The utility of HFUS and MRI in dermal fillers evaluation

The utility of High frequency US and MRI in dermal fillers evaluation. Background and objective: many new materials were introduced in the market for cosmetic tissue augmentation claiming to be permanent or long lasting, inert, well tolerated, non migrating and easily removable in the rare event of complication. Patients aren’t always aware of the materials implanted in previous treatments, or may disguise that they have already had a treatment: this make difficult to safely perform further cosmetic procedures as required. Severe complications may show up even years after the subcutaneous injection of dermal fillers. The aim of the study is to describe the use of high frequency ultrasound (HFUS) and MRI to ascertain the site, quantity and type of filler injected in the soft tissue of the face for cosmetic purposes with respect to reliability of the procedure and the analysis costs. . Materials and methods: 45 subjects were enrolled in the study after treatment with temporary or permanent dermal fillers, of these 19 didn’t show complications (Group A) while 26 presented with filler related complications (Group B) as erythema and swelling, lumps, cutaneous blisters and ulceration. The composition of filler was diverse: in Group A were included pts with hyaluronic acid (7), Collagen (5), Polylactic acid (1), Polyacrylamide hydrogel (3), polyalkylimide (2), synthetic calcium hydroxyl apatite (1), silicone (2). Group B included pts with hyaluronic acid (2), collagen (2), Polylactic acid (1), Polyacrylamide hydrogel (3), Polyalkylimide (4), synthetic calcium hydroxylapatite(1), polymethylmethacrylate with collagen (3), Polyvinyl alcohol (2), DEAE Sephadex and hyaluronic acid (2), silicone (4), unknown (6). 2 pts in Group A and 5 pts in Group B were treated with multiple fillers. All the sample underwent high frequency US and MRI examinations of the face seeking the presence, the site and quantity of dermal filler, its nature, and the presence of granuloma or fluid collections. Results: In all pts but 2, it was possible to detect the filler at the site of injection, even in pts without its clinical evidence. HFUS and MRI consented to discover a silent inflammatory reaction, otherwise unsuspected and to diagnose granulomatous reactions or abscess formation. Both techniques consent to precisely measure the dimension of the dermal fillers, and to evaluate its extension and depth in the soft tissue of the face. HFUS images differed according with the temporary or permanent nature of the filler. HFUS has proved to be an useful, non invasive tool for the identification of the presence and type of the filler injected. MRI clearly determined the site of dermal fillers, allowing its precise anatomical location considering the anatomical landmarks on axial and coronal scans. Co operation between radiologists and plastic surgeons is mandatory in order to obtain the best diagnostic results, aiming to offer optimal and customized cares to patients presenting with a clinical history of dermal fillers or with complications related to the treatment.