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Aim. To develop a method and obtain proof-of-principle for immunolymphoscintigraphy for identification of metastatic sentinel nodes. Methods. We selected one of four tumour-specific antibodies against human breast cancer and investigated (1), in immunedeficient (nude) mice with xenograft human breast cancer expressing the antigen if specific binding of the intratumorally injected, radioactively labelled, monoclonal antibody could be scintigraphically visualized, and (2) transportation to and retention in regional lymph nodes of the radioactively labelled antibody after subcutaneous injection in healthy rabbits. Results and Conclusion. Our paper suggests the theoretical possibility of amodel of dual isotope immuno-lymphoscintigraphy for noninvasive, preoperative, malignant sentinel node imaging. [ABSTRACT FROM AUTHOR]

We describe a small-angle x-ray scattering-based imaging technique that reveals the distribution and orientation of nano-scale structures over extended areas. By combining two measurement and analysis schemes, complementary structural information is available which renders the technique suitable for a broad range of applications, e.g. in materials science and bioimaging. Through a combination of current techniques and on-line analysis schemes, measurements with a so far unprecedented combination of speed, dynamic range and point density became feasible. This is illustrated by data recorded for a section of a mouse soleus muscle visualizing fine muscle and Achilles tendon structures down to the 10 nm range over a 10mm² sample area. [ABSTRACT FROM AUTHOR]

Introduction: miRNAs are small non-coding RNAs that post-transcriptionally regulate gene expression by binding to comple mentary sequences on target mRNAs and their expression is often dysregulated in cancer. Aim(s): Little is known about the carcinogenesis of the slow growing neuroendocrine tumors and we therefore wanted to characterize miRNA expression in these. Materials and methods: miRNA expression in carcinoids, metastasis and normal intestinal tissue was characterized using miRNA arrays. Changes in miRNA expression were validated by in-situ hybridization and qPCR. miR-129-Sp and let-7 was selected and further characterized by mRNA arrays on total RNA from cells transfected with either miRNA. Heatmaps identified let-7 target genes involved in metastasis, miR-129-5p and its two targets EGR1 and G3BP 1 were validated by western blot analysis and luciferase assay and further examined by growth assays with ceils transfected with miR-129-5p or siRNAs against EGR1 and G3BP1. Results: miR-129-5p is down-regulated in carcinoids and the let-7 family is reduced in metastasis. When transfected into carcinoid cells, both Let-7 and miR-129-5p inhibited their growth and miR-129-5p was shown to target EGR1 and G3BP1. Knock down of EGR1 and G3BP 1 also resulted in growth inhibition mimicking that of miR-129-5p. Conclusion: miRNA expression alters intestinal carcinoids, leading to down regulation of miR-129-5p, and the let-7 family is lost in metastasis. Both are important for growth inhibition. [ABSTRACT FROM AUTHOR]

Abstract Background In animal studies tumor size is used to assess responses to anticancer therapy. Current standard for volumetric measurement of xenografted tumors is by external caliper, a method often affected by error. The aim of the present study was to evaluate if microCT gives more accurate and reproducible measures of tumor size in mice compared with caliper measurements. Furthermore, we evaluated the accuracy of tumor volume determined from 18F-fluorodeoxyglucose (18F-FDG) PET. Methods Subcutaneously implanted human breast adenocarcinoma cells in NMRI nude mice served as tumor model. Tumor volume (n = 20) was determined in vivo by external caliper, microCT and 18F-FDG-PET and subsequently reference volume was determined ex vivo. Intra-observer reproducibility of the microCT and caliper methods were determined by acquiring 10 repeated volume measurements. Volumes of a group of tumors (n = 10) were determined independently by two observers to assess inter-observer variation. Results Tumor volume measured by microCT, PET and caliper all correlated with reference volume. No significant bias of microCT measurements compared with the reference was found, whereas both PET and caliper had systematic bias compared to reference volume. Coefficients of variation for intra-observer variation were 7% and 14% for microCT and caliper measurements, respectively. Regression coefficients between observers were 0.97 for microCT and 0.91 for caliper measurements. Conclusion MicroCT was more accurate than both caliper and 18F-FDG-PET for in vivo volumetric measurements of subcutaneous tumors in mice.18F-FDG-PET was considered unsuitable for determination of tumor size. External caliper were inaccurate and encumbered with a significant and size dependent bias. MicroCT was also the most reproducible of the methods.

Introduction: Liver metastases (LM) are frequent in patients with neuroendocrine tumors (NETs) and are associated with decreased overall survival (OS). Several treatment options are available depending on degree, localization, size and number of LM. For optimal choice of treatment and correct staging, accurate imaging modalities are crucial. Aim(s): To assess and compare several different imaging options available for patients with NETs and to evaluate if presence of LM was associated with decreased OS. Materials and methods: Ninety-two prospectively enrolled patients with histologically verified NETs underwent 111In-DTPAOctreotide scintigraphy (SRS), 123I-Metaiodobenzylguanidine(M IBG) scintigraphy, 18F-Fluorodeoxyglucose-PET(FDG-PET) and computer tomography(CT). OS based on presence of LM was estimated by the Kaplan-Meier method. Mean follow-up time from FDG-PET was 31 months. Results: Ninety-two patients were enrolled and imaged by SRS, MIBG, FDG and CT. SRS was positive in 52 patients (56%). MIBG was positive in 37 patients (39%). FDG was positive in 27 patients (29%). CT was positive in 61 patients (66%). Sixty-six patients (72%) had liver-positive loci on at least one scan. Patients with FDG-PET positive LM had significantly poorer OS than FDG-PET negative patients with a hazard ration of 3.7 (95% CI:1.9-7.2, p<0.001). Conclusion: The sensitivity of CT seems to be superior to the radionuclide-based methods for detection of LM. FDG-PET identified the least LM. However, the only prognostic imaging modality was FDG-PET where detection of LM was associated with decreased OS. [ABSTRACT FROM AUTHOR]

Introduction: Today, grading, and thereby choice of treatment strategy for patients with neuroendocrine (NE) tumors, is mainly based on the proliferation index, Ki-67. As a supplement to this pathological evaluation, a whole body image analysis could be of value. Aim(s): To investigate the prognostic value of FDG-PET in patients with WHO grade I and IINE tumors. Materials and methods: Eighty-one prospectively enrolled patients with NE tumors grade I and II underwent FDG-PET imaging. The prognostic value of the FDG-PET scan was evaluated. There were 47 grade I tumors (Ki-67 index2<20). Follow-up time after the FDG-PET scan was 31 ± 12.6 months (mean + SD). Results: FDG-PET identified pathological loci in 42 of 81 patients, giving an overall modest sensitivity of 52%. During the 3-year follow-up, 22 of the 81 patients died, and of these 22 events, 19 were FDG-PET positive and three were FDG-PET negative. Thus, in the FDG-positive group, 45% died, compared to 7.7% of the FDG-negative. A positive FDG-PET scan was associated with a significantly higher risk of death (p<0.001), with an HR of 7.3 (95% confidence interval: 2.1 - 24.6) in these low-grade NE tumors. Conclusion: FDG-PET predicts survival of grade I and IINE tumors. We therefore propose that FDG-PET can be a valuable prognostic tool even in NE tumors classified as low-grade. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the immunologic profile of chronic subdural hematoma (CSDH) subtypes based on their radiologic appearances, with a focus on comparing the membranous CSDH to other subtypes., Methods: We prospectively analyzed 170 CSDH cases from 138 patients, categorizing them into "Membranous" and 'Other' subtypes based on computed tomography scans. Samples were collected from the subdural fluid and systemic blood and analyzed for a panel of inflammatory markers. Demographic data, clinical characteristics, and time since trauma were also assessed., Results: Time since trauma to diagnostic computed tomography was significantly longer for the "membranous" subtype (P = 0.001). 'Membranous" CSDH exhibited a distinct immunoprofile, including lower hemoglobin levels (P = 0.0002) and higher concentrations of matrix metallopeptidase 9 (P = 0.005) and interleukin-8 (IL-8) (P < 0.0001). Additionally, "Membranous" CSDH showed elevated levels of interferon gamma-induced protein 10, monokine induced by gamma interferon, and uPAR compared to 'Other' subtypes, with significant correlations between interferon gamma-induced protein 10 and monocyte chemoattractant protein-1 (P = 0.013), monokine induced by gamma interferon (P = 0.002), and urokinase-type plasminogen activator receptor (P = 0.006). IL-8 levels also correlated significantly with monocyte chemoattractant protein-1 (P = 0.02), suggesting distinct inflammatory pathways in the "Membranous" subtype., Conclusions: This study demonstrates that CSDH subtypes, particularly the "Membranous" subtype, possess a distinct immunologic profile. These findings provide novel insights into CSDH pathophysiology. The unique inflammatory landscape of "Membranous" CSDH, marked by elevated matrix metallopeptidase 9 and IL-8 levels, may contribute to its chronic nature., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Doxorubicin (DOX) is a common and highly effective chemotherapeutic. However, its use is limited by cardiotoxic effects and the lack of methods to detect these at early time points. In the present study, we evaluated if [ 64 Cu]Cu-NODAGA-E[(cRGDyK)]2 positron emission tomography-computed tomography ([ 64 Cu]Cu-RGD PET/CT) could detect cardiotoxicity in a rat model of DOX-induced heart failure. Male Lewis rats were divided into two groups and treated with either a cumulative dose of 15 mg/kg of DOX or left untreated. Cardiac anatomy and function were assessed using magnetic resonance imaging at baseline and in week 8. [ 64 Cu]Cu-RGD PET/CT scans were performed in week 4. DOX treatment led to a decline in pump function as well as an increase in cardiac and thymic uptake of [ 64 Cu]Cu-RGD. In addition, DOX altered cardiac gene expression, led to infiltration of immune cells, reduced endothelial content, and increased interstitial fibrosis. Furthermore, concentrations of inflammatory plasma proteins were increased in the DOX group. In conclusion, DOX treatment resulted in the development of cardiotoxicity and heart failure, which could be detected using [ 64 Cu]Cu-RGD PET/CT at early time points. [ 64 Cu]Cu-RGD uptake in the myocardial septum and thymus predicted a low left ventricular ejection fraction in week 8.

