Microanatomy of the subcallosal artery: an in-vivo 7 T magnetic resonance angiography study.

Objectives: To investigate in-vivo microanatomy of the subcallosal artery branching from the anterior communicating artery (ACoA) using time-of-flight (TOF) magnetic resonance angiography (MRA) at 7 Tesla.

Methods: Seventy-five subjects, including 15 healthy volunteers and 60 patients, were included in this prospective study. Three raters characterized branches from ACoA in maximum intensity projections of TOF MRA at 7 Tesla acquired with 0.22 × 0.22 × 0.41 mm(3) resolution. Furthermore, course patterns and anatomical features of the subcallosal artery (maximum diameter, length, and branching angle from ACoA) were measured.

Results: Branches from the anterior communicating artery were visualized in 63 of 74 (85.1 %) subjects and were identified as the subcallosal artery (93.7 %) and the accessory anterior cerebral artery (6.3 %). The course of the subcallosal artery was classified into 3 groups; C-shaped (55.9 %), straight (16.9 %), and S-shaped (27.2 %). There was a significant difference between the branching angles of C-shaped and straight (p < 0.0001), between C-shaped and S-shaped (p < 0.0001), as well as between straight and S-shaped (p = 0.0113) course patterns.

Conclusions: High-resolution in-vivo 7 T TOF MRA can delineate the microanatomy of the subcallosal artery. Three main variants of course patterns and branching angles from ACoA could be identified.

Key Points: • In-vivo 7 Tesla TOF MRA can delineate the subcallosal artery microanatomy • Three distinct course patterns of the subcallosal artery were identified • Branching angles from ACoA significantly differed between subcallosal artery course patterns.