<b><i>Background:</i></b> Positron emission tomography (PET) imaging in epilepsy is an in vivo technique that allows the localization of a possible seizure onset zone (SOZ) during the interictal period. Stereo-electro-encephalography (SEEG) is the gold standard to define the SOZ. The objective of this research was to evaluate the accuracy of PET imaging in localizing the site of SOZ compared with SEEG. <b><i>Methods:</i></b> Seven patients with refractory temporal lobe epilepsy (Ep) and 2 healthy controls (HC) underwent 2 PET scans, one with 2-[<sup>18</sup>F]-fluoro-2-deoxy-D-glucose (FDG) and another with 2’-[<sup>18</sup>F]fluoroflumazenil (FFMZ), acquired 1 day apart. FDG was acquired for 10 min (static scan) 1 h after administration. An FFMZ scan was acquired for 60 min from radiopharmaceutical administration in a dynamic mode. Each brain PET image was segmented using a standard template implemented in PMOD 3.8. The pons was used as the reference region for modeling of the nondisplaceable binding potential (BP<sub>ND</sub>)<sub></sub>for FFMZ, and to obtain uptake ratios for FDG. SEEG studies of patients were performed as a part of their surgical evaluation to define the SOZ. <b><i>Results:</i></b> Well-defined differences between HC and Ep were found with both radiopharmaceuticals, showing the utility to identify abnormal brain regions using quantitative PET imaging. Lateralization of the SOZ findings by PET (lower uptake/binding in a specific brain hemisphere) matched in 86% for FFMZ and 71% for FDG with SEEG data. <b><i>Conclusion:</i></b> Quantitative PET imaging is an excellent complementary tool that matches reasonably well with SEEG to define SOZ in presurgical evaluation.
Objective The aim of the study was to evaluate the 18F-PSMA-1007 PET/computed tomography (CT) semiautomatic volumetric parameters to assess the whole-body tumor burden and its correlation with prostate-specific antigen (PSA) and Gleason score in patients with biochemically recurrent prostate cancer (PCa). Materials and methods A total of 110 patients referred for 18F-PSMA-1007 PET/CT due to biochemical recurrence were retrospectively analyzed. Whole-body total lesion prostate-specific membrane antigen (wbTl-PSMA) and whole-body PSMA-derived tumor volume (wbPSMA-TV) metrics on 18F-PSMA-1007 were obtained semiautomatically in dedicated software. A Spearman test was performed to explore the correlation of volumetric imaging parameters with PSA levels and Gleason score. To analyze the association between volumetric measures and PSA subgroups, we used a Kruskal–Wallis test and a Dunn’s test to identify each group causing an observed difference. Results A total of 492 metastatic lesions were analyzed, and a significant correlation was found between wbTL-PSMA (R = 0.63, P < 0.0001) and wbPSMA-TV (R = 0.49, P < 0.0001) with serum PSA. A statistically significant difference with wbTL-PSMA was found in patients with a PSA less than or equal 0.5 ng/ml and PSA in the range of 0.51–1.0 ng/ml. Conclusion 18F-PSMA-1007 PSMA volumetric parameters can provide a quantitative imaging biomarker for whole-body tumor burden.
Positron-emission tomography (PET) molecular imaging is a medical diagnostic imaging technique that provides biochemical or functional information at the molecular and cellular level of biological processes. Developed in the mid-1970s, it was introduced in Mexico by the Faculty of Medicine of the National Autonomous University of Mexico early in the year 2000, when this institution acquired a cyclotron and a PET camera and created the PET-Cyclotron Unit, thus becoming a PET pioneer in Mexico. PE molecular imaging in MexicoCurrently, in Mexico there are eight cyclotrons in operation (Table 1), half of them in Mexico City, and only two belong to public institutions: the one at the National Autonomous University of Mexico and that of the National Cancer Institute, which started operating in 2017. Regarding PET/computed tomography (CT) cameras, there are already 50 in the country: 21 in Mexico City and the others distributed in the rest of the states (Fig. 1). Ten PET/CT cameras belong to public institutions, two to universities (National Autonomous University of Mexico and Autonomous University of Nuevo León), one to a private assistance institution (Telethon Children's Oncology Hospital, Querétaro) and 37 to private institutions or companies.Almost two decades after having implemented this diagnostic technique in Mexico there have been
Introduction Microvascular Dysfunction defined as a Myocardial Flow Reserve (MFR) <2 or <2.5 depending on the center, may present in the absence of significant obstruction (1,2); it is included as a diagnosis criteria of Microvascular Angina (MVA) (3,4) and is an independent risk factor associated with poor prognosis (5–7). Traditional Coronary Artery Disease (CAD)risk factors have also been associated with MVA (8–10), however, there is reduced data in latin populations with high prevalence of comorbidities. The aim of this study was to identify the comorbidities that alter MFR with 13N-ammonia Positron Emission Tomography/Cardiac Tomography (PET/CT) and Cardiac Computed Tomography Angiography (CCTA) in a cardiovascular imaging referral center. Methods Retrospective cross-sectional study of patients with suspected CAD in which both PET/CT and CCTA were performed. Inclusion:CCTA with obstruction <50%. Exclusion: incomplete study, previous infarction or intervention. Clinical data was assessed. Mean (±DE) or median (interquartile range) to present continuous variables according to their distribution; T student or U Man Whitney to compare them. For each variable two groups were conformed depending on its presence or absence in order to compare MFR between them. Statistical analysis was performed with Statistical Package for Social Science (SPSs Inc, Chicago, IL; version 23.0) and GraphPad Prism version 9.0. p<0.05 was considered as significant. Results 335 patients included. MFR difference for each variable: female sex, hypertension (HT), Type 2 diabetes (T2D) and smoking – Appendix 1. Significant MFR difference for HT (p=0.024) and T2D (p=0.046). Severe ischemia had significant MFR reduction (p=0.006); patients with both HT and mild ischemia (p=0.018) – Appendix 2. Discussion Individuals with HT and T2D had a significantly lower MFR, consistent with previous studies (8,9). Absence of correlation with other risk factors, such as smoking (10) and female sex (11); latter may be caused by a significant lower number of women (108 vs 227). Further analysis in this subgroup ought to be done. When comparing MFR between level-of-ischemia groups, microvascular function was not reduced until severe ischemia. Remarkably, if we analyze the coexistence of HT with ischemia, MFR is reduced even in patients with mild ischemia. This finding highlights the importance of HT which alters function in early stages even in the absence of significant obstruction. This is one of the first studies correlating MFR with comorbidities in our population. Limitations the retrospective nature of the study. Conclusions MFR non-invasive assessment by PET/CT allows identifying very early stages of MVD, even in asymptomatic patients and when there's no evidence of ischemia or CAD. Therefore, timely recognition of this problem is mandatory to implement action strategies to stop the triggered events' cascade. FUNDunding Acknowledgement Type of funding sources: None.
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