Artificial Intelligence on FDG PET Images Identifies Mild Cognitive Impairment Patients with Neurodegenerative Disease

[EN] The purpose of this project is to develop and validate a Deep Learning (DL) FDG PET imaging algorithm able to identify patients with any neurodegenerative diseases (Alzheimer's Disease (AD), Frontotemporal Degeneration (FTD) or Dementia with Lewy Bodies (DLB)) among patients with Mild Cognitive Impairment (MCI). A 3D Convolutional neural network was trained using images from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. The ADNI dataset used for the model training and testing consisted of 822 subjects (472 AD and 350 MCI). The validation was performed on an independent dataset from La Fe University and Polytechnic Hospital. This dataset contained 90 subjects with MCI, 71 of them developed a neurodegenerative disease (64 AD, 4 FTD and 3 DLB) while 19 did not associate any neurodegenerative disease. The model had 79% accuracy, 88% sensitivity and 71% specificity in the identification of patients with neurodegenerative diseases tested on the 10% ADNI dataset, achieving an area under the receiver operating characteristic curve (AUC) of 0.90. On the external validation, the model preserved 80% balanced accuracy, 75% sensitivity, 84% specificity and 0.86 AUC. This binary classifier model based on FDG PET images allows the early prediction of neurodegenerative diseases in MCI patients in standard clinical settings with an overall 80% classification balanced accuracy.This work was financially supported by INBIO 2019 (DEEPBRAIN), INNVA1/2020/83(DEEPPET) funded by Generalitat Valenciana, and PID2019-107790RB-C22 funded by MCIN/AEI/10.13039/501100011033/. Data collection and sharing for this project was funded by the Alzheimer's Disease Neuroimaging Initiative (ADNI) (National Institutes of Health Grant U01 AG024904) and DOD ADNI (Department of Defense award number W81XWH-12-2-0012). ADNI is funded by the National Institute on Aging, the National Institute of Biomedical Imaging and Bioengineering, and through generous contributions from the following: AbbVie, Alzheimer's Association; Alzheimer's Drug Discovery Foundation; Araclon Biotech; BioClinica, Inc.; Biogen; Bristol-Myers Squibb Company; CereSpir, Inc.; Cogstate; Eisai Inc.; Elan Pharmaceuticals, Inc.; Eli Lilly and Company; EuroImmun; F. Hoffmann-La Roche Ltd and its affiliated company Genentech, Inc.; Fujirebio; GE Healthcare; IXICO Ltd.; Janssen Alzheimer Immunotherapy Research & Development, LLC.; Johnson & Johnson Pharmaceutical Research & Development LLC.; Lumosity; Lundbeck; Merck & Co., Inc.; Meso Scale Diagnostics, LLC.; NeuroRx Research; Neurotrack Technologies; Novartis Pharmaceuticals Corporation; Pfizer Inc.; Piramal Imaging; Servier; Takeda Pharmaceutical Company; and Transition Therapeutics. The Canadian Institutes of Health Research is providing funds to support ADNI clinical sites in Canada. Private sector contributions are facilitated by the Foundation for the National Institutes of Health (www.fnih.org).The grantee organization is the Northern California Institute for Research and Education, and the study is coordinated by the Alzheimer's Therapeutic Research Institute at the University of Southern California. ADNI data are disseminated by the Laboratory for Neuro Imaging at the University of Southern California.Prats-Climent, J.; Gandia-Ferrero, MT.; Torres-Espallardo, I.; Álvarez-Sanchez, L.; Martinez-Sanchis, B.; Cháfer-Pericás, C.; Gómez-Rico, I.... (2022). Artificial Intelligence on FDG PET Images Identifies Mild Cognitive Impairment Patients with Neurodegenerative Disease. Journal of Medical Systems. 46(8):1-13. https://doi.org/10.1007/s10916-022-01836-w11346

Image Reconstruction and Correction Methods for MADPET-II based on Monte Carlo Techniques

