Female 19 months old with history of arachnoid cyst, surveillance imaging There is no evidence of intracranial hemorrhage, mass, or acute infarct. The brain parenchyma, ventricles, cisterns, and myelination appear appropriate for patient's age. There is no abnormal intracranial enhancement. There is redemonstration of mildly increased T2 signal, which is less than that of CSF, located at the midline underneath the tentorium and measuring up to 12 x 5 mm (coronal T2 image 6). The lesion appears unchanged from prior exams and demonstrates mild corresponding FLAIR hyperintensity with respect to CSF, with no restricted diffusion. The lesion also demonstrates no significant mass effect, although located adjacent to the dural venous sinuses.There is no midline shift or herniation. The major cerebral flow voids are intact. No significant abnormality within the orbits, skull, paranasal sinuses, or scalp soft tissues.
Stable non-enhancing infratentorial lesion along the dural venous sinuses, which demonstrates benign characteristics and likely represents a developmental cyst although not of CSF signal intensity. No acute intracranial abnormalities identified. If future follow-up imaging is desired, 3-D T1 post contrast and 3-D T2W imaging may be helpful for more complete evaluation.