Headache [R51] / Arnold-Chiari syndrome without spina bifida or hydrocephalus [Q07.00], Reason for Study: ^Reason: r/o dural enhancement or other signs of intracranial hypotension. Also has a mild Chiari malformation History: Postural headache The left transverse sinus lumen is not fully patent with internal T1 high to intermediate/T2 medium or high signal intensity signal intensity lesions indicating blood product. However, on FLAIR and T2 weighted images, there is no evidence of venous congestive encephalopathy. In addition, on Gad enhanced scan, the left transverse sinus appears to be well enhanced and continuous to the left sigmoid sinus. Comparing to prior MRI/MRV, the left transverse sinus signal intensity has been evolving demonstrating more flow related signal loss. Constellation of above findings indicate the left transverse sinus was incompletely thrombosed and the thrombus has been resolving since prior scan. No evidence of acute ischemic or hemorrhagic lesion. There is a focal area of the vascular conglomeration on the genuine of corpus callosum indicating small developmental venous anomaly. Otherwise there is no evidence of abnormal enhancement.The tonsilar ectopia (about 6.8mm) is seen and no change since prior scan. Phase contrast MR venography showed biphasic CSF flow through the foramen magnum especially anterior aspect of the brainstem. In addition, the forward flow of superior sagittal sinus , internal cerebral vein, vein of Galen and straight sinus toward torcular appears to be well maintained. Cavum septum pellucidum was seen, no change since prior scan.The ventricles, sulci and cisterns are symmetric and unremarkable. There is no mass, mass effect, edema, midline shift, intra or extra-axial fluid collection/hemorrhage, restricted diffusion/acute ischemia, or abnormal contrast enhancement. Normal flow voids are identified in the major intracranial arteries. The paranasal sinuses and mastoid air cells are clear.
1. Evolving left transverse sinus incomplete thrombosis since prior scan without associated venous congestive encephalopathy or hemorrhage.2. No acute ischemic or hemorrhagic lesion.3. No change of tonsilar ectopia in terms of its degree.4. Maintained biphasic CSF flow through the foramen magnum, most significant on the anterior aspect of brain stem.