title: Tryptophan PET predicts spatial and temporal patterns of post-treatment glioblastoma progression detected by contrast-enhanced MRI.
abstract: Amino acid PET is increasingly utilized for the detection of recurrent gliomas. Increased amino acid uptake is often observed outside the contrast-enhancing brain tumor mass. In this study, we evaluated if non-enhancing PET+ regions could predict spatial and temporal patterns of subsequent MRI progression in previously treated glioblastomas. Twelve patients with a contrast-enhancing area suspicious for glioblastoma recurrence on MRI underwent PET scanning with the amino acid radiotracer alpha-[(11)C]-methyl-L-tryptophan (AMT). Brain regions showing increased AMT uptake in and outside the contrast-enhancing volume were objectively delineated to include high uptake consistent with glioma (as defined by previous studies). Volume and tracer uptake of such non-enhancing PET+ regions were compared to spatial patterns and timing of subsequent progression of the contrast-enhancing lesion, as defined by serial surveillance MRI. Non-enhancing PET+ volumes varied widely across patients and extended up to 24 mm from the edge of MRI contrast enhancement. In ten patients with clear progression of the contrast-enhancing lesion, the non-enhancing PET+ volumes predicted the location of new enhancement, which extended beyond the PET+ brain tissue in six. In two patients, with no PET+ area beyond the initial contrast enhancement, MRI remained stable. There was a negative correlation between AMT uptake in non-enhancing brain and time to subsequent progression (r = -0.77, p = 0.003). Amino acid PET imaging could complement MRI not only for detecting glioma recurrence but also predicting the location and timing of subsequent tumor progression. This could support decisions for surgical intervention or other targeted therapies for recurrent gliomas.
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, 3901 Beaubien Street, Detroit, MI, 48201, USA.|Department of Pediatrics, Wayne State University, Detroit, MI, USA.
authors.forename: Edit
authors.initials: E
authors.lastname: Bosnyák
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, 3901 Beaubien Street, Detroit, MI, 48201, USA.|Department of Pediatrics, Wayne State University, Detroit, MI, USA.
authors.forename: David O
authors.initials: DO
authors.lastname: Kamson
authors.affiliation: Department of Radiology, Wayne State University, Detroit, MI, USA.|Karmanos Cancer Institute, Detroit, MI, USA.
authors.forename: Natasha L
authors.initials: NL
authors.lastname: Robinette
authors.affiliation: Department of Neurology, Wayne State University, Detroit, MI, USA.|Karmanos Cancer Institute, Detroit, MI, USA.
authors.forename: Geoffrey R
authors.initials: GR
authors.lastname: Barger
authors.affiliation: Department of Neurosurgery, Wayne State University, Detroit, MI, USA.|Department of Oncology, Wayne State University, Detroit, MI, USA.|Karmanos Cancer Institute, Detroit, MI, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Mittal
authors.affiliation: PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, 3901 Beaubien Street, Detroit, MI, 48201, USA. juhasz@pet.wayne.edu.|Department of Pediatrics, Wayne State University, Detroit, MI, USA. juhasz@pet.wayne.edu.|Department of Neurology, Wayne State University, Detroit, MI, USA. juhasz@pet.wayne.edu.|Karmanos Cancer Institute, Detroit, MI, USA. juhasz@pet.wayne.edu.
authors.forename: Csaba
authors.initials: C
authors.lastname: Juhász
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D003287:Contrast Media; D014364:Tryptophan
keywords: Alpha-[11C]-methyl-L-tryptophan (AMT); Glioblastoma; MRI; Positron emission tomography (PET); Tumor recurrence