Evaluation of Peripheral Nerve Injury According to the Severity of Damage Using 18F-FDG PET/MRI in a Rat Model of Sciatic Nerve Injury

Abstract

Reports suggest a high incidence of nerve injuries, and diverse methods, such as two-point discrimination and the pin prick test, have been attempted to evaluate the severity of nerve damage. However, these tests rely on subjective sensations and may not accurately represent the damaged area. A previous experiment revealed that 18F‑FDG positron emission tomography/magnetic resonance imaging (PET/MRI) detect peripheral nerve damage. This study aimed to assess peripheral nerve damage according to severities of damage using 18F-FDG PET/MRI in a rat sciatic nerve. Eighteen rats were divided into three groups: 30-second (G1), 2-minute (G2), and 5-minute (G3) crushing injury groups. The severity of nerve damage was measured in the third week after the crushing injury using three methods: revised withdrawal threshold (RevWT)), standardized uptake values ratio on PET/MRI (SUVR), and immunohistochemistry (intensity ratio (IntR)). There were significant differences between G1 and G3 in both SUVR and IntR. There were no significant differences in both SUVR and IntR between G2 and G3 and no significant differences in RevWT among the three groups. There was a significant difference in SUVR but no significant difference in IntR between G1 and G2. Although PET/MRI did not show results consistent with the immunohistochemistry in all respects, this study demonstrated that the severity of nerve damage as assessed by PET/MRI increased with a longer crushing time. PET/MRI showed potential as an objective diagnostic tool in this peripheral nerve injury model. If research is supplemented through further experiments, PET/MRI can be used as an effective diagnostic modality.