Nazofarinks Kanserli Hastalarda Radyoterapi Sonrası MRG'de Klivustaki Medüller Intensite Değişiklikleri

Abstract

Clivus is commonly involved in nasopharyngeal carcinoma (NPC) and the intensity changes in the bone marrow can persist after the radiation therapy (RT) even after the disappearance of the mucosal soft tissue mass. Furthermore the appearance of the bone marrow (BM) can also show radiation-related changes. The differentiation of residual benign signal change from a recurrent/persistent lesion may be challenging. We wanted to investigate the signal changes of the clivus in patients with nasopharyngeal carcinoma receiving RT in order to define an expected temporal evolution. Baseline and follow up MR imaging of 68 NPC patients that had undergone RT were retrospectively examined. The degree of the clival involvement (graded into 4 groups regarding its anterior-posterior extension), the BM signal changes and contrast enhancement were evaluated on baseline and 4.3 follow up studies (min/max: 2/7) per patient. The persistence of BM intensity changes were noted and correlated with the grade of initial clival involvement, the RT dose, the size of the initial mass. 46 patients who had involvement of the clivus in baseline imaging were evaluated with a mean follow up period of 46 months (max 100 months). Signal changes persisted for 31 months (max: 99 months) and clival enhancement persisted for 17.5 months (max: 99 months) for a mean period time. The signal intensity changes completely disappeared for 23.5% and enhancement of the BM completely disappeared for 68.2% patients who had clival signal changes/enhancement on first follow up MRI. 6 patients (8.8%) had recurrence in the follow up. There were correlation between the baseline clivus involvement and the resolution of signal changes (p=0.000) as well as resolution of the enhancement (p=0.000) on follow up MR studies. The resolution of the signal intensity changes/enhancement represented no correlation with the radiation therapy dose (p=0.310/0.307). In conclusion signal intensity changes and enhancement of the clivus after RT showed a large spectrum with residual signal changes even after years of remission in the majority of the patients.