Abstract:

Objective To analyze characteristics and diagnostic value of conventional Magnetic Resonance Imaging (MRI) combined with Diffusion Weighted Imaging (DWI) and dynamic contrast-enhanced MRI for the orbital lymphoma. Design Retrospective case series. Participants Twenty-one orbital lymphoma patients confirmed by pathology. Methods All patients underwent MR T1-weighted, T2-weighted and enhanced T1-weighted examinations, three patients underwent DWI and eight patients underwent dynamic contrast enhanced （DCE） MR imaging. Main Outcome Measures Focal location and extents, shape, boundary, relationship with the adjacent structures, the characteristics of MR signal (general sequence and DWI) and the time-intensity curve （TIC）. Results 17 patients had unilateral orbital lesions and 4 cases had bilateral orbital lesions. 16 orbits' lesions were local and 9 orbits were diffuse. The lesions involved anterior compartments in six orbits, lacrimal areas in seven, intraconal spaces in six, orbital muscles cones in four, extraconal spaces in twelve, optic nerve areas in two and subperiosteal area in one. Ten lesions' shapes were nodosity, nine lesions grew as "casting mould", two were pacity, and the exteaocular muscles or optic nerves were enlarged or wrapped in seven orbits. The lesions' margins of thirteen orbits were sharp and of twelve orbits were indistinct. The masses appeared iso-intensity in twenty-three orbits and slightly lower in two orbits on T1WI. The masses appeared iso-intensity in nineteen orbits, slightly higher signal in one orbit and slightly lower in five orbits on T2WI. The lesions in four orbits appeared iso-intensity on DWI. The lesions were enhanced markedly and homogeneously in twenty-four orbits but one. The TIC showed platform pattern in seven orbits, inflow-outflow pattern in nine and mixed pattern in one.  Conclusion Conventional MRI can show the orbital lymphoma's location, shape, internal characteristics and the relationship with the surrounding structures. DWI and DCE-MR imaging provide the benign and malignant information about the lesion. （Ophthalmol CHN， 2016, 25: 371-375）

Key words: orbital lymphoma, magnetic resonance imaging