Magnetic resonance spectroscopy guided brain tumor resection: differentiation between recurrent glioma and radiation change in two diagnostically difficult cases

• Published in: Canadian journal of neurological sciences Vol. 25; no. 1; p. 13
• Main Authors: Preul, M C, Leblanc, R, Caramanos, Z, Kasrai, R, Narayanan, S, Arnold, D L
• Format: Journal Article
• Language: English
• Published: England 01.02.1998
• Subjects: Adult; Brain - metabolism; Brain - pathology; Brain - radiation effects; Brain Neoplasms - diagnosis; Brain Neoplasms - radiotherapy; Brain Neoplasms - surgery; Choline - metabolism; Combined Modality Therapy; Diagnosis, Differential; Glioma - diagnosis; Glioma - radiotherapy; Glioma - surgery; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Neoplasm Recurrence, Local - diagnosis; Phospholipids - metabolism; Radiation Injuries - diagnosis; Stereotaxic Techniques; Tomography, Emission-Computed
• ISSN: 0317-1671
• DOI: 10.1017/S0317167100033436

It is often difficult to differentiate a recurrent glioma from the effects of post-operative radiotherapy by means of conventional neurodiagnostic imaging. Proton magnetic resonance spectroscopic imaging (1H-MRSI), that allows in vivo measurements of the concentration of brain metabolites such as choline-containing phospholipids (Cho), may provide in vivo biochemical information helpful in distinguishing areas of tumor recurrence from areas of radiation effect. Two patients who had undergone resection and post-operative radiotherapy for a cerebral glioma became newly symptomatic. Computed tomographic (CT) and magnetic resonance imaging (MRI) performed after the intravenous infusion of contrast material, and in one case, [18F]fluorodeoxyglucose positron emission tomography (PET), could not differentiate between the possibilities of recurrent glioma and radiation effect. The patients underwent 1H-MRSI prior to reoperation and the 1H-MRSI results were compared to histological findings originating from the same locations. A high Cho signal measured by 1H-MRSI was seen in areas of histologically-proven dense tumor recurrence, while low Cho signal was present where radiation changes predominated. The differentiation between the recurrence of a cerebral glioma and the effects of post-operative irradiation was achieved using 1H-MRSI in these two patients whose conventional neurodiagnostic imaging was equivocal for such a distinction. Where these two conditions are present, metabolite images from 1H-MRSI, such as that based on Cho, can be co-registered with other imaging modalities such as MRI and may also be integrated with functional MRI or functional PET within a multimodal imaging-guided surgical navigation system to assure maximal resection of recurrent tumor while minimizing the risk of added neurological damage.