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Comparative assessment of linear least-squares, nonlinear least-squares, and Patlak graphical method for regional and local quantitative tracer kinetic modelling in cerebral dynamic <sup>18</sup> F-FDG PET
摘要： Purpose: Dynamic 18F-FDG PET allows quantitative estimation of cerebral glucose metabolism both at the regional and local (voxel) level. Although sensitive to noise and highly computationally expensive, nonlinear least-squares (NLS) optimization stands as the reference approach for the estimation of the kinetic model parameters. Nevertheless, faster techniques, including linear least-squares (LLS) and Patlak graphical method, have been proposed to deal with high resolution noisy data, representing a more adaptable solution for routine clinical implementation. Former research investigating the relative performance of the available algorithms lack precise evaluation of kinetic parameter estimates under realistic acquisition conditions. Methods: The present study aims at the systematic comparison of the feasibility and pertinence of kinetic modelling of dynamic cerebral 18F-FDG PET using NLS, LLS, and Patlak method, based on numerical simulations and patient data. Numerical simulations were used to study and parameters estimation bias and variance under representative noise levels. Patient data allowed to assess the concordance between the three methods at the regional and voxel scale, and to evaluate the robustness of the estimations with respect to patient head motion. Results and Conclusions: Our findings indicate that at the regional level NLS and LLS provide kinetic parameter estimates ( and ) with similar bias and variance characteristics ( bias ± rel. std dev. 0.0±5.1% and 0.1%±4.9% for NLS and LLS respectively, bias ± rel. std dev. 0.1%±4.5% and -0.7%±4.4% for NLS and LLS respectively), NLS estimates being however slightly less sensitive to patient motion. At the voxel level, provided that patient motion is negligible or corrected, LLS offers an appealing alternative solution for local mapping, with high correlation with NLS values (Pearson’s r = 0.95 on actual data) in computations times less than two orders of magnitude lower. Last, Patlak method appears as the most robust and accurate technique for the estimation of values at the regional and voxel scale, with or without head motion. It provides low bias / low variance quantification (bias ± rel. std dev. -1.5±9.5% and -4.1±19.7% for Patlak and NLS respectively) as well as smooth parametric images suitable for visual assessment.
关键词： kinetic analysis,18F-FDG PET,cerebral glucose metabolism,quantification
更新于2025-09-23 15:23:52
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Performance of whole-body 18F-FDG PET/CT as a posttreatment surveillance tool for sinonasal malignancies
摘要： Purpose To determine the diagnostic utility of posttreatment surveillance whole-body 18F-FDG PET/CT in detecting local tumor recurrence (R), regional lymph-node metastasis (LM), and distant metastasis (DM) in asymptomatic sinonasal cancer patients. Methods Eighty consecutive patients (53 men, 27 women; mean age, 60 years; range, 28–92 years) who had undergone 197 posttreatment whole-body 18F-FDG PET/CT examinations for sinonasal malignancies between January 2009 and August 2017 were retrospectively reviewed. 18F-FDG PET/CT findings were categorized as positive or negative for R, LM, and DM, separately. Outcomes of 18F-FDG PET/CT scans were compared with the final diagnosis confirmed by histological analysis or follow-up period for a minimum 12 months. The diagnostic accuracy of scans was calculated for each site using contingency tables. Impact on the management of 18F-FDG PET/CT examinations was additionally evaluated. Results 18F-FDG PET/CT scans identified 37/44 of local recurrences, 21/23 of LMs, and 30/37 of DMs. For local recurrence, sensitivity, specificity, positive predictive value, and negative predictive value were 84% (68–97%), 95% (80–100%), 84% (68–97%), and 95% (80–100%), respectively. For LM, the respective values were 91% (75–100%), 99% (83–100%), 91% (75–100%), and 99% (83–100%). For DM, the values were 81% (64–97%), 99% (85–100%), 97% (81–100%), and 96% (81–100%), respectively. 18F-FDG PET/CT accounted for a change in management of 85% patients with recurrences. Conclusions Whole-body 18F-FDG PET/CT is a suitable surveillance tool for sinonasal malignancies in detecting locoregional and distant recurrences in asymptomatic patients without any evidence of recurrence on regular follow-up and endoscopy during the posttreatment period.
