Abstract:

Objective To evaluate the diagnostic value of dynamic contrast-enhanced MRI(DCE-MRI) in the differentiation on benign and malignant masses in the orbit.Methods Eighty-nine patients with orbital masses confirmed by pathology were studied.The study group consisted of 54 women and 35 men.After conventional MR imaging,dynamic contrast-enhanced MR imaging was performed using a 3D fast spoiled gradient echo sequence.Calculated values included time to peak(Tpeak),washout ratio(WR),Slope and enhancement ratio(ER),The types of the time-intensity curves(TICs) were studied.Tpeak,WR,slope and ER were calculated preoperatively.Results The TIC of 48 of 64 benign masses were type A,while 17 of 25 malignant masses were type C.Benign masses of the orbit had a significantly longer Tpeak(P<0.01),slower WR(P<0.05) and lower slope(P<0.01) than malignant masses.No significant differences in ER(P>0.05) was seen between benign and malignant masses.Of masses of lacrimal gland region,within the extraconal space,and involving both the extra and intra-conal spaces,There was longer Tpeak(P<0.05),slower WR(P<0.05) and lower slope(P<0.05) in benign masses compared with malignant masses.There was no significant differences between the benign and malignant tumors within the intraconal space(P>0.05).Conclusion DCE-MRI is useful in the diagnosis and differential diagnosis of benign and malignant masses of the orbit.

Key words: MRI, orbit, mass, dynamic