Variation of post-treatment H-MRSI choline signal intensity in pediatric gliomas

Pediatric brain gliomas are not always amenable for complete surgical excis ion, therefore adjuvant treatment for a large tumor mass is often required. As tumor volume shrinkage may not be a reliable method for assessing respo nse to treatment, information about the tumor growth potential is desirable for an adequate follow-up of the patients. Choline (Cho) signal intensity, determined by proton magnetic resonance spectroscopy imaging (H-MRSI), has proved to be a reliable indicator of the metabolic activity and of tumor p rogression in various intracranial tumors. In this study we have sought to determine if H-MRSI can be of use in monitoring the response of pediatric g liomas to different forms of therapy. We performed pretreatment and post-tr eatment H-MRSI in 10 children with biopsed or partially excised brain gliom as. The follow-up period ranged between 6 and 40 months. A total of 38 H-MR SI were performed. All the patients had chemotherapy or radiotherapy. As an indicator of tumor activity we utilized the ratio between tumor/brain Cho signal intensity. Treatment response was evaluated as a function of tumor v olume and clinical outcome. In 6 patients whose tumor volume decreased or r emained stable we observed that the Chu ratio decreased (p < 0.01) after tr eatment and remained low during longitudinal follow-up. In the 4 patients w hose tumors progressed the Cho ratio increased after treatment. These obser vations suggest that serial H-MRSI can provide valuable information regardi ng the response to therapy in pediatric gliomas and therefore be of use in the follow-up of these neoplasms of childhood.