Magnetic Resonance Imaging Evaluation of the Clivus and Nasopharyngeal Carcinoma

Objectives: To establish the age-related distribution of clival marrow magnetic resonance imaging appearances in ethnic Chinese and to compare these findings with the clival marrow magnetic resonance imaging appearances seen in Chinese patients with nasopharyngeal carcinoma. Materials and Methods: T1-weighted sagittal cranial magnetic resonance images of 41 normal individuals and 40 patients newly diagnosed with nasopharyngeal carcinoma were reviewed. The clivus marrow signal intensity pattern seen for each normal subject was graded. The clivus marrow signal intensity pattern of patients with nasopharyngeal carcinoma without direct clival involvement was also graded, using the same grading system. Results: Grade 2 clivus marrow signal intensity pattern (heterogeneous pattern, with the low intensity portion occupying 20 to 50%) was the most common pattern in the youngest age group (20-39 years old) of normal subjects. The proportion of grades 1 and 2 clivus marrow signal intensity pattern declined steadily in the intermediate (40-59 years old) and oldest (> 60 years old) age groups. The grade 3 clivus marrow signal intensity pattern (homogeneous high signal intensity pattern, with the low signal portion occupying less than 20%) was the most prevalent pattern in normal subjects over 60 years of age. In patients with nasopharyngeal carcinoma without direct clival invasion, similar age-related patterns were observed. Conclusion: The age distribution of clival bone marrow signals on magnetic resonance imaging has been described in Chinese subjects. No significant difference in pattern between patients with nasopharyngeal carcinoma without direct clival invasion and normal subjects was seen. This suggests that infiltration of the clivus in nasopharyngeal carcinoma is by direct contiguous invasion.