Detailed magnetic resonance imaging anatomy of the cisternal segment of the abducent nerve : Dorello's canal and neurovascular relationships and landmarks

• Published in: Journal of neurosurgery Vol. 91; no. 2; pp. 276 - 283
• Main Authors: YOUSRY, I, CAMELIO, S, WIESMANN, M, SCHMID, U. D, MORIGGL, B, BRÜCKMANN, H, YOUSRY, T. A
• Format: Journal Article
• Language: English
• Published: Park Ridge, IL American Association of Neurological Surgeons 01-08-1999
• Subjects: Abducens Nerve - anatomy & histology; Adult; Aged; Arteries - anatomy & histology; Basilar Artery - anatomy & histology; Biological and medical sciences; Brain - blood supply; Cavernous Sinus - anatomy & histology; Cerebellum - blood supply; Cisterna Magna - anatomy & histology; Facial Nerve - anatomy & histology; Female; Fourier Analysis; Humans; Image Processing, Computer-Assisted - methods; Investigative techniques, diagnostic techniques (general aspects); Magnetic Resonance Angiography; Magnetic Resonance Imaging - methods; Male; Median Eminence - anatomy & histology; Medical sciences; Medulla Oblongata - anatomy & histology; Middle Aged; Nervous system; Pons - anatomy & histology; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Skull Base - anatomy & histology; Vertebral Artery - anatomy & histology; Human; Abducens nerve; Medical imagery; Exploration; Anatomy; NMR angiography; Nuclear magnetic resonance imaging
• ISSN: 0022-3085; 1933-0693
• DOI: 10.3171/jns.1999.91.2.0276

The goal of this study was to identify reliably the cisternal segment of the abducent nerve by using the three-dimensional Fourier transform constructive interference in steady-state (3-D CISS) magnetic resonance (MR) imaging sequence to define landmarks that assist in the identification of the abducent nerve on MR imaging and to describe the nerve's relationship to the anterior inferior cerebellar artery (AICA).
A total of 26 volunteers underwent 3-D CISS MR imaging, and 10 of these volunteers also underwent MR angiography in which a time-of-flight sequence was used to identify the facial colliculus, the abducent nerve and its apparent origin, Dorello's canal, and the AICA. The authors identified the abducent nerve with certainty in 96% of 3-D CISS sequences obtained in the axial and sagittal planes and in 94% obtained in the coronal plane. The nerve emerged from the pontomedullary sulcus in 94% of cases. The facial colliculus could always be identified, and Dorello's canal was identified in 94% of cases. In 76.6% of cases, the abducent nerve was seen to contact the AICA, which passed inferior to the nerve in 63.8% of cases and superior to it in 29.8%.
The anatomical course of the abducent nerve and its relationship to the AICA and other blood vessels can be reliably identified using a 3-D CISS MR sequence with the facial colliculus and Dorello's canal serving as landmarks.