Orbital malignant lesions in adults: multiparametric MR imaging.

PURPOSE: To assess the benefit of combining diffusion-weighted imaging and dynamic contrast-enhanced (DCE) MR imaging in the preoperative evaluation of orbital lymphoma and other malignancies in adults.

MATERIALS AND METHODS: This retrospective study was institutional review board-approved and informed consent was waived. Pretreatment MR imaging was performed in 52 patients with malignant orbital lesions. Apparent diffusion coefficient (ADC) and DCE MR parameters were evaluated in 30 patients with orbital lymphoma and 22 patients with other orbital malignancies. Independent-samples t-test or Wilcoxon rank-sum test was used to compare parameters. The diagnostic capability was evaluated by using receiver operating characteristic curve (ROC) analysis.

RESULTS: Lymphoma demonstrated significantly lower mean ADC (P < 0.001), Tmax (P = 0.001), enhancement ratio (ER) (P < 0.001), contrast index (CI) (P < 0.001) and significantly higher washout ratio (WR) (P = 0.002) than other malignancies in the orbit. ROC analysis indicated that Tmax alone or a combination with ADC and ER showed the optimal sensitivity (96.67%), a combination of ADC and WR showed optimal specificity (95.45%), while a combination of ADC and ER showed optimal accuracy (90.38%) in differentiating lymphoma from other malignancies.

CONCLUSION: Multiparametric MRI can help to differentiate orbital lymphoma and other malignancies.