Diffusion-weighted MRI: Distinction of skull base chordoma from chondrosarcoma

Abstract

BACKGROUND AND PURPOSE: Chordoma and chondrosarcoma of the skull base are rare tumors with overlapping presentations and anatomic imaging features but different prognoses. We hypothesized that these tumors might be distinguished by using diffusion-weighted MR imaging. MATERIALS AND METHODS: We retrospectively reviewed 19 patients with pathologically confirmed chordoma or chondrosarcoma who underwent both conventional and diffusion-weighted MR imaging. Differences in distributions of ADC were assessed by the Kruskal-Wallis test. Associations between histopathologic diagnosis and conventional MR imaging features (T2 signal intensity, contrast enhancement, and tumor location) were assessed with the Fisher exact test. RESULTS: Chondrosarcoma was associated with the highest mean ADC value (2051 ± 261 × 10-6 mm2/s) and was significantly different from classic chordoma (1474 ± 117 × 10-6 mm2/s) and poorly differentiated chordoma (875 ± 100 × 10-6 mm2/s) (P