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Cancer Innovation Apr 2024Rhabdomyosarcoma (RMS) originates from primitive mesenchymal cells and is the most common soft tissue tumor in childhood. F-fluoro-deoxyglucose (F-FDG) positron emission...
Rhabdomyosarcoma (RMS) originates from primitive mesenchymal cells and is the most common soft tissue tumor in childhood. F-fluoro-deoxyglucose (F-FDG) positron emission tomography (PET)/computed tomography (CT) has been reported to be valuable in RMS staging and risk stratification. Paratesticular RMS is a relatively uncommon form of RMS, most of which are of the embryonal histologic type. Paratesticular alveolar RMS is associated with aggressive behavior, high metastatic potential, and poor outcomes. To the best of our knowledge, F-FDG PET/CT imaging findings of paratesticular alveolar RMS have never been described. Here, we report on a 16-year-old boy's rare paratesticular alveolar RMS with multiple metastases and its findings on F-FDG PET/CT. This case also demonstrates the potential value of F-FDG PET/CT in RMS staging and treatment decisions, and may aid in the differential diagnosis.
PubMed: 38946934
DOI: 10.1002/cai2.121 -
World Journal of Gastrointestinal... Jun 2024Pleomorphic leiomyosarcomas make up around 8.6% of all leiomyosarcomas. They behave aggressively and often have poor prognoses. They can affect the gastrointestinal...
BACKGROUND
Pleomorphic leiomyosarcomas make up around 8.6% of all leiomyosarcomas. They behave aggressively and often have poor prognoses. They can affect the gastrointestinal tract and retroperitoneum. To date, pleomorphic leiomyosarcoma involving the mesocolon have been reported in nine patients.
CASE SUMMARY
The patient was a 44-year-old man with a history of pleomorphic leiomyosarcoma of the left maxilla with metastasis to the lung and liver. His most recent positron emission tomography-computed tomography (PET-CT) scan showed uptake in the ascending and transverse colons. A colonoscopy revealed a 5.0 cm × 3.5 cm × 3.0 cm pedunculated polyp in the ascending colon. The polyp was removed using hot snare polypectomy technique and retrieved with Rothnet. Histopathologic examination of the polyp showed a metastatic pleomorphic leiomyosarcoma.
CONCLUSION
Uptake(s) on PET-CT in a patient with pleomorphic leiomyosarcoma should raise suspicion for metastasis.
PubMed: 38946849
DOI: 10.4253/wjge.v16.i6.361 -
Biomedical Engineering Letters Jul 2024As silicon photomultiplier (SiPM)-based time-of-flight (TOF) positron emission tomography (PET) becomes popular, the need for sophisticated PET data acquisition (DAQ)...
As silicon photomultiplier (SiPM)-based time-of-flight (TOF) positron emission tomography (PET) becomes popular, the need for sophisticated PET data acquisition (DAQ) systems is increasing. One promising solution to this challenge is the adoption of a field-programmable gate array (FPGA)-only signal digitization method. In this paper, we propose a new approach to efficiently implement an FPGA-only digitizer. We configured the input/output (IO) port of the FPGA to function as a dual-threshold voltage comparator through the use of simple passive circuitry and heterogeneous IO standards. This configuration overcomes the limitations of existing methods by allowing different threshold voltages for adjacent IO pins, effectively reducing routing complexity and lowering manufacturing costs. An FPGA-only digitizer was implemented by integrating the dual-threshold voltage comparator and FPGA-based time-to-digital converter. By combining the dual-threshold time-over-threshold (TOT) method and curve fitting, precise energy information could be obtained. The performance of the FPGA-only digitizer was assessed using a detector setup comprising a 3 × 3 × 20 mm LYSO scintillation crystal and a single pixel SiPM. Using the configured evaluation setup, an energy resolution of 12.5% and a time resolution of 146 ± 9 ps were achieved for a 20 mm scintillation crystal. The dual-threshold TOT implemented using the proposed method showed consistent linearity across an energy range of 100 keV to 600 keV. The proposed method is well-suited for the development of cost-effective DAQ systems in highly integrated TOF PET systems.
