Vertebro Basilar hypoplasia presenting with Episodic Dizziness

A 58 yo male with recurrent episodic dizziness since long time, accompanied with episodes of blurring of vision. MRI study of Brain was normal, no any ischemic lesion in posterior circulation territory.
MR Angiography was advised with clinical diagnosis of vertebro basilar insufficiency.

The Non contrast 3 D TOF MR Angiography of brain and neck shows:

Smaller diameter of intra cranial portion of both the vertebral and basilar. Narrowing is diffuse and smooth ,  not irregular as we see in atherosclerotic  patients.

Right intra cranial vertebral measures ~1.7mm

Left intra cranial vertebral measures ~ 1.6mm

Basilar measures ~ 2.2mm

Right Pcoms is continuing as PCA – fetal PCA on right side. Basilar continuing as left PCA. Rest of the intra cranial vessels and neck vessel show course and calibre.

Imaging diagnosis : Hypoplastic bilateral intra cranial vertebral and Basilar.

The Episodic dizziness of patient can be attributed to vertebro basilar hypoplasia and is consistent with clinical diagnosis of  vertebro basilar insufficiency.

Discussion: 

On TOF MRA Vertebral hypoplasia (VH) is when vertebral artery (VA) is less than 2.0 mm in diameter and Basilar hypoplasia (BH) when basilar is less than its normal average diameter of 3 to 5mm.

Basilar hypoplasia is usually accompanied with unilateral vertebral artery hypoplasia; however, BH with bilateral VH composing vertebrao basilar hypoplasia (VBH) is rare but a significant normal anatomical variation in a patient clinically presenting with vertebro basilar insufficiency where other ENT causes of dizziness are ruled out.

Reference: Intracranial Vertebral-Basilar Artery Hypoplasia Presenting with Episodic Dizziness, Ghana Med J, Jiann Jy Chen and Dem Lion Chen, 2010 September; 44.

Special thanks to Dr Sachin Baldawa MS Mch (Neurosurgery)