Intermittent visual loss. Note from the on-call resident: Per ophthalmology, patient with strong clinical concern for carotid cavernous sinus fistula. Patient has 6 weeks pregnant and therefore decision was made to proceed with MRI versus CTA. Brain MRI: There is no brain signal abnormality. Gray-white matter differentiation is preserved. There is no mass effect, midline shift or brain herniation. The ventricles and the other CSF-containing spaces are normal in size. There is no susceptibility artifact or diffusion restriction to indicate intracranial hemorrhage or acute/recent infarct, respectively. Major intracranial arterial and venous flow voids are preserved.There is no gross orbital abnormality. The mastoid air cells and middle the middle ear cavities are clear. There is polypoid mucosal thickening/retention cyst in the left maxillary sinus. The anterior nasal septum is deviated to the left, with spurring. The other paranasal sinuses are clear.There is no evidence for any skull lesion or scalp gross abnormality.Cranial MR venogram:The superior sagittal sinus is patent. The internal cerebral veins, vein of Galen and straight sinus are patent as well. The superior sagittal sinus preferentially drains into the right transverse and sigmoid sinuses which are patent. The left transverse and sigmoid sinuses are small and preferentially drained the deep venous system. This is a common variation. There is asymmetrically increased T1 and T2 signal in the included upper most segment of the left internal jugular vein just below the skull base which is probably related to slow flow, less likely thrombosis, given the congenitally smaller left transverse and sigmoid sinuses. This is associated with attenuated signal on phase contrast MR venogram.Cranial MR angiogram:There is no significant narrowing of the intracranial arteries. Of note, the right A1 segment is small but the A2 and downstream segments are symmetric. There is no or very small right posterior communicating artery. There is no sign of carotid-cavernous fistula.
1.There is no brain abnormality2.MR venogram shows no intracranial venous thrombosis. Attenuated signal on phase contrast MRV as well as increased T1 signal in the included upper most segment of the left internal jugular vein just below the skull base is probably related to slow flow rather than thrombosis. However, if there is high clinical index of suspicion for venous thrombosis, the more caudal segments of the jugular veins can be assessed with Doppler ultrasound to avoid radiation exposure. 3.MR angiogram shows no significant vessel stenosis. There is no sign of carotid-cavernous fistula.