# Magnetic resonance and ultrasound imaging as biomarkers for detection and monitoring of Parsonage-Turner Syndrome (PTS)

> **NIH NIH R21** · HOSPITAL FOR SPECIAL SURGERY · 2021 · $100,475

## Abstract

Project Abstract
 Parsonage-Turner Syndrome (PTS) is characterized by marked weakness in the
distribution of one or more upper extremity peripheral nerves and typically ensues following an
intense pain prodrome. PTS likely arises from an immune-mediated, inflammatory response to a
stressful trigger (e.g. exertion, viral infection), but its specific pathogenesis is unknown. There is
a significant burden of disability in PTS, with up to two-thirds of patients reporting chronic pain
and/or persistent weakness.
 Recent electrodiagnostic and imaging research by our group and others has localized
PTS lesions to brachial plexus branches and more peripheral nerves. Using high-resolution MRI
and ultrasound (US) techniques, we routinely identify intrinsic, ‘hourglass’ constrictions (HGCs)
of involved nerves or nerve fascicles and detect denervation changes in muscles they supply.
 There is no currently accepted treatment or published randomized, controlled trial
evaluating immunomodulatory therapy for PTS, with only a few retrospective reports of
improvement with steroids and/or intravenous immunoglobulin (IVIg). This is attributed to the
absence of a validated disease biomarker for PTS, with the diagnosis currently hinging on the
clinical presentation. In recalcitrant cases, surgical microneurolysis of the HGC is sometimes
recommended. Precise, pre-operative imaging localization of HGCs at our institution has
facilitated targeted microneurolysis in recalcitrant cases, with positive early results. Pre-
operative localization reduces potential morbidity associated with a time-intensive, extensive
nerve exploration and the possibility of missing pathology.
 This research plan aims to understand the natural course of imaging and serologic
findings in PTS and to determine if they can serve as non-invasive markers of motor and overall
functional recovery. Subjects will undergo MRI and US of their upper extremities, and HGC
findings will be correlated with pain scores, muscle strength, electrodiagnostic testing, serologic
inflammatory markers, and patient reported outcome measures, all obtained upon initial
evaluation and at follow-up intervals of 3 and 6 months. We will also evaluate MRI as a potential
quantitative biomarker of muscle denervation that can be used to predict patient outcomes.
 Validated disease biomarkers would facilitate a subsequent randomized trial comprising
medical therapy (e.g. steroids, IVIg) or surgical microneurolysis of HGCs. Early identification of
PTS cases involving nerves that have limited or no potential for reinnervation (because of
constrictions) may ultimately increase the success of microneurolysis.

## Key facts

- **NIH application ID:** 10132430
- **Project number:** 5R21TR003033-02
- **Recipient organization:** HOSPITAL FOR SPECIAL SURGERY
- **Principal Investigator:** Darryl Sneag
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $100,475
- **Award type:** 5
- **Project period:** 2020-04-01 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10132430

## Citation

> US National Institutes of Health, RePORTER application 10132430, Magnetic resonance and ultrasound imaging as biomarkers for detection and monitoring of Parsonage-Turner Syndrome (PTS) (5R21TR003033-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10132430. Licensed CC0.

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