Ultrasound speckle tracking method based on gradient optical flow to quantify small longitudinal displacement, shear and longitudinal strain in peripheral nerves

Snoj, Žiga (author), Omejec, Gregor (author), Javh, Jaka (author), Umek, Nejc (author)

Objective: This study aimed to develop, validate and test the clinical feasibility of ultrasound (US) speckle tracking method based on gradient optical flow for quantifying small longitudinal displacements, shear and strain in peripheral nerves. Methods: The speckle tracking method was validated using seven thawed, fresh-frozen isolated cadaveric forearms. Longitudinal motion of the median nerve was captured using a high-frequency 22 MHz linear probe. An air bubble marker was inserted as a reference point for manual measurement comparison. The precision and accuracy of the method were assessed by comparing manual and automatic measurements. Clinical feasibility was tested on eight healthy subjects, measuring the longitudinal displacement of the median nerve during elbow extension and shoulder anteflexion. Results: The method demonstrated linearity, high precision and accuracy, particularly with a backtrace of five frames, reducing the displacement underestimation to 4%. In cadaveric models, the highest shear strain was observed at the nerve-tissue interfaces. In healthy subjects, the mean displacement of the median nerve was 3.3 ± 1.0 mm, with good inter-rater reliability (intraclass correlation coefficient = 0.87). Conclusion: The US speckle tracking method based on gradient optical flow effectively quantifies small longitudinal displacements and shear strain in peripheral nerves, with high precision and accuracy. However, the method could not detect longitudinal strain in nerves within the range of tested displacements. Future studies should investigate its applicability to smaller and deeper nerves and its usefulness in different pathological conditions.

• Language: English
• Keywords: gradient optical flow, high-resolution ultrasound, peripheral nerve displacement, shear strain quantification, speckle tracking
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: Str. 280-287
• Numbering: Vol. 51, iss. 2
• PID: 20.500.12556/RUL-166345
• UDC: 616-07
• ISSN on article: 0301-5629
• DOI: 10.1016/j.ultrasmedbio.2024.10.002
• COBISS.SI-ID: 214411267
• Publication date in RUL: 08.01.2025

Record is a part of a journal

• Title: Ultrasound in medicine & biology
• Shortened title: Ultrasound med. biol.
• Publisher: Elsevier, World Federation for Ultrasound in Medicine & Biology
• ISSN: 0301-5629
• COBISS.SI-ID: 26569984

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: gradientni optični tok, ultrazvok visoke ločljivosti, premik perifernega živca, kvantifikacija strižne deformacije, pegasto sledenje

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: J3-4507
• Name: Razvoj metod v diagnostiki in zdravljenju sindroma karpalnega kanala

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P3-0043
• Name: Molekularni mehanizmi razvoja in delovanja skeletne mišice