关键词： Posttreatment,Recurrence,Surveillance,Sinonasal malignancies,18F-FDG PET/CT
更新于2025-09-23 15:23:52
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18F-FDG PET/TC para la estadificación y la delineación del volumen de radioterapia en el cáncer de cabeza y cuello
摘要： Purpose: The aim is to investigate the use of 18F-FDG (fluorine-18 fluorodeoxyglucose) PET/CT in head and neck cancer (HNC) staging and its effect on the therapeutic strategy and radiotherapy (RT) planning. Methods and materials: One hundred patients with HNC were included. Primary tumor sites: 18% oral cavity, 20% oropharynx, 12% hypopharynx, 11% nasopharynx, 37% larynx, 2% paranasal sinuses. Patients were staged according to the American Joint Committee of Cancer 7th edition. Stage: 5% stage I, 7% stage II, 14% stage III, 61% stage IVA, 7% stage IVB and 6% stage IVC. A contrast-enhanced CT and a 18F-FDG PET/CT acquired under RT position were performed. Both exams were compared to analyze patients' staging reclassification. Changes in therapeutic strategy were analyzed. Results: 18F-FDG PET/CT detected 6 distant metastases and treatment intention changed to palliative. Eight synchronous tumors were detected; one received palliative treatment. 18F-FDG PET/CT reclassified cTNM staging in 27 patients. Tumor extension changed in 28 (14% up-staged; 14% down-staged), implying a change in GTV (Gross Tumor Volume) delineation. Nodal detection was reclassified in 47 patients: 8 patients down-staged (N2C to N2A/N2B/N1) and 2 were false positive. Nineteen patients were false negatives and 5 staged as N+ (N1/N2A/N2B) turned out into N2C. These staging modifications imply adapting the nodal volume to be irradiated. Conclusions: 18F-FDG PET/CT reclassification was higher than 10% in almost all categories studied (cTNM, tumor extension and nodal disease) and detects more metastases and synchronous tumors than conventional studies, which has an impact on the therapeutic patient management and RT planning.
关键词： Head and neck cancer,18F-FDG PET/CT,Radiotherapy planning,Staging
更新于2025-09-23 15:22:29
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Primary Pulmonary Low-Grade Angiosarcoma Characterized by Mismatch between <sup>18</sup> F-FDG PET and Dynamic Contrast-Enhanced CT
摘要： We report a rare case of primary pulmonary low-grade angiosarcoma on dynamic contrast-enhanced CT and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT imaging. A 38-year-old, asymptomatic woman was hospitalized because of an abnormality on chest radiography. A dynamic contrast-enhanced chest CT showed a 1.2 cm-sized irregular-margined nodule with strong and persistent enhancement in the right lower lobe. The lesion had low metabolic activity on an 18F-FDG PET/CT scan. The patient underwent a wedge resection for the lesion, and pathology revealed a primary pulmonary low-grade angiosarcoma.
关键词： Primary pulmonary angiosarcoma,Dynamic contrast-enhanced CT,Low-grade,18F-FDG PET/CT
更新于2025-09-23 15:22:29
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Optimized feature extraction for radiomics analysis of <sup>18</sup> F-FDG-PET imaging
摘要： Radiomics analysis of 18F-FDG-PET/CT images promises for an improved in-vivo disease characterization. To date, several studies reported significant variations in textural features due to differences in patient preparation, imaging protocols, lesion delineation and feature extraction. Our objective was to study variations of features prior to a radiomics analysis of 18F-FDG-PET data and to identify those feature extraction and imaging protocol parameters that minimize radiomic feature variations across PET imaging systems. Methods. A whole-body National Electrical Manufacturers Association image quality phantom was imaged with 13 PET/CT systems at 12 different sites following local protocols. We selected 37 radiomic features related to the four largest spheres (17-37 mm) in the phantom. Based on a combined analysis of voxel size, bin size and lesion volume changes, feature and imaging system ranks were established. A 1-way analysis of variance (ANOVA) was performed over voxel size, bin size and lesion volume subgroups to identify the dependency and the trend change of feature variations across these parameters. Results. Feature ranking revealed that the gray-level co-occurrence matrix (GLCM) and shape features are the least sensitive to PET imaging system variations. Imaging system ranking illustrated that the use of point-spread function (PSF), small voxel sizes and narrow Gaussian post-filtering helped minimize feature variations. ANOVA subgroup analysis indicated that variations of each of the 37 features and for a given voxel size and bin size parameter can be minimized. Conclusions. Our study provides guidance to selecting optimized features from 18F-FDG-PET/CT studies. We were able to demonstrate that feature variations can be minimized for selected image parameters and imaging systems. These results can help imaging specialists and feature engineers in increasing the quality of future radiomic studies involving PET/CT.
关键词： radiomics,18F-FDG PET/CT,feature extraction
更新于2025-09-23 15:21:01
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Diagnostic performance of fluorine-18 fluorodeoxyglucose positron emission tomography in the management of solitary pulmonary nodule: a meta-analysis
摘要： Background: In the setting of solitary pulmonary nodules (SPNs), fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) is considered a useful non-invasive diagnostic tool though false positive (FP) and false negative (FN) results affects accuracy due to different conditions, such as inflammatory diseases or low-uptake neoplasms. Aim of this study is to evaluate overall diagnostic performance of 18F-FDG-PET/CT for malignant pulmonary nodules. Methods: A computerized research, including published articles from 2012 and 2017, was carried out. 18F-FDG-PET/CT overall sensitivity (Se), specificity (Spe), positive likelihood ratio (PLR), negative likelihood ratio (NLR), positive predictive value (PPV), negative predictive value (NPV), diagnostic index and odds ratio were pooled. No selection-bias were found according to asymmetry test. Results: A total of twelve studies were included in the meta-analysis. The pooled Se, Spe, PLR, NLR, PPV, NPV and accuracy index (AI) with relative 95% confidence intervals (CI) were 0.819 (95% CI: 0.794–0.843), 0.624 (95% CI: 0.582–0.665), 2.190 (95% CI: 1.950–2.440), 0.290 (95% CI: 0.250–0.330), 0.802 (95% CI: 0.783–0.819), 0.652 (95% CI: 0.618–0.684) and 0.649 (95% CI: 0.625–0.673), respectively. The diagnostic odds ratio (DOR) was 7.049 with a relative 95% CI between 5.550 and 8.944. Conclusions: The results suggest 18F-FDG-PET/CT has good diagnostic accuracy in SPNs evaluation; but, it should not be considered as a discriminatory test rather than a method to be included in a clinical and diagnostic pathway.
关键词： Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT),solitary pulmonary nodules (SPNs),lung cancer
更新于2025-09-19 17:15:36
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Repeatability of <sup>18</sup> F-FDG PET Radiomic Features: a Phantom Study to Explore Sensitivity to Image Reconstruction Settings, Noise, and Delineation Method
摘要： Background: 18F-fluoro-2-deoxy-D-Glucose positron emission tomography (18F-FDG PET) radiomics has the potential to guide the clinical decision making in cancer patients, but validation is required before radiomics can be implemented in the clinical setting. The aim of this study was to explore how feature space reduction and repeatability of 18F-FDG PET radiomic features are affected by various sources of variation such as underlying data (e.g. object size and uptake), image reconstruction methods and settings, noise, discretization method, and delineation method.
关键词： 18F-FDG PET/CT radiomic features,delineation,image reconstruction settings
更新于2025-09-10 09:29:36
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Radiobiological Modeling Based on 18F-Fluorodeoxyglucose Positron Emission Tomography Data for Esophageal Cancer
摘要： Background: We investigated the relationship of standardized uptake values (SUVs) to radiobiological parameters, such a 25 s tumor control probability (TCP), to allow for quantitative prediction of tumor response based on SUVs from 18F fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) before and after treatment for esophageal cancer. Methods: We analyzed data from 20 esophageal cancer patients treated with chemoradiotherapy (CRT) followed by surgery. Tumor pathologic response to CRT was assessed in surgical specimens. Patients underwent 18F-FDG PET imaging before and after CRT. Rigid image registration was performed between both images. Because TCP in a heterogeneous tumor is a function of average cell survival, we modeled TCP as a function of <SUVR>, a possible surrogate for average cell survival (<SUVR>=<SUVafter/SUVbefore>). TCP was represented by a sigmoid function with two parameters: SUVR50, the <SUVR> at which TCP=0.5, and γ50, the slope of the curve at SUVR50. The two parameters and their confidence intervals (CIs) were estimated using the maximum-likelihood method. The correlation between SUV before CRT and SUV change <SUVbefore – SUVafter> was also studied. Results: A TCP model as a function of SUV before and after treatment was developed for esophageal cancer patients. The maximum-likelihood estimate of SUVR50 was 0.47 (90% CI, 0.30-0.61) and for γ50was 1.62 (90% CI, 0-4.2). High initial SUV and larger metabolic response (larger <SUVbefore –SUVafter>) were correlated, and this correlation was stronger among responders. Conclusions: Our TCP model indicates that <SUVafter/SUVbefore> is a possible surrogate for cell survival in esophageal cancer patients. Although CIs are large as a result of the small patient sample, parameters for a TCP curve can be derived and an individualized TCP can be calculated for future patients. Initial SUV does not predict response, whereas a correlation is found between surrogates for initial tumor burden and cell kill during therapy.
关键词： Quantitative imaging,Esophageal cancer,18F-FDG PET/CT,Tumor response,Radiation therapy
更新于2025-09-09 09:28:46