Advancing dermatology with ultrasonography: a review on filler differentiation

Abstract

Dermal fillers play a significant role in nonsurgical facial rejuvenation, including facial contouring and addressing concerns such as volume loss, rhytides, and scars. However, patients often fail to provide precise details about their filler procedures, including the injection site, depth, or the specific type of filler used. Ultrasonography can be a valuable tool in assessing the type of filler, injection site, effectiveness, and the need for extraction in cases of complications. A literature review was conducted by searching the terms “dermal fillers” and “ultrasonography” on PubMed, supplemented by a manual search. A total of 20 articles were included for synthesis in this review along with some references from the included articles. Additionally, we incorporated original ultrasonographic images of various dermal fillers, obtained directly from our patients. This review explores the classification and characteristics of available dermal fillers, the challenges associated with their use, the role of ultrasonography in preventing complications, and the ultrasonographic features of different dermal fillers. Most permanent fillers, including polymethylmethacrylate (PMMA), poly-L-lactic acid (PLLA), polyacrylamide, silicone, silicone oil, and autologous fat, appear hyperechoic on ultrasonography. Due to their non-degradable nature, their size and shape remain constant over time. In contrast, non-permanent fillers typically exhibit hypoechogenicity on ultrasonographic imaging. A distinguishing feature of non-permanent fillers is their gradual decrease in size, which can be observed over time as they degrade. Ultrasonography is a reliable tool for detecting dermal filler injections in patients and assessing the filler type, injection site, effectiveness, and the need for extraction in cases of complications. Sonographic evaluation of dermal fillers is based on various parameters, including echogenicity, texture, shape, quantity, borders, artifacts, diameter, anatomical location, internal characteristics, and changes over time.