Skull metastases and osseous venous malformations: The role of diffusion‐weighted and dynamic contrast‐enhanced MRI

BACKGROUND AND PURPOSE: Skull metastasis (SM) is a common secondary malignancy. We evaluated the diagnostic performance of diffusion‐weighted imaging (DWI) and dynamic contrast‐enhanced magnetic resonance imaging (MRI) in differentiating SM from osseous venous malformations and SM of various origins. METHODS: This study included 31 patients with SM (median age, 64 years; range, 41‐87 years; 29 women; 24 and 7 patients with breast and non‐small cell lung cancer, respectively) and 16 with osseous venous malformations (median age, 68 years; range, 20‐81 years; 10 women) who underwent both DWI and dynamic contrast‐enhanced MRI between January 2015 and October 2021. Normalized mean apparent diffusion coefficients (ADCs) and dynamic contrast‐enhanced MRI parameters were compared between SM and osseous venous malformations, and between breast cancer and non‐small cell lung cancer. Multivariate stepwise logistic regression analyses were performed to identify statistically significant parameters. RESULTS: Plasma volume and time‐to‐maximum enhancement were the most statistically significant parameters for differentiating SM from osseous venous malformations, with an area under the receiver operating characteristic curve of 0.962. The normalized mean ADC and peak enhancement values were the most statistically significant parameters for differentiating breast cancer from non‐small cell lung cancer, with an area under the curve of 0.924. CONCLUSIONS: Our results highlight the efficacious diagnostic performance of DWI and dynamic contrast‐enhanced MRI in distinguishing SM from osseous venous malformations and differentiating SM of various origins.