The imaging of abducens nerve in normal volunteers and palsy cases using 1.5T MRI 3-D CISS

The purpose of this study was to identify the cisternal segment of the abducens nerve and to investigate its anatomical features using three-dimensional Fourier transform constructive interference in steady-state (3-D CISS) sequence with a 1.5-tesla magnetic resonance (MR) imaging system. Images of abducens nerve palsy were also studied. Using this imaging system, the following procedures were performed to identify the abducens nerve. First, gray scale of the original images was inverted (inverted image). Second, Dollero's canal was identified, which contains the abducens nerve, and third, the nerve was followed to the root exit zone with a multiple-planar reconstruction method. Twenty-one volunteers and 3 patients with abducens nerve palsies participated in this study and following results were derived: all nerves in volunteers were clearly identified in the coronal and sagittal planes, the images closely resembled autopsy cases, seven nerves in asymptomatic cases were remarkably distorted by the vessels, and the cause of the palsy was not clear by their shapes in the images; this technique, however, can play a great role in evaluating abducens nerve palsy. (author)