Clinical Applications of High-Frequency Ultrasound in Filler Identification and Complication Management

The growing use of soft tissue fillers in aesthetic medicine has increased complication rates. High-frequency ultrasound (HFUS) provides real-time imaging of fillers and adjacent tissues, aiding in filler identification, adverse event detection, and complication management. To summarize sonographic features of common soft tissue fillers and emphasize HFUS's role in filler identification, complication diagnosis, and treatment guidance. This review synthesizes recent studies and case reports on HFUS assessment of cosmetic fillers, analyzing ultrasound characteristics of filler materials, related complications, and guided interventions. Different fillers exhibit distinct ultrasound features. Hyaluronic acid (HA) typically appears as well-defined anechoic or hypoechoic pseudocystic areas. Calcium hydroxyapatite characteristically presents as irregular hyperechoic deposits with marked posterior acoustic shadowing. Polymethylmethacrylate demonstrates hyperechoic foci with characteristic comet-tail artifacts, whereas polycaprolactone appears as hypoechoic material containing scattered hyperechoic foci corresponding to suspended microspheres. Poly-L-lactic acid generally presents as hyperechoic subcutaneous deposits during the early post-injection period. HFUS enables accurate filler localization and real-time detection of complications, including nodules, vascular occlusion, and granulomatous reactions, while also supporting targeted ultrasound-guided interventions such as low-dose hyaluronidase injection. HFUS serves as a non-invasive, effective modality for identifying soft tissue fillers and managing complications. Its clinical adoption enhances diagnostic accuracy, therapeutic precision, and patient safety.