RT Journal Article SR Electronic T1 Actinomycosis in the Mandible: CT and MR Findings JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology DO 10.3174/ajnr.A3673 A1 Y. Sasaki A1 T. Kaneda A1 J.W. Uyeda A1 H. Okada A1 K. Sekiya A1 M. Suemitsu A1 O. Sakai YR 2013 UL http://www.ajnr.org/content/early/2013/08/08/ajnr.A3673.abstract AB SUMMARY: Mandibular actinomycosis is an uncommon disease. We retrospectively reviewed 6 patients with pathologically proven mandibular actinomycosis who underwent both CT and MR imaging to evaluate the characteristic imaging findings. CT results showed an irregularly marginated lesion with increased bone marrow attenuation, osteolysis, and involvement of the skin in all patients. Periosteal reaction and intralesional gas were seen in 4 patients. MR imaging results revealed low signal on T1-weighted and high signal on T2-weighted images of the mandible, and moderate heterogeneous enhancement was seen in all patients who received intravenous contrast. Cervical lymphadenopathy was not observed. Involvement of the masseter, lateral pterygoid, and medial pterygoid muscles was seen in 4 patients, whereas parotid gland and submandibular gland as well as parapharyngeal space involvement were seen in 3 patients. Familiarity with the imaging findings of mandibular actinomycosis may help to diagnosis this entity. Abbreviations MAmandibular actinomycosis