Simplified MR Neurography Protocol for Pudendal Neuropathy Using a 1.5-Tesla Magnet and Black Blood sequence: Technique, Grading system and Validation
Main Article Content
Abstract
Background: Pudendal neuropathy diagnosis currently relies on advanced MR neurography using 3-Tesla magnets, 3D imaging, and contrast enhancement. Despite these innovations, diagnostic accuracy remains uncertain.
Purpose: To validate a simplified MR imaging protocol and grading system for pudendal nerve damage using a conventional 1.5-Tesla magnet without contrast.
Materials and Methods: We retrospectively analyzed 100 consecutive patients (60 females, 40 males; mean age: 48 years, 95% CI: 45.1–50.9) with suspected pudendal neuropathy (Nantes criteria) examined between January and May 2024. MR neurography was performed using a 1.5-T horizontal magnet and phased-array coil in two phases: (1) T2-weighted turbo spin echo sequences in multiple planes; (2) proton density SPAIR sequences with fat and flow suppression. Two blinded radiologists independently assessed signal hyperintensity in Alcock’s canal using a 0–3 brightness scale. Discrepancies were resolved by a third expert. Inter- and intra-observer agreement was calculated via weighted kappa (WK).
Results: Of 87 frames with abnormalities, 13 were grade 0, 33 grade 1, 37 grade 2, and 17 grade 3. Intra-observer agreement was excellent (WK = 0.875 and 0.920), and inter-observer agreement was high (WK = 0.78). Observer 3 resolved 30 discrepancies, mostly minor (27 cases with one-point difference). Major discordance occurred in only 3 cases.
Conclusion: This simplified, contrast-free MR protocol using a 1.5-T magnet shows high reliability even among non-specialized readers and may offer a practical tool for pudendal neuropathy assessment, especially in resource-limited settings.
Article Details
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