Although the vestibular nuclei are predominantly located at the medulla which is seen here compressed by the dilated left vertebral artery, the findings are likely not related to the patient's symptom of vertigo. Since there is no underlying signal alteration of the compressed medulla and no definite cranial nerve compression. Dolichoectasia is also a long standing process, while the patient's symptoms have started only 1 month prior to the exam. Further more, there is no associated neurological deficits or localizing symptoms which would be the case if the medullary compression was significant enough to affect the corticospinal tracts that are even located more anterior and closer to the abnormal artery than the vestibular nuclei.
The V4 segment of the left VA is dominant (the right side could not be identified) with tortuous course and above normal caliber of 5.5 mm. Bright signal is also seen within the artery lumen on filtered phase SWI, which is likely reflects underlying atherosclerotic calcifications, since this MRI sequence has the ability to differentiate between substances with paramagnetic and diamagnetic effect, hence differentiating between calcium and iron contents.