Hyaluronic Acid Filler in HIV-Associated Facial Lipoatrophy: Evaluation of Tissue Distribution and Morphology with MRI

OBJECTIVE: This prospective observational study evaluated magnetic resonance imaging (MRI) findings of hyaluronic acid (HA) injections used for the correction of HIV-associated facial lipoatrophy. METHODS: Ten consecutive males underwent subdermal HA injection (mean 1.3 ± 0.6 ml per side) and MRI examinations prior to and then 1, 6 and 12 months after injection. Two radiologists blinded to the clinical data assessed morphologic and quantitative changes. RESULTS: MRI revealed HA deposition in the subdermal and deep fat compartments. A significant HA volume increase was observed 1 month after injection (mean increase 331%, p < 0.0001) as compared to the injected amount. No volume reduction occurred at 12 months (p = 0.9961). The measured bound water content did not change (p > 0.9991), whereas skin thickness and tissue vascularization increased during the first 6 months (p = 0.01). CONCLUSION: Our data show that the cosmetic results of HA injections are caused by water binding in the deep facial fat and by a transient increase in vascularization and skin thickness.