Abstract

Background: Posterior Inferior cerebellar artery (PICA) is the largest and most distal branch of Vertebral artery (VA) arising near the lower end of olive. Variations of PICA are numerous but have been infrequently reported in this region. Occlusion or blockage of PICA may cause an infarction of the medulla oblongata which plays an important role in circulatory and respiratory functioning. This may lead to lateral medullary syndrome, also called Wallenberg syndrome. The study focuses on normal and variant anatomy of PICA in Uttar Pradesh region of North India. Materials and Methods: The study population included 100 subjects, of either sex, who underwent Head and Neck CT Angiography in the Department of Radiodiagnosis, King George’s Medical College, Lucknow, Uttar Pradesh. The diameters of PICAs of both sides were measured and variations encountered were noted. Results: Mean diameter of PICA was 1.76±0.64 mm on right side and 1.73±0.60 mm on left side. Mean diameter in males was 1.75±0.62 mm and in females was 1.73±0.62 mm. Variations observed included: Unilateral aplasia of PICA in 16% with equal prevalence on both sides; bilateral aplasia in 3% cases; hypoplasia of RPICA in10% and hypoplasia of LPICA in 6%. VA-PICA variation where the VA continued as posterior inferior cerebellar artery was observed in 8 subjects (4 right, 4 left). Conclusion: The knowledge of normal diameters and variations in PICA supplying the brain can be a useful guide to the surgeons and interventional radiologists for careful pre-operative planning thus helping them in avoiding potentially life threatening complications.

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