Thalamo-mesencephalic Branches of the Posterior Cerebral Artery: a3D Rotational Angiography Study.

Abstract

The thalamo-mesencephalic (TM) branches of the posterior cerebral artery (PCA) supply critical structures. Previous descriptions of these vessels are inconsistent and almost exclusively rely on cadaver studies. We aimed to provide aneuroradiological description of TM vessels in vivo based on routine 3D rotational angiographies (3D-RA). We analyzed 3D-RAs of 58patients with pathologies remote from the PCA. PCA-origins were considered. Delineation, origin and number of branches of the collicular artery (CA), the accessory CA (ACA), the posterior thalamoperforating artery (PTA), the thalamogeniculate artery (TGA), and the posterior medial (PMCA) and lateral (PCLA) choroid arteries were assessed. The PTAs were categorized based on Percheron's suggested classification. ACA was identified in 84%, an ACA in 20%. The PTA was delineated in 100%. In 27%, PTA anatomy had features of several Percheron types (n = 7) or vessels emanating from anet like origin (n = 9). 26% had atypeIIb PTA. Afetal type PCA origin with hypoplastic ipsilateral P1 was observed in 5cases with typeIIa (n = 2) or typeIIb (n = 3) PTAs originating from contralateral P1. The TGA was identified in 85% of patients, with ≥ 2 branches in 67%. The PMCA was delineable in 41%, the PLCA in 100%. The prevalence of aproper "Artery of Percheron" typeIIb PTA seems to be higher than previously reported. Afetal type P1-origin may be predictive of atypeIIa/b PTA emanating from contralateral P1. 3D-RA may be useful for planning PCA interventions, as impairment of TM branches is asevere risk.