{'fraction_non_alphanumeric': 0.024671052631578948, 'fraction_numerical': 0.013980263157894737, 'mean_word_length': 5.508021390374331, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Spinal cord ependymomas: MR imaging features.

PURPOSE
To assess the magnetic resonance (MR) imaging characteristics of spinal intramedullary ependymomas.


MATERIALS AND METHODS
MR images obtained in 25 patients (aged 12-73 years) with proved intramedullary ependymomas were retrospectively reviewed. T1- and T2-weighted images were obtained in all patients. Gadopentetate dimeglumine was intravenously administered in 23 patients; enhanced sagittal and axial T1-weighted spin-echo images were reviewed.


RESULTS
All tumors had hyperintense signal on T2-weighted images. In the 23 patients who received contrast material, all tumors became enhanced; enhancement was heterogeneous in 15 patients and homogeneous in eight patients. Twenty tumors had sharply defined, enhanced borders. Nineteen tumors were centrally located in the spinal cord. A hypointense rim on T2-weighted images was noted in five patients.


CONCLUSION
Intramedullary ependymomas become enhanced after administration of gadopentetate dimeglumine; the enhanced borders are usually sharply marginated. They are characteristically located centrally in an expanded spinal cord. Hemosiderin is often present at the periphery of cervical ependymomas.