T2-SPACE MRI for the ocular motor nerves in the brainstem of normal controls

Abstract

To study the detail functional anatomy of ocular motor nerves in the brainstem by high-resolution magnetic resonance imaging (MRI). Sixty eight normal subjects with high resolution MRI were recruited in our study. The ocular motor nerves at the brainstem were performed using 3-dimensional, T(2)-weighted Turbo-Spin-Echo sequence with high sampling efficiency sequence (3D T(2)-SPACE), Parameters: TR = 1000 ms, TE = 134 ms, averages = 2, thickness = 0.8 mm, FOV = 225 mm×225 mm, matrix = 384×384, total scanning time is 4 min 2 s. Nerves in the brainstem were observed in oblique axial, oblique sagittal and coronal planes acquired with multi-planar reformation (MPR). The diameters of oculomotor nerves (CN3) and abducens (CN6) in the brainstem were measured in 68 normal subjects on MR images by 2 neuro-radiologists. All of 136 CN3 and CN6 of the cisternal segment were well demonstrable in 68 normal subjects (100%). Trochlear nerves (CN4) were depicted 87%. The diameters of CN3 and CN6 in the cistern were 2.2 mm, 1.3 mm, had no linear correlation with age. There were no significant difference between the results of the 2 radiologist (F = 2.557, 1.329, P = 0.085, 0.271). T(2)-SPACE sequence combined with MPR could precisely show the ocular motor nerves, as well as the relationship with adjacent structures in the cistern. The exact data measurement can provide more accurate anatomical basis for some special forms of neuropathic strabismus.