Ultrasound Imaging of the Facial Muscles and Relevance with Botulinum Toxin Injections: A Pictorial Essay and Narrative Review

Ultrasound in Aesthetics: Filler and Non-Filler Applications

Ultrasound in aesthetics presents multiple applications in several areas, including diagnosing fillers and non-fillers complications, the performance of ultrasound-guided injections in real-time, and identifying the most common types of cosmetic fillers. Furthermore, this application of ultrasound in aesthetics has become a must for managing aesthetic patients because, to date, this modality is the one that provides the higher resolution among imaging techniques, detailed anatomical information, and blood flow detection, besides showing worldwide availability. This paper aims to review the current applications of ultrasound in aesthetics based on publications from scientific literature and the authors' experience.

Automatic labeling of facial zones for digital clinical application: An ensemble of semantic segmentation models

INTRODUCTION

The application of artificial intelligence to facial aesthetics has been limited by the inability to discern facial zones of interest, as defined by complex facial musculature and underlying structures. Although semantic segmentation models (SSMs) could potentially overcome this limitation, existing facial SSMs distinguish only three to nine facial zones of interest.

METHODS

We developed a new supervised SSM, trained on 669 high-resolution clinical-grade facial images; a subset of these images was used in an iterative process between facial aesthetics experts and manual annotators that defined and labeled 33 facial zones of interest.

RESULTS

Because some zones overlap, some pixels are included in multiple zones, violating the one-to-one relationship between a given pixel and a specific class (zone) required for SSMs. The full facial zone model was therefore used to create three sub-models, each with completely non-overlapping zones, generating three outputs for each input image that can be treated as standalone models. For each facial zone, the output demonstrating the best Intersection Over Union (IOU) value was selected as the winning prediction.

CONCLUSIONS

The new SSM demonstrates mean IOU values superior to manual annotation and landmark analyses, and it is more robust than landmark methods in handling variances in facial shape and structure.

Boosting brain-computer interfaces with functional electrical stimulation: potential applications in people with locked-in syndrome

Individuals with a locked-in state live with severe whole-body paralysis that limits their ability to communicate with family and loved ones. Recent advances in brain-computer interface (BCI) technology have presented a potential alternative for these people to communicate by detecting neural activity associated with attempted hand or speech movements and translating the decoded intended movements to a control signal for a computer. A technique that could potentially enrich the communication capacity of BCIs is functional electrical stimulation (FES) of paralyzed limbs and face to restore body and facial movements of paralyzed individuals, allowing to add body language and facial expression to communication BCI utterances. Here, we review the current state of the art of existing BCI and FES work in people with paralysis of body and face and propose that a combined BCI-FES approach, which has already proved successful in several applications in stroke and spinal cord injury, can provide a novel promising mode of communication for locked-in individuals.

The growing importance of ultrasonography in cosmetic dermatology: An update after the 23rd IMCAS Annual World Congress (2022)

BACKGROUND

Ultrasound (US) has been used for many years in the field of medicine. Many specialties have embraced US as a quick, painless, and relatively inexpensive tool to assist the clinician in determining anatomy, pathology, and aid in diagnostic or therapeutic procedures. US allows for precise mapping of cutaneous and subcutaneous structures in the face, in particular vascular structures. The use of US leads to reduced chances of complications and clinical failures, rendering more safety and high quality.

METHODS

US is considered the first-imaging technique for dealing with fillers and managing their potential complications. US can be deployed for vascular mapping, safe placement of fillers, and directed low-dose hyaluronidase reversal of vascular adverse events. It is a noninvasive imaging modality that provides a good definition for studying the skin, deeper layers, and blood flow in real time. In other words, we go from static to dynamic anatomy. In addition, US can guide with the application of botulinum toxin, in order to define the muscular planes. US may contribute to a more personalized procedure, better cosmetic results, and help to avoid complications. In general, physicians tend to use it for prevention. Last, for research purposes, US examination provides valuable information on the behavior, longevity, and interaction of the filler within the tissues.

CONCLUSION

This new approach for US-guided treatments is a very practical and an effective method in cosmetic dermatology. As doctors, we owe it to our patients to do our best to prevent any harm. We feel that in near future, US will be an essential diagnostic tool in any dermatology or cosmetic doctor's office to both ensure safety and provide legal protection for the professional.

Congenital unilateral lower lip palsy: a case-based review

BACKGROUND

Congenital unilateral lower lip palsy (CULLP), also referred to as congenital asymmetric crying facies (ACF), is a rare condition that causes pronounced depression of the unaffected lower lip when crying, despite symmetric appearance of the mouth and lips at rest. Unlike the acquired form of ACF, CULLP is idiopathic and often involves permanent defect.

METHODS AND RESULTS

We present a case-based review of CULLP, including a thorough analysis of the relevant literature and a discussion of the exemplary case of 5-year-old patient presenting with unilateral facial asymmetry resulting from left-sided facial weakness. The patient was diagnosed with ACF at birth, and documentation from a previous neurologic consultation specifies the root cause of the asymmetry as developmental aplasia of the left depressor anguli oris muscle (DAOM). However, there is no record of electrodiagnostic testing or B-scan ultrasound imaging that would support this conclusion, and the patient's dysarthric speech may suggest lower motor neuron involvement. Botox chemodenervation of the right, unaffected side was recommended to deanimate the contralateral lower lip and achieve facial symmetry, in addition to potentially resolving some of the patient's speech difficulties.

CONCLUSIONS

There are several approaches, both surgical and non-surgical, to the management and correction of CULLP. These include weakening the muscles of the contralateral side or increasing muscular tension on the ipsilateral side, referred to as deanimation and reanimation procedures, respectively.

Ultrasound Imaging of Facial Vascular Neural Structures and Relevance to Aesthetic Injections: A Pictorial Essay

The facial and submental regions are supplied by complicated neurovascular networks; therefore, facial aesthetic injections may be associated with serious adverse events such as skin necrosis and blindness. Pre-injection localization of neurovascular structures using high-resolution ultrasound can theoretically prevent unexpected complications. Therefore, a systematic protocol that focuses on these facial neurovascular structures is warranted. In this pictorial essay, we discuss the sonoanatomy of facial and submental neurovascular structures and its relevance to aesthetic injections. Moreover, we have highlighted the mechanisms underlying potential neurovascular injuries during aesthetic injections.