ABSTRACT
BACKGROUND: Non-invasive devices for fat reduction involving high-intensity focused ultrasound (HIFU) are attracting attention. HIFU can deliver energy to the desired depth and can ablate subcutaneous adipose tissue (SAT), but purpura and pain may still limit its use. OBJECTIVES: The aim of this study was to investigate the effects of a novel HIFU device for fat destruction with a contact cooling system compared to HIFU without contact cooling. METHODS: A group of three pigs were administered a series of four HIFU treatments with or without contact cooling over a period of 12 weeks. Energy fluence parameters ranged from 60 to 300 J/cm2 . Immediately after the treatment and at 1, 4, and 12 weeks, the tissue was studied by hematoxylin and eosin (H&E), Masson-trichrome, toluidine blue, CD68 staining, and transmission electron microscopy. Three human volunteers also received treatment with this HIFU device with cooling and were evaluated subjectively and objectively by computed tomography (CT). RESULTS: HIFU treatment with a contact cooling decreased the skin surface temperature and prevented epidermal damage. Ecchymosis was observed on the non-cooled area immediately after HIFU treatment, but not on the cooled area. Histological analyses on both areas (cooled and non-cooled) revealed disrupted adipocytes in the treatment area immediately, at 1 and 4 weeks following treatment. Lipophagic histiocytic fat necrosis was evident at 4 weeks. Finally, at 12 weeks all inflammation subsided, and the lobules were markedly atrophied with reduced SAT thickness. The human volunteers experienced reduction of a few centimeter-range reduction in waist circumference after 4 weeks and pain was tolerable without bruising. CONCLUSIONS: HIFU treatment with a cooling system efficiently destroyed adipocytes. This novel HIFU device with an added contact cooling system may provide an effective, safe and less painful treatment as a non-invasive device for fat reduction. Lasers Surg. Med. 48:878-886, 2016. © 2016 Wiley Periodicals, Inc.
