MRI findings of solitary fibrous tumours in the head and neck region.

OBJECTIVES: To analyse the MRI findings of solitary fibrous tumours in the head and neck region.
METHODS: We retrospectively reviewed MR images in eight patients with solitary fibrous tumours proven on histological examination. All the patients underwent conventional MRI, and four patients also underwent dynamic contrast-enhanced MRI and diffusion-weighted imaging in five cases. Image characteristics were analysed.
RESULTS: All lesions were found as solitary well-defined masses ranging in size from 1.9 to 6.8 cm (mean, 4.1 cm). They were mostly homogeneous and isointense to the muscle on T1 weighted images and heterogeneous and mildly hyperintense on T2 weighted images. After gadolinium administration, areas that were mildly hyperintense on T2 weighted images were strongly enhanced. They were mildly hyperintense on diffusion-weighted imaging. The average tumour-apparent diffusion coefficient values were 0.001 157 ± 0.000 304 9 mm s(-2) compared with the muscle 0.000 760 ± 0.000 265 0 mm s(-2), and there was a statistical difference of p = 0.002. The time-intensity curves exhibited a rapidly enhancing and a slow washout pattern on dynamic contrast-enhanced MRI.
CONCLUSIONS: Solitary fibrous tumours should be considered in cases of heterogeneous hypervascular tumours in the head and neck region. Areas of mild hyperintense intensity on T2 weighted images that are strongly enhanced after gadolinium injection are suggestive of this diagnosis. Non-restricted diffusion and rapidly enhancing and slow washout pattern time-intensity curves may be additional valuable features.