A novel, integrated PET-guided MRS technique resulting in more accurate initial diagnosis of high-grade glioma.
Glioblastoma multiforme (GBM) is the most common and lethal malignant glioma in adults. Currently, the modality of choice for diagnosing brain tumor is high-resolution magnetic resonance imaging (MRI) with contrast, which provides anatomic detail and localization. Studies have demonstrated, however, that MRI may have limited utility in delineating the full tumor extent precisely. Studies suggest that MR spectroscopy (MRS) can also be used to distinguish high-grade from low-grade gliomas. However, due to operator dependent variables and the heterogeneous nature of gliomas, the potential for error in diagnostic accuracy with MRS is a concern. Positron emission tomography (PET) imaging with (11)C-methionine (MET) and (18)F-fluorodeoxyglucose (FDG) has been shown to add additional information with respect to tumor grade, extent, and prognosis based on the premise of biochemical changes preceding anatomic changes. Combined PET/MRS is a technique that integrates information from PET in guiding the location for the most accurate metabolic characterization of a lesion via MRS. We describe a case of glioblastoma multiforme in which MRS was initially non-diagnostic for malignancy, but when MRS was repeated with PET guidance, demonstrated elevated choline/N-acetylaspartate (Cho/NAA) ratio in the right parietal mass consistent with a high-grade malignancy. Stereotactic biopsy, followed by PET image-guided resection, confirmed the diagnosis of grade IV GBM. To our knowledge, this is the first reported case of an integrated PET/MRS technique for the voxel placement of MRS. Our findings suggest that integrated PET/MRS may potentially improve diagnostic accuracy in high-grade gliomas.
Department of Internal Medicine, Kettering Medical Center, USA Ellen.Kim@khnetwork.org.
Ellen S
ES
Kim
Department of Nuclear Medicine/PET, Kettering Medical Center, USA.
Martin
M
Satter
Department of Neuro Sciences Service Line, Kettering Medical Center, USA.
Marilyn
M
Reed
Department of Radiology, Kettering Medical Center, USA.
Ronald
R
Fadell
Department of Nuclear Medicine/PET, Kettering Medical Center, USA Boonshoft School of Medicine, Wright State University, USA.
Arash
A
Kardan
D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008875:Middle Aged; D060787:Neoplasm Grading; D049268:Positron-Emission Tomography / Q000379:methods*; D012680:Sensitivity and Specificity
Glioblastoma multiforme; MR spectroscopy imaging; PET imaging