known brainstem lesion interval change, projectile vomiting. No evidence of acute ischemic or hemorrhagic lesion.Multifocal scattered high signal intensities on FLAIR images on bilateral periventricular white matter and centrum semiovale indicate non specific small vessel ischemic disease.There is ovoid shaped lesion on the left dorsal medulla (6mm x 5mm x 5mm) with subtle enhancement on Gad infusion. There is no evidence of surrounding edema. Possible diagnosis of the lesion is likely low grade glioma.There is no other abnormal enhancement on this scan.The ventricles, sulci and cisterns are symmetric and unremarkable. There is no edema, midline shift, intra or extra-axial fluid collection/hemorrhage, restricted diffusion/acute ischemia. The midline structures and cranial-cervical junction are normal. Normal flow voids are identified in the major intracranial vessels. The paranasal sinuses and mastoid air cells are clear.
1. Ovoid subtle enhancing left dorsal medullar lesion without surrounding edema, comparing to out side MR scan on Nov 18 2014, the size and MR characteristics do not show any significant interval change.2. Underlying non specific small vessel ischemic disease.