186 páginas. Tesis Doctoral del Departamento de Física Atómica, Molecular y Nuclear, de la Universidad de Valencia, y el Instituto de Física Corpuscular (IFIC). Fecha de lectura: 02-22-2010Bajo el título Reconstrucción de la Imagen y Correcciones para MADPET-II usando Técnicas de Montecarlo hemos englobado diversos temas relacionados con la obtención de imágenes y correcciones necesarias para obtener información cuantitativa del escáner MADPET-II. En particular se han investigado las correcciones de coincidencias accidentales y la normalización para dicho sistema. MADPET-II, que viene de Munich Avalanche photoDiode PET, es un escáner para el estudio de animales pequeños desarrollado en el departamento de Medicina Nuclear del Klinikum rechts der Isar en Múnich. Sus rasgos más característicos son la distribución de los cristales centelleadores en dos capas radiales y la lectura individual de cada uno de sus cristales por un fotodiodo de avalancha (APD).Peer reviewe

Reconstruction from truncated projections using constrained total-variation minimization applied to PET for hadron-therapy monitoring

Hadron-therapy exploits light ions to treat tumors by maximizing the dose released to the target and sparing healthy tissues. With hadrons, the dose distribution rises sharply at the end of the range, providing the Bragg peak, and drops quickly to a negligible value. During hadron-therapy, positron-emitters are produced along the beam path before the Bragg peak. Following positron annihilation, two γ-photons are produced, which can be detected with a PET scanner. However, low yield of β-emitters and the wash out of the positron activity from the target region make the use of PET in hadron-therapy a significant challenge. In-beam PET represents a potential candidate to measure high fluence of β-emitters, at the cost of degraded contrast due to the partial rings. TOF information can potentially be used to enhance image contrast, and counteract for the loss of information. Alternatively, including total variation (TV) as prior information in the MAP reconstruction produces images with low noise without degrading spatial resolution. In this work we compare hadron-beams simulated using a complete and a partial ring Gemini TF PET scanner as model, reconstructed with ML-EM with and without TOF, and MAP-TV. MAP-TV demonstrates to produce lower noise images compared to ML-EM without and with TOF. Additionally, distal fall-off has been measured and no resolution loss has been observed

Estimating accidental coincidences for pixelated PET detectors and singles list-mode acquisition

4 pages, 1 figure.-- PACS nrs.: 87.57.Fg; 87.64.Aa; 87.53.Wz.-- ISI Article Identifier: 000244599100069Online version available 10 November 2006.We have studied the validity of random estimation techniques for various low energy thresholds (LETs) and single list-mode data sets in small animal PET. While a LET below 255 keV helps to increase the sensitivity, it also results in an increase of random coincidences and inter-crystal scatter (ICS). The study is carried out for MADPET-II, a dual-layer positron emission tomography (PET) scanner prototype consisting of LSO crystals read out individually by APDs. The data are acquired in singles list-mode format, and coincidences are computed post-acquisition. To estimate randoms, we have used the delayed coincidence window method (DW), and the singles rate model (SR). Various phantoms were simulated using GATE. For LETs under 255 keV, the number of random events R, estimated using the SR and the DW methods, is larger than the number of randoms which was directly computed from GATE simulations, and R(SR) > R(DW) > R(GATE). The higher the LET, the smaller the overestimation. For LETs > 255 keV, R(DW)/R(GATE) approximate to 1. If scattered singles were excluded from the file, this discrepancy between R(DW or SR) and R(GATE) significantly diminished. This fact points out to ICS as the effect responsible for the mismatch, since for LETs lower than 255 keV, all singles related to an ICS event can be detected independently, thus altering the singles rate. Therefore, if low LETs are used, random estimation techniques should account for ICS. (c) 2006 Elsevier B.V. All rights reserved.This work was supported in part by the Deutsche Forschungsgemeinschaft (DFG Zi615/1-2). Additional support came from the Travel Grants Acciones Integradas (Spanish Ministry of Eduaction and Science and the German DAAD, HA2004-0082) and Marina Bueno (CSIC, Spain, B2004DE01).Peer reviewe

