Clinical question: History of brain lesion-occipital, evaluate for change. History of Chiari decompression. Signs and symptoms: Surveillance scan. Nonenhanced cervical spine MRI:There is evidence of postoperative changes of Chiari decompression which is often expansion of subarachnoid space at the level of foramen magnum. There is resultant resolution of previously noted flattening deformity of the cerebellar tonsils and effacement of subarachnoid space at the level of foramen magnum.There is also interval significant decreased size of a severely dilated syrinx of entire cervical cord and with extension into the superior most visualized thoracic cord to T3 level.The remaining small syrinx at C2 level measures approximately at 4 x 2 mm in transaxial dimensions compared to prior study measurement of 16 x 11 mm. The syrinx at C5 level measures at 3.5 x 1.2 mm compared to prior study measurement of 13 x 7 mm. The syrinx at T2 level measures approximately 2 x 2.3 mm compared to prior study compared to prior study measurement of 11.5 x 11 millimeter.Decreased size of syrinx results in better visualization of subarachnoid space. Degenerative changes at C6/C7 level and including a central and left paramedian disc protrusion demonstrate no significant change. Mild degenerative changes at C5-C6 with shallow bulging disc also remains is stable since prior exam.CSF flow study demonstrate normal appearing biphasic flow through the foramen magnum anteriorly. Trace biphasic flow through the foramen magnum posterior to the cord and through the fourth ventricle and aqueduct is also detected. There is significant interval improvement of CSF flow study at the level of foramen magnum since prior exam.Pre and post enhanced brain MRI:Negative diffusion weighted series.Examination redemonstrates stable right occipital region tumor in signal pattern, size and uniform pattern of enhancement. This mass lesion measures approximately 10 x 11 mm which is not significantly different than prior study measurement. Similar to prior exam this mass demonstrate no evidence of internal hemorrhagic changes, surrounding edema or appreciable mass effect. Differentials of primary brain tumor and less likely possibility of a metastatic lesion should be considered. Additionally possibility of a dural base benign tumor such as a meningioma should also be considered. Recommend continued follow-up studies. There is no evidence of any additional foci of abnormal parenchymal or leptomeningeal enhancement.Stable few scattered tiny foci of FLAIR hyperintensity in the periventricular and subcortical white matter is a nonspecific finding however in proper clinical setting could represent minute chronic small vessel ischemic strokes.Expected postoperative changes of suboccipital craniectomy as reported on cervical MRI is again noted.
1.MRI of cervical spine demonstrate interval expected postoperative changes of suboccipital craniectomy with resultant expansion of subarachnoid space. Significant interval decreased size of the expanded syrinx of entire cervical cord with extension into the upper most visualized thoracic cord as detailed/measured above. Significant interval improvement of CSF flow study through the foramen magnum anteriorly and a trace flow posteriorly through the foramen magnum, fourth ventricle and the aqueduct.2.Brain MRI demonstrate stable right occipital enhancing lesion which although could represent a primary brain tumor and less likely a metastases focus other differential of a benign extra-axial tumor such as a meningioma cannot be entirely excluded and continued further follow-up is recommended.