Aim: Sacral chordoma is a primarily benign tumor with a high tendency to recur. A correct definition of tumor volume is a significant prognostic factor. We compared the value of CT and MRI in diagnosing a sacral chordoma.
Methods: 31 patients with a histologically proven sacral chordoma were included in this study. Following parameters were analyzed by two independent radiologists: septation, signs of blood and ossification in the tumor tissue, contrast enhancement, maximal tumor diameter, infiltration of the soft tissue, the dural salc and the cauda equina and multifocality.
Results: In CT all chordomas showed a hypodensity to the normal tissue and in MRI a hyperintensity on T2w images with a low level of contrast enhancement. On the basis of the more precise soft tissue contrast of MRI compared with CT, MRI was significantly more accurate in all tested parameters (p <0.05) besides in detecting tumor ossification. In CT tumor volume was frequently underestimated.
Conclusion: MRI in sacral chordoma is an essential tool in the pretherapeutic diagnostic regimen and in a state of relapse.