Clinical question: cryptogenic SAH, s/p neg angiography, eval for dural AVF or CVTSigns and Symptoms: cryptogenic SAH, s/p neg angiography, eval for dural AVF or CVT MRI of the brainNo diffusion weighted abnormalities are appreciated.The CSF spaces are appropriate for the patient's stated age with no midline shift. There is a punctate signal hyperintensity is present on the DWI images within the left frontal subcortical white matter without ADC signal change.There is a mild degree of periventricular and subcortical punctate hyperintense white matter lesions present identified on the FLAIR and T2 images.There is FLAIR and T2 signal hyperintensity in the periaqueductal gray matter without contrast enhancement.No abnormal mass lesions are appreciated intracranially. No intracranial hemorrhage is identified. No edema is identified within the brain parenchyma.Normal vascular flow voids are present in the distal carotid and vertebral arteries, the basilar artery and the proximal anterior, middle and posterior cerebral arteries as well as the internal cerebral veins and superior sagittal sinus.The visualized portions of the paranasal sinuses demonstrate mucosal thickening in the maxillary and sphenoid sinuses. The visualized portions of the mastoid air cells are clear. The visualized portions of the orbits are intact.Incidental note is made of partial empty sella.MRA brain:Antegrade flow is present in the distal internal carotid arteries, the distal vertebral arteries, the basilar artery and the proximal anterior, middle and posterior cerebral arteries.There is no evidence for intracranial aneurysm or cerebrovascular occlusion.The anterior communicating artery is identified. The posterior communicating arteries are not readily identified. The vertebral arteries are similar in size.MRV brain:The dural venous sinuses are patent. Straight sinus, internal cerebral veins and basal veins are identified and appear patent.
1.No evidence for cerebrovascular occlusive disease.2.No evidence for intracranial aneurysm.3.MR venogram of the brain is within normal limits.4.Periventricular and subcortical white matter signal changes of a mild degree are present which are nonspecific. They could be vascular related, related to demyelination, trauma, vasculitis, sarcoid. They are nonspecific. 5.There is a punctate focus of in the left frontal subcortical white matter which is nonspecific but could represent a microinfarct.6.Periaqueductal gray signal abnormality without enhancement is non-specific. This could be reactive, related to thiamine deficiency or a toxic or metabolic cause. 