Sectional anatomy of the abducens nerve: according to 3D-SPACE magnetic resonance sequences correlated with cryosectional specimens.

Abstract

To identify and justify the best section to reveal each segment of the abducens nerve according to 3D-SPACE magnetic resonance sequences and correlate with cryosectional specimens. Thirty-four healthy adults were recruited for MRI using a 3D-SPACE sequence. Eighteen adult head specimens were cut into serial transverse, sagittal and coronal section using an electric band saw after the specimens were frozen. The MRI characteristics and the anatomical features of the abducens nerve were analyzed by correlation with the cryosection. We divided the abducens nerve into five segments, the cisternal segment, Dorello canal (DC) segment, cavernous sinus (CS) segment, superior orbital fissure (SOF) segment and intraorbital segment. In the transverse sections, the detection rates for the cisternal and Dorello canal segments of the abducens nerve were 97.06 and 94.12 %, respectively, on 3D-SPACE MR images. In the sagittal section of the frozen specimens, only the cisternal segment of the abducens nerve could be observed, and its detection rate was 51.50 %. In the coronal section, the CS segment of the abducens nerve was located inferior lateral to the ICA as well as, inferior to the oculomotor and trochlear nerves, and the detection rate of the CS segment was 42.60 % on 3D-SPACE MR images. 3D-SPACE sequence MR scanning was a useful method for observing the cisternal and DC segment of the abducens nerve in a transverse section, observing the cisternal segment in a sagittal section and observing the CS segment in a coronal section.