Can Abnormal Pudendal Nerve Be Detected and Evaluated Using MR DWI ADC Values - A Preliminary Study
J James*, PhD, A Jawahar, MD, Department of Radiology, Loyola University Medical Center, Maywood, IL
Presentations
MO-C930-IePD-F9-1 (Monday, 7/11/2022) 9:30 AM - 10:00 AM [Eastern Time (GMT-4)]
Exhibit Hall | Forum 9
Purpose: The capability of detecting pudendal nerves from an adjacent vessel is a challenging task in MRI due to spatial resolution limitations and its inherent small caliber. Aim of this study is to evaluate if quantitative Apparent-Diffusion-Coefficient (ADC) values can aid in detection of the abnormal pudendal nerve and help distinguish from normal vessels in cases of absent or mild neuropathy.
Methods: A retrospective review of patients >18 years (n=17) with chronic pelvic pain and clinical symptoms of pudendal neuralgia who underwent institutional MR pelvis neurography protocol was performed. MR protocol included sagittal-T2, axial 3D-DESS, T2-FS, T1, and DWI (b-values: 50,400,800 s/mm²) with total scan time: 20min. Mean ADC values from MR-DWI were noted from ROIs placed by the radiologist on the abnormal nerve (identified on DESS, T2-FS and/or DWI-ADC using DynaCAD). ROIs were placed on single and multiple slices along the course of the nerve, and then further normalized with bladder to account for any signal fluctuations.
Results: Mean ADC ± standard error from the abnormal pudendal nerves were 1343.98±54.14 (single slice) and 1294.73±52.81 (multiple slice) (x10⁻⁶mm²/s) respectively, indicating restricted motion, possibly due to the presence of abnormal nerve fibers. The nerves were confirmed by quantified ADC values in comparison to adjacent vessels with higher ADC (~2000 x1010⁻⁶mm²/s). No statistically significant difference between ADCs from single vs. multiple slices (p > 0.05) was observed. Normalized ADC of pudendal nerves to bladder was as follows: single slice: 0.44±0.02 and multiple slices: 0.39±0.02. Limitations included small sample size and nerve not detectable on ADC maps when normal or with mild neuropathy.
Conclusion: This study shows that quantitative ADC values can be used as a potential marker to detect and distinguish the challenging abnormal pudendal nerve in patients and aid in treatments with nerve block injections typically done without precise image guidance.
Keywords
Diffusion, MRI, Quantitative Imaging
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