Carmustine wafers (
Gliadel Wafer) are implanted at resection in some patients with high-grade
gliomas. Studies suggest that
proton magnetic resonance spectroscopic imaging ((1)H MRSI) demonstrates early changes predictive of future failure or response to systemic
chemotherapy. This study explores (1)H MRSI as a means to assess peri-tumoral tissue response post-resection and
Gliadel((R)) implantation in patients with high-grade
gliomas. Pilot (1)H MRSI data are presented that demonstrate noninvasive, serial monitoring of metabolic changes at the
tumor site following
Gliadel implantation. Three patients with newly diagnosed
glioblastoma multiforme (GBM) underwent MRI and (1)H MRSI at 3.0 Tesla prior to resection and at 3-5 and > or =12 weeks post-operatively. Baseline MRS spectra of
tumor tissue from all patients were characterized by marked increases of
choline (CHO) and
lactate (LAC), and a decrease of
N-acetylaspartate (NAA), typical of GBM compared with normal contra-lateral brain tissue. Post-operatively, spectra were analyzed from the resection cavity and peri-tumoral regions and compared with normal tissue from the contra-lateral brain at baseline. In 2 of 3 patients, peri-tumoral NAA/CRE increased and CHO/NAA decreased compared to contra-lateral brain at 3-5 weeks compared with baseline following
Gliadel therapy and surgery but prior to
radiotherapy. This study indicates that (1)H MRSI has the ability to localize regions of heterogeneous response following
Gliadel treatment. Although data are limited, these results suggest that metabolic indicators of outcome can be successfully monitored pre- and post-surgical resection and
Gliadel implantation with (1)H MRSI. Additional study of patients receiving
Gliadel Wafers using (1)H MRSI may serve to aid clinicians in assessing
tumor regression and gauging efficacy of this
chemotherapy treatment.