The masticator space. Value of computed tomography and magnetic resonance imaging in localisation and characterisation of lesions.

Aim of the study was to assess the different roles of magnetic resonance imaging and computed tomography in the evaluation of anatomical origin and pathological nature of lesions involving the masticator space. Overall 41 cases (31 computed tomography and 14 magnetic resonance imaging) of lesions involving masticator space were retrospectively reviewed by two experienced radiologists in consensus. Reference standards were histopathological results and clinical-radiological follow-up after one year. Both computed tomography and magnetic resonance imaging were performed with and without intravenous injection of contrast. Computed tomography and magnetic resonance imaging were correct in identifying the space of origin of lesions respectively in 96% and 92% of cases. Computed tomography correctly diagnosed the nature of lesions in 81% of cases and magnetic resonance imaging in 93% of cases; computed tomography and magnetic resonance imaging correctly characterized, respectively, 88% and 100% of malignant lesions and, respectively, 73% and 83% of benign lesions. In conclusion both computed tomography and magnetic resonance imaging were effective in the identification of the origin of non-extensive lesions involving masticator space. Computed tomography was more precise in depicting lesions originating from masticator space, while magnetic resonance imaging was more correct in depicting lesions originating from contiguous spaces and involving secondarily the masticator space. Magnetic resonance imaging should always be preferred to characterise lesions, nevertheless computed tomography should be chosen in cases with suspected inflammatory involvement of mandible bone.