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Journal of Nuclear Medicine Technology Mar 2021Our objective was to investigate the differences in texture features between step-and-shoot (SS) and continuous-bed-motion (CBM) imaging in phantom and clinical studies....
Our objective was to investigate the differences in texture features between step-and-shoot (SS) and continuous-bed-motion (CBM) imaging in phantom and clinical studies. A National Electrical Manufacturers Association body phantom was filled with F-FDG solution at a sphere-to-background ratio of 4:1. SS and CBM were performed using the same acquisition duration, and the data were reconstructed using 3-dimensional ordered-subset expectation maximization with time-of-flight algorithms. Texture features were extracted using the software LIFEx. A volume of interest was delineated on the 22-, 28-, and 37-mm spheres with a threshold of 42% of the maximum SUV. The voxel intensities were discretized using 2 resampling methods, namely a fixed bin size and a fixed bin number discretization. The discrete resampling values were set to 64 and 128. In total, 31 texture features were calculated with gray-level cooccurrence matrix (GLCM), gray-level run length matrix, neighborhood gray-level different matrix, and gray-level zone length matrix. The texture features of the SS and CBM images were compared for all settings using the paired test and the coefficient of variation. In a clinical study, 27 lesions from 20 patients were examined using the same acquisition and image processing as were used during the phantom study. The percentage difference (%Diff) and correlation between the texture features from SS and CBM images were calculated to evaluate agreement between the 2 scanning techniques. In the phantom study, the 11 features exhibited no significant difference between SS and CBM images, and the coefficient of variation was no more than 10%, depending on resampling conditions, whereas entropy and dissimilarity from GLCM fulfilled the criteria for all settings. In the clinical study, the entropy and dissimilarity from GLCM exhibited a low %Diff and excellent correlation in all resampling conditions. The %Diff of entropy was lower than that of dissimilarity. Differences between the texture features of SS and CBM images varied depending on the type of feature. Because entropy for GLCM exhibits minimal differences between SS and CBM images irrespective of resampling conditions, entropy may be the optimal feature to reduce the differences between the 2 scanning techniques.
Topics: Algorithms; Fluorodeoxyglucose F18; Humans; Image Processing, Computer-Assisted; Motion; Phantoms, Imaging
PubMed: 33020230
DOI: 10.2967/jnmt.120.246157 -
Medical Physics Nov 2019Numerous image reconstruction methodologies for positron emission tomography (PET) have been developed that incorporate magnetic resonance (MR) imaging structural... (Comparative Study)
Comparative Study
PURPOSE
Numerous image reconstruction methodologies for positron emission tomography (PET) have been developed that incorporate magnetic resonance (MR) imaging structural information, producing reconstructed images with improved suppression of noise and reduced partial volume effects. However, the influence of MR structural information also increases the possibility of suppression or bias of structures present only in the PET data (PET-unique regions). To address this, further developments for MR-informed methods have been proposed, for example, through inclusion of the current reconstructed PET image, alongside the MR image, in the iterative reconstruction process. In this present work, a number of kernel and maximum a posteriori (MAP) methodologies are compared, with the aim of identifying methods that enable a favorable trade-off between the suppression of noise and the retention of unique features present in the PET data.
METHODS
The reconstruction methods investigated were: the MR-informed conventional and spatially compact kernel methods, referred to as KEM and KEM largest value sparsification (LVS) respectively; the MR-informed Bowsher and Gaussian MR-guided MAP methods; and the PET-MR-informed hybrid kernel and anato-functional MAP methods. The trade-off between improving the reconstruction of the whole brain region and the PET-unique regions was investigated for all methods in comparison with postsmoothed maximum likelihood expectation maximization (MLEM), evaluated in terms of structural similarity index (SSIM), normalized root mean square error (NRMSE), bias, and standard deviation. Both simulated BrainWeb (10 noise realizations) and real [ F] fluorodeoxyglucose (FDG) three-dimensional datasets were used. The real [ F]FDG dataset was augmented with simulated tumors to allow comparison of the reconstruction methodologies for the case of known regions of PET-MR discrepancy and evaluated at full counts (100%) and at a reduced (10%) count level.
RESULTS
For the high-count simulated and real data studies, the anato-functional MAP method performed better than the other methods under investigation (MR-informed, PET-MR-informed and postsmoothed MLEM), in terms of achieving the best trade-off for the reconstruction of the whole brain and PET-unique regions, assessed in terms of the SSIM, NRMSE, and bias vs standard deviation. The inclusion of PET information in the anato-functional MAP method enables the reconstruction of PET-unique regions to attain similarly low levels of bias as unsmoothed MLEM, while moderately improving the whole brain image quality for low levels of regularization. However, for low count simulated datasets the anato-functional MAP method performs poorly, due to the inclusion of noisy PET information in the regularization term. For the low counts simulated dataset, KEM LVS and to a lesser extent, HKEM performed better than the other methods under investigation in terms of achieving the best trade-off for the reconstruction of the whole brain and PET-unique regions, assessed in terms of the SSIM, NRMSE, and bias vs standard deviation.
