Treatment of Gastrocnemius Muscle Hypertrophy with Botulinum Toxin Injection Followed by Magnetic Resonance Imaging Assessment and 3-Dimensional Evaluation

Background: Hypertrophy of the gastrocnemius muscle is considered to be a hindrance to lower leg beauty in the Asian aesthetic market. A noninvasive technique that has been gaining recognition involves botulinum toxin A injection; however, there are no proper guidelines or standardized protocols for the administration of botulinum toxin to correct gastrocnemius hypertrophy. Objectives: This study sought to determine the most effective botulinum toxin injection method for correcting the contour of the lower leg calf, as well as to determine the dose that can produce the maximum effect in meeting the demands of the physician and patient. Methods: Eighteen female patients aged between 18 and 35 years were enrolled in this study from January 2015 to July 2015. Two injection methods were compared: (I) 48 injection points with a distance of 2 cm between every point; and (II) 10 injection points. Magnetic resonance imaging examinations were conducted at baseline prior to treatment and at one month and 6 months after treatment. A 3-dimensional study was performed to analyze the volumetric changes. Results: The most effective and significant treatment method for hypertrophic gastrocnemius muscle was the 48-point method (scattering injection). Following injection, this method exhibited a significant level of satisfaction with outcome. Conclusions: Our study reveals that injection dosage and method have a strong relationship with achieving a better contouring result. Level of Evidence: 3.