Clinical question: Rule out dural sinus thrombosis and assess Chiari. Signs and symptoms: Headaches and postural lightheadedness. CT of brain without the infusion:No evidence of hemorrhage, edema, mass-effect, midline shift or hydrocephalus is detected. Cortical sulci, ventricular system and all CSF cisterns remain within normal for patient stated age. Redemonstration of slight crowding of the cerebellar tonsils at the level of foramen magnum. No change since prior exam.CTA of intracranial circulation:Vertebral -- basilar system.There is normal visualization of bilateral vertebral arteries across the skull base (dominant left vertebral). Basilar artery, posterior cerebral arteries and superior cerebellar arteries are all within normal limits. No evidence of vascular lesion in particular aneurysm or any atherosclerotic stenosis is detected.Carotid system.Patent normal appearing internal carotid arteries across to skull base and in their supraclinoid portions. Anterior and middle cerebral arteries and their branches are well visualized and no evidence of vascular lesions of aneurysm or atherosclerotic disease is detected.CTV of the intracranial venous sinuses.Superior sagittal sinus, confluence of sinuses, bilateral transverse sinuses, sigmoid sinuses, jugular bulbs and proximal portion of bilateral internal jugular veins are within normal limits.There is normal visualization of bilateral internal cerebral veins, vein of Galen and straight sinus.On the reformatted MIP images both on sagittal and coronal plane low positioning of the cerebellar tonsils with effacement of subarachnoid space is noted. This is believed to represent ectopia of the cerebellar tonsil and not Chiari malformation due to its minimal protrusion through the foramina magnum. This finding can be further evaluated if clinically is indicated with an MRI of cervical spine and cranial/cervical junction as well as CSF flow study65 cc of Omnipaque 350 with the injection rate of 4.5 CC/sec was utilized for the above studies.
1.Unremarkable CTA of the intracranial circulation.2.Unremarkable CT of the of intracranial venous sinuses.3.Minimally ectopic cerebellar tonsils. Correlate with history and neurological findings and if clinically indicated further follow-up with MRI of cranial cervical junction and with CSF the study across the foramen magnum.4.Negative CT of brain without the infusion and stable since prior study.