Chronic subdural hematoma (CSDH) development involves inflammatory, angiogenetic, and fibrinolytic mechanisms, several components of which are now unraveled through intensive research. The urokinase plasminogen activator receptor (uPAR) is part of the plasminogen activator system and possesses inflammatory, angiogenetic, and fibrinolytic capabilities. As a first, this study aims to identify uPAR in the hematoma fluid, hematoma membrane, dura mater, and systemic blood from patients with CSDH and, if present, to investigate if the uPAR level at the time of surgery may be a predictor for later developing recurrent CSDH. uPAR expression in the hematoma membrane and dura mater was analyzed using immunohistochemistry and presented as the H-score of the positive immunostaining. The uPAR levels in the hematoma fluid and systemic blood were determined using a multiplex antibody bead kit (Luminex). Samples were collected at the time of the first CSDH surgery, and in the case of recurrent CSDH within 90 days, the samples were again collected at reoperation. A comparison of uPAR expression between the hematoma membrane and dura mater, as well as uPAR levels in systemic blood and hematoma fluid, was performed using the Wilcoxon rank sum test. We included 112 patients, 26 of whom had recurrent CSDH. The median hematoma uPAR level was 22,125 (14,845-33,237) and significantly higher than the median systemic blood level of 789 pg/L (465-2,088) (p < 0.001). Similarly, the uPAR level of the hematoma membrane was 14.3 (7.54-44.8) and significantly higher than the dural uPAR level of 0.81 (0.3-1.98) (p < 0.001). For the first time, we identified uPAR in the subdural fluid, hematoma membrane, dura mater, and systemic blood from patients with CSDH. The high expression of uPAR in the subdural fluid and hematoma membrane indicates that the mechanisms of CSDH are predominantly in the subdural fluid collection and surrounding hematoma membrane., (© 2024. The Author(s).)

Introduction: The pathophysiology of chronic subdural hematoma (CSDH) remains to be fully understood. Basic knowledge of the composition and features of cells in the CSDH fluid may contribute to the understanding of the seemingly complex processes involved in CSDH formation and recurrence. This study is the first to examine the composition of cells and of cellular features in both systemic blood and subdural fluid from CSDH patients. We hypothesized that the cellular composition and features in the hematoma fluid may be; 1) different from that in the systemic blood; 2) different between patients with and without recurrence; 3) and different between the first and second operation in patients with recurrent CSDH., Methods: Systemic blood and subdural hematoma fluid were collected from CSDH patients with and without recurrent CSDH at the time of primary and secondary surgery. Analyses of cells and cellular features included total number of white blood cells, erythroblasts, reticulocytes, platelets, neutrophilocytes, lymphocytes, monocytes, eosinophils, basophils, reticulocytes, immature granulocytes, mean corpuscular cell volume (MCV), mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, hemoglobin and hematocrit., Results: Of the 85 included patients, 20 patients were operated for a recurrent CSDH within 90 days follow-up. All cells found in the systemic blood were present in the CSDH fluid, but the composition was different (p < 0.0001). MCV was higher in the hematoma fluid from the primary operation of patients later developing a recurrent CSDH compared to patients not developing recurrence (p = 0.009). Also, the percentage distribution of inflammatory cells in hematoma fluid from patients with recurrent CSDH was different between the first and second operation (p = 0.0017)., Conclusion: This study is the first to investigate the cellular composition of CSDH fluid. Compared to systemic blood and to a reference distribution, an increased number of immune cells were present in the hematoma fluid, supporting an inflammatory component of the CSDH pathophysiology. MCV was higher in the subdural fluid at time of the first operation of CSDH patients later developing recurrence., Clinical Trial Registration: The study was approved by the Scientific Ethical Committee of the Capital Region of Denmark (Journal no. H-20051073., (© 2024. The Author(s).)

Objectives: The mean standardized uptake value (SUVmean) and maximum standardized uptake value (SUVmax) on fluorine-18 fluorodeoxyglucose-positron emission tomography are prognostic biomarkers for survival and nodal involvement in non-small-cell lung cancer but their prognostic value in lung neuroendocrine neoplasms (NENs) remains unexplored. In this study, we aimed to examine whether they are also prognostic biomarkers for survival and nodal involvement in lung NENs., Methods: We retrospectively studied patients with typical carcinoid, atypical carcinoid or large cell neuroendocrine carcinoma who had been radically resected at our institution between 2008 and 2020. We measured SUVmean and SUVmax on all primary tumours and lymph nodes that were clinically and/or pathologically involved. We dichotomized the patients into groups of high or low SUVmean and SUVmax of the primary tumour using time-dependent receiver operating characteristic curves and compared their overall survival using Kaplan-Meier curves and Cox models. Lastly, we predicted the patients' pathological nodal status with SUVmean and SUVmax of the lymph nodes using binomial logistic models., Results: The study included 245 patients. Patients died earlier if their SUVmean of the primary tumour exceeded 3.9 [hazard ratio 1.97, 95% confidence interval (CI) 1.27-3.04, P = 0.002] or SUVmax exceeded 5.3 (hazard ratio 1.85, 95% CI 1.20-2.87, P = 0.006). Likewise, patients had a higher risk of pathological nodal involvement if their SUVmean of the lymph nodes exceeded 3.3 (odds ratio 10.00, 95% CI 2.59-51.01, P = 0.002) or SUVmax exceeded 4.2 (odds ratio 4.00, 95% CI 1.20-14.65, P = 0.028)., Conclusions: The fluorine-18 fluorodeoxyglucose-positron emission tomography SUVmean and SUVmax are strong prognostic biomarkers for survival and nodal involvement in lung NENs and could be important guides for making treatment decisions., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

In a longitudinal design, four arterial segments in mice were followed by positron emission tomography/computed tomography (PET/CT) imaging. We aimed to determine how the tracers reflected the development of atherosclerosis via the uptake of 2-deoxy-2-[ 18 F]fluoro-D-glucose ([ 18 F]FDG) for imaging inflammation and [ 18 F]-sodium fluoride (Na[ 18 F]F) for imaging active microcalcification in a murine model of atherosclerosis. Apolipoprotein E knock-out (ApoE) mice and C57 BL/6NtaC (B6) mice were divided into four groups. They received either normal chow (N = 7, ApoE mice and N = 6, B6 mice) for 32 weeks or a high-fat diet (N = 6, ApoEHFD mice and N = 9, B6HFD mice) for 32 weeks. The mice were scanned with [ 18 F]FDG and Na[ 18 F]F using a dedicated small animal PET/CT scanner at three timepoints. The tracer uptakes in four aortic segments (abdominal aorta, aortic arch, ascending aorta, and thoracic aorta) were measured and reported as SUV max values. The uptake of [ 18 F]FDG (SUV max : 5.7 ± 0.5 vs 1.9 ± 0.2, 230.3%, p =  < 0.0001) and Na[ 18 F]F (SUV max : 9.6 ± 1.8 vs 4.0 ± 0.3, 175%, p = 0.007) was significantly increased in the abdominal aorta of ApoEHFD mice at Week 32 compared to baseline abdominal aorta values of ApoEHFD mice. [ 18 F]FDG uptake in the aortic arch, ascending aorta and the thoracic aorta of B6HFD mice at Week 32 showed a robust resemblance to the abdominal aorta uptake whereas the Na[ 18 F]F uptake only resembled in the thoracic aorta of B6HFD mice at Week 32 compared to the abdominal aorta. The uptake of both [ 18 F]FDG and Na[ 18 F]F increased as the disease progressed over time, and the abdominal aorta provided a robust measure across mouse strain and diet. Therefore, it seems to be the preferred region for image readout. For [ 18 F]FDG-PET, both B6 and ApoE mice provide valuable information and either mouse strain may be used in preclinical cardiovascular studies, whereas for Na[ 18 F]F -PET, ApoE mice should be preferred., (© 2023. The Author(s).)

Purpose: [ 64 Cu]Cu-DOTA-AE105 urokinase-type plasminogen activator receptor (uPAR)-PET/CT is a novel and promising imaging modality for cancer visualization, although it has not been tested in head and neck cancer patients nor in preclinical models that closely resemble these heterogenous tumors, i.e., patient-derived xenograft (PDX) models. The aim of the present study was to establish and validate oral squamous cell carcinoma (OSCC) PDX models and to evaluate [ 64 Cu]Cu-uPAR-PET/CT for tumor imaging in these models., Procedures: PDX flank tumor models were established by engrafting tumor tissue from three patients with locally advanced OSCC into immunodeficient mice. [ 64 Cu]Cu-DOTA-AE105 was injected in passage 2 (P2) mice, and [ 64 Cu]Cu-uPAR-PET/CT was performed 1 h and 24 h after injection. After the last PET scan, all animals were euthanized, and tumors dissected for autoradiography and immunohistochemical (IHC) staining., Results: Three PDX models were established, and all of them showed histological stability and unchanged heterogenicity, uPAR expression, and Ki67 expression through passages. A significant correlation between uPAR expression and tumor growth was found. All tumors of all models (n=29) showed tumor uptake of [ 64 Cu]Cu-DOTA-AE105. There was a clear visual concordance between the distribution of uPAR expression (IHC) and [ 64 Cu]Cu-DOTA-AE105 uptake pattern in tumor tissue (autoradiography). No significant correlation was found between IHC (H-score) and PET-signal (SUV max ) (r=0.34; p=0.07)., Conclusions: OSCC PDX models in early passages histologically mimic donor tumors and could serve as a valuable platform for the development of uPAR-targeted imaging and therapeutic modalities. Furthermore, [64Cu]Cu-uPAR-PET/CT showed target- and tumor-specific uptake in OSCC PDX models demonstrating the diagnostic potential of this modality for OSCC patients., (© 2023. The Author(s).)

Background: Angiogenesis has increasingly been a target for imaging and treatment over the last decade. The integrin α v β 3 is highly expressed in cells during angiogenesis and are therefore a promising target for imaging. In this study, we aimed to investigate the PET tracer [ 68 Ga]Ga-RGD as a marker of angiogenesis following MI and its ability to predict cardiac functional parameters., Methods: First, the real-time interaction between [ 68 Ga]Ga-RGD and integrin α v β 3 was investigated using surface plasmon resonance (SPR). Second, an animal study was performed to investigate the [ 68 Ga]Ga-RGD uptake in the infarcted area after one and four weeks following MI in a rat model (MI = 68, sham surgery = 36). Finally, the specificity of the [ 68 Ga]Ga-RGD tracer was evaluated ex vivo using histology, autoradiography, gamma counting and flow cytometry., Results: SPR showed that [ 68 Ga]Ga-RGD has a high affinity for integrin α v β 3 , forming a strong and stable binding. PET/CT showed a significantly higher uptake of [ 68 Ga]Ga-RGD in the infarcted area compared to sham one week (p < 0.001) and four weeks (p < 0.001) after MI. The uptake of [ 68 Ga]Ga-RGD after one week correlated to end diastolic volume (r = 0.74, p < 0.001) and ejection fraction (r = - 0.71, p < 0.001) after four weeks., Conclusion: This study demonstrates that [ 68 Ga]Ga-RGD has a high affinity for integrin α v β 3 , which enables the evaluation of angiogenesis and remodeling. The [ 68 Ga]Ga-RGD uptake after one week indicates that [ 68 Ga]Ga-RGD may be used as an early predictor of cardiac functional parameters and possible development of heart failure after MI. These encouraging data supports the clinical translation and future use in MI patients., (© 2023. The Author(s).)

Anti-inflammatory treatment reduces the risk of recurrent chronic subdural hematoma (CSDH), but clinical implementation is improper due to side effects. Exact knowledge of subdural molecules involved in recurrent CSDH may lead to targeted medical treatment and possibly improve the prospect of a personalized approach by eliminating the broad use of anti-inflammatory drugs on the entire CSDH population. With this study, we aim to (1) describe the associations between cytokine levels at the primary surgery and the risk of subsequent recurrence and (2) describe the association between cytokines in patients with recurrent CSDH between the first and second operations. Systemic and subdural levels of pro- and anti-inflammatory cytokines were measured and compared between patients with the first-time CSDH and recurrent CSDH. Cytokine levels were analyzed using a multiplex antibody bead kit. In case of recurrent CSDH within 90 days of follow-up, the samples were re-collected and analyzed. We included 101 adult CSDH patients of which 20 had a recurrence. The levels of cytokines in the CSDH fluid from patients who were operated on for the first-time CSDH were not associated with the risk of later developing a recurrence. We found interleukin-1 receptor antagonist (IL-1ra) to be elevated in subdural fluid in patients with recurrent CSDH at the time of their second operation (p = 0.0005). This study provides knowledge on cytokine composition in the subdural fluid in patients with CSDH with and without recurrence. IL-1ra is elevated in subdural fluid in patients with recurrent CSDH at the time of the second operation, identifying a possible medical target., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Atherosclerosis is a chronic inflammatory disease of the larger arteries that may lead to cardiovascular events. Identification of patients at highest risk of cardiovascular events is challenging, but molecular imaging using positron emission tomography (PET) may prove useful. The aim of this study was to evaluate and compare head-to-head three different PET tracers. Furthermore, tracer uptake is compared to gene expression alterations of the arterial vessel wall. Male New Zealand White rabbits (control group; n = 10, atherosclerotic group; n = 11) were used for the study. Vessel wall uptake was assessed with the three different PET tracers: [ 18 F]FDG (inflammation), Na[ 18 F]F (microcalcification), and [ 64 Cu]Cu-DOTA-TATE (macrophages), using PET/computed tomography (CT). Tracer uptake was measured as standardized uptake value (SUV), and arteries from both groups were analyzed ex vivo by autoradiography, qPCR, histology, and immunohistochemistry. In rabbits, the atherosclerotic group showed significantly higher uptake of all three tracers compared to the control group [ 18 F]FDG: SUV mean 1.50 ± 0.11 versus 1.23 ± 0.09, p = 0.025; Na[ 18 F]F: SUV mean 1.54 ± 0.06 versus 1.18 ± 0.10, p = 0.006; and [ 64 Cu]Cu-DOTA-TATE: SUV mean 2.30 ± 0.27 versus 1.65 ± 0.16; p = 0.047. Of the 102 genes analyzed, 52 were differentially expressed in the atherosclerotic group compared to the control group and several genes correlated with tracer uptake. In conclusion, we demonstrated the diagnostic value of [ 64 Cu]Cu-DOTA-TATE and Na[ 18 F]F for identifying atherosclerosis in rabbits. The two PET tracers provided information distinct from that obtained with [ 18 F]FDG. None of the three tracers correlated significantly to each other, but [ 64 Cu]Cu-DOTA-TATE and Na[ 18 F]F uptake both correlated with markers of inflammation. [ 64 Cu]Cu-DOTA-TATE was higher in atherosclerotic rabbits compared to [ 18 F]FDG and Na[ 18 F]F., (© 2023. The Author(s).)

An increasing number of patients are living with chronic ischemic cardiomyopathy (ICM) and/or heart failure. Treatment options and prognostic tools are lacking for many of these patients. Our aim was to investigate the prognostic value of imaging angiogenesis and macrophage activation via positron emission tomography (PET) in terms of functional improvement after cell therapy. Myocardial infarction was induced in rats. Animals were scanned with [ 18 F]FDG PET and echocardiography after four weeks and randomized to allogeneic adipose tissue-derived stromal cells (ASCs, n = 18) or saline ( n = 9). Angiogenesis and macrophage activation were assessed before and after treatment by [ 68 Ga]Ga-RGD and [ 64 Cu]Cu-DOTATATE. There was no overall effect of the treatment. Rats that improved left ventricular ejection fraction (LVEF) had higher uptake of both [ 68 Ga]Ga-RGD and [ 64 Cu]Cu-DOTATATE at follow-up ( p = 0.006 and p = 0.008, respectively). The uptake of the two tracers correlated with each other (r = 0.683, p = 0.003 pre-treatment and r = 0.666, p = 0.004 post-treatment). SUVmax at follow-up could predict improvement in LVEF ( p = 0.016 for [ 68 Ga]Ga-RGD and p = 0.045 for [ 64 Cu]Cu-DOTATATE). High uptake of [ 68 Ga]Ga-RGD and [ 64 Cu]Cu-DOTATATE PET after injection of ASCs or saline preceded improvement in LVEF. The use of these tracers could improve the monitoring of heart failure patients in treatment.

Strong prognostic biomarkers are lacking regarding the stratification of treatment and surveillance regimens in head and neck squamous cell carcinoma (HNSCC). The study aimed to assess the prognostic value of soluble urokinase-type plasminogen activator receptor in plasma (suPAR) compared to evaluation by uPAR-positron-emission-tomography (PET) in HNSCC patients. Plasma from 19 controls and 49 HNSCC patients referred to curatively intended radiotherapy (2017-2021) was collected pre-treatment and post-treatment (n = 37). Information on uPAR-PET was available from previous evaluation. Patient median suPAR was significantly higher pre- and post-treatment compared to controls (p = 0.013, p = 0.003) and increased significantly during radiotherapy (p = 0.003). Pre-treatment suPAR did not predict survival outcomes. Post-treatment suPAR significantly predicted RFS (HR = 6.67 (95% CI 1.44-30.9) p = 0.015), but not OS (HR = 3.29 (95% CI 0.882-12.3) p = 0.076) in univariate analysis. RFS prediction was maintained for post-treatment suPAR in multivariate analysis, including TNM-stage (HR = 6.62 (95% CI 1.40-31.4) p = 0.017). Pre-treatment uPAR-PET/CT and post-treatment suPAR was available in 24 patients. High uPAR-estimates on both modalities was significantly associated with poor RFS compared to patients with low uPAR-estimates (log-rank, p = 0.008). Patients with discordant uPAR-estimates (one-low/one-high) were at intermediate risk, although non-significant (p = 0.131). In conclusion, pre-treatment suPAR did not predict RFS or OS. Pre-treatment uPAR-PET and post-treatment suPAR predicted RFS., (© 2022. The Author(s).)

Background and Aims: Urokinase-type plasminogen activator receptor (uPAR) is associated with extracellular matrix (ECM) degradation and cancer aggressiveness. Its role in arterial atherogenesis as a molecular imaging target is not well-established. The aim of this study was to non-invasively visualize uPAR expression in atherosclerosis by a novel uPAR-targeting positron emission tomography (PET) tracer [ 64 Cu]Cu-DOTA-AE105., Methods: We used molecular biology to investigate uPAR expression by analyzing human atherosclerotic plaques and cultured cells. A retrospective analysis was performed on patients, who underwent combined PET/CT (n = 10) to measure [ 64 Cu]Cu-DOTA-AE105 uptake in five large arteries, divided into a high and low-risk group based on coronary artery calcium score (CAC score)., Results: The in vitro assay for THP-1 monocytes displayed a significantly upregulated uPAR expression upon stimulation (5.2-fold upregulation, p < 0.0001 by a one-way ANOVA followed by Tukey's test) by single-cell flowcytometric analysis. Freshly excised human atherosclerotic plaques underwent flow cytometric and microarray analyses manifesting 73.9 ± 2.9% of mononuclear phagocyte system (MPS) cells expressing uPAR and had a greater than 7-fold higher gene expression of plasminogen activator urokinase receptor (PLAUR, p = 0.002), integrin subunit alpha X (ITGAX, p = 0.0008), and cluster of differentiation 163 (CD163, p < 0.0001). The tissue-to-background ratios (TBR max ) in five large arteries showed a higher [ 64 Cu]Cu-DOTA-AE105 uptake in the group with high CAC score compared to the group with low CAC score (2.4 ± 0.1 vs 1.7 ± 0.1, p = 0.057), significantly higher in the ascending aorta (2.7 ± 0.1 vs 2.0 ± 0.1, p = 0.038) and the abdominal aorta (3.2 ± 0.2 vs 2.0 ± 0.2, p = 0.038) by a non-parametric Mann-Whitney test., Conclusions: uPAR is abundantly expressed by MPS cells in atherosclerotic plaques and can be visualized by the novel PET tracer [ 64 Cu]Cu-DOTA-AE105 that may non-invasively detect extracellular matrix remodeling during atherogenesis., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background and Aims: The objective of this study was to investigate the effects of semaglutide, a long acting glucagon-like peptide-1 receptor agonist, on atherosclerotic inflammation and calcification using a multimodality positron emission tomography and computed tomography (PET/CT) approach., Methods: Atherosclerotic New Zealand White rabbits were randomized to an intervention- (n = 12) or placebo group (n = 11) receiving either semaglutide or saline-placebo. PET/CT imaging was done before and after 16-weeks of intervention. Three different radiotracers were used: [ 64 Cu]Cu-DOTATATE for imaging of activated macrophages, [ 18 F]FDG imaging cellular metabolism and [ 18 F]NaF PET visualizing micro-calcifications. Tracer uptake was quantified by maximum standardized uptake value (SUV max ) and target-to-background-ratio (TBR max ). Animals were euthanized for autoradiographic imaging and histological analyses., Results: A reduction in activated macrophage tracer-uptake was observed in the semaglutide group (SUV max : p = 0.001 and TBR max : p = 0.029). When imaging cellular metabolism, an attenuation of SUV max and TBR max was observed in the semaglutide group (p = 0.034 and p = 0.044). We found no difference in uptake of the micro-calcification tracer between the two groups (SUV max : p = 0.62 and TBR max : p = 0.36). Values of macrophage density in the vessel wall were significantly correlated with SUV max values of the activated macrophage (r = 0.54, p = 0.0086) and cellular metabolism tracers (r = 0.51, p = 0.013)., Conclusions: Semaglutide decreased vascular uptake of tracers imaging activated macrophages and cellular metabolism but not micro-calcifications compared to a saline placebo. This supports the hypothesis that semaglutide reduces atherosclerotic inflammation by means of decreased activated macrophage activity., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Pulmonary large-cell neuroendocrine carcinoma (LCNEC) is a rare subtype of lung cancer with dismal prognosis. Long-term outcomes after primarily video-assisted thoracoscopic surgery (VATS) have not yet been described in LCNEC. This study aims to determine overall survival and recurrence-free survival after VATS as well as to identify prognostic factors for survival and recurrence., Methods: Data were obtained from a prospective institutional database. Kaplan-Meier estimates of overall survival and recurrence-free survival were determined and compared across prognostic factors using log-rank analysis and the Cox proportional hazards model., Results: Data from 82 consecutive patients undergoing surgical resection from 2009 to 2020 were included. All patients underwent surgical resection with curative intent, of whom 96.3% were by a VATS approach. Morbidity was low without any conversions or 30-day mortality. Lobectomy was performed in 87.8% of patients, followed by wedge resection in 4.9% and segmentectomy in 3.7%. No pneumonectomies were performed. Radical resection (R0) was achieved in 97.6%. Thirty-four patients (41.5%) had adjuvant platinum-based chemotherapy and high proportion completed at least four series (76.7%). The mean follow-up was 5.1 years. The 1-year, 3-year, and 5-year overall survival rates were 86%, 54%, and 45%, while the corresponding recurrence-free survival rates were 67%, 45%, and 35%. Advanced age was an independent predictor of poor overall survival (HR 2.08; 95% CI 1.04-4.17; p = 0.038)., Conclusion: A 96.3% VATS rate was feasible in LCNEC and associated with a low morbidity rate and a high compliance with adjuvant chemotherapy. Overall survival and recurrence-free survival was comparable to previous series using thoracotomy., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The mechanism behind the cardiovascular protection observed with human GLP-1 RA (glucagon-like peptide-1 receptor agonists) in type 2 diabetes is unknown. We hypothesized that treatment with the GLP-1 RA liraglutide had a positive effect on vascular inflammation., Methods: LIRAFLAME (Effect of liraglutide on vascular inflammation in type-2 diabetes: A randomized, placebocontrolled, double-blind, parallel clinical PET/CT trial) was a double-blind, randomized controlled trial performed at a single university hospital clinic in Denmark. Patients with type 2 diabetes were via computer-generated randomization list assigned (1:1) liraglutide up to 1.8 mg or placebo once daily for 26 weeks. The primary end point was change in vascular inflammation over 26 weeks assessed by [ 18 F]-fluorodeoxyglucose positron emission tomography/computed tomography. Analyses were based on intention-to-treat. Key secondary outcomes included change in other indices of atherosclerosis., Results: Between October 26, 2017, and August 16, 2019, 147 patients were screened and 102 were randomly assigned to liraglutide (n=51) or placebo (n=51) and 99 (97%) completed the trial. Change in the [ 18 F]-fluorodeoxyglucose positron emission tomography measure of vascular inflammation (active-segment target-to-background ratio) did not differ between treatment groups: change from baseline to 26 weeks was -0.04 (95% CI, -0.17 to 0.08) in the liraglutide group compared with -0.09 (-0.19 to 0.01) in the placebo group (mean difference, 0.05 [95% CI, -0.11 to 0.21], P =0.53). Secondary analyses restricted to [ 18 F]-fluorodeoxyglucose positron emission tomography of the carotid arteries as well as other indices of atherosclerosis confirmed the primary result. We performed an explorative analysis of interaction between treatment group and history of cardiovascular disease ( P =0.052)., Conclusions: In this low to moderate risk population with type 2 diabetes, liraglutide did not change vascular inflammation assessed as [ 18 F]-fluorodeoxyglucose uptake compared with placebo. An explorative analysis indicated a possible effect in persons with history of cardiovascular disease, in line with current guidelines where liraglutide is recommended to patients with history of cardiovascular disease. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03449654.

Objective: The aim of this study was to determine overall survival and recurrence-free survival after resection of bronchopulmonary carcinoids by means of predominantly minimally invasive surgery and lung-sparing resections. In addition, we aimed to identify prognostic factors for overall survival., Materials and Methods: Retrospective review of consecutive patients operated for bronchopulmonary carcinoids between January 2009 and October 2020 identified from a prospectively collected database., Results: A total of 236 patients representing 240 cases of bronchopulmonary carcinoids were included. Of these, 212 (88.3 %) were typical carcinoids, while 28 (11.7 %) were atypical carcinoids. A Video-Assisted Thoracoscopic Surgery (VATS) approach was used in 75 % of cases. There was no 30-day mortality. The median follow-up was 5.6 years for overall survival and 4.7 years for recurrence-free survival. 5- and 10-year overall survival rates were 89 % and 71 %, while 5- and 10-year recurrence-free survival rates were 84 % and 71 %. Patients with atypical carcinoids had significantly reduced overall survival and recurrence-free survival rates (HR 3.4; 95 % CI 1.5-7.6; p = 0.003 and HR 5.4; 95 % CI 2.6-11.4; p < 0.001). Independent predictors of overall survival included atypical carcinoid (HR 2.7; 95 % CI 1.2-6.0; p = 0.018) and age > 60 years (HR 2.9; 95 % CI 1.2-7.3; p = 0.021)., Conclusion: Surgery for bronchopulmonary carcinoids by means of predominantly VATS and lung-sparing resections provides favorable long-term survival. Atypical carcinoids and age > 60 years are independent predictors of poor overall survival., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Accurate grading of patients with neuroendocrine neoplasms (NENs) is essential for risk stratification and optimal choice of therapy. Currently, grading is based on histologically assessed degree of tumor proliferation. The aim of the present study was to assess the long-term prognostic value of 18 F-FDG PET imaging for risk stratification of NENs and compare it with tumor grading (World Health Organization 2010 classification). Methods: We conducted a prospective cohort study evaluating the prognostic value of 18 F-FDG PET imaging and compared it with histologic grading. Enrolled were 166 patients of all grades and with histologically confirmed NENs of gastroenteropancreatic origin. The primary endpoint was overall survival (OS). Progression-free survival (PFS) was a secondary endpoint. In addition, OS in relation to peptide receptor radionuclide therapy (PRRT) was analyzed as an exploratory endpoint. The median follow-up time was 9.8 y. Results: Analysis of the whole cohort revealed that a positive 18 F-FDG PET scan was associated with a shorter OS than a negative 18 F-FDG PET scan (hazard ratio: 3.8; 95% CI: 2.4-5.9; P < 0.001). In G1 and G2 patients ( n = 140), a positive 18 F-FDG PET scan was the only identifier of high risk for death (hazard ratio: 3.6; 95% CI, 2.2-5.9; P < 0.001). In multivariate analysis, 18 F-FDG PET, G3 tumor, ≥2 liver metastases, and ≥2 prior therapies were independent prognostic factors for OS, and 18 F-FDG PET, G3 tumor, and ≥3 liver metastases were independent prognostic factors for PFS. For patients receiving PRRT, 18 F-FDG-negative cases had a significantly longer survival than 18 F-FDG-positive cases, whereas no difference was identified for tumor grading. 18 F-FDG-positive patients receiving PRRT had a significantly longer median survival than patients not receiving PRRT (4.4 vs. 1.4 y, P = 0.001), whereas no difference was seen for 18 F-FDG-negative patients. Conclusion: 18 F-FDG PET is useful for risk stratification of all NEN grades and is superior to histologic grading. 18 F-FDG PET could differentiate G1 and G2 tumors into low- and high-risk groups. In the selection of therapy and for risk stratification of NEN patients, 18 F-FDG PET status should be considered., (© 2021 by the Society of Nuclear Medicine and Molecular Imaging.)

64 Cu-DOTATATE PET/CT imaging 1 h after injection is excellent for lesion detection in patients with neuroendocrine neoplasms (NENs). We hypothesized that the imaging time window can be extended up to 3 h after injection without significant differences in the number of lesions detected. Methods: From a prospective study, we compared, on a head-to-head basis, sets of 64 Cu-DOTATATE PET/CT images from 35 patients with NENs scanned 1 and 3 h after injection of 200 MBq of 64 Cu-DOTATATE. The number of lesions on both PET scans was counted and grouped according to organs or regions and compared with negative binomial regression. Discordant lesions (visible on only the 1-h images or only the 3-h 64 Cu-DOTATATE PET images) were considered true if found on simultaneous CT or later MR, CT, or somatostatin receptor imaging. We measured lesion SUV max , reference normal-organ or -tissue SUV mean , and tumor-to-normal-tissue ratios calculated from SUV max and SUV mean Results: We found 822 concordant lesions (visible on both 1-h and 3-h 64 Cu-DOTATATE PET) and 5 discordant lesions, of which 4 were considered true. One discordant case in 1 patient involved a discordant organ system (lymph node) detected on 3-h but not 1-h 64 Cu-DOTATATE PET that did not alter the patient's disease stage (stage IV) because the patient had 11 additional concordant liver lesions. We found no significant differences between the number of lesions detected on 1-h and 3-h 64 Cu-DOTATATE PET. Throughout the 1- to 3-h imaging window, the mean tumor-to-normal-tissue ratio remained high in all key organs: liver (1 h: 12.6 [95% confidence interval (CI), 10.2-14.9]; 3 h: 11.0 [95%CI, 8.7-13.4]), intestines (1 h: 24.2 [95%CI, 14.9-33.4]; 3 h: 28.2 [95%CI, 16.5-40.0]), pancreas (1 h: 42.4 [95%CI, 12.3-72.5]; 3 h: 41.1 [95%CI, 8.7-73.4]), and bone (1 h: 103.0 [95%CI, 38.6-167.4]; 3 h: 124.2 [95%CI, 57.1-191.2]). Conclusion: The imaging time window of 64 Cu-DOTATATE PET/CT for patients with NENs can be expanded from 1 h to 1-3 h without significant differences in the number of lesions detected., (© 2021 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: DOTA-D-Phe 1 -Tyr 3 -octreotide with gallium-68 ([ 68 Ga]Ga-DOTA-TOC) is one of the PET tracers that forms the basis for peptide receptor radionuclide therapy based on somatostatin receptor subtype 2 (SSTR2) expression in meningiomas. Yet, the quantitative relationship between [ 68 Ga]Ga-DOTA-TOC accumulation and SSTR2 is unknown. We conducted a correlative analysis of a range of [ 68 Ga]Ga-DOTA-TOC PET metric(s) as imaging surrogate(s) of the receptor binding in meningiomas by correlating the PET results with SSTR2 expression from surgical specimens. We additionally investigated possible influences of secondary biological factors such as vascularization, inflammation and proliferation., Methods: Fifteen patients with MRI-presumed or recurrent meningiomas underwent a 60-min dynamic [ 68 Ga]Ga-DOTA-TOC PET/CT before surgery. The PET data comprised maximum and mean standardized uptake values (SUV max , SUV mean ) with and without normalization to reference regions, and quantitative measurements derived from kinetic modelling using a reversible two-tissue compartment model with the fractional blood volume (V B ). Expressions of SSTR2 and proliferation (Ki-67, phosphohistone-H3, proliferating cell nuclear antigen) were determined by immunohistochemistry and/or quantitative polymerase chain reaction (qPCR), while biomarkers of vascularization (vascular endothelial growth factor A (VEGFA), endothelial marker CD34) and inflammation (cytokine interleukin-18, microglia/macrophage-specific marker CD68) by qPCR., Results: Histopathology revealed 12 World Health Organization (WHO) grade I and three WHO grade II meningiomas showing no link to SSTR2. The majority of [ 68 Ga]Ga-DOTA-TOC PET metrics showed significant associations with SSTR2 protein, while all PET metrics were positively correlated with SSTR2 mRNA with the best results for mean tumour-to-blood ratio (TBR mean ) (r = 0.757, P = 0.001) and SUV mean (r = 0.714, P = 0.003). Significant positive correlations were also found between [ 68 Ga]Ga-DOTA-TOC PET metrics, and VEGFA and V B . SSTR2 mRNA was moderately correlated with VEGFA (r = 0.539, P = 0.038). Neither [ 68 Ga]Ga-DOTA-TOC PET metrics nor SSTR2 were correlated with proliferation or inflammation., Conclusion: [ 68 Ga]Ga-DOTA-TOC accumulation in meningiomas is associated with SSTR2 binding and vascularization with TBR mean being the best PET metric for assessing SSTR2.

Overexpression of somatostatin receptors (SSTRs) in patients with neuroendocrine neoplasms (NENs) is used for both diagnosis and treatment. Receptor density may reflect tumor differentiation and thus be associated with prognosis. Noninvasive visualization and quantification of SSTR density is possible by SSTR imaging (SRI) using PET. Recently, we introduced 64 Cu-DOTATATE for SRI, and we hypothesized that uptake of this tracer could be associated with overall survival (OS) and progression-free survival (PFS). Methods: We evaluated patients with NENs who underwent 64 Cu-DOTATATE PET/CT SRI in 2 prospective studies. Tracer uptake was determined as the maximal SUV (SUV max ) for each patient. Kaplan-Meier analysis with log-rank was used to determine the predictive value of 64 Cu-DOTATATE SUV max for OS and PFS. Specificity, sensitivity, and accuracy were calculated for prediction of outcome at 24 mo after 64 Cu-DOTATATE PET/CT. Results: In total, 128 patients with NENs were included and followed for a median of 73 mo (range, 1-112 mo). During follow-up, 112 experienced disease progression, and 69 died. The optimal cutoff for 64 Cu-DOTATATE SUV max was 43.3 for prediction of PFS, with a hazard ratio of 0.56 (95% confidence interval, 0.38-0.84) for patients with an SUV max of more than 43.3. However, no significant cutoff was found for prediction of OS. In multiple Cox regression adjusted for age, sex, primary tumor site, and tumor grade, the SUV max cutoff hazard ratio was 0.50 (range, 0.32-0.77) for PFS. The accuracy was moderate for predicting PFS (57%) at 24 mo after 64 Cu-DOTATATE PET/CT. Conclusion: In this first study to report the association of 64 Cu-DOTATATE PET/CT and outcome in patients with NENs, tumor SSTR density as visualized with 64 Cu-DOTATATE PET/CT was prognostic for PFS but not OS. However, the accuracy of prediction of PFS at 24 mo after 64 Cu-DOTATATE PET/CT SRI was moderate, limiting the value on an individual-patient basis., (© 2020 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: Positron emission tomography (PET) with 3'-deoxy-3'-[ 18 F]fluorothymidine ([ 18 F]FLT) provides a noninvasive assessment of tumour proliferation in vivo and could be a valuable imaging modality for assessing malignancy in meningiomas. We investigated a range of static and dynamic [ 18 F]FLT metrics by correlating the findings with cellular biomarkers of proliferation and angiogenesis., Methods: Seventeen prospectively recruited adult patients with intracranial meningiomas underwent a 60-min dynamic [ 18 F]FLT PET following surgery. Maximum and mean standardized uptake values (SUV max , SUV mean ) with and without normalization to healthy brain tissue and blood radioactivity obtained from 40 to 60 min summed dynamic images (PET 40-60 ) and ~ 60-min blood samples were calculated. Kinetic modelling using a two-tissue reversible compartmental model with a fractioned blood volume (V B ) was performed to determine the total distribution volume (V T ). Expressions of proliferation and angiogenesis with key parameters including Ki-67 index, phosphohistone-H3 (phh3), MKI67, thymidine kinase 1 (TK1), proliferating cell nuclear antigen (PCNA), Kirsten RAt Sarcoma viral oncogene homolog (KRAS), TIMP metallopeptidase inhibitor 3 (TIMP3), and vascular endothelial growth factor A (VEGFA) were determined by immunohistochemistry and/or quantitative polymerase chain reaction., Results: Immunohistochemistry revealed 13 World Health Organization (WHO) grade I and four WHO grade II meningiomas. SUV max and SUV mean normalized to blood radioactivity from PET 40-60 and blood sampling, and V T were able to significantly differentiate between WHO grades with the best results for maximum and mean tumour-to-whole-blood ratios (sensitivity 100%, specificity 94-95%, accuracy 99%; P = 0.003). Static [ 18 F]FLT metrics were significantly correlated with proliferative biomarkers, especially Ki-67 index, phh3, and TK1, while no correlations were found with VEGFA or V B . Using Ki-67 index with a threshold > 4%, the majority of [ 18 F]FLT metrics showed a high ability to identify aggressive meningiomas with SUV mean demonstrating the best performance (sensitivity 80%, specificity 81%, accuracy 80%; P = 0.024)., Conclusion: [ 18 F]FLT PET could be a useful imaging modality for assessing cellular proliferation in meningiomas.

Nanotherapy has recently emerged as an experimental treatment option for atherosclerosis. To fulfill its promise, robust noninvasive imaging approaches for subject selection and treatment evaluation are warranted. To that end, we present here a positron emission tomography (PET)-based method for quantification of liposomal nanoparticle uptake in the atherosclerotic vessel wall. We evaluated a modular procedure to label liposomal nanoparticles with the radioisotope zirconium-89 ( 89 Zr). Their biodistribution and vessel wall targeting in a rabbit atherosclerosis model was evaluated up to 15 days after intravenous injection by PET/computed tomography (CT) and PET/magnetic resonance imaging (PET/MRI). Vascular permeability was assessed in vivo using three-dimensional dynamic contrast-enhanced MRI (3D DCE-MRI) and ex vivo using near-infrared fluorescence (NIRF) imaging. The 89 Zr-radiolabeled liposomes displayed a biodistribution pattern typical of long-circulating nanoparticles. Importantly, they markedly accumulated in atherosclerotic lesions in the abdominal aorta, as evident on PET/MRI and confirmed by autoradiography, and this uptake moderately correlated with vascular permeability. The method presented herein facilitates the development of nanotherapy for atherosclerotic disease as it provides a tool to screen for nanoparticle targeting in individual subjects' plaques.

Background: High grade gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) with a Ki67 proliferation index > 20%, include well-differentiated tumours grade 3 (NET G3) and poorly differentiated (PD) neuroendocrine carcinomas (NEC). Abnormal p53-expression is a feature of PD tumours, while expression of chromogranin A (CgA) and somatostatin-receptor 2a (SSTR-2a) may be a feature of well-differentiated tumours. The aim of this study was to elucidate the expression and prognostic value of these three markers in 163 GEP-NEN patients with a Ki67-index > 20%., Method: Clinical data, histopathology and overall survival were analysed according to Kaplan-Meier's method and Cox regression. The expression of SSTR-2a, CgA and synaptophysin was analysed in tumour specimens by immunohistochemistry, and semi-quantitatively scored as negative (< 5%), heterogeneously positive (5-30%) or strongly positive (> 30%). P53 was defined as normal when scored as heterogeneously positive (1-30%), and abnormal when negative (0%) or strongly positive (> 30%)., Results: In multivariate analysis, better survival was observed among patients with heterogeneously positive p53 compared to strongly positive (p < 0.001). When dichotomised, tumours with a heterogeneously positive p53 vs. negative and strongly positive p53 also showed a significantly better survival (p = 0.002). Survival was significantly worse for negative CgA compared to heterogeneously positive CgA (p = 0.02). Strongly positive SSTR-2a expression was found in 26% of the 163 included patients. Well-differentiated morphology correlated with strong expression of SSTR-2a and CgA, and heterogeneously positive p53-staining, and was more frequent in pancreatic primaries. In pancreatic primaries, strongly positive SSTR-2a was associated with longer survival (univariate analysis, p = 0.02). A significantly lower Ki67 proliferation index was found in patients with a heterogeneously positive p53, a positive SSTR-2a and CgA expression., Conclusion: Our results suggest that abnormal p53-expression is an independent negative prognostic marker in GEP-NEN with a Ki67-index > 20%. Patients with heterogeneously positive p53 had the best prognosis. SSTR-2a was a positive prognostic marker in pancreatic NEN. Negative CgA was associated with a significantly worse OS compared to heterogeneously positive CgA-expression in a multivariate sub-analysis. Lower Ki67 index correlated significantly with heterogeneously positive p53, positive SSTR-2a and CgA expression.

Nanomedicine research produces hundreds of studies every year, yet very few formulations have been approved for clinical use. This is due in part to a reliance on murine studies, which have limited value in accurately predicting translational efficacy in larger animal models and humans. Here, we report the scale-up of a nanoimmunotherapy from mouse to large rabbit and porcine atherosclerosis models, with an emphasis on the solutions we implemented to overcome production and evaluation challenges. Specifically, we integrated translational imaging readouts within our workflow to both analyze the nanoimmunotherapeutic's in vivo behavior and assess treatment response in larger animals. We observed our nanoimmunotherapeutic's anti-inflammatory efficacy in mice, as well as rabbits and pigs. Nanoimmunotherapy-mediated reduction of inflammation in the large animal models halted plaque progression, supporting the approach's translatability and potential to acutely treat atherosclerosis., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Somatostatin (SST) analogues are used to control the proliferation and symptoms of neuroendocrine tumors (NETs). MicroRNAs (miRNA) are small non-coding RNAs that modulate posttranscriptional gene expression. We wanted to characterize the miRNAs operating under the control of SST to elucidate to what extent they mediate STT actions. NCI-H727 carcinoid cell line was treated with either a chimeric SST/dopamine analogue; a SST or dopamine analogue for proliferation assays and for identifying differentially expressed miRNAs using miRNA microarray. The miRNAs induced by SST analogue treatment are investigated in carcinoid cell lines NCI-H727 and CNDT2 using in situ hybridization, qPCR and proliferation assays. SST analogues inhibited the growth of carcinoid cells more potently compared to the dopamine analogue. Principal Component Analysis (PCA) of the samples based on miRNA expression clearly separated the samples based on treatment. Two miRNAs which were highly induced by SST analogues, miR-7 and miR-148a, were shown to inhibit the proliferation of NCI-H727 and CNDT2 cells. SST analogues also produced a general up-regulation of the let-7 family members. SST analogues control and induce distinct miRNA expression patterns among which miR-7 and miR-148a both have growth inhibitory properties.

Macrophage accumulation in atherosclerosis is directly linked to the destabilization and rupture of plaque, causing acute atherothrombotic events. Circulating monocytes enter the plaque and differentiate into macrophages, where they are activated by CD4 + T lymphocytes through CD40-CD40 ligand signalling. Here, we report the development and multiparametric evaluation of a nanoimmunotherapy that moderates CD40-CD40 ligand signalling in monocytes and macrophages by blocking the interaction between CD40 and tumour necrosis factor receptor-associated factor 6 (TRAF6). We evaluated the biodistribution characteristics of the nanoimmunotherapy in apolipoprotein E-deficient (Apoe -/- ) mice and in non-human primates by in vivo positron-emission tomography imaging. In Apoe -/- mice, a 1-week nanoimmunotherapy treatment regimen achieved significant anti-inflammatory effects, which was due to the impaired migration capacity of monocytes, as established by a transcriptome analysis. The rapid reduction of plaque inflammation by the TRAF6-targeted nanoimmunotherapy and its favourable toxicity profiles in both mice and non-human primates highlights the translational potential of this strategy for the treatment of atherosclerosis.

Polymeric micelles in nanomedicine are often cross-linked to prevent disintegration in vivo. This typically requires clinically problematic chemicals or laborious procedures. In addition, cross-linking may interfere with advanced release strategies. Despite this, it is often not investigated whether cross-linking is necessary for efficient drug delivery. We used positron emission tomography (PET) imaging with 64 Cu to demonstrate general methodology for real-time in vivo investigations of micelle stability. Triblock copolymers with 4-methylcoumarin cores of ABC-type (PEG-PHEMA-PCMA) were functionalized in the handle region (PHEMA) with CB-TE2A chelators. Polymeric micelles were formed by dialysis and one half was core cross-linked (CL) by UV light and the other half was not (nonCL). Both CL and nonCL were radiolabeled with 64 Cu and compared in vivo in tumor-bearing mice, with free 64 Cu as control. Accumulation in relevant organs was quantified by region of interest analysis on PET images and ex vivo counting. It was observed that CL and nonCL showed limited differences in biodistribution from each other, whereas both differed markedly from control (free 64 Cu). This demonstrated that 4-methylcoumarin core micelles may form micelles that are stable in circulation even without cross-linking. The methodology presented here where individual unimers are radiolabeled is applicable to a wide range of polymeric micelle types., (Copyright © 2017 John Wiley & Sons, Ltd.)

Neuroendocrine neoplasms (NENs) constitute a heterogeneous group of tumors arising in various organs and with a large span of aggressiveness and survival rates. The Ki-67 proliferation index is presently used as the key marker of prognosis, and treatment guidelines are largely based on this index. 3'-deoxy-3'- 18 F-fluorothymidine ( 18 F-FLT) is a proliferation tracer for PET imaging valuable in the monitoring of disease progression and treatment response in various types of cancer. However, until now only data from 10 patients with NEN were available in the literature. The aim of the present study was to investigate 18 F-FLT PET as a prognostic marker for NENs in comparison with 18 F-FDG PET and Ki-67 index., Methods: One hundred patients were PET-scanned with both 18 F-FLT and 18 F-FDG within the same week, and the prognostic value of a positive scan was examined in terms of progression-free survival (PFS) and overall survival (OS). The correlation between the Ki-67 index and 18 F-FLT uptake was also investigated., Results: Thirty-seven percent of patients had a positive 18 F-FLT PET scan, and 49% had 18 F-FDG PET-positive foci. Patients with a high 18 F-FLT uptake had a significantly shorter OS and PFS than patients with low or no 18 F-FLT uptake. No correlation was found between Ki-67 index and 18 F-FLT uptake. In a multivariate analysis 18 F-FLT, 18 F-FDG, and Ki-67 all were significant prognostic markers of PFS. For OS, only 18 F-FDG and Ki-67 remained significant., Conclusion: 18 F-FLT PET has prognostic value in NEN patients but when 18 F-FDG PET and Ki-67 index are also available, a multivariate model revealed that 18 F-FLT PET only adds information regarding PFS but not OS, whereas 18 F-FDG PET remains predictive of both PFS and OS. However, a clinically robust algorithm including 18 F-FLT in addition to 18 F-FDG and Ki-67 could not be found. Accordingly, the exact role, if any, of 18 F-FLT PET in NENs remains to be established., (© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

Objectives: The goal of this study was to develop and validate a noninvasive imaging tool to visualize the in vivo behavior of high-density lipoprotein (HDL) by using positron emission tomography (PET), with an emphasis on its plaque-targeting abilities., Background: HDL is a natural nanoparticle that interacts with atherosclerotic plaque macrophages to facilitate reverse cholesterol transport. HDL-cholesterol concentration in blood is inversely associated with risk of coronary heart disease and remains one of the strongest independent predictors of incident cardiovascular events., Methods: Discoidal HDL nanoparticles were prepared by reconstitution of its components apolipoprotein A-I (apo A-I) and the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine. For radiolabeling with zirconium-89 ((89)Zr), the chelator deferoxamine B was introduced by conjugation to apo A-I or as a phospholipid-chelator (1,2-distearoyl-sn-glycero-3-phosphoethanolamine-deferoxamine B). Biodistribution and plaque targeting of radiolabeled HDL were studied in established murine, rabbit, and porcine atherosclerosis models by using PET combined with computed tomography (PET/CT) imaging or PET combined with magnetic resonance imaging. Ex vivo validation was conducted by radioactivity counting, autoradiography, and near-infrared fluorescence imaging. Flow cytometric assessment of cellular specificity in different tissues was performed in the murine model., Results: We observed distinct pharmacokinetic profiles for the two (89)Zr-HDL nanoparticles. Both apo A-I- and phospholipid-labeled HDL mainly accumulated in the kidneys, liver, and spleen, with some marked quantitative differences in radioactivity uptake values. Radioactivity concentrations in rabbit atherosclerotic aortas were 3- to 4-fold higher than in control animals at 5 days' post-injection for both (89)Zr-HDL nanoparticles. In the porcine model, increased accumulation of radioactivity was observed in lesions by using in vivo PET imaging. Irrespective of the radiolabel's location, HDL nanoparticles were able to preferentially target plaque macrophages and monocytes., Conclusions: (89)Zr labeling of HDL allows study of its in vivo behavior by using noninvasive PET imaging, including visualization of its accumulation in advanced atherosclerotic lesions. The different labeling strategies provide insight on the pharmacokinetics and biodistribution of HDL's main components (i.e., phospholipids, apo A-I)., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose: The objective of this study was to evaluate the potential of PEGylated (64)Cu-liposomes in clinical diagnostic positron emission tomography (PET) imaging and PEGylated (177)Lu-liposomes in internal tumor radiotherapy through in vivo characterization and dosimetric analysis in a human xenograft mouse model., Methods: Liposomes with 5 and 10 mol% PEG were characterized with respect to size, charge, and (64)Cu- and (177)Lu-loading efficiency. The tumor imaging potential of (64)Cu-loaded liposomes was evaluated in terms of in vivo biodistribution, tumor accumulation and tumor-to-muscle (T/M) ratios, using PET imaging. The potential of PEGylated liposomes for diagnostic and therapeutic applications was further evaluated through dosimetry analysis using OLINDA/EXM software. The (64)Cu-liposomes were used as biological surrogates to estimate the organ and tumor kinetics of (177)Lu-liposomes., Results: High remote loading efficiency (>95 %) was obtained for both (64)Cu and (177)Lu radionuclides with PEGylated liposomes, and essentially no leakage of the encapsulated radionuclide was observed upon storage and after serum incubation for 24 h at 37 °C. The 10 mol% PEG liposomes showed higher tumor accumulation (6.2 ± 0.2 %ID/g) than the 5 mol% PEG liposomes, as evaluated by PET imaging. The dosimetry analysis of the (64)Cu-liposomes estimated an acceptable total effective dose of 3.3·10(-2) mSv/MBq for diagnostic imaging in patients. A high absorbed tumor dose (114 mGy/MBq) was estimated for the potential radiotherapeutic (177)Lu-liposomes., Conclusion: The overall preclinical profile of PEGylated (64)Cu-liposomes showed high potential as a new PET theranostic tracer for imaging in humans. Dosimetry results predicted that initial administered activity of 200 MBq of (64)Cu-liposomes should be acceptable in patients. Work is in progress to validate the utility of PEGylated (64)Cu-liposomes in a clinical research programme. The high absorbed tumor dose (114 mGy/MBq) estimated for (177)Lu-liposomes and the preliminary dosimetric studies justify further therapeutic and dosimetry investigation of (177)Lu-liposomes in animals before potential testing in man.

Background/objective: Neuroendocrine neoplasms of the pancreas and duodenum with predominant or exclusive immunoreactivity for somatostatin (pdSOMs) are rare, and knowledge about tumour biology, treatment, survival and prognostic factors is limited. This study aims to describe clinical, pathological and biochemical features as well as treatment and prognosis of pdSOMs., Design: Twenty-three patients with pdSOM (9 duodenal, 12 pancreatic and 2 unknown primary tumours) were identified from our prospective neuroendocrine tumour database, and data according to the study aims were recorded., Results: Among the 9 patients with duodenal SOM, the male/female ratio was 4/5. All males and 1 female had neurofibromatosis type 1. Seven patients had stage 1A/B and 2 had stage 2B disease. The Ki-67 index was 1-5% (median 2%). Plasma somatostatin was elevated in the patients with 2B disease. Of the 14 patients with pancreatic SOM or an unknown primary tumour, the male/female ratio was 2/12. One male had multiple endocrine neoplasia type 1. Five had stage 1A/2B and 9 had stage 4. The Ki-67 index was 1-40% (median 7%). Plasma somatostatin was elevated in 7 patients. Patients reported symptoms related to the somatostatinoma syndrome, but none fulfilled the criteria for a full syndrome. Primary tumour in the pancreas, metastatic disease at diagnosis and higher tumour grade were all associated with significantly poorer survival., Conclusion: None of the patients with pdSOM presented with the full somatostatinoma syndrome. Prognostic factors are localisation of the primary tumour, dissemination and tumour grade. A Ki-67 index of 5% may discriminate the course of the disease., (© 2015 S. Karger AG, Basel.)

Rationale: Local plaque macrophage proliferation and monocyte production in hematopoietic organs promote progression of atherosclerosis. Therefore, noninvasive imaging of proliferation could serve as a biomarker and monitor therapeutic intervention., Objective: To explore (18)F-FLT positron emission tomography-computed tomography imaging of cell proliferation in atherosclerosis., Methods and Results: (18)F-FLT positron emission tomography-computed tomography was performed in mice, rabbits, and humans with atherosclerosis. In apolipoprotein E knock out mice, increased (18)F-FLT signal was observed in atherosclerotic lesions, spleen, and bone marrow (standardized uptake values wild-type versus apolipoprotein E knock out mice, 0.05 ± 0.01 versus 0.17 ± 0.01, P<0.05 in aorta; 0.13 ± 0.01 versus 0.28 ± 0.02, P<0.05 in bone marrow; 0.06 ± 0.01 versus 0.22 ± 0.01, P<0.05 in spleen), corroborated by ex vivo scintillation counting and autoradiography. Flow cytometry confirmed significantly higher proliferation of macrophages in aortic lesions and hematopoietic stem and progenitor cells in the spleen and bone marrow in these mice. In addition, (18)F-FLT plaque signal correlated with the duration of high cholesterol diet (r(2)=0.33, P<0.05). Aortic (18)F-FLT uptake was reduced when cell proliferation was suppressed with fluorouracil in apolipoprotein E knock out mice (P<0.05). In rabbits, inflamed atherosclerotic vasculature with the highest (18)F-fluorodeoxyglucose uptake enriched (18)F-FLT. In patients with atherosclerosis, (18)F-FLT signal significantly increased in the inflamed carotid artery and in the aorta., Conclusions: (18)F-FLT positron emission tomography imaging may serve as an imaging biomarker for cell proliferation in plaque and hematopoietic activity in individuals with atherosclerosis., (© 2015 American Heart Association, Inc.)

64Cu radiolabelled nanodiscs based on the 11 α-helix MSP1E3D1 protein and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine lipids were, for the first time, followed in vivo by positron emission tomography for evaluating the biodistribution of nanodiscs. A cancer tumor bearing mouse model was used for the investigations, and it was found that the approximately 13 nm nanodiscs, due to their size, permeate deeply into cancer tissue. This makes them promising candidates for both drug delivery purposes and as advanced imaging agents. For the radiolabelling, a simple approach for 64Cu radiolabelling of proteins via a chelating agent, DOTA, was developed. The reaction was performed at sufficiently mild conditions to be compatible with labelling of the protein part of a lipid-protein particle while fully conserving the particle structure including the amphipathic protein fold.

Unlabelled: Neuroendocrine tumors (NETs) can be visualized using radiolabeled somatostatin analogs. We have previously shown the clinical potential of (64)Cu-DOTATATE in a small first-in-human feasibility study. The aim of the present study was, in a larger prospective design, to compare on a head-to-head basis the performance of (64)Cu-DOTATATE and (111)In-diethylenetriