Superb microvascular imaging enhances detection of microvascularity in plantar fasciosis: a clinical correlation study.

Abstract

Objective: To evaluate superb microvascular imaging (SMI) for detecting microvascularity in chronic plantar heel pain and to assess its clinical correlation in comparison with grayscale ultrasound and conventional Doppler, using a standardized clinical diagnosis as the reference standard.

Materials and methods: In this prospective study, 29 patients (58 fasciae) with bilateral plantar fasciosis and 30 matched asymptomatic controls (60 fasciae) underwent ultrasound examinations. Assessments included grayscale parameters (thickness > 4 mm, swelling hypoechogenicity), color/power Doppler, and SMI. Pain and function were evaluated using the VAS and FAOS-derived impairment scores. Discriminative ability was assessed via receiver operating characteristic (ROC) curves.

Results: Symptomatic fasciae had significantly greater fascial thickness (5.02 ± 1.29 mm vs. 3.27 ± 0.56 mm, p < 0.001) and exceeded 4 mm in 82.8%/9.3% (right/left) versus 6.7%/10.0% of controls. Color Doppler detected no signals; power Doppler identified flow in 10.3% of symptomatic fasciae. SMI detected microvascular flow in 41.4%/44.8% (right/left) of symptomatic fasciae versus none (0%) of asymptomatic control fasciae (p < 0.001). SMI-detected vascularity showed a moderate association with clinical disease status (right r = 0.494; left r = 0.510; p < 0.001). ROC analysis demonstrated good discriminative ability for fascial thickness (AUC = 0.886) and fair performance for SMI (AUC = 0.707), both outperforming power Doppler (AUC = 0.603).

Conclusion: SMI is substantially more sensitive than conventional Doppler for detecting microvascularity in plantar fasciopathy. However, grayscale fascial thickness retained the highest single-test discriminative ability, and many symptomatic fasciae remained SMI-negative. Therefore, SMI should be considered a complementary vascular assessment rather than a stand-alone diagnostic test. Larger multicenter studies are required to define its routine clinical role.