title: Synergistic role of simultaneous PET/MRI-MRS in soft tissue sarcoma metabolism imaging.
abstract: The primary objective of this study was to develop and validate simultaneous PET/MRI-MRS as a novel biological image-guided approach to neoadjuvant radiotherapy (RT) and/or chemoradiation (chemoRT) in soft tissue sarcomas (STS). A patient with sarcoma of the right thigh underwent PET/MRI scan before and after neoadjuvant (preoperative) radiotherapy. The magnetic resonance imaging (MRI) and 2-deoxy-2-[fluorine-18]-fluoro-D-glucose-Positron Emission Tomography ((18)F-FDG-PET) scans were performed simultaneously. In the post-radiation scan, magnetic resonance spectroscopy (MRS) was subsequently acquired with volume of interest positioned in a residual hyper-metabolic region detected by PET. Post-radiation PET/MRI showed a residual T2-hyperintense mass with significantly reduced (18)F-FDG-uptake, compatible with near complete response to radiotherapy. However, a small region of residual high (18)F-FDG uptake was detected at the tumor margin. MRS of this region had similar metabolite profile as normal tissue, and was thus considered false positive on PET scan. Pathology results were obtained after surgery for confirmation of imaging findings.
authors.affiliation: Gordon Center for Medical Imaging, Radiology Department, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114. Electronic address: zhang@pet.mgh.harvard.edu.
authors.forename: Xiaomeng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Gordon Center for Medical Imaging, Radiology Department, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts 02114.
authors.forename: Yen-Lin E
authors.initials: YL
authors.lastname: Chen
authors.affiliation: Gordon Center for Medical Imaging, Radiology Department, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114.
authors.forename: Ruth
authors.initials: R
authors.lastname: Lim
authors.affiliation: Gordon Center for Medical Imaging, Radiology Department, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Department of Radiology and Psychiatry, Stony Brook Medicine, Stony Brook, NY 11794.
authors.forename: Chuan
authors.initials: C
authors.lastname: Huang
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts 02114.
authors.forename: Ivan A
authors.initials: IA
authors.lastname: Chebib
authors.affiliation: Gordon Center for Medical Imaging, Radiology Department, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114. Electronic address: elfakhri@pet.mgh.harvard.edu.
authors.forename: Georges
authors.initials: G
authors.lastname: El Fakhri
mesh_terms: D017024:Chemotherapy, Adjuvant; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D011878:Radiotherapy; D012509:Sarcoma / Q000000981:diagnostic imaging* / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose
keywords: PET guided MR spectroscopy; Simultaneous PET/MR; Soft tissue sarcoma