Artery, Posterior Inferior Cerebellar

The posterior inferior cerebellar artery, AKA PICA, normally originates from the intracranial VA (V4). In some cases, the PICA could be absent with a big AICA.



This patient presented with cerebellar IPH with IVH. DSA showed diffuse vascular irregularities, such as the BA and left AICA, without an obvious cause for the hemorrhage. Interestingly, there is an absence of bilateral PICAs

(A): Towne's view, right VA injection.
(C): Water's view, left VA injection.


This right vertebral artery injection yielded several noteworthy observations:

  1. Identification of an anastomosis (blue arrow) between a muscular branch of the right VA (green arrow) and the right occipital artery (red arrow).
  2. Observation of a reduction in the size of the VA intracranially, resulting in the equalization of sizes between the PICA (brown arrow) and distal VA.

(A): PA view during the early arterial phase.
(B): Lateral view during the early arterial phase.
(C): PA view during the late arterial/early capillary phase.
(D): Lateral view during the late arterial/early capillary phase.

PICA anatomy on (D)

  1. Anterior medullary segment
  2. Lateral medullary segment
  3. Tonsillomedullary segment
  4. Telovelotonsillar segment
  5. Cortical segments

Orange arrow: Basilar artery.


This left VA DSA revealed an extra-cranial origin (yellow arrow) of the left PICA. It is imperative to acknowledge this anatomical variation prior to conducting sub-occipital craniotomy or atlanto-occipital procedures.


This right VA DSA demonstrated two interesting findings: 1. The right VA ends at PICA; 2. There is a PICA origin aneurysm (top row). The aneurysm was subsequently coiled without complications (bottom row).