## 3 Results  
From the results of our systematic review, it appears that there are few studies (\(n=22\)) assessing complications from HIFU treatment in esthetic procedures over a sixteen-year period. Of these studies, some reported one or two cases with rare complications and others reported more generally mild adverse effects that are transient and reversible, without, however, reporting the exact percentage of patients. From these few studies, we summarized all the mild and serious complications that have been recorded so far, and one of the first findings was that all patients who experienced complications did not have any particular characteristics, apart from more sensitive and dehydrated skin. However, all the studies had a shared characteristic in that the wrong diagnosis and application by the operator caused the complication. Another result of this review was that none of the other HIFU devices (except micro-focused ultrasound with visualization) provide visualization or verification of reaching the superficial myofasical system. Although HIFU devices are marketed for indications similar to those of MFU-V, studies suggest that these indications are limited [8]. These studies with MFU-V/HIFU report that real-time visualization and the ability to detect coupling contribute to efficacy and prevention of complications. Features such as tight thermal regulation, large focal gain, and short beam length contribute to the safety and efficacy of HIFU application, but they were not collectively found in any of the HIFU devices, except for MFU-V. Careful selection of the parameters in HIFU devices (e.g., fluency, etc.) will minimize any adverse effects [6; 8]. Only two of the twenty-two studies that were included in this review reported complications from MFU-V, which are analyzed in the following section. However, one of the major advantages of macro- and micro-HIFU treatment is the immediacy of initial results. Studies have shown that the characteristics of the HIFU's headpiece and the selected fluency (J/cm\({}^{2}\)) are the most important device parameters, and these will determine the outcome in skin or fat tissue. Many patients notice improvements in skin texture and firmness immediately after their first session. However, the full effects of the treatment unfold progressively over time due to the body's natural wound-healing response and collagen remodeling. The most significant esthetic improvements typically become apparent between 90 and 180 days following the procedure [1]. The longevity of these results varies depending on individual biological responses, but in general, the benefits of HIFU treatment can last for up to 18 months [1,8]. A recent systematic review assessing the effectiveness of HIFU utilized the Global Esthetic Improvement Scale (GAIS) as a measurement tool. The findings from this review indicated that approximately 88% of patients who underwent HIFU treatment experienced some degree of visible enhancement in skin laxity and contouring [4]. Furthermore, studies suggest that HIFU is particularly well suited for non-obese individuals who are looking for a moderate yet noticeable reduction in localized fat deposits. Compared to other non-invasive fat reduction technologies (e.g., radiofrequency, laser, cavitation, etc. ), HIFU stands out as the only method capable of delivering substantial results after a single treatment session. In the United States, HIFU has received regulatory approval for fat reduction alongside other non-invasive procedures, including radiofrequency, low-level laser therapy, and cryolipolysis. However, among these techniques, HIFU remains one of the most widely regarded solutions due to its high efficacy and reduced likelihood of complications. Unlike traditional surgical interventions such as lipoplasty, HIFU treatments do not require anesthesia, incisions, or prolonged recovery periods. Early clinical data support the effectiveness and safety of HIFU for fat reduction and body contouring.