The influence of evaluator experience, dynamic versus static ultrasound image interpretation, and probe frequency on fascicle differentiation

Pušnik, Luka (author), Winter, Natalie (author), Cuzak, Maks Matej (author), Serša, Igor (author), Umek, Nejc (author), Snoj, Žiga (author), Omejec, Gregor (author)

Purpose: To determine the influence of evaluator experience, dynamic versus static ultrasound (US) image interpretation, and probe frequency on fascicle differentiation. Methods: Evaluator experience and dynamic versus static US image interpretation were assessed on 12 cadaveric forearms. Median nerves were scanned using a 23-MHz US probe, followed by nerve excision and high-field magnetic resonance imaging (MRI) at 9.4-T. Five independent evaluators with different experience levels delineated fascicles twice, using static and dynamic US images. Delineations were compared with high-field MRI. The influence of probe frequency was evaluated on 12 median nerves of healthy volunteers. Median nerves at wrist were scanned using 14-, 18-, 24-, and 70-MHz US probes. Images were cross-referenced, and fascicle counts were compared relative to the highest-frequency probe. Results: Dynamic imaging improved fascicle differentiation by 27.6% to 51.2% compared to static (P < .001), with a greater benefit for less experienced evaluators. The most experienced evaluator identified on average 62.3% more fascicles in dynamic assessment compared to the least experienced. The 70-MHz probe showed the highest mean fascicle count (27.6 ± 3.7), while 24-, 18-, and 14-MHz probes differentiated 26%, 46%, and 63% fewer fascicles, respectively (P <. 0001). Conclusions: Fascicle differentiation improves significantly with evaluator experience, using dynamic US image interpretation, and higher probe frequency. These findings support the clinical utility of ultrahigh-frequency US for detailed evaluation of superficial nerves. Clinical relevance: Experience and dynamic image interpretation are important for reliable fascicle recognition and to minimize misinterpretation. Ultrahigh-frequency US probes substantially improve fascicle differentiation, but their limited penetration requires careful selection of probe frequency based on nerve depth.

• Language: English
• Keywords: differentiation, experience, fascicle, image analysis, magnetic resonance microscopy, probe, ultrasonography
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 9 str.
• Numbering: Vol. 51, iss. 9
• PID: 20.500.12556/RUL-186750
• UDC: 616-07
• ISSN on article: 1531-6564
• DOI: 10.1016/j.jhsa.2026.04.004
• COBISS.SI-ID: 281469443
• Publication date in RUL: 04.09.2026

Record is a part of a journal

• Title: The Journal of hand surgery
• Shortened title: J. hand surg.
• Publisher: Elsevier, American Society for Surgery of the Hand
• ISSN: 1531-6564
• COBISS.SI-ID: 3614740

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: diferenciacija, izkušnja, živčni snopič, mišični snopič, slikovna analiza, magnetnoresonančna mirkoskopija, sonda, ultrasonografija

Projects

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

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: N3-0256
• Name: Spremembe nevro-mišično-fascialnega sistema pri sladkorni bolezni analizirane s 3D mikroskopijo in biomehanskimi testi