CONCLUSION
For the reconstruction of noisy data, multiple MR-informed methods produce favorable whole brain vs PET-unique region trade-off in terms of the image quality metrics of SSIM and NRMSE, comfortably outperforming the whole image denoising of postsmoothed MLEM.
Topics: Fluorodeoxyglucose F18; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Positron-Emission Tomography
PubMed: 31494961
DOI: 10.1002/mp.13812 -
Tomography (Ann Arbor, Mich.) Mar 2023We have integrated a compact and lightweight PET with an existing CT image-guided small animal irradiator to enable practical onboard PET/CT image-guided preclinical...
We have integrated a compact and lightweight PET with an existing CT image-guided small animal irradiator to enable practical onboard PET/CT image-guided preclinical radiation therapy (RT) research. The PET with a stationary and full-ring detectors has ~1.1 mm uniform spatial resolution over its imaging field-of-view of 8.0 cm diameter and 3.5 cm axial length and was mechanically installed inside the irradiator in a tandem configuration with CT and radiation unit. A common animal bed was used for acquiring sequential dual functional and anatomical images with independent PET and CT control and acquisition systems. The reconstructed dual images were co-registered based on standard multi-modality image calibration and registration processes. Phantom studies were conducted to evaluate the integrated system and dual imaging performance. The measured mean PET/CT image registration error was ~0.3 mm. With one-bed and three-bed acquisitions, initial tumor focused and whole-body [F]FDG animal images were acquired to test the capability of onboard PET/CT image guidance for preclinical RT research. Overall, the results have shown that integrated PET/CT/RT can provide advantageous and practical onboard PET/CT image to significantly enhance the accuracy of tumor delineation and radiation targeting that should enhance the existing and enable new and potentially breakthrough preclinical RT research and applications.
Topics: Animals; Positron Emission Tomography Computed Tomography; Radiation Oncology; Fluorodeoxyglucose F18; Phantoms, Imaging
PubMed: 36961005
DOI: 10.3390/tomography9020046 -
International Journal of Molecular... Jan 2022Excessive glucose metabolism and disruptions in Wnt signaling are important molecular changes present in oral cancer cells. The aim of this study was to evaluate the...
Excessive glucose metabolism and disruptions in Wnt signaling are important molecular changes present in oral cancer cells. The aim of this study was to evaluate the effects of the combinatorial use of glycolysis and Wnt signaling inhibitors on viability, cytotoxicity, apoptosis induction, cell cycle distribution and the glycolytic activity of tongue carcinoma cells. CAL 27, SCC-25 and BICR 22 tongue cancer cell lines were used. Cells were treated with inhibitors of glycolysis (2-deoxyglucose and lonidamine) and of Wnt signaling (PRI-724 and IWP-O1). The effects of the compounds on cell viability and cytotoxicity were evaluated with MTS and CellTox Green tests, respectively. Apoptosis was evaluated by MitoPotential Dye staining and cell cycle distribution by staining with propidium iodide, followed by flow cytometric cell analysis. Glucose and lactate concentrations in a culture medium were evaluated luminometrically. Combinations of 2-deoxyglucose and lonidamine with Wnt pathway inhibitors were similarly effective in the impairment of oral cancer cells' survival. However, the inhibition of the canonical Wnt pathway by PRI-724 was more beneficial, based on the glycolytic activity of the cells. The results point to the therapeutic potential of the combination of low concentrations of glycolytic modulators with Wnt pathway inhibitors in oral cancer cells.
Topics: Apoptosis; Bridged Bicyclo Compounds, Heterocyclic; Cell Cycle; Cell Line, Tumor; Cell Survival; Deoxyglucose; Glucose; Glycolysis; Head and Neck Neoplasms; Humans; Indazoles; Pyrimidinones; Tongue; Tongue Neoplasms; Wnt Signaling Pathway
PubMed: 35163171
DOI: 10.3390/ijms23031248 -
PloS One 2022One major challenge in PET radiomics is its sensitivity to noise. Low signal-to-noise ratio (SNR) affects not only the precision but also the accuracy of quantitative...
