Related Experiment Video
Updated: Jun 11, 2025
Fabrication of the Composite Regenerative Peripheral Nerve Interface C-RPNI in the Adult Rat
Published on: February 25, 2020
Magnetic Resonance Imaging appearance of regenerative peripheral nerve interface
Yoav Morag1, Theodore A Kung2, Samer Soussahn1
1Musculoskeletal Imaging Division, Department of Radiology, University of Michigan, Ann Arbor, MI, United States.
Purpose:
To describe the MRI appearance of regenerative peripheral nerve interface (RPNI) and the potential association between the MRI appearance and RPNI revision.
Material And Methods:
A retrospective assessment was undertaken of the MRI appearance of RPNIs performed at our institution between 1/1/2010 and 7/29/2023 with clinical correlation.
Results:
Fourteen patients (8 men and 6 women, age range 31-80 years, median age 51 years) with technically adequate MRI of RPNIs were included in this study including 5 patients with below knee amputation with 5 tibial and 4 common peroneal nerves RPNI, 8 patients with above knee amputations (AKA) with sciatic RPNIs, and 1 patient following forequarter amputation with a brachial plexus RPNI. Two patients underwent revision RPNI surgery thrice (AKA-sciatic nerve) for a total of 6 RPNI revisions. On T1 weighted sequences, all RPNIs were isointense to the muscle and blended with the surrounding scar and muscle tissues whereas on T2 weighted sequences, all RPNIs were hyperintense in signal compared to the muscle. All but 1 RPNI underwent post contrast enhancement in variable patterns. No statistically significant difference in MRI appearance was found between RPNIs with or without a following RPNI revision surgery.
Conclusion:
RPNI on MRI typically have a bright and intermediate signal on T2 and T1 weighted sequences, respectively, and typically undergo postcontrast enhancement in variable patterns without a statistically significant difference between the cases with and without follow-up RPNI revision. However, enhancement of RPNI should not be misconstrued as pathological.
Insights
Regenerative peripheral nerve interfaces (RPNIs) appear bright on T2 and intermediate on T1 MRI sequences. Their appearance on MRI does not significantly differ between RPNIs with or without revision surgery.
Area of Science:
- Radiology
- Neurosurgery
- Medical Imaging
Background:
- Regenerative peripheral nerve interfaces (RPNIs) are crucial for restoring nerve function after amputation.
- Understanding the imaging characteristics of RPNIs is important for clinical management.
- Magnetic resonance imaging (MRI) offers detailed visualization of soft tissues, including RPNIs.
Purpose of the Study:
- To characterize the MRI appearance of RPNIs.
- To investigate potential associations between MRI findings and the need for RPNI revision surgery.
Main Methods:
- Retrospective review of MRI scans of RPNIs performed between 2010 and 2023.
- Clinical correlation of imaging findings with surgical history.
- Analysis of RPNI appearance on T1-weighted, T2-weighted, and post-contrast sequences.
Main Results:
- RPNIs typically show isointensity to muscle on T1-weighted images and hyperintensity on T2-weighted images.
- Most RPNIs demonstrated variable post-contrast enhancement.
- No statistically significant difference in MRI appearance was observed between RPNIs that underwent revision surgery and those that did not.
Conclusions:
- RPNIs exhibit characteristic signal intensities and enhancement patterns on MRI.
- The typical MRI appearance of an RPNI should not be mistaken for pathology.
- MRI findings did not reliably predict the need for RPNI revision in this cohort.
