Distinguishing Intracranial Solitary Fibrous Tumors from Meningiomas: The Diagnostic Value of T1-Weighted MRI Signal Intensity and ADC Values.

Background and purpose: Intracranial solitary fibrous tumors (SFTs) and meningiomas are CNS tumors that share similar imaging manifestations but exhibit different clinical behaviors. This study aimed to compare ADC values and conventional imaging features, particularly pre-contrast T1-weighted signal intensity, between intracranial SFTs and meningiomas.

Materials and methods: We retrospectively evaluated 13 patients with pathologically proven intracranial SFTs and 27 patients with meningiomas who attended our hospital between January 2002 and December 2023. Signal intensity on pre-contrast T1-weighted imaging (compared to cerebral cortex), presence of dural tail sign, flow voids, hyperostosis, calcification, and normalized mean T1-weighted imaging values and mean ADC values were assessed.

Results: T1-weighted hyperintensity was significantly more frequent in SFTs (10/13, 76.9%) compared to meningiomas (5/27, 18.5%) (P=0.0010). Normalized mean T1-weighted imaging values (P=0.035) and normalized mean ADC values (P=0.039) were significantly higher in SFTs compared to meningiomas. A significant inverse correlation between normalized mean T1-weighted imaging and ADC values was observed in SFTs (R-squared=0.42, P=0.017). Binomial logistic regression analysis showed moderate efficacy in differentiating these tumors (mean cross-validation score=0.83). Dural tail sign, hyperostosis, and calcification were more frequent in meningiomas, although these differences were not statistically significant.

Conclusions: Pre-contrast T1-weighted signal intensity is a useful characteristic for differentiating intracranial SFTs from meningiomas, with hyperintensity compared to cerebral cortex being a distinctive feature of SFTs. The combination of normalized T1-weighted imaging and ADC values provides moderate diagnostic accuracy.

Abbreviations: SFT = solitary fibrous tumors.