Same-day comparative protocol PET/CT-PET/MRI [68 Ga]Ga-DOTA-TOC in paragangliomas and pheochromocytomas: an approach to personalized medicine

Abstract Background PET/MRI is an emerging imaging modality which enables the evaluation and quantification of biochemical processes in tissues, complemented with accurate anatomical information and low radiation exposure. In the framework of theragnosis, PET/MRI is of special interest due to its ability to delineate small lesions, adequately quantify them, and therefore to plan targeted therapies. The aim of this study was to validate the diagnostic performance of [68 Ga]Ga-DOTA-TOC PET/MRI compared to PET/CT in advanced disease paragangliomas and pheochromocytomas (PGGLs) to assess in which clinical settings, PET/MRI may have a greater diagnostic yield. Methods We performed a same-day protocol with consecutive acquisition of a PET/CT and a PET/MRI after a single [68 Ga]Ga-DOTA-TOC injection in 25 patients. Intermodality agreement, Krenning Score (KS), SUVmax (Standard Uptake Value), target-to-liver-ratio (TLR), clinical setting, location, and size were assessed. Results The diagnostic accuracy with PET/MRI increased by 14.6% compared to PET/CT especially in bone and liver locations (mean size of new lesions was 3.73 mm). PET/MRI revealed a higher overall lesion uptake than PET/CT (TLR 4.12 vs 2.44) and implied an upward elevation of the KS in up to 60% of patients. The KS changed in 30.4% of the evaluated lesions (mean size 11.89 mm), in 18.4% of the lesions it increased from KS 2 on PET/CT to a KS ≥ 3 on PET/MRI and 24.96% of the lesions per patient with multifocal disease displayed a KS ≥ 3 on PET/MR, that were not detected or showed lower KS on PET/CT. In 12% of patients, PET/MRI modified clinical management. Conclusions PET/MRI showed minor advantages over conventional PET/CT in the detection of new lesions but increased the intensity of SSRs expression in a significant number of them, opening the door to select which patients and clinical settings can benefit from performing PET/MRI

Comparison study of RPC and crystal based PET systems for hadron therapy monitoring

PET is the only clinically proven method for hadron-therapy monitoring. This method uses imaging of the positron emitting isotopes produced during patient irradiation in hadron-therapy. To maximize the count rates in-beam PET is the preferred option, which requires partial ring configuration. Usage of partial ring PET system causes image artifact and low quality image due to incomplete data. The Time-of-flight (TOF) information provides better image quality for partial ring PET systems. Therefore, PET system with very good time and spatial resolution is necessary for hadron-therapy monitoring. The Resistive-Plate-Chambers (RPCs) providing very good time and spatial resolution might be used for the quality control of hadron-therapy. The objective of this study is the comparison of the performance of two TOF-PET systems, one multi-gap RPC (mRPC) system currently under investigation by the TERA group and a commercially available scintillator-based PET system (Philips GEMINI TF) in order to analyze their feasibility of being applied to monitor cancer treatment with ion- and proton-beams. Various Monte-Carlo simulations were performed using GATE to evaluate the performance of the both systems following NEMA protocols. Furthermore, a set of sources emulating the annihilation photons from β+-emitters produced after proton irradiation on a PMMA target were employed to study the capability to reproduce the proton beam path and the distal edge. Finally, we calculated the activity distribution produced on the basis of one field of the treatment plan for one patient data. The results obtained indicate that mRPC system is not suited for hadron therapy monitoring due to its low sensitivity. On the other side, the Philips GEMINI TF does not provide convincing results either, thus other configurations are still under investigation

Performance of MACACO Compton telescope for ion-beam therapy monitoring: First test with proton beams

In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing Na-22 and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy

Medical Imaging

F. Azaiez et al.; Chapter II; 28 figs.; 5 tabs.Peer Reviewe