are composed of many different tissues including articular cartilage, calcified cartilage,
menisci, ligaments, tendons and bone all of which are important for the health of the joint. Recent research
suggests that osteoarthritis (OA) is not just a disease of hyaline cartilage, but rather of the entire joint. Several
researchers have demonstrated that the T1ρ relaxation time is more sensitive to proteoglycan (PG) content of
the cartilage, while T2 relaxation time is more sensitive to collagen orientation, integrity of network and
hydration. The short T1ρ menisci, calcified cartilage, tendons, and ligaments are integral part of joint
biomechanics and abnormalities in these tissues may impact joint degeneration and onset of OA. Therefore,
quantitative evaluation of relaxation times in these tissues may provide sensitive biochemical markers for early
OA diagnosis, and disease progression. However, conventional T1ρ-MRI sequences (e.g., GRE and FSE
readouts) are limited value in detecting early macromolecular changes in semi-solid short T1ρ tissues or tissue
components such as menisci, ligaments and tendons. Most of the knee joint structures, including menisci,
ligaments and tendons have both dominant short (bound/restricted water associated with collagen and/or
proteoglycans) and minor long (less restricted/free water associated with macromolecules) components.
Therefore, there is a significant need for reliable, non-invasive, time efficient, ZTE-based biexponential 3D-T1ρ
imaging sequence for quantitative assessment of semi-solid structures in the knee joint that could detect the
early biochemical changes in extracellular matrix (ECM) with short and long relaxation components and their
corresponding fractions.
The overarching goal of this R21 proposal is to develop, optimize, and translate ZTE (PETRA)-based
biexponential 3D-T1ρ imaging pulse sequence for improved quantitative assessment of morphological and
biochemical characterization of semi-solid short T1ρ structures in the knee joint (menisci, ligaments and
tendons) on a standard clinical 3T scanner employing multicoil compressed sensing (CS).

## Key facts

- **NIH application ID:** 10075231
- **Project number:** 5R21AR075259-02
- **Recipient organization:** NEW YORK UNIVERSITY SCHOOL OF MEDICINE
- **Principal Investigator:** Ravinder Regatte
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $217,027
- **Award type:** 5
- **Project period:** 2020-01-01 → 2022-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10075231

## Citation

> US National Institutes of Health, RePORTER application 10075231, Zero Echo Time Imaging of Knee Joint (5R21AR075259-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10075231. Licensed CC0.

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