68 years, Male, Reason: hx base of skull osteomyelitis and osteoradionecrosis, mastoiditis History: otorrhea, left otalgia, headache, neck stiffness. Again seen are areas of abnormal low T1 signal, enhancement, and erosive changes involving the skull base including the left occipital condyles and left greater than right C1 arch. Diffuse low T1 signal involving the clivus is also again seen. Findings are consistent with prior osteomyelitis/osteoradionecrosis. No new marrow signal abnormality compared to prior MRI from 12/9/2014. There are post-treatment findings in the left nasopharyngeal region with soft tissue deficiency involving the pharyngeal mucosal and left parapharyngeal spaces. No mass to suggest residual or recurrent tumor. There are small amount of secretions are noted within the posterior nasopharyngeal cavity layering dependently.There are postsurgical changes related to left mastoidectomy, with T2 hyperintensity and enhancement filling the surgical bed, which may represent graft material and/or granulation tissue. There is a peripherally enhancing fluid collection measuring up to 10 x 3 mm in the lateral aspect of the mastoidectomy cavity. Diffuse opacification of the left middle ear cavity and residual mastoid air cells also again seen.There is dehiscence involving the tegmen tympani and tegmen mastoideum as seen on recent CT. No adjacent epidural enhancement or fluid collections intracranially are appreciated.Examination of the brain demonstrates no evidence of acute ischemia, hemorrhage, intracranial mass, or mass effect. No abnormal extra-axial collections. No hydrocephalus. No abnormal parenchymal or meningeal enhancement. Few foci of susceptibility are noted involving the cerebellum bilaterally compatible with chronic microhemorrhages which appear new since prior MRI brain from 9/8/2014. There is also new focus of FLAIR hyperintensity involving the left posterior cerebellar hemisphere with foci of susceptibility compatible with hemorrhage.Moderate mucosal thickening involving the paranasal sinuses diffusely appear similar to prior. Dehiscence involving the sphenoid sinus floor is again seen which may be postsurgical versus related to prior infection.
1. Sequela of prior osteomyelitis/osteoradionecrosis with no significant change in extensive erosive changes involving the posterior skull base.2. Images of the brain demonstrate no abnormal parenchymal or meningeal enhancement to suggest intracranial extension of infection. No evidence of cerebritis, abscess, or empyema. Lumbar puncture can be considered if there is significant suspicion for meningitis.3. Focus of encephalomalacia with susceptibility involving the left posterior cerebellar hemisphere which is new since prior brain MRI from 9/8/2014 and suggests interval small hemorrhagic infarct. Few additional foci of susceptibility compatible with chronic microhemorrhages are seen bilaterally in the cerebellar hemisphere. Follow-up MRA neck can be considered if clinically indicated.4. Evidence of left-sided mastoidectomy as seen on recent CT from 11/2/2015 but new since prior MRI from 12/9/2014. There is diffuse T2 hyperintensity and enhancement involving the mastoidectomy bed which may represent granulation tissue and/or graft material and can be correlated with surgical history. There is however a focus of peripherally enhancing fluid collection measuring 10 x 3 mm in the lateral aspect of the mastoidectomy bed, which is nonspecific and may represent a small seroma, CSF collection, or abscess. Dehiscence involving the left tegmen tympani and tegmen mastoideum better seen on recent CT. Left middle ear cavity and residual mastoid air cells remain opacified.