Abstract B44: Value of 1H-magnetic resonance spectroscopy chemical shift imaging (CSI) for detection of anaplastic foci in diffusely infiltrating gliomas with non-significant contrast-enhancement

Abstract

Abstract Objective: In diffusely infiltrating gliomas (DIG), positron emission tomography (PET) imaging is a clinically powerful method for detection of anaplastic foci. Recently, 1H-magnetic resonance spectroscopy chemical shift imaging (CSI) using choline/creatine (Cho/Cr) or choline/N-acetylaspartate (Cho/NAA) ratios has emerged as new non-invasive and widely available alternative. We therefore correlated CSI with 11C-methionine (MET)-PET data in a series of DIG with non-significant contrast-enhancement (CE). Methods: Thirty-two patients with DIG were examined with CSI on 3T MRI scanner and MET-PET. Maximum pathologic intratumoral ratios of CSI (=CSImax) and maximum tumor-to-normal-brain PET ratios (=PETmax; T/N ratio) were determined. Co-registration of MRI with CSI and PET was performed and the topographic overlap of CSImax and PETmax was analyzed. Cell proliferation rate in tumor samples inside and outside of CSImax was assessed by MIB-1 labeling index (LI). Results: CSI showed a pathologic ratio in all patients, whereas PET demonstrated a pathologic T/N ratio in 21/32 patients. Topographical correlation of CSImax and PETmax revealed a ≥50% overlap in 18/21 and <50% overlap in 3/21 patients, respectively. Cho/Crmax and Cho/NAAmax showed a ≥50% overlap in 24/32, a <50% overlap in 8/32 patients. MIB-1 LI was significantly higher inside than outside the CSImax (13.6% versus 6.9%, p<0.001). Conclusion: Our results indicate that CSI is a promising method for detection of anaplastic foci within DIG with non-significant CE. Intraoperative use of CSI by multimodal neuronavigation may increase the reliability of detection of malignant areas in glioma surgery and therefore optimize allocation of patients to adjuvant treatments. Citation Information: Clin Cancer Res 2010;16(7 Suppl):B44