INTRODUCTION
One major challenge in PET radiomics is its sensitivity to noise. Low signal-to-noise ratio (SNR) affects not only the precision but also the accuracy of quantitative metrics extracted from the images resulting in noise-induced bias. This phantom study aims to identify the radiomic features that are robust to noise in terms of precision and accuracy and to explore some methods that might help to correct noise-induced bias.
METHODS
A phantom containing three 18F-FDG filled 3D printed inserts, reflecting heterogeneous tracer uptake and realistic tumor shapes, was used in the study. The three different phantom inserts were filled and scanned with three different tumor-to-background ratios, simulating a total of nine different tumors. From the 40-minute list-mode data, ten frames each for 5 s, 10 s, 30 s, and 120 s frame duration were reconstructed to generate images with different noise levels. Under these noise conditions, the precision and accuracy of the radiomic features were analyzed using intraclass correlation coefficient (ICC) and similarity distance metric (SDM) respectively. Based on the ICC and SDM values, the radiomic features were categorized into four groups: poor, moderate, good, and excellent precision and accuracy. A "difference image" created by subtracting two statistically equivalent replicate images was used to develop a model to correct the noise-induced bias. Several regression methods (e.g., linear, exponential, sigmoid, and power-law) were tested. The best fitting model was chosen based on Akaike information criteria.
RESULTS
Several radiomic features derived from low SNR images have high repeatability, with 68% of radiomic features having ICC ≥ 0.9 for images with a frame duration of 5 s. However, most features show a systematic bias that correlates with the increase in noise level. Out of 143 features with noise-induced bias, the SDM values were improved based on a regression model (53 features to excellent and 67 to good) indicating that the noise-induced bias of these features can be, at least partially, corrected.
CONCLUSION
To have a predictive value, radiomic features should reflect tumor characteristics and be minimally affected by noise. The present study has shown that it is possible to correct for noise-induced bias, at least in a subset of the features, using a regression model based on the local image noise estimates.
Topics: Bias; Fluorodeoxyglucose F18; Image Processing, Computer-Assisted; Phantoms, Imaging; Positron-Emission Tomography
PubMed: 36006959
DOI: 10.1371/journal.pone.0272643 -
Biochemical and Biophysical Research... Mar 2015Dicarbonyl stress is the abnormal accumulation of dicarbonyl metabolites leading to increased protein and DNA modification contributing to cell and tissue dysfunction in... (Review)
Review
Dicarbonyl stress is the abnormal accumulation of dicarbonyl metabolites leading to increased protein and DNA modification contributing to cell and tissue dysfunction in ageing and disease. Enzymes metabolising dicarbonyls, glyoxalase 1 and aldoketo reductases, provide an efficient and stress-response enzyme defence against dicarbonyl stress. Dicarbonyl stress is produced by increased formation and/or decreased metabolism of dicarbonyl metabolites, and by exposure to exogenous dicarbonyls. It contributes to ageing, disease and activity of cytototoxic chemotherapeutic agents.
Topics: Aging; Aldehydes; Cardiovascular Diseases; Deoxyglucose; Diabetes Mellitus; Glyoxal; Humans; Inflammation; Kidney Diseases; Models, Biological; Oxidative Stress; Pyruvaldehyde; Stress, Physiological
PubMed: 25666945
DOI: 10.1016/j.bbrc.2015.01.140 -
Epilepsia Open Mar 2022Infantile spasms (IS) is an epileptic encephalopathy with a poor neurodevelopmental prognosis, and limited, often ineffective treatment options. The effectiveness of...
Infantile spasms (IS) is an epileptic encephalopathy with a poor neurodevelopmental prognosis, and limited, often ineffective treatment options. The effectiveness of metabolic approaches to seizure control is being increasingly shown in a wide variety of epilepsies. This study investigates the efficacy of the glycolysis inhibitor 2-deoxyglucose (2-DG) and the ketone body β-hydroxybutyrate (BHB) in the betamethasone-NMDA model of rat IS. Prenatal rats were exposed to betamethasone on gestational day 15 (G15) and NMDA on postnatal day 15 (P15). Video-electroencephalography (v-EEG) was used to monitor spasms. NMDA consistently induced hyperflexion spasms associated with interictal sharp-slow wave EEG activity and ictal flattening of EEG signals, reminiscent of hypsarrhythmia and electrodecrement, respectively. 2-DG (500 mg/kg, i.p), BHB (200 mg/kg, i.p.), or both were administered immediately after occurrence of the first spasm. No experimental treatment altered significantly the number, severity, or progression of spasms compared with saline treatment. These data suggest that metabolic inhibition of glycolysis or ketogenesis does not reduce infantile spasms in the NMDA model. The study further validates the betamethasone-NMDA model in terms of its behavioral and electrographic resemblance to human IS and supports its use for preclinical drug screening.
Topics: 3-Hydroxybutyric Acid; Adrenocorticotropic Hormone; Animals; Animals, Newborn; Betamethasone; Deoxyglucose; Disease Models, Animal; Female; N-Methylaspartate; Pregnancy; Rats; Seizures; Spasm; Spasms, Infantile
PubMed: 34784103
DOI: 10.1002/epi4.12561 -
BioMed Research International 2020Our previous research suggests that 3-deoxyglucosone (3DG), formed in the caramelization course and Maillard reactions in food, is an independent factor for the...
Our previous research suggests that 3-deoxyglucosone (3DG), formed in the caramelization course and Maillard reactions in food, is an independent factor for the development of prediabetes. Since the relationship between type 2 diabetes (T2D) and intestinal microbiota is moving from correlation to causality, we investigated the alterations in the composition and function of the intestinal microbiota in 3DG-induced prediabetic rats. Rats were given 50 mg/kg 3DG by intragastric administration for two weeks. Microbial profiling in faeces samples was determined through the 16S rRNA gene sequence. The glucagon-like peptide 2 (GLP-2) and lipopolysaccharide (LPS) levels in plasma and intestinal tissues were measured by ELISA and Limulus test, respectively. 3DG treatment did not significantly change the richness and evenness but affected the composition of intestinal microbiota. At the phylum level, 3DG treatment increased the abundance of nondominant bacteria but did not cause the change of the dominant bacteria. Meanwhile, the abundance of the family and genus and the family and order and its attachment to the class were overrepresented in the 3DG group. The bacteria of genus, genus, and family and its attachment to order were apparently more abundant in the control group. In addition, 45 KEGG pathways were altered after two-week intragastric administration of 3DG. Among these KEGG pathways, 13 KEGG pathways were involved in host metabolic function related to amino acid metabolism, carbohydrate metabolism, metabolism of cofactors and vitamins, and metabolism of terpenoids and polyketides. Moreover, the increased LPS levels and the decreased GLP-2 concentration in plasma and intestinal tissues were observed in 3DG-treated rats, together with the impaired fasting glucose and oral glucose tolerance. The alterations in composition and function of the intestinal microbiota were observed in 3DG-treated rats, which provides a possible mechanism linking exogenous 3DG intake to the development of prediabetes.
Topics: Administration, Oral; Animals; Deoxyglucose; Gastrointestinal Microbiome; Glucagon-Like Peptide 2; Glucose Tolerance Test; Lipopolysaccharides; Male; Prediabetic State; RNA, Ribosomal, 16S; Rats, Sprague-Dawley
PubMed: 32908918
DOI: 10.1155/2020/8406846 -
Cancer Imaging : the Official... Nov 2014Positron emission tomography (PET) using 18fluoro-2-deoxyglucose (FDG) has become a standard clinical tool for staging and response assessment in aggressive lymphomas.... (Review)
Review
Positron emission tomography (PET) using 18fluoro-2-deoxyglucose (FDG) has become a standard clinical tool for staging and response assessment in aggressive lymphomas. The use of PET scans in clinical trials is still under exploration, however. In this review, we examine current data regarding PET in DLBCL, and its potential applicability to development of a surrogate endpoint to expedite clinical trial conduct. Interim PET scanning in DLBCL shows mixed results, with qualitative assessment variably associated with outcome. Addition of quantitative assessment might improve predictive power of interim scans. Data from multiple retrospective studies support that PET-defined response at end of treatment correlates with outcome in DLBCL. Optimal technical criteria for standardization of acquisition and criteria for interpretation of scans require further study. Prospective studies to define the correlation of PET-defined response and time-dependent outcomes such as progression free survival (PFS) and overall survival (OS), critical for development of PET as a surrogate endpoint for clinical trials, are ongoing. In conclusion, evolving data regarding utility of PET in predictcing outcome of patients with DLBCL show promise to support the use of PET as a surrogate endpoint in clinical trials of DLBCL in the future.
Topics: Clinical Trials as Topic; Fluorodeoxyglucose F18; Humans; Lymphoma, Large B-Cell, Diffuse; Positron-Emission Tomography; Radiopharmaceuticals
PubMed: 25608713
DOI: 10.1186/s40644-014-0034-9 -
Journal of Nuclear Medicine : Official... Apr 2021
Topics: Fluorodeoxyglucose F18; Magnetic Resonance Imaging; Positron Emission Tomography Computed Tomography; Tomography, X-Ray Computed
PubMed: 33037093
DOI: 10.2967/jnumed.120.256453