PubMed: 38946816
DOI: 10.1007/s13534-024-00380-5 -
EJNMMI Reports Jul 2024This study aimed to establish radiomics models based on positron emission tomography (PET) images to longitudinally predict transition from mild cognitive impairment...
BACKGROUND
This study aimed to establish radiomics models based on positron emission tomography (PET) images to longitudinally predict transition from mild cognitive impairment (MCI) to Alzheimer's disease (AD).
METHODS
In our study, 278 MCI patients from the ADNI database were analyzed, where 60 transitioned to AD (pMCI) and 218 remained stable (sMCI) over 48 months. Patients were divided into a training set (n = 222) and a validation set (n = 56). We first employed voxel-based analysis of 18F-FDG PET images to identify brain regions that present significant SUV difference between pMCI and sMCI groups. Radiomic features were extracted from these regions, key features were selected, and predictive models were developed for individual and combined brain regions. The models' effectiveness was evaluated using metrics like AUC to determine the most accurate predictive model for MCI progression.
RESULTS
Voxel-based analysis revealed four brain regions implicated in the progression from MCI to AD. These include ROI1 within the Temporal lobe, ROI2 and ROI3 in the Thalamus, and ROI4 in the Limbic system. Among the predictive models developed for these individual regions, the model utilizing ROI4 demonstrated superior predictive accuracy. In the training set, the AUC for the ROI4 model was 0.803 (95% CI 0.736, 0.865), and in the validation set, it achieved an AUC of 0.733 (95% CI 0.559, 0.893). Conversely, the model based on ROI3 showed the lowest performance, with an AUC of 0.75 (95% CI 0.685, 0.809). Notably, the comprehensive model encompassing all identified regions (ROI total) outperformed the single-region models, achieving an AUC of 0.884 (95% CI 0.845, 0.921) in the training set and 0.816 (95% CI 0.705, 0.909) in the validation set, indicating significantly enhanced predictive capability for MCI progression to AD.
CONCLUSION
Our findings underscore the Limbic system as the brain region most closely associated with the progression from MCI to AD. Importantly, our study demonstrates that a PET brain radiomics model encompassing multiple brain regions (ROI total) significantly outperforms models based on single brain regions. This comprehensive approach more accurately identifies MCI patients at high risk of progressing to AD, offering valuable insights for non-invasive diagnostics and facilitating early and timely interventions in clinical settings.
PubMed: 38945980
DOI: 10.1186/s41824-024-00206-8 -
Igaku Butsuri : Nihon Igaku Butsuri... 2024This is an explanatory paper on Sun Il Kwon et al., Nat. Photon. 15: 914-918, 2021 and some parts of this manuscript are translated from the paper. Medical imaging...
This is an explanatory paper on Sun Il Kwon et al., Nat. Photon. 15: 914-918, 2021 and some parts of this manuscript are translated from the paper. Medical imaging modalities such as X-ray computed tomography, Magnetic resonance imaging, positron emission tomography (PET), and single photon emission computed tomography, require image reconstruction processes, consequently constraining them to form cylindrical shapes. However, among them, only PET can use additional information, so called time of flight, on an event-by-event basis. If coincidence time resolution (CTR) of PET detectors improved to 30 ps, which corresponds to spatial resolution of 4.5 mm, directly localizing electron-positron annihilation point is possible, allowing us to circumvent image reconstruction processes and free us from the geometric constraint. We call this concept direct positron emission imaging (dPEI). We have developed ultrafast radiation detectors by focusing on Cherenkov photon detection. Furthermore, the CTR of 32 ps being equivalent to 4.8 mm spatial resolution is achieved by combining deep learning-based signal processing with the detectors. In this article, we explain how we developed the detectors and demonstrated the first dPEI using different types of phantoms, how we will tackle limitations to be addressed to make the dPEI more practical, and how dPEI will emerge as an imaging modality in nuclear medicine.
Topics: Image Processing, Computer-Assisted; Phantoms, Imaging; Photons; Positron-Emission Tomography; Time Factors
PubMed: 38945880
DOI: 10.11323/jjmp.44.2_29 -
PET Clinics Jun 2024The 2-deoxy-2-[F]fluoro-D-glucose positron emission tomography combined with computed tomography (PET/CT) has contributed to outcome improvement of patients with... (Review)
Review
The 2-deoxy-2-[F]fluoro-D-glucose positron emission tomography combined with computed tomography (PET/CT) has contributed to outcome improvement of patients with lymphoma. The use of [F]FDG PET/CT for staging and response assessment is successfully applied both in routine clinical practice and in clinical trials. The challenges lie in enhancing the outcomes of lymphoma patients, particularly those with advanced or refractory/relapsed disease, and to minimize the long-term toxicity associated with treatments, including radiation therapy. The objective of this review article is to present contemporary data on the use of [F]FDG PET/CT for treatment assessment of aggressive lymphomas.
PubMed: 38945737
DOI: 10.1016/j.cpet.2024.05.001 -
Experimental Eye Research Jun 2024Ocular complications of diabetes mellitus (DM) are the leading cause of vision loss. Ocular inflammation often occurs in the early stage of DM; however, there are no...
Ocular complications of diabetes mellitus (DM) are the leading cause of vision loss. Ocular inflammation often occurs in the early stage of DM; however, there are no proven quantitative methods to evaluate the inflammatory status of eyes in DM. The 18 kDa translocator protein (TSPO) is an evolutionarily conserved cholesterol binding protein localized in the outer mitochondrial membrane. It is a biomarker of activated microglia/macrophages; however, its role in ocular inflammation is unclear. In this study, fluorine-18-DPA-714 ([F]-DPA-714) was evaluated as a specific TSPO probe by cell uptake, cell binding assays and micro positron emission tomography (microPET) imaging in both in vitro and in vivo models. Primary microglia/macrophages (PMs) extracted from the cornea, retina, choroid or sclera of neonatal rats with or without high glucose (50 mM) treatment were used as the in vitro model. Sprague-Dawley (SD) rats that received an intraperitoneal administration of streptozotocin (STZ, 60 mg/kg once) were used as the in vivo model. Increased cell uptake and high binding affinity of [F]-DPA-714 were observed in primary PMs under hyperglycemic stress. These findings were consistent with cellular morphological changes, cell activation, and TSPO up-regulation. [F]-DPA-714 PET imaging and biodistribution in the eyes of DM rats revealed that inflammation initiates in microglia/macrophages in the early stages (3 weeks and 6 weeks), corresponding with up-regulated TSPO levels. Thus, [F]-DPA-714 microPET imaging may be an effective approach for the early evaluation of ocular inflammation in DM.
PubMed: 38945519
DOI: 10.1016/j.exer.2024.109986 -
Clinical Radiology May 2024Radiomics involves the extraction of quantitative data from medical images to facilitate the diagnosis, prognosis, and staging of tumors. This study provides a...
Systematic review and meta-analysis of the prognostic value of F-Fluorodeoxyglucose (F-FDG) positron emission tomography (PET) and/or computed tomography (CT)-based radiomics in head and neck cancer.
AIM
Radiomics involves the extraction of quantitative data from medical images to facilitate the diagnosis, prognosis, and staging of tumors. This study provides a comprehensive overview of the efficacy of radiomics in prognostic applications for head and neck cancer (HNC) in recent years. It undertakes a systematic review of prognostic models specific to HNC and conducts a meta-analysis to evaluate their predictive performance.
MATERIALS AND METHODS
This study adhered rigorously to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for literature searches. The literature databases, including PubMed, Embase, Cochrane, and Scopus were systematically searched individually. The methodological quality of the incorporated studies underwent assessment utilizing the radiomics quality score (RQS) tool. A random-effects meta-analysis employing the Harrell concordance index (C-index) was conducted to evaluate the performance of all radiomics models.
RESULTS
Among the 388 studies retrieved, 24 studies encompassing a total of 6,978 cases were incorporated into the systematic review. Furthermore, eight studies, focusing on overall survival as an endpoint, were included in the meta-analysis. The meta-analysis revealed that the estimated random effect of the C-index for all studies utilizing radiomics alone was 0.77 (0.71-0.82), with a substantial degree of heterogeneity indicated by an I of 80.17%.
CONCLUSIONS
Based on this review, prognostic modeling utilizing radiomics has demonstrated enhanced efficacy for head and neck cancers; however, there remains room for improvement in this approach. In the future, advancements are warranted in the integration of clinical parameters and multimodal features, balancing multicenter data, as well as in feature screening and model construction within this field.
PubMed: 38944542
DOI: 10.1016/j.crad.2024.05.016 -
Clinical Neurology and Neurosurgery Jun 2024Parkinson's disease (PD) is the second most prevalent neurodegenerative condition after Alzheimer's disease and it represents one of the fastest emerging neurological... (Review)
Review
Parkinson's disease (PD) is the second most prevalent neurodegenerative condition after Alzheimer's disease and it represents one of the fastest emerging neurological diseases worldwide. PD is usually diagnosed after the third decade of life with symptoms like tremors at rest and muscle stiffness. Rapid Eye Movement sleep behavioral disorder (RBD) is another disorder that is caused by a loss of typical muscle relaxation during sleep with a lot of motor activity. Usually, RBD is strongly associated with PD. Recent studies have demonstrated that PD reduces the life expectancy of patients to 10 and 20 years after being diagnosed. In addition, delayed diagnosis and treatment of these neurological disorders have significant socio-economic impacts on patients, their partners and on the general public. Often, it is not clear about PD associated financial burdens both in low and high-income countries. On the other hand, PD triggers neurological variations that affect differences in the dopamine transporter (DAT) and in glucose metabolism. Therefore, positron emission tomography (PET) using specific DAT radiotracers and fluorine-18 labeled desoxyglucose (FDG) has being considered a key imaging technique that could be applied clinically for the very early diagnosis of RBD and in PD. However, a few myths about PET is that it is very expensive. Here, we looked at the cost of treatment of PD and RBD in relation to early PET imaging. Our finding suggests that PET imaging might also be a cost sparing diagnostic option in the management of patients with PD and RBD, not only for first world countries as it is the case now but also for the third world countries. Therefore, PET is a cost-effective imaging technique for very early diagnostic of RBD and PD.
PubMed: 38944021
DOI: 10.1016/j.clineuro.2024.108404 -
Neoplasia (New York, N.Y.) Jun 2024Gastrointestinal stromal tumor (GIST) is the most prevalent mesenchymal tumor of the digestive tract. Its growth is primarily influenced by mutations in KIT or PDGFRA.... (Review)
Review
Gastrointestinal stromal tumor (GIST) is the most prevalent mesenchymal tumor of the digestive tract. Its growth is primarily influenced by mutations in KIT or PDGFRA. Surgery is the primary treatment option for GIST; however, KIT inhibitors, such as imatinib, are used for inoperable cases. Resistance to imatinib is an upcoming challenge, especially because the effectiveness of alternative drugs is limited. Enhancement of the glycolysis pathway in cancer cells has been identified as a key feature in cancer. This unique metabolic activity has implications on tumor growth, prognosis, and resistance to therapy, even in GIST. Members of the glucose transporter (GLUT) family (particularly GLUT-1) play a significant role in GIST progression and response to treatment. Diagnostic imaging using 18F-fluorodeoxyglucose positron emission tomography/computed tomography, which enables visualization of glucose metabolism, can aid in GIST diagnosis and risk assessment. The interplay between glycolysis and GIST can lead to the development of various therapeutic strategies, especially those involving glycolysis-related molecules, such as hexokinase and lactate dehydrogenase. However, further research is required to understand the full spectrum of glycolysis in GIST and its therapeutic potential. Herein, we present an exhaustive overview and analysis of the role of glycolysis in GIST, especially as a therapeutic target.
PubMed: 38943997
DOI: 10.1016/j.neo.2024.101022