Diffusion-weighted MR imaging in benign and malignant orbital masses / 中华放射学杂志

ABSTRACT

Objective To analyse the characteristics of orbital benign and malignant masses on diffusion weighted imaging in combination with conventional MR imaging and evaluate the diagnostic value of apparent diffusion coefficient in distinguishing benign and malignant orbital lesions.Methods Seventy- seven cases with orbital masses,including fifty-five benign lesions and twenty-two malignant tumors,who underwent conventional MRI and diffusion imaging scanning were studied with use of a 1.5 T magnetic resonance system.Quantitative ADC measurements of masses(ADC_M)and of the white matter of eontralateral temporal lobe(ADC_W)were made with two different b-values of 0 and 1000 s/mm~2.The ADC ratio(ADCR)of the lesion to the control was calculated.The receiver operating characteristic curves(ROC) were constructed using various cut points of ADC_M and ADCR for different parameters to differentiate between benign and malignant masses.The area under the ROC curve for each parameter was also calculated. Results All cases were proved by histopathology.The mean ADC_M and ADCR of benign orbital masses were(1.56?0.75)?10~(-3)mm~2/s and 1.85?0.91,respectively.The mean ADC_M and ADCR of malignant orbital masses were(1.09?0.42)?10~(-3)mm~2/s and 1.28?0.53,respectively.There were significant difference both between ADC_M and ADCR of benign and malignant masses(t=2.803,2.735,P