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Purpose: Left ventricular assisting device (LVAD) is a vital mechanical circulatory assist device for patients with end-stage heart disease, serving as either a bridge to transplantation or palliative destination therapy. Yet device infection represents a major lethal complication, warranting a multi-step, complex therapy approach including an urgent device exchange or heart transplantation. Still, timely diagnosis of site and extent of VAD-specific infection for a proper therapy planning poses challenges in regular clinical care. This single-center, retrospective study aimed to evaluate the impact of volumetric PET parameters with different thresholding compared to semiquantitative PET parameters for accurate diagnosis of VAD-specific infection. Procedures: Seventeen patients (1 female, 16 males; mean age 57 ± 11 years) underwent [18F]FDG imaging for suspected VAD-specific infection between April 2013 and October 2023. Various metabolic and volumetric PET parameters with different thresholding were collected for specific LVAD components including driveline entry point, subcutaneous driveline, pump pocket, inner cannula and outflow tract. Microbiology and clinical follow-up were used as the final diagnosis standard. Results: Nine of eleven patients with VAD-specific infection underwent urgent heart transplantation, and one had a surgical revision of LVAD. Two patients had non-VAD specific infections, and two had non-VAD related infections. Metabolic burden determination using a fixed absolute threshold provided the best outcome compared to relative thresholding or other metabolic SUV parameters. The total metabolic tumor volume (MTV) cutoff value was 9.3 cm3, and the corresponding sensitivity, specificity, accuracy, and AUC were 90.0%, 71.43%, 82.5%, and 0.814 (95% CI 0.555–0.958), respectively. The total lesion glycolysis (TLG) was 30.6, and the corresponding sensitivity, specificity, accuracy, and AUC were 90.0%, 71.4%, 82.5%, and 0.829 (95% CI 0.571–0.964), respectively. Conclusions: Volumetric PET parameters with fixed absolute thresholding appear to be a valuable auxiliary tool in the evaluation of [18F]FDG imaging to enhance the diagnostic accuracy of VAD-specific infection. [ABSTRACT FROM AUTHOR]

The dynamical behavior of one‐dimensional compressible Navier–Stokes equation with density‐dependent viscosity coefficient is considered. A new sufficient condition under which the solution blows up is established. [ABSTRACT FROM AUTHOR]

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrosing interstitial lung disease with a poor prognosis. 68Ga-labeled FAP ligands exhibited highly promising results due to the crucial role of activated fibroblasts in fibrosis imaging of the lung. However, 18F-labeled FAP ligands might provide qualitatively much higher imaging results with accompanying economic benefits due to large-scale production. Thus, we sought to investigate the potential of [18F]FAPI-74 prospectively in a small patient cohort. Methods: Eight patients underwent both [18F]FAPI-74-PET/CT and HRCT scans and were then compared with a control group without any fibrosing pulmonary disease. The tracer uptake of fibrotic lung areas was analyzed in synopsis with radiological and clinical parameters. Results: We observed a positive correlation between the fibrotic active volume, the Hounsfield scale, as well as the vital and diffusing capacity of the lung. Conclusion: The initial results confirm our assumption that [18F]FAPI-74 offers a viable non-invasive assessment method for pulmonary fibrotic changes in patients with IPF. [ABSTRACT FROM AUTHOR]

Simple Summary: The roll-out of the novel pan-cancer tracer family, fibroblast activation protein (FAP) ligands, has opened a new avenue for the diagnosis of numerous epithelial malignancies. These ligands bind to these transmembrane proteins with enzymatic activity, which is predominantly found on the cell membranes of cancer-associated fibroblasts and regulate the interaction of tumor cells and the tumor microenvironment. The upregulation of these membrane proteins enhances tumor growth and leads to poor outcomes. The first studies with Ga-labeled FAP ligands in patients with pancreatic cancer led to very promising results. However, due to production and financial challenges of 68Ga-labeling, 18F-labeled FAP ligands emerge as the "diagnostic" FAP-tracer with the potential of widespread, economical use in regular healthcare. With this monocentric, prospective study, we aimed to investigate the utility of [18F]FAPI-74 PET/CT examination in patients with pancreatic cancer. Background: Radiolabeled fibroblast activation protein (FAP) ligands, a novel class of tracers for PET/CT imaging, have demonstrated very promising results in various oncological, as well as in some benign, diseases with long-term potential to supplant the current pan-cancer agent [18F]FDG in some cancer types. Pancreatic ductal carcinoma (PDAC) belongs to the group of epithelial malignancies with a strong so-called "desmoplastic reaction", leading to a prominent tumor stroma with cancer-associated fibroblasts that exhibit a marked overexpression of fibroblast activation protein (FAP). The first clinical experiences in PDAC with 68Ga-labeled FAP ligands suggested superior sensitivity to [18F]FDG. However, there is limited data with 18F-labeled FAP derivatives, i.e. [18F]FAPI-74, yet prospective single- and multicenter trials are already ongoing. In this proof-of-concept study, we sought to evaluate the biodistribution, tumor uptake, and lesion detectability in patients with PDAC using [18F]FAPI-74 PET/CT as compared to [18F]FDG PET/CT scans for staging. Methods: This study includes 7 patients (median age 69) who underwent both [18F]FDG PET/CT with contrast-enhancement and [18F]FAPI-74 PET with low-dose CT for primary staging (n = 3) and therapy response control after neoadjuvant (n = 1) or re-staging after palliative therapy (n = 3). The mean interval between PET scans was 11 ± 4 days (range 1–15 days). The [18F]FDG and [18F]FAPI-74 PET/CT scans were acquired at 64 ± 4.1 min (range 61–91 min) and 66.4 ± 6.3 min (range 60–76 min), respectively, after administration of 200 ± 94 MBq (range 79–318 MBq) and 235 ± 88 MBq (range 90–321 MBq), respectively. Quantification of tracer uptake was determined with SUVmax and SUVmean. Furthermore, the tumor-to-background ratio (TBR) was derived by dividing the SUVmax of tumor lesions by the SUVmax of adipose tissue, skeletal muscle, and blood pool. Results: Overall, 32 lesions were detected in 7 patients including primary (n = 7), lung (n = 7), bone (n = 3), lymph node (n = 13), and peritoneal metastases (n = 2). [18F]FAPI-74 detected 22% more lesions compared with [18F]FDG with a better TBR and visual lesion delineation. In one patient the primary lesion could be detected unequivocally with [18F]FAPI-74 but was missed by [18F]FDG imaging. Altogether, most of the lesions demonstrated markedly elevated uptake of [18F]FAPI-74 with a simultaneous lower uptake in the background, providing a very high visual contrast. Conclusion: To the best of our knowledge, this is the first, prospective, intra-individual investigation comparing [18F]FAPI-74 with [18F]FDG imaging in PDAC with encouraging results. These pivotalresults supporta larger, multicentric, prospective study to determine the value of [18F]FAPI-74 in detecting and staging PDAC in comparison with current standard of care imaging. [ABSTRACT FROM AUTHOR]

Simple Summary: Since the introduction of PSMA imaging around a decade ago, the faint tracer uptake of ganglia in the neck, abdomen, and presacral region has been an imaging challenge due to difficult discrimination from suspicious lymph nodes. Moreover, PSMA tracers labelled with different radionuclides demonstrate varying levels of ganglion uptake despite having the same target structure on the cell membrane, resulting in distinct imaging pitfall patterns. Our study aims to investigate the underlying mechanisms of the varying detectability of PSMA ligands labelled with different radionuclides. Background: Several studies indicate, particularly in the case of [18F]PSMA-1007, a relatively high rate of detection of ganglia in PSMA PET imaging. Ganglia are an integral part of the sympathetic portion of the autonomous nervous system. To date, no studies have directly compared [68Ga]Ga-PSMA-11 and [18F]PSMA-1007 ganglionic uptake intra-individually and analyzed the underlying molecular and physical mechanisms of different detection rates. With this monocentric retrospective study, we sought to evaluate the intra-individual physiological ganglion uptake of these different PSMA ligands in evidence-based imaging for prostate cancer. Methods: Our cohort consists of 19 male patients (median age 72 ± 9 with a range of 56–85) with biochemical recurrence of prostate cancer who underwent both [68Ga]Ga-PSMA-11 and [18F]PSMA-1007 PET/CT in our clinic on the same scanner per standard care between March 2015 and March 2022. Tracer uptake was quantified according to maximum standardized uptake value (SUVmax) for both [68Ga]Ga-PSMA-11 and [18F]PSMA-1007 PET/CT scans. Ganglia-to-background ratios (GBRs) were determined to quantify the image contrast through dividing the SUVmax of the ganglia by the background value (SUVmax of blood pool in the descending aorta, fatty tissue, and skeletal muscle in gluteal region). We used descriptive analyses for demographics and tumor characteristics and performed two-way repeated-measures ANOVA (analysis of variance) for SUV metrics including GBR measurements. Results: In total, we examined 101 ganglia with [18F]PSMA-1007 scanning, localized mostly in pairs as stellate, coeliac, and sacral, of which 76 were also detected with [68Ga]Ga-PSMA-11 PET/CT scanning. There was no statistically significant difference in PSMA uptake in terms of SUVmax between [18F]PSMA-1007 and [68Ga]Ga-PSMA-11 (p value: 0.052). In contrast, the comparison of GBRs revealed a higher detectability rate of ganglia with [18F]PSMA-1007 imaging (p < 0.001). Furthermore, a separate comparison of ganglia with respect to their anatomical location also demonstrated statistically significant differences both within and between [18F]PSMA-1007 and [68Ga]Ga-PSMA-11 PET/CT scans. Conclusion: Given the impression of more accentuated [18F]PSMA-1007 uptake in ganglia compared with 68Ga-labelled counterparts, our study demonstrated that the better detectability of ganglia is not due to more intense [18F]PSMA-1007 uptake by these small structures but to much more favorable physical properties of the radionuclide 18F. The most relevant limitations of our study are its retrospective design and the small patient cohort. [ABSTRACT FROM AUTHOR]

We investigate the blow-up phenomena for the two-component generalization of hyper-elastic rod equation on the real line. We establish some blow-up criteria for system of coupled equations with density function that in one case alternates its sign and keeps its sign in another case under certain natural initial profiles. Presented results extend and specify the earlier blow-up criteria for such type system. [ABSTRACT FROM AUTHOR]

We investigate the blow-up phenomena for the two-component generalizations of Camassa-Holm equation on the real line. We establish some a local-in-space blow-up criterion for system of coupled equations under certain natural initial profiles. Presented result extend and specify the earlier blow-up criteria for such type the system. [ABSTRACT FROM AUTHOR]

Objectives: Studies have indicated that oxytocin (OT), a regulatory nonapeptide synthesized in the hypothalamic supraoptic and paraventricular nuclei, is endogenously released into blood following a fatty meal or by the stimulation of exogenous cholecystokinin (CCK). Despite OT's acceleratory effect on gastric emptying, there are also experimental studies documenting its delaying action. Methods: Sprague Dawley rats were used to evaluate the effect of centrally or peripherally administered OT on the gastric emptying rate of a liquid meal in awake rats and to explain the interaction of OT and CCK-2 receptors in these effects. Under anesthesia, a group of rats was inserted intracerebroventricularly (icv) for drug applications, while some were inserted with stainless steel gastric cannulas for gastric emptying. Before gastric emptying tests were performed, rats were given intraperitoneally or icv saline, OT, OT antagonist atosiban (ATO) and/or CCK-2 antagonist L365,260. Following the drug injections, in another group that had no gastric cannula placement, rats were given orogastrically methylcellulose containing phenol red, and the gastric emptying rate was calculated. Results: Both central and peripheral injections of OT slowed the gastric emptying of physiological saline in rats with gastric cannula, while gastric emptying of methyl cellulose was accelerated at the 30th minute. It has been shown by using the receptor antagonist ATO that endogenous OT has an accelerating effect. The acceleratory effect of the exogenous OT on methyl cellulose in the late period was suppressed by ATO, but CCK-2 antagonist had no effect. Conclusion: In the experiments performed by using a viscous methyl cellulose meal and solutions through the gastric cannulas, exogenous OT inhibits gastric motility for a short term and then accelerates. Endogenous OT increases gastric emptying, while OT and CCK-2 receptors mediate these effects. [ABSTRACT FROM AUTHOR]