Case Of the Week (COW) 06 March 2016
Persistent trigeminal Artery
Findings
Persistent trigeminal Artery connecting left internal carotid Artery and basilar Artery
Discussion
Type of persistent embryonic carotid – basilar anastamosis Most common – 0.1 – 0.2% cases Two types: Saltzman type 1 – PTA supplies then distal basilar artery, PCoAs are usually absent and the proximzl basilar artery is hypoplastic Saltzman type 2 – PTA fills the superior cerebellar arteries while the PCAs are supplies via patent PCoAs. IMAGING FINDINGS Large vessel that connects the cavernous ICA with the basilar artery. In 60% - PTA courses posteromedially running through dorsum sella In 40% - PTA runs posterolaterally along the trigeminal nerve curving around (not through) the dorsum sellae. Sagittal MR scans and MRA shows a “Neptune’s trident” configuration. Nearly one quarter of all PTAs have associated vascular abnormalities such as saccular aneurysm, moya moya, aortic coarctation, and arterial fenestrations.
Persistent trigeminal Artery
Findings
Persistent trigeminal Artery connecting left internal carotid Artery and basilar Artery
Discussion
Type of persistent embryonic carotid – basilar anastamosis Most common – 0.1 – 0.2% cases Two types: Saltzman type 1 – PTA supplies then distal basilar artery, PCoAs are usually absent and the proximzl basilar artery is hypoplastic Saltzman type 2 – PTA fills the superior cerebellar arteries while the PCAs are supplies via patent PCoAs. IMAGING FINDINGS Large vessel that connects the cavernous ICA with the basilar artery. In 60% - PTA courses posteromedially running through dorsum sella In 40% - PTA runs posterolaterally along the trigeminal nerve curving around (not through) the dorsum sellae. Sagittal MR scans and MRA shows a “Neptune’s trident” configuration. Nearly one quarter of all PTAs have associated vascular abnormalities such as saccular aneurysm, moya moya, aortic coarctation, and arterial fenestrations.