Evaluating tumors and tumorlike lesions of the nasal cavity, the paranasal sinuses, and the adjacent skull base with diffusion-weighted MRI

PURPOSE: The purpose of this study was to analyze the relationship of apparent diffusion coefficients (ADCs) to the malignant degree and the histopathological features of the lesions in the nasal cavity, the paranasal sinuses, and the adjacent skull base. METHOD: We evaluated the differences of the ADCs between the malignancies (n = 18) and the benign lesions (n = 6). The correlations between lesion ADCs and lesion cellularity, stroma, and necrosis were calculated. RESULTS: The ADCs of the malignancies were significantly lower than the benign lesions (P < 0.0125). The ADCs were inversely correlated with tumor cellularity (P < 0.01, r = -0.556). CONCLUSIONS: ADCs provide quantitative information that has limited utility in the differential diagnosis between malignant and benign lesions. The correlation of the histopathology of a lesion with ADCs is quite complex and affected by numerous tumor components besides cellularity including keratin, collagen, myxoid stroma, and necrosis.