MRI in detecting facial cosmetic injectable fillers

Background: Despite being considered a non-invasive procedure, injections can cause adverse outcomes including infections, overfilling, asymmetry, foreign body granulomas, and reactions that lead to scarring. Complications may be associated with the procedure itself, the physician's technique, and/or the type of agent injected. In these instances, it is important to be able locate and identify the substance used. This study investigated the viability of using MRI to correctly identify injected substances, their symmetry of distribution, and related complications. Methods: Fourteen patients with suspected injectable filler complications were identified by our institution's plastic surgery service. All subjects were scanned with MRI, using highly specific face-oriented sequences at high resolution with small field of view and thin slices across the axial and coronal planes by T1 Dixon non-contrast, T2 Dixon, and T1 Dixon after gadolinium injection. Two independent and blinded radiologists evaluated the images and reported (1) the likely injected substance, (2) symmetry, and (3) complications. These radiological results were compared against clinical data provided by the plastic surgery service. Results: Ten patients (83 %) presented objective injectable complications: 4 had abscess, 4 granulomata, and 2 had allergic reactions to the injected substance. The Fleiss Kappa for inter-rater agreement on substances was 0.80. Asymmetry was identified in six patients (50 %) with a Kappa between radiology evaluators of 1. MRI characteristics of these common fillers are summarized in table form. Conclusions: Given the growing awareness among referring physicians of the value of dedicated facial MRI, utilization of this imaging technique may lead to discovery of the injected substance's true identity, evaluation of symmetry and/or complications.