FDG uptake of pulmonary lesions in synchronous primary lung cancers and lung metastases.

Purpose: In lung cancer patients, the distinction between synchronous primary lung cancer and intrapulmonary metastasis can be challenging. The intensity of FDG uptake in pulmonary lesions has been shown to be potentially useful in classifying synchronous lung cancer. The aim of this retrospective study is to investigate the effectiveness of FDG uptake in differentiating metastases from synchronous primary lesions in the setting of lung cancer. Methods: Consecutive patients with primary lung cancer with two or more malignant lung lesions referred for (18F)-FDG PET-CT imaging between 2010 and 2019 were reviewed and classified into synchronous and metastasis groups. Lesional maximum standardized uptake values (SUVmax), relative differences in SUVmax and SUVmax ratios were calculated and compared using receiver operating characteristic (ROC) curve analysis. Intra-group correlation in SUVmax between lesion pairs was examined using Pearson's and Spearman's correlation analysis. Results: 94 patients were included for analysis, divided into synchronous (n = 62; 68 lesion pairs) and metastasis (n = 32; 33 lesion pairs) groups. The correlation of FDG uptake between lesions in the metastasis group was strong (r = 0.81). A significant difference in mean relative difference in SUVmax (synchronous: 0.50±0.23 metastasis: 0.34±0.17, p = 0.001) and mean SUVmax ratio (synchronous: 2.6 ± 1.7 metastasis: 1.7 ± 0.6, p < 0.001) was observed. ROC analysis revealed a fair AUC (0.71-0.72) for these parameters, with an associated sensitivity of 59 % and specificity of 82 % at optimal cut-off values. Conclusion: Differences in FDG uptake intensity among multiple synchronously presenting malignant nodules may be helpful to distinguish second primary lung tumours from metastatic spread.

Graves' disease post-COVID-19 m-RNA vaccine in pediatric age group.

The surge of the COVID-19 pandemic (December / 2019 - May/2023) and its catastrophic effect worldwide have necessitated emergent intervention to reduce its influence on people's health and life. To eliminate and reduce the impact of COVID-19 infection, COVID-19 vaccination was emergently authorized in December 2020 which has established good safety and efficacy. Having said that, some adverse effects merged in a few individuals. We are reporting an adolescent patient a 17-year-old female who has been diagnosed with Graves' disease after post-COVID-19 vaccinations. In addition, she was a confirmed case of COVID-19 infection three months earlier. The patient presented with typical features of hyperthyroidism 30 days post receiving the first dose of the vaccination. Based on the patient's presentation relative to the administration of the vaccine and prior infection of the virus. We proposed the synergistic effect of both factors to induce Graves' disease in this young healthy female with no family history of autoimmune disease. We are reporting this case for pediatric endocrinologists to be aware of the interaction and possible impact of the COVID-19 vaccine on thyroid function.

Development and validation of the Lesion Synthesis Toolbox and the Perception Study Tool for quantifying observer limits of detection of lesions in positron emission tomography.

Purpose: Accurate detection of cancer lesions in positron emission tomography (PET) is fundamental to achieving favorable clinical outcomes. Therefore, image reconstruction, processing, visualization, and interpretation techniques must be optimized for this task. The objective of this work was to (1) develop and validate an efficient method to generate well-characterized synthetic lesions in real patient data and (2) to apply these lesions in a human perception experiment to establish baseline measurements of the limits of lesion detection as a function of lesion size and contrast using current imaging technologies. Approach: A fully integrated software package for synthesizing well-characterized lesions in real patient PET was developed using a vendor provided PET image reconstruction toolbox (REGRECON5, General Electric Healthcare, Waukesha, Wisconsin). Lesion characteristics were validated experimentally for geometric accuracy, activity accuracy, and absence of artifacts. The Lesion Synthesis Toolbox was used to generate a library of 133 synthetic lesions of varying sizes ( n = 7 ) and contrast levels ( n = 19 ) in manually defined locations in the livers of 37 patient studies. A lesion-localization perception study was performed with seven observers to determine the limits of detection with regard to lesion size and contrast using our web-based perception study tool. Results: The Lesion Synthesis Toolbox was validated for accurate lesion placement and size. Lesion intensities were deemed accurate with slightly elevated activities (5% at 2:1 lesion-to-background contrast) in small lesions ( Ø = 15 mm spheres), and no bias in large lesions ( Ø = 22.5 mm ). Bed-stitching artifacts were not observed, and lesion attenuation correction bias was small ( - 1.6 ± 1.2 % ). The 133 liver lesions were synthesized in ∼ 50 h , and readers were able to complete the perception study of these lesions in 12 ± 3 min with consistent limits of detection amongst all readers. Conclusions: Our open-source utilities can be employed by nonexperts to generate well-characterized synthetic lesions in real patient PET images and for administering perception studies on clinical workstations without the need to install proprietary software.