Can DTI Evaluate Lumbosacral Plexus Nerve Integrity, and What can this Tell us About Lower Urinary Tract Dysfunction? A Narrative Review.

PURPOSE OF REVIEW: Peripheral neuropathy affecting the lumbosacral plexus (LSP) is a potential contributor to "idiopathic" lower urinary tract dysfunction (LUTD), yet objective methods to assess peripheral nerve integrity in vivo remain limited. This narrative review evaluates the feasibility of diffusion tensor imaging (DTI) in assessing LSP microstructural integrity and explores what this may tell us about lower urinary tract dysfunction.

RECENT FINDINGS: Twelve studies met inclusion criteria from 91 screened abstracts. All studies successfully imaged and quantified sacral nerve microstructure using DTI parameters including fractional anisotropy (FA), mean diffusivity (MD), and apparent diffusion coefficient (ADC), demonstrating the technical feasibility of DTI across independent centres. Five case-control studies were identified, of which 4/5 included populations with pathologies known to result in LUTD and demonstrated significant differences in DTI parameters between patient and control groups within individual studies. However, findings are limited by small study cohorts, heterogeneous imaging protocols, and a lack of standardised lower urinary tract outcome measures across included studies. DTI can quantify the microstructural properties of peripheral nerves in the LSP and demonstrates consistent differences between patients with LUT dysfunction and controls. Therefore, this work supports a potential role for DTI to evaluate the contribution of peripheral neuropathy in patients with "idiopathic" LUT symptoms.