High-Frequency Ultrasound Imaging Findings of Different Mental Injectable Soft Tissue Fillers

Background In recent years, the use of mental injectable soft tissue fillers is popular. However, some fillers are difficult to distinguish from pathological tissue, and some non-absorbable fillers need to be removed in time. Therefore, identification of different fillers is important. In this study, we summarized the ultrasonic manifestations of different mental injectable soft tissue fillers to provide references for clinical practice. Methods We screened the mental ultrasound images from November 2014 to November 2021 in the Plastic Surgery Hospital of Chinese Academy of Medical Sciences, identified different filling injection materials, and summarized and classified the ultrasonic characteristics of each filling material. Results A total of 244 cases were included, involving 62 cases of hyaluronic acid, 126 cases of polyacrylamide hydrogel, 19 cases of growth factor, 16 cases of calcium hydroxyapatite, 15 cases of silicone oil and 6 cases of fat. The ultrasonic manifestation of hyaluronic acid was anechoic area, which could be divided into six types according to the distribution characteristics. The ultrasonography of polyacrylamide hydrogel showed fine punctate echo, which could be divided into nine types. The ultrasonographic appearance of growth factor was similar to the echo of the surrounding tissue, and the boundary was not clear. Calcium hydroxyapatite was characterized by uneven hyperechoic area, which was spread in the tissue space, with unclear boundary with surrounding tissues. Sonographic patterns of silicone oil were hyperechoic and cloudy on high-frequency ultrasound. The deep tissue and periosteum layer were not clear. Transplanted fat showed isoechoic area or uneven low-echo area, with clear boundary and peripheral adipose tissue acoustic enhancement. Conclusions High-frequency ultrasound is safe and reliable for identification and typing of chin filling injection materials, which can be applied in clinical practice. Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .