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Urso L, Bonatto E, Nieri A, Castello A, Maffione AM, Marzola MC, Cittanti C, Bartolomei M, Panareo S, Mansi L, Lopci E, Florimonte L, Castellani M. The Role of Molecular Imaging in Patients with Brain Metastases: A Literature Review. Cancers (Basel) 2023; 15:cancers15072184. [PMID: 37046845 PMCID: PMC10093739 DOI: 10.3390/cancers15072184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/28/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023] Open
Abstract
Over the last several years, molecular imaging has gained a primary role in the evaluation of patients with brain metastases (BM). Therefore, the "Response Assessment in Neuro-Oncology" (RANO) group recommends amino acid radiotracers for the assessment of BM. Our review summarizes the current use of positron emission tomography (PET) radiotracers in patients with BM, ranging from present to future perspectives with new PET radiotracers, including the role of radiomics and potential theranostics approaches. A comprehensive search of PubMed results was conducted. All studies published in English up to and including December 2022 were reviewed. Current evidence confirms the important role of amino acid PET radiotracers for the delineation of BM extension, for the assessment of response to therapy, and particularly for the differentiation between tumor progression and radionecrosis. The newer radiotracers explore non-invasively different biological tumor processes, although more consistent findings in larger clinical trials are necessary to confirm preliminary results. Our review illustrates the role of molecular imaging in patients with BM. Along with magnetic resonance imaging (MRI), the gold standard for diagnosis of BM, PET is a useful complementary technique for processes that otherwise cannot be obtained from anatomical MRI alone.
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Affiliation(s)
- Luca Urso
- Department of Nuclear Medicine PET/CT Centre, S. Maria della Misericordia Hospital, 45100 Rovigo, Italy
| | - Elena Bonatto
- Nuclear Medicine Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Alberto Nieri
- Nuclear Medicine Unit, Oncological Medical and Specialist Department, University Hospital of Ferrara, 44124 Cona, Italy
| | - Angelo Castello
- Nuclear Medicine Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Anna Margherita Maffione
- Department of Nuclear Medicine PET/CT Centre, S. Maria della Misericordia Hospital, 45100 Rovigo, Italy
| | - Maria Cristina Marzola
- Department of Nuclear Medicine PET/CT Centre, S. Maria della Misericordia Hospital, 45100 Rovigo, Italy
| | - Corrado Cittanti
- Nuclear Medicine Unit, Oncological Medical and Specialist Department, University Hospital of Ferrara, 44124 Cona, Italy
- Department of Translational Medicine, University of Ferrara, Via Aldo Moro 8, 44124 Ferrara, Italy
| | - Mirco Bartolomei
- Nuclear Medicine Unit, Oncological Medical and Specialist Department, University Hospital of Ferrara, 44124 Cona, Italy
| | - Stefano Panareo
- Nuclear Medicine Unit, Oncology and Haematology Department, University Hospital of Modena, 41125 Modena, Italy
| | - Luigi Mansi
- Interuniversity Research Center for the Sustainable Development (CIRPS), 00152 Rome, Italy
| | - Egesta Lopci
- Nuclear Medicine Unit, IRCCS-Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
| | - Luigia Florimonte
- Nuclear Medicine Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Massimo Castellani
- Nuclear Medicine Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
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Diagnostic Value of 18 F-FACBC PET/MRI in Brain Metastases. Clin Nucl Med 2022; 47:1030-1039. [PMID: 36241129 PMCID: PMC9653108 DOI: 10.1097/rlu.0000000000004435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE The study aims to evaluate whether combined 18 F-FACBC PET/MRI could provide additional diagnostic information compared with MRI alone in brain metastases. PATIENTS AND METHODS Eighteen patients with newly diagnosed or suspected recurrence of brain metastases received dynamic 18 F-FACBC PET/MRI. Lesion detection was evaluated on PET and MRI scans in 2 groups depending on prior stereotactic radiosurgery (SRS group) or not (no-SRS group). SUVs, time-activity curves, and volumetric analyses of the lesions were performed. RESULTS In the no-SRS group, 29/29 brain lesions were defined as "MRI positive." With PET, 19/29 lesions were detected and had high tumor-to-background ratios (TBRs) (D max MR , ≥7 mm; SUV max , 1.2-8.4; TBR, 3.9-25.9), whereas 10/29 lesions were undetected (D max MR , ≤8 mm; SUV max , 0.3-1.2; TBR, 1.0-2.7). In the SRS group, 4/6 lesions were defined as "MRI positive," whereas 2/6 lesions were defined as "MRI negative" indicative of radiation necrosis. All 6 lesions were detected with PET (D max MR , ≥15 mm; SUV max , 1.4-4.2; TBR, 3.6-12.6). PET volumes correlated and were comparable in size with contrast-enhanced MRI volumes but were only partially congruent (mean DSC, 0.66). All time-activity curves had an early peak, followed by a plateau or a decreasing slope. CONCLUSIONS 18 F-FACBC PET demonstrated uptake in brain metastases from cancer of different origins (lung, gastrointestinal tract, breast, thyroid, and malignant melanoma). However, 18 F-FACBC PET/MRI did not improve detection of brain metastases compared with MRI but might detect tumor tissue beyond contrast enhancement on MRI. 18 F-FACBC PET should be further evaluated in recurrent brain metastases.
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Azar M, Mohsenian Sisakht A, Kazemi Gazik F, Shahrokhi P, Rastegar K, Karamzade-Ziarati N. PET-guided gamma knife radiosurgery in brain tumors: a brief review. Clin Transl Imaging 2021. [DOI: 10.1007/s40336-021-00447-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Ferjančič P, Ebert MA, Francis R, Nowak AK, Jeraj R. Repeatability of Quantitative 18F-FET PET in Glioblastoma. Biomed Phys Eng Express 2021; 7. [PMID: 33887712 DOI: 10.1088/2057-1976/abfae9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/22/2021] [Indexed: 12/16/2022]
Abstract
Purpose: O-(2-[18F]fluoroethyl)-L-tyrosine (FET), a PET radiotracer of amino acid uptake, has shown potential for diagnosis and treatment planning in patients with glioblastoma (GBM). To improve quantitative assessment of FET PET imaging, we evaluated the repeatability of uptake of this tracer in patients with GBM.Methods: Test-retest FET PET imaging was performed on 8 patients with histologically confirmed GBM, who previously underwent surgical resection of the tumour. Data were acquired according to the protocol of a prospective clinical trial validating FET PET as a clinical tool in GBM. SUVmean, SUVmaxand SUV98%metrics were extracted for both test and retest images and used to calculate 95% Bland-Altman limits of agreement (LoA) on lesion-level, as well as on volumes of varying sizes. Impact of healthy brain normalization on repeatability of lesion SUV metrics was evaluated.Results: Tumour LoA were [0.72, 1.46] for SUVmeanand SUVtotal, [0.79,1.23] for SUVmax, and [0.80,1.18] for SUV98%. Healthy brain LoA were [0.80,1.25] for SUVmean, [0.80,1.25] for SUVmax, and [0.81,1.23] for SUV98%. Voxel-level SUV LoA were [0.76, 1.32] for tumour volumes and [0.80, 1.25] for healthy brain. When sampled over maximum volume, SUV LoA were [0.90,1.12] for tumour and [0.92,1.08] for healthy brain. Normalization of uptake using healthy brain volumes was found to improve repeatability, but not after normalization volume size of about 15 cm3.Conclusions Advances in Knowledge and Implications for Patient Care: Repeatability of FET PET is comparable to existing tracers such as FDG and FLT. Healthy brain uptake is slightly more repeatable than uptake of tumour volumes. Repeatability was found to increase with sampled volume. SUV normalization between scans using healthy brain uptake should be performed using volumes at least 15 cm3in size to ensure best imaging repeatability.
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Affiliation(s)
- Peter Ferjančič
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Martin A Ebert
- Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Medical School, University of Western Australia, Crawley, Western Australia, Australia.,5D Clinics, Perth, Western Australia, Australia
| | - Roslyn Francis
- Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Medical School, University of Western Australia, Crawley, Western Australia, Australia
| | - Anna K Nowak
- Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Medical School, University of Western Australia, Crawley, Western Australia, Australia
| | - Robert Jeraj
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States of America.,Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
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Johannessen K, Berntsen EM, Johansen H, Solheim TS, Karlberg A, Eikenes L. 18F-FACBC PET/MRI in the evaluation of human brain metastases: a case report. Eur J Hybrid Imaging 2021; 5:7. [PMID: 34181107 PMCID: PMC8218039 DOI: 10.1186/s41824-021-00101-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/28/2021] [Indexed: 12/31/2022] Open
Abstract
Background Patients with metastatic cancer to the brain have a poor prognosis. In clinical practice, MRI is used to delineate, diagnose and plan treatment of brain metastases. However, MRI alone is limited in detecting micro-metastases, delineating lesions and discriminating progression from pseudo-progression. Combined PET/MRI utilises superior soft tissue images from MRI and metabolic data from PET to evaluate tumour structure and function. The amino acid PET tracer 18F-FACBC has shown promising results in discriminating high- and low-grade gliomas, but there are currently no reports on its use on brain metastases. This is the first study to evaluate the use of 18F-FACBC on brain metastases. Case presentation A middle-aged female patient with brain metastases was evaluated using hybrid PET/MRI with 18F-FACBC before and after stereotactic radiotherapy, and at suspicion of recurrence. Static/dynamic PET and contrast-enhanced T1 MRI data were acquired and analysed. This case report includes the analysis of four 18F-FACBC PET/MRI examinations, investigating their utility in evaluating functional and structural metastasis properties. Conclusion Analysis showed high tumour-to-background ratios in brain metastases compared to other amino acid PET tracers, including high uptake in a very small cerebellar metastasis, suggesting that 18F-FACBC PET can provide early detection of otherwise overlooked metastases. Further studies to determine a threshold for 18F-FACBC brain tumour boundaries and explore its utility in clinical practice should be performed.
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Affiliation(s)
- Knut Johannessen
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, Postboks 8905, 7491, Trondheim, Norway
| | - Erik Magnus Berntsen
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, Postboks 8905, 7491, Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Håkon Johansen
- Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Tora S Solheim
- Cancer Clinic, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.,Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Anna Karlberg
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, Postboks 8905, 7491, Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Live Eikenes
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, Postboks 8905, 7491, Trondheim, Norway.
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Early Monitoring Response to Therapy in Patients with Brain Lesions Using the Cumulative SUV Histogram. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11072999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Gamma Knife treatment is an alternative to traditional brain surgery and whole-brain radiation therapy for treating cancers that are inaccessible via conventional treatments. To assess the effectiveness of Gamma Knife treatments, functional imaging can play a crucial role. The aim of this study is to evaluate new prognostic indices to perform an early assessment of treatment response to therapy using positron emission tomography imaging. The parameters currently used in nuclear medicine assessments can be affected by statistical fluctuation errors and/or cannot provide information on tumor extension and heterogeneity. To overcome these limitations, the Cumulative standardized uptake value (SUV) Histogram (CSH) and Area Under the Curve (AUC) indices were evaluated to obtain additional information on treatment response. For this purpose, the absolute level of [11C]-Methionine (MET) uptake was measured and its heterogeneity distribution within lesions was evaluated by calculating the CSH and AUC indices. CSH and AUC parameters show good agreement with patient outcomes after Gamma Knife treatments. Furthermore, no relevant correlations were found between CSH and AUC indices and those usually used in the nuclear medicine environment. CSH and AUC indices could be a useful tool for assessing patient responses to therapy.
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[ 18F]FET PET Uptake Indicates High Tumor and Low Necrosis Content in Brain Metastasis. Cancers (Basel) 2021; 13:cancers13020355. [PMID: 33478030 PMCID: PMC7835779 DOI: 10.3390/cancers13020355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 12/20/2022] Open
Abstract
Simple Summary Various types of cancers can lead to brain metastasis. Treatment strategies have improved substantially in the past decade, leading to longer survival in many cases, but also to new diagnostic challenges. Being able to locate those parts of a lesion suspicious for brain metastasis that contain the highest concentrations of viable tumor cells can be crucial, e.g., to obtain a precise diagnosis via targeted biopsies or to differentiate recurring tumor from dead tissue after treatment. Positron emission tomography (PET) imaging has the potential to provide this kind of information. However, studies relating PET findings to actual tissue properties are sparse. The aim of this study was to investigate the association of PET imaging with microscopic tissue properties in samples obtained neurosurgically from brain metastases. Our findings can improve the planning and yield of biopsies from brain metastases, and they may inform future studies aimed at improving the discrimination of recurring from dead tumor in treated brain metastases using PET. Abstract Amino acid positron emission tomography (PET) has been employed in the management of brain metastases. Yet, histopathological correlates of PET findings remain poorly understood. We investigated the relationship of O-(2-[18F]Fluoroethyl)-L-tyrosine ([18F]FET) PET, magnetic resonance imaging (MRI), and histology in brain metastases. Fifteen patients undergoing brain metastasis resection were included prospectively. Using intraoperative navigation, 39 targeted biopsies were obtained from parts of the metastases that were either PET-positive or negative and MRI-positive or negative. Tumor and necrosis content, proliferation index, lymphocyte infiltration, and vascularization were determined histopathologically. [18F]FET PET had higher specificity than MRI (66% vs. 56%) and increased sensitivity for tumor from 73% to 93% when combined with MRI. Tumor content per sample increased with PET uptake (rs = 0.3, p = 0.045), whereas necrosis content decreased (rs = −0.4, p = 0.014). PET-positive samples had more tumor (median: 75%; interquartile range: 10–97%; p = 0.016) than PET-negative samples. The other investigated histological properties were not correlated with [18F]FET PET intensity. Tumors were heterogeneous at the levels of imaging and histology. [18F]FET PET can be a valuable tool in the management of brain metastases. In biopsies, one should aim for PET hotspots to increase the chance for retrieval of samples with high tumor cell concentrations. Multiple biopsies should be performed to account for intra-tumor heterogeneity. PET could be useful for differentiating treatment-related changes (e.g., radiation necrosis) from tumor recurrence.
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Aasen SN, Espedal H, Keunen O, Adamsen TCH, Bjerkvig R, Thorsen F. Current landscape and future perspectives in preclinical MR and PET imaging of brain metastasis. Neurooncol Adv 2021; 3:vdab151. [PMID: 34988446 PMCID: PMC8704384 DOI: 10.1093/noajnl/vdab151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Brain metastasis (BM) is a major cause of cancer patient morbidity. Clinical magnetic resonance imaging (MRI) and positron emission tomography (PET) represent important resources to assess tumor progression and treatment responses. In preclinical research, anatomical MRI and to some extent functional MRI have frequently been used to assess tumor progression. In contrast, PET has only to a limited extent been used in animal BM research. A considerable culprit is that results from most preclinical studies have shown little impact on the implementation of new treatment strategies in the clinic. This emphasizes the need for the development of robust, high-quality preclinical imaging strategies with potential for clinical translation. This review focuses on advanced preclinical MRI and PET imaging methods for BM, describing their applications in the context of what has been done in the clinic. The strengths and shortcomings of each technology are presented, and recommendations for future directions in the development of the individual imaging modalities are suggested. Finally, we highlight recent developments in quantitative MRI and PET, the use of radiomics and multimodal imaging, and the need for a standardization of imaging technologies and protocols between preclinical centers.
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Affiliation(s)
- Synnøve Nymark Aasen
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Department of Health and Functioning, Western Norway University of Applied Sciences, Bergen, Norway
| | - Heidi Espedal
- The Molecular Imaging Center, Department of Biomedicine, University of Bergen, Bergen, Norway
- Mohn Medical Imaging and Visualization Centre, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Olivier Keunen
- Translational Radiomics, Department of Oncology, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Tom Christian Holm Adamsen
- Centre for Nuclear Medicine, Department of Radiology, Haukeland University Hospital, Bergen, Norway
- 180 °N – Bergen Tracer Development Centre, Department of Radiology, Haukeland University Hospital, Bergen, Norway
- Department of Chemistry, University of Bergen, Bergen, Norway
| | - Rolf Bjerkvig
- Department of Biomedicine, University of Bergen, Bergen, Norway
- NorLux Neuro-Oncology Laboratory, Department of Oncology, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Frits Thorsen
- Department of Biomedicine, University of Bergen, Bergen, Norway
- The Molecular Imaging Center, Department of Biomedicine, University of Bergen, Bergen, Norway
- Department of Neurosurgery, Qilu Hospital of Shandong University and Brain Science Research Institute, Shandong University, Key Laboratory of Brain Functional Remodeling, Shandong, Jinan, P.R. China
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Fuenfgeld B, Mächler P, Fischer DR, Esposito G, Rushing EJ, Kaufmann PA, Stolzmann P, Huellner MW. Reference values of physiological 18F-FET uptake: Implications for brain tumor discrimination. PLoS One 2020; 15:e0230618. [PMID: 32302317 PMCID: PMC7164612 DOI: 10.1371/journal.pone.0230618] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 02/28/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose The aim of this study was to derive reference values of 18F-fluoro-ethyl-L-tyrosine positron emission tomography (18F-FET-PET) uptake in normal brain and head structures to allow for differentiation from tumor tissue. Materials and methods We examined the datasets of 70 patients (median age 53 years, range 15–79), whose dynamic 18F-FET-PET was acquired between January 2016 and October 2017. Maximum standardized uptake value (SUVmax), target-to-background standardized uptake value ratio (TBR), and time activity curve (TAC) of the 18F-FET-PET were assessed in tumor tissue and in eight normal anatomic structures and compared using the t-test and Mann-Whitney U-test. Correlation analyses were performed using Pearson or Spearman coefficients, and comparisons between several variables with Pearson’s chi-squared tests and Kruskal-Wallis tests as well as the Benjamini-Hochberg correction. Results All analyzed structures showed an 18F-FET uptake higher than background (threshold: TBR > 1.5). The venous sinuses and cranial muscles exhibited a TBR of 2.03±0.46 (confidence interval (CI) 1.92–2.14), higher than the uptake of caudate nucleus, pineal gland, putamen, and thalamus (TBR 1.42±0.17, CI 1.38–1.47). SUVmax, TBR, and TAC showed no difference in the analyzed structures between subjects with high-grade gliomas and subjects with low-grade gliomas, except the SUVmax of the pineal gland (t-tests of the pineal gland: SUVmax: p = 0.022; TBR: p = 0.411). No significant differences were found for gender and age. Conclusion Normal brain tissue demonstrates increased 18F-FET uptake compared to background tissue. Two distinct clusters have been identified, comprising venous structures and gray matter with a reference uptake of up to SUVmax of 2.99 and 2.33, respectively.
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Affiliation(s)
- Brigitte Fuenfgeld
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Philipp Mächler
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Dorothee R. Fischer
- Department of Radiology and Nuclear Medicine, Hospital St. Anna, Lucerne, Switzerland
| | - Giuseppe Esposito
- Department of Neurosurgery, University Hospital Zurich, Zurich, Switzerland
| | - Elisabeth Jane Rushing
- University of Zurich, Zurich, Switzerland
- Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
| | - Philipp A. Kaufmann
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Paul Stolzmann
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Martin W. Huellner
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
- * E-mail:
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Prognostic impact of combining whole-body PET/CT and brain PET/MR in patients with lung adenocarcinoma and brain metastases. Eur J Nucl Med Mol Imaging 2018; 46:467-477. [PMID: 30415280 DOI: 10.1007/s00259-018-4210-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/02/2018] [Indexed: 12/25/2022]
Abstract
PURPOSE The role of brain FDG-PET in patients with lung cancer and brain metastases remains unclear. Here, we sought to determine the prognostic significance of whole-body PET/CT plus brain PET/MR in predicting the time to neurological progression (nTTP) and overall survival (OS) in this patient group. METHODS Of 802 patients with non-small cell lung cancer who underwent primary staging by a single-day protocol of whole-body PET/CT plus brain PET/MR, 72 cases with adenocarcinoma and brain metastases were enrolled for a prognostic analysis of OS. On the basis of the available follow-up brain status, only 52 patients were eligible for prognostic analysis of nTTP. Metastatic brain tumors were identified on post-contrast MR imaging, and the tumor-to-brain ratio (TBR) was measured on PET images. RESULTS Multivariate analysis revealed that FDG-PET findings and eligibility for initial treatment with targeted therapy were significant independent predictors of nTTP and OS. A new index, termed the molecular imaging prognostic (MIP) score, was proposed to define three disease classes. MIP scores were significant predictors of both nTTP and OS (P < 0.001). Pre-existing prognostic indices such as Lung-molGPA scores were significant predictors of OS but did not predict nTTP. CONCLUSIONS When staging is performed with whole-body PET/CT plus brain PET/MR, our new prognostic index may be helpful to stratify the outcomes of patients with lung adenocarcinoma and brain metastases. The superior prognostic power of this index for nTTP might be used to select appropriate patients for intracranial control and thereby achieve better quality of life.
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Impact of 18F-FET PET on Target Volume Definition and Tumor Progression of Recurrent High Grade Glioma Treated with Carbon-Ion Radiotherapy. Sci Rep 2018; 8:7201. [PMID: 29740097 PMCID: PMC5940831 DOI: 10.1038/s41598-018-25350-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 04/17/2018] [Indexed: 11/26/2022] Open
Abstract
High-precision radiotherapy (HPR) of recurrent high grade glioma (HGG) requires accurate spatial allocation of these infiltrative tumors. We investigated the impact of 18F-FET PET on tumor delineation and progression of recurrent HGG after HPR with carbon ions. T1 contrast enhanced MRI and 18F-FET-PET scans of 26 HGG patients were fused with radiotherapy planning volumes. PET-positive (PET+) tumor volumes using different isocontours (I%) were systematically investigated and compared with MRI-derived gross tumor volumes (GTV). Standardized uptake ratios (SUR) were further correlated with GTV and tumor progression patterns. In grade IV glioma, SUR > 2.92 significantly correlated with poor median overall survival (6.5 vs 13.1 months, p = 0.00016). We found no reliable SUR cut-off criteria for definition of PET+ volumes. Overall conformity between PET and MRI-based contours was low, with maximum conformities between 0.42–0.51 at I40%. The maximum sensitivity and specificity for PET+ volumes outside of GTV predicting tumor progression were 0.16 (I40%) and 0.52 (I50%), respectively. In 75% of cases, FLAIR hyperintense area covered over 80% of PET+ volumes. 18F-FET-PET derived SUR has a prognostic impact in grade IV glioma. The value of substantial mismatches between MRI-based GTV and PET+ volumes to improve tumor delineation in radiotherapy awaits further validation in randomized prospective trials.
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Blanc-Durand P, Van Der Gucht A, Schaefer N, Itti E, Prior JO. Automatic lesion detection and segmentation of 18F-FET PET in gliomas: A full 3D U-Net convolutional neural network study. PLoS One 2018; 13:e0195798. [PMID: 29652908 PMCID: PMC5898737 DOI: 10.1371/journal.pone.0195798] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/29/2018] [Indexed: 01/17/2023] Open
Abstract
INTRODUCTION Amino-acids positron emission tomography (PET) is increasingly used in the diagnostic workup of patients with gliomas, including differential diagnosis, evaluation of tumor extension, treatment planning and follow-up. Recently, progresses of computer vision and machine learning have been translated for medical imaging. Aim was to demonstrate the feasibility of an automated 18F-fluoro-ethyl-tyrosine (18F-FET) PET lesion detection and segmentation relying on a full 3D U-Net Convolutional Neural Network (CNN). METHODS All dynamic 18F-FET PET brain image volumes were temporally realigned to the first dynamic acquisition, coregistered and spatially normalized onto the Montreal Neurological Institute template. Ground truth segmentations were obtained using manual delineation and thresholding (1.3 x background). The volumetric CNN was implemented based on a modified Keras implementation of a U-Net library with 3 layers for the encoding and decoding paths. Dice similarity coefficient (DSC) was used as an accuracy measure of segmentation. RESULTS Thirty-seven patients were included (26 [70%] in the training set and 11 [30%] in the validation set). All 11 lesions were accurately detected with no false positive, resulting in a sensitivity and a specificity for the detection at the tumor level of 100%. After 150 epochs, DSC reached 0.7924 in the training set and 0.7911 in the validation set. After morphological dilatation and fixed thresholding of the predicted U-Net mask a substantial improvement of the DSC to 0.8231 (+ 4.1%) was noted. At the voxel level, this segmentation led to a 0.88 sensitivity [95% CI, 87.1 to, 88.2%] a 0.99 specificity [99.9 to 99.9%], a 0.78 positive predictive value: [76.9 to 78.3%], and a 0.99 negative predictive value [99.9 to 99.9%]. CONCLUSIONS With relatively high performance, it was proposed the first full 3D automated procedure for segmentation of 18F-FET PET brain images of patients with different gliomas using a U-Net CNN architecture.
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Affiliation(s)
- Paul Blanc-Durand
- Department of Nuclear Medicine, Henri Mondor University Hospital, Créteil, France
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Lausanne, Switzerland
- * E-mail: (PBD); (AVDG)
| | - Axel Van Der Gucht
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Lausanne, Switzerland
- * E-mail: (PBD); (AVDG)
| | - Niklaus Schaefer
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Lausanne, Switzerland
| | - Emmanuel Itti
- Department of Nuclear Medicine, Henri Mondor University Hospital, Créteil, France
| | - John O. Prior
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Lausanne, Switzerland
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Infarct volume after glioblastoma surgery as an independent prognostic factor. Oncotarget 2018; 7:61945-61954. [PMID: 27566556 PMCID: PMC5308702 DOI: 10.18632/oncotarget.11482] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 07/29/2016] [Indexed: 11/25/2022] Open
Abstract
Postoperative ischemia is associated with reduced functional independence measured by karnofsky performance score (KPS), which correlates well with overall survival. Other studies suggest that postoperative hypoxia might initiate infiltrative tumor growth. Therefore, aim of this study was to analyze the impact of infarct volume on overall survival and progression free survival (PFS) of glioblastoma patients. 251 patients with surgery for a newly diagnosed glioblastoma (WHO IV) were retrospectively assessed. Pre- and postoperative KPS, date of death/last follow-up and histopathological markers were recorded. Pre- and postoperative tumor volume and the volume of postoperative infarction were manually segmented. A significant correlation of infarct volume with postoperative KPS decrease (P = 0.001) was observed. Infarct volume showed a significant impact on overall survival (P = 0.014), but not on PFS (P = 0.112) in univariate analysis. This effect increased in the subgroup of patients with near-total tumor resection (> 90%) (overall survival: P = 0.006, PFS: P = 0.066). Infarct volume remained as an independent prognostic factor for overall survival in multivariate analysis (HR 1.013 [1.000–1.026], P = 0.042) including other prognostic factors (age, extent of resection, postoperative KPS). Postoperative infarct volume significantly correlates as an independent factor with overall survival after glioblastoma surgery. Besides the influence of perioperative infarction on postoperative KPS, postoperative hypoxia might also have an effect on tumor biology initiating infiltrative growth and therefore impaired survival.
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Abstract
Magnetic resonance imaging (MRI) is the cornerstone for evaluating patients with brain masses such as primary and metastatic tumors. Important challenges in effectively detecting and diagnosing brain metastases and in accurately characterizing their subsequent response to treatment remain. These difficulties include discriminating metastases from potential mimics such as primary brain tumors and infection, detecting small metastases, and differentiating treatment response from tumor recurrence and progression. Optimal patient management could be benefited by improved and well-validated prognostic and predictive imaging markers, as well as early response markers to identify successful treatment prior to changes in tumor size. To address these fundamental needs, newer MRI techniques including diffusion and perfusion imaging, MR spectroscopy, and positron emission tomography (PET) tracers beyond traditionally used 18-fluorodeoxyglucose are the subject of extensive ongoing investigations, with several promising avenues of added value already identified. These newer techniques provide a wealth of physiologic and metabolic information that may supplement standard MR evaluation, by providing the ability to monitor and characterize cellularity, angiogenesis, perfusion, pH, hypoxia, metabolite concentrations, and other critical features of malignancy. This chapter reviews standard and advanced imaging of brain metastases provided by computed tomography, MRI, and amino acid PET, focusing on potential biomarkers that can serve as problem-solving tools in the clinical management of patients with brain metastases.
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Affiliation(s)
- Whitney B Pope
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, United States.
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15
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Unterrainer M, Galldiks N, Suchorska B, Kowalew LC, Wenter V, Schmid-Tannwald C, Niyazi M, Bartenstein P, Langen KJ, Albert NL. 18F-FET PET Uptake Characteristics in Patients with Newly Diagnosed and Untreated Brain Metastasis. J Nucl Med 2016; 58:584-589. [PMID: 27754904 DOI: 10.2967/jnumed.116.180075] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/12/2016] [Indexed: 01/03/2023] Open
Abstract
In patients with brain metastasis, PET using labeled amino acids has gained clinical importance, mainly regarding the differentiation of viable tumor tissue from treatment-related effects. However, there is still limited knowledge concerning the uptake characteristics in patients with newly diagnosed and untreated brain metastases. Hence, we evaluated the uptake characteristics in these patients using dynamic O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) PET. Methods: Patients with newly diagnosed brain metastases without prior local therapy and 18F-FET PET scanning were retrospectively identified in 2 centers. Static and dynamic PET parameters (maximal/mean tumor-to-brain-ratio [TBRmax/TBRmean], biologic tumor volume [BTV], and time-activity curves with minimal time to peak [TTPmin]) were evaluated and correlated with MRI parameters (maximal lesion diameter, volume of contrast enhancement) and originating primary tumor. Results: Forty-five brain metastases in 30 patients were included. Forty of 45 metastases (89%) had a TBRmax ≥ 1.6 and were classified as 18F-FET-positive (median TBRmax, 2.53 [range, 1.64-9.47]; TBRmean, 1.86 [range, 1.63-5.48]; and BTV, 3.59 mL [range, 0.04-23.98 mL], respectively). In 39 of 45 brain metastases eligible for dynamic analysis, a wide range of TTPmin was observed (median, 22.5 min; range, 4.5-47.5 min). All 18F-FET-negative metastases had a diameter of ≤ 1.0 cm, whereas metastases with a > 1.0 cm diameter all showed pathologic 18F-FET uptake, which did not correlate with lesion size. The highest variability of uptake intensity was observed within the group of melanoma metastases. Conclusion: Untreated metastases predominantly show increased 18F-FET uptake, and only a third of metastases < 1.0 cm were 18F-FET-negative, most likely because of scanner resolution and partial-volume effects. In metastases > 1.0 cm, 18F-FET uptake intensity was highly variable and independent of tumor size (even intraindividually). 18F-FET PET might provide additional information beyond the tumor extent by reflecting molecular features of a metastasis and might be a useful tool for future clinical applications, for example, response assessment.
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Affiliation(s)
- Marcus Unterrainer
- Department of Nuclear Medicine, University of Munich (LMU), Munich, Germany
| | - Norbert Galldiks
- Institute of Neuroscience and Medicine, Research Center Juelich, Juelich, Germany.,Department of Neurology, University Hospital Cologne, Cologne, Germany
| | | | | | - Vera Wenter
- Department of Nuclear Medicine, University of Munich (LMU), Munich, Germany
| | | | - Maximilian Niyazi
- Department of Radiation Oncology, LMU, Munich, Germany.,German Cancer Consortium (DKTK) & German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University of Munich (LMU), Munich, Germany
| | - Karl-Josef Langen
- Institute of Neuroscience and Medicine, Research Center Juelich, Juelich, Germany.,Department of Nuclear Medicine, University of Aachen, Aachen, Germany; and.,JARA-Brain Section, Juelich-Aachen-Research-Alliance (JARA), Juelich, Germany
| | - Nathalie L Albert
- Department of Nuclear Medicine, University of Munich (LMU), Munich, Germany
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ANG1005 for breast cancer brain metastases: correlation between 18F-FLT-PET after first cycle and MRI in response assessment. Breast Cancer Res Treat 2016; 160:51-59. [PMID: 27620882 DOI: 10.1007/s10549-016-3972-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/02/2016] [Indexed: 01/07/2023]
Abstract
PURPOSE Improved therapies and imaging modalities are needed for the treatment of breast cancer brain metastases (BCBM). ANG1005 is a drug conjugate consisting of paclitaxel covalently linked to Angiopep-2, designed to cross the blood-brain barrier. We conducted a biomarker substudy to evaluate 18F-FLT-PET for response assessment. METHODS Ten patients with measurable BCBM received ANG1005 at a dose of 550 mg/m2 IV every 21 days. Before and after cycle 1, patients underwent PET imaging with 18F-FLT, a thymidine analog, retention of which reflects cellular proliferation, for comparison with gadolinium-contrast magnetic resonance imaging (Gd-MRI) in brain metastases detection and response assessment. A 20 % change in uptake after one cycle of ANG1005 was deemed significant. RESULTS Thirty-two target and twenty non-target metastatic brain lesions were analyzed. The median tumor reduction by MRI after cycle 1 was -17.5 % (n = 10 patients, lower, upper quartiles: -25.5, -4.8 %) in target lesion size compared with baseline. Fifteen of twenty-nine target lesions (52 %) and 12/20 nontarget lesions (60 %) showed a ≥20 % decrease post-therapy in FLT-PET SUV change (odds ratio 0.71, 95 % CI: 0.19, 2.61). The median percentage change in SUVmax was -20.9 % (n = 29 lesions; lower, upper quartiles: -42.4, 2.0 %), and the median percentage change in SUV80 was also -20.9 % (n = 29; lower, upper quartiles: -49.0, 0.0 %). Two patients had confirmed partial responses by PET and MRI lasting 6 and 18 cycles, respectively. Seven patients had stable disease, receiving a median of six cycles. CONCLUSIONS ANG1005 warrants further study in BCBM. Results demonstrated a moderately strong association between MRI and 18F-FLT-PET imaging.
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Gempt J, Pyka T, Bette S, Ryang YM, Meyer B, Ringel F. In Reply to the Letter to the Editor: “Comparing the Volume of Brain Metastases in F-18-FET-PET and MRI”. World Neurosurg 2016; 89:723. [DOI: 10.1016/j.wneu.2016.03.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 03/14/2016] [Indexed: 12/01/2022]
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Langen KJ, Tonn JC, Albert NL, Galldiks N. Letter to the Editor: “Comparing the Volume of Brain Metastases in F-18-FET-PET and MRI”. World Neurosurg 2016; 89:722. [DOI: 10.1016/j.wneu.2015.10.084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 10/24/2015] [Indexed: 11/29/2022]
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Bette S, Kaesmacher J, Huber T, Delbridge C, Ringel F, Boeckh-Behrens T, Meyer B, Zimmer C, Kirschke JS, Gempt J. Value of Early Postoperative FLAIR Volume Dynamic in Glioma with No or Minimal Enhancement. World Neurosurg 2016; 91:548-559.e1. [PMID: 27004759 DOI: 10.1016/j.wneu.2016.03.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 03/11/2016] [Accepted: 03/12/2016] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The evaluation of postoperative magnetic resonance imaging (MRI) in glioma with no or minimal enhancement is controversial because the evaluation of residual tumor volume can be biased. The purpose of this study was to clarify the value of early postoperative and 3-month MRI regarding its validity in predicting recurrent disease. METHODS For this retrospective, single-center study, overall fluid attenuated inversion recovery (FLAIR) volumes (early postoperative [<48 hours] and 3-month MRI including FLAIR and T1-weighted sequences with and without contrast agent) of 99 patients were assessed using manual segmentation. FLAIR volume dynamic over the first 3 months after surgery and its effect on disease recurrence were evaluated while considering histopathologic features. RESULTS Overall FLAIR-hyperintense volume significantly decreased between early postoperative and 3-month follow-up MRIs (P < 0.001). Early FLAIR volume increase had a high positive predictive value for overall disease recurrence after resection (85.71% [95%-CI: 62.64-96.24]). Early FLAIR volume dynamic (P < 0.001), isocitrate dehydrogenase 1/2 status (P = 0.002), and preoperative Karnofsky Performance Status (P = 0.012) were observed as independent factors for progression-free survival in multivariate analysis. CONCLUSION Early postoperative FLAIR volume assessment in gliomas with no or minimal enhancement is susceptible to a systematic overestimation of residual tumors. Nevertheless, early FLAIR volume dynamic is an independent factor for tumor recurrence that should be evaluated in order timely adapt surveillance and therapy regimens accordingly.
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Affiliation(s)
- Stefanie Bette
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
| | - Johannes Kaesmacher
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Thomas Huber
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Claire Delbridge
- Department of Neuropathology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Florian Ringel
- Department of Neurorsurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Tobias Boeckh-Behrens
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Bernhard Meyer
- Department of Neurorsurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Claus Zimmer
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Jan S Kirschke
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Jens Gempt
- Department of Neurorsurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
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Prognostic Value of O-(2-[18F]-Fluoroethyl)-L-Tyrosine-Positron Emission Tomography Imaging for Histopathologic Characteristics and Progression-Free Survival in Patients with Low-Grade Glioma. World Neurosurg 2016; 89:230-9. [PMID: 26855307 DOI: 10.1016/j.wneu.2016.01.085] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 01/28/2016] [Accepted: 01/29/2016] [Indexed: 01/19/2023]
Abstract
OBJECTIVE O-(2-[18F]-fluoroethyl)-L-tyrosine positron emission tomography ((18)F-FET-PET) imaging is applied for tumor grading, prognostic stratification, and diagnosis of tumor recurrence, especially in high-grade gliomas. Experience with (18)F-FET-PET imaging in low-grade gliomas is limited. Therefore, the objective of the present study was to assess (18)F-FET-PET tracer uptake in low-grade gliomas and to investigate possible correlations with contrast enhancement in magnetic resonance imaging (MRI) and histopathology. METHODS A total of 65 patients (29 female, 36 male, median age 38 years) with newly diagnosed or recurrent low-grade gliomas for whom preoperative MRI and (18)F-FET-PET imaging were available were included. Tumor entity, tumor location, as well as histopathology (isocitrate dehydrogenase [IDH] 1/2 mutation, Ki67, p53, oligodendroglial differentiation, 1p19q codeletion), and progression-free survival were assessed. (18)F-FET-PET images were acquired and fused to MRI (T2-weighted fluid-attenuated inversion recovery) and tumor volume was measured in areas with a tumor-to-background ratio >1.3, >1.6, and >2.0 and in MRI. RESULTS PET tracer uptake was observed in 78.5% of all World Health Organization Grade I and II tumors. (18)F-FET uptake showed a high negative predictive value for oligodendroglial components and for 1p19q codeletion. No further significant correlation between histologic features, progression-free survival, or IDH1/2 mutation status and tracer uptake was observed. CONCLUSIONS We found that 78.5% of low-grade gliomas do show elevated tracer uptake in (18)F-FET-PET imaging. Low-grade glioma without tracer uptake exclude oligodendroglial differentiation and 1p19q codeletion. Further differentiation between molecular subtypes is not possible with static (18)F-FET-PET. No correlation of progression-free survival to tracer uptake and IDH1/2-mutation status was observed.
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Static FET-PET and MR Imaging in Anaplastic Gliomas (WHO III). World Neurosurg 2016; 91:524-531.e1. [PMID: 26947726 DOI: 10.1016/j.wneu.2016.02.094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/23/2016] [Accepted: 02/24/2016] [Indexed: 02/05/2023]
Abstract
OBJECTIVE O-(2-[18F]-fluoroethyl)-L-tyrosine-positron emission tomography (FET-PET) imaging is an additional tool for tumor grading and surgery planning. Up to now, not much is known about FET-PET imaging in anaplastic gliomas. Our objective was to assess the FET uptake in anaplastic gliomas, compared with magnetic resonance imaging (MRI), histopathologic markers, and its prognostic value. PATIENTS AND METHODS Forty-six patients (27 males/19 females) with an anaplastic glioma (WHO III) who received MRI and FET-PET imaging before surgery were retrospectively analyzed. Tumor volume was calculated in MRI and FET-PET imaging using a tumor-to-background ratio (TBR), and maximum FET uptake (TBRmax) was calculated. Overall survival (OS) and histopathologic markers (isocitrate-dehydrogenase 1/2-mutation, oligodendrial differentiation, and Ki67 proliferation index) were assessed. Univariate and multivariate analysis was performed for OS. RESULTS In univariate analysis a significant correlation of TBRmax to OS was observed (P = 0.031). Tumor volume in FET-PET imaging (TBR > 2.0) (P = 0.028) showed a higher correlation to OS than the volume of the contrast-enhancing tumor part (P = 0.031). The highest correlation was observed for intersection of volume TBR > 1.3 and the volume of the contrast-enhancing tumor part (P = 0.005); fluid-attenuated inversion recovery volume showed no significant correlation to OS (P = 0.401) in the univariate analysis. Anaplastic glioma with oligodendrial differentiation showed significantly higher TBRmax values (P = 0.029), while no significant difference was observed for isocitrate hydrogenase 1/2-mutation (P = 0.752). CONCLUSION Static FET-PET provides significant prognostic information in anaplastic gliomas, which adds to the value of MRI, supporting the use of both modalities preoperatively to assess individual risks and estimate prognosis. Definition of the histopathologic subtype using static FET-PET remains challenging.
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