Orbital observation using three dimensional fourier transform technique of MRI

Detailed observation of the orbit was performed with magnetic resonance imaging (MRI), using the 0.5 Tesla superconducting magnetic system manufacutured by the Siemens Company. The MRI technique employed the three dimensional fourier transform (3 D-FT) technique, operated in conjunction with the spin echo technique (TR=500 msec, TE=38 msec, SL=1.9 mm, matrices=256 x 256 x 14). In the 3 D-FT technique, the volume to be observed is excited in its full thickness, and the matrices are divided into three dimensions. With this technique, gapless slice of extreme thinness can be obtained, enabling the detailed observation of fine orbital structures such as extraocular muscles (especially the superior oblique muscles), optic nerves and vessels. The quality and definition of the image is superior to that obtained with the earlier two dimensional Fourier transform technique. The 3 D-FT technique will enable more accurate analysis of eye movement and improved observasion of fine lesions in the orbit. (author)