Application of magnetic resonance imaging and ultrasonography to preoperative evaluation of masseteric hypertrophy

Bilateral temporalis hypertrophy

“…MRI scanning is a recognized method of evaluating muscle hypertrophy and is used in preference to CT scanning. 9 Reduction in muscle bulk was achieved within 4 weeks of botulinum toxin treatment. Follow-up is recommended to monitor any recurrence of muscle hypertrophy and the need for further medical therapy.…”

“…Temporalis muscle hypertrophy is regarded as reactive in nature, but may be idiopathic 6,7 . Traditionally, surgical reduction was the treatment of choice for correction of muscle hypertrophy in the maxillofacial region 8,9 . Medical management utilizing botulinum toxin A, has become the treatment of choice and has been used successfully to correct temporalis and masseteric hypertrophy 2,3,4 .…”

The Use of Ultrasound in the Investigation of the Muscles of Mastication

“…However, it offers a potential advantage because it can be performed noninvasively, repeatedly and easily, even at the bedside (Ariji et al 1994;Martin 1984;Stewart and Moore 1984). US with a narrow-surfaced probe is helpful in evaluating whether the hypertrophic portion is located in the lower, middle or upper third of the masseter (Sano et al 1991). With a high-resolution transducer, it is possible to demonstrate in detail structures of the superficial tissues and any associated lesions.…”

“…Moreover, it has been demonstrated that US is a valuable technique for the precision analysis of muscle shape (Kubo et al 2006). US has been described as an accurate and reliable imaging technique for measuring the thickness and crosssectional area of the masticatory muscles and for detecting changes in local cross-sectional dimensions of the head and neck muscles in vivo (Bakke et al 1992;Bertram et al 2001Bertram et al , 2003aClose et al 1995;Emshoff and Bertram 1998;Kiliaridis and Kälebo 1991;Kubota et al 1998;Raadsheer et al 1994Raadsheer et al , 1996Sano et al 1991;Wilson and Crocker 1985). It allows for the large-scale longitudinal study of changes in jaw-muscle thickness during growth in relation to changes in biomechanical properties of masticatory muscles (Raadsheer et al 1994).…”

Estudo comparativo da espessura do músculo masseter em seres humanos através de exames de tomografia computadorizada e ultrassonografia

“…A ultrassonografia pode ser utilizada na traumatologia, na determinação da localização de corpos estranhos (Abe et al, 1994) ou no auxílio da redução de fraturas do arco zigomático no trans-operatorio, como descrito por Akizuki et al em 1990. No diagnóstico das hipertrofias do músculo masseter, ela auxilia na eliminação dos diagnósticos diferenciais, excluindo as lesões de glândula parótida, os abscessos, tumores: musculares, vasculares, ósseos ( Morse e Brown, 1990) e auxiliando o controle pós-operatório, (Sano et al, 1991).…”