Abstract
Purpose :
To show the importance of Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) as an additional diagnostic tool to improve the diagnostic accuracy of MRI in the characterization of diffuse orbital masses.
Methods :
A retrospective study was done involving 39 diffuse orbital mass carriers examined between the years 2000 to 2015 at King Khaled Eye Specialist Hospital – Saudi Arabia. All the patients were evaluated using DW-MRI and after that they had incisional or excisional biopsy. According to the histopathologic result, the lesions were grouped as benign or malignant. Also, lymphoproliferative lesions were sub-grouped in lymphoma or other lymphoproliferative lesions. Validity of apparent diffusion coefficient (ADC) value were compared to histopathology based sub-groups. Area under curve (AUC) were calculated.
Results :
Malignant diffuse orbital mass tumors presented median ADC 0.58 (25% quartile 0.48; minimum: 0.45; maximum: 1.72x 10(-3) and benign, median ADC 1.19 (25% quartile 0.7; minimum: 0.49; maximum: 1.95x 10(-3) mm(2) s(-1). The difference in ADC value between the malignant and benign lesions was statistically significant (p < 0.001). Lymphoma median ADC was 0.51 (25% quartile; 0.48) and for the sub-group composed by other lymphoproliferative lesions median ADC was of 0.9 (25% quartile = 0.7). The difference of ADC in two sub-groups was also significant (MW p =0.02). ADC value of 0.8x10(-3)mm(2) s(-1) was used as a threshold value for differentiating malignant from benign orbital mass. The validity of predicting type of diffuse tumor mass according to DW-MRI median ADC was grouped showing sensitivity of 87% and specificity of 67%.
Conclusions :
DW- MRI is a promising not invasive imaging approach to characterize malign and benign diffuse orbital mass.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.