le of Magnetic Resonance Imaging in Diagnosis of Orbital Masses

Abstract

The bony orbit is a pear shaped cavity that hol:lses the globe and all of its upportive tissues .It contains blood vessels, nerves,fibrous connective tissue• ,fat and ther structures crowded into a volume of about 30c.c.,reacting to various -pathologic timuli with a limited range of symptoms and signs. So, The eye &orbit comprise a unique and complex region of the nervous ystyem ,which presents a challenge to the ophthalmologist because of its highly pecialized anatomy &pathology. MRI of the orbital soft tissue is extremely promising and is particularly ttractive in the evaluation of the eye and orbit because of certain distinctive atures: Superb inherent soft tissue resolution,absence of ionizing radiation, ssentially non invasive , and multiplanner capability i.e cat1 be ootained in any esired plane without any change in physical position of the patient.(e.g sagittal para-sagittal planes), allowing optimum delineation of orbital lesions by imaging in. everal planes. There fore, MRI is ideal for displaying all types of orbital masses

The tremendous upsurge in the number of MRscanners ,new soft w:_are urface coil development as well as utilization of paramagnetic contrast agent with t suppression techniques have made M.Rl a serious comp titor to CT. Thin sections multiple planes with high resolution can now be obtained without penality of long nning time. This study aims at describing MRI tech., shedding light on the role of RI in diagnosis of orbital masses regarding the exat site, extension of lesions as ell as defining their nature and gaining more knowledge about MRI features of rare bital masses. The material included 140 cases either presented by orbital mass or fferenl symptom. and suspected ••hy ophthalmologist after clinical exam.to have ita\ mass. The following has been carried out: -Clinical exam.(general and ophthalmological) _Lab. Investigation. _I\1RI for all patients CT ................ for 100 cases. -Ocular U.S.... .for 18 cases &Color Doppler ...... for 7 cases. _Carotid• angiography ...... for 2 cases Other complementary imaging studies for selected cases ammography,Bone survey,thyroid ,Abd.US ... others.)according to the need each case.