Angio planewave ultrasensitive imaging (Angio PLUS) as an innovative technique in depicting vascularity of median nerve: a prospective observational study

Assessment of median nerve (MN) microvascularity is critical for early diagnosis of neuropathy, yet conventional techniques like color Doppler flow imaging (CDFI) lack sensitivity for small vessels, while contrast-enhanced ultrasound (CEUS) is invasive. Angio Planewave Ultrasensitive imaging (AP), a novel non-invasive modality, offers high-resolution microvascular visualization, but its application in MN vascularity remains unexplored. To determine the feasibility of Angio Planewave Ultrasensitive imaging (AP) in comparison with color Doppler flow imaging (CDFI) for detection of median nerve (MN) vascularity in healthy volunteers and to explore the correlation between the blood flow distribution of MN on AP and the clinical parameters. 30 healthy volunteers were prospectively enrolled in our study. CDFI and AP were performed to evaluate the vascularity of MN in the wrist level and the mid-forearm level. MN vascularity using Adler’s grading on CDFI and AP were compared, and a new classification of vascular distribution was proposed. Two radiologists performed image review for evaluation of intra- and interobserver agreements. The new vascular types in the wrist level and the mid-forearm level were compared. The correlation of clinical parameters and the new vascular types were analyzed. AP was more sensitive in displaying the vascularity of MN compared with CDFI (p < 0.0001), presenting excellent intra- and inter-observer agreements (k > 0.90) based on the new vascular types. Type I and type II were most frequently detected in the wrist level and the mid-forearm level respectively. There was a weak correlation between the cross-sectional area and vascular distribution at the wrist level and the mid-forearm level (r = 0.290, r = 0.304 respectively, both p < 0.05). AP demonstrated superior sensitivity in visualizing MN vascularity compared to CDFI, with excellent intra- and inter-observer reproducibility using the proposed vascular classification. These findings provide a critical technical foundation for future studies exploring vascular changes in neuropathies and their correlation with clinical outcomes.