Diagnostic Accuracy of Ultrasound in Vasculitis - A Systematic Review and Meta- analysis

Abstract

Background: Vasculitis encompasses inflammatory disorders of blood vessels where early recognition is vital to prevent complications. Tissue biopsy, the traditional diagnostic standard, is invasive and subject to sampling error. Ultrasound has emerged as a non-invasive alternative, but interpretation is challenged by variability in protocols, operator expertise, and treatment effects.

Objectives: To systematically review and meta-analyze the diagnostic accuracy of ultrasound in vasculitis compared with biopsy or clinical diagnosis.

Methods: This systematic review and meta-analysis followed PRISMA-DTA guidelines (protocol registered in PROSPERO). Eligible studies included adults undergoing cranial and/or extracranial ultrasound. A bivariate random-effects model was used for pooled estimates. Risk of bias was assessed with QUADAS-2, and certainty of evidence with GRADE.

Results: Nineteen studies met inclusion. Pooled sensitivity was 0.85 (95% CI, 0.81–0.89) and specificity 0.95 (95% CI, 0.92–0.97). Extended vascular protocols improved sensitivity compared with cranial-only imaging, while specificity remained high. Sensitivity declined with delayed imaging after immunosuppressive therapy. Operator expertise strongly influenced results. HSROC analysis confirmed robustness, and Deeks’ funnel plot showed no significant asymmetry (p = 0.05).

Conclusions: Ultrasound demonstrates excellent specificity and consistent sensitivity for diagnosing vasculitis. Wider adoption of extended protocols and specialized training may reduce reliance on invasive biopsy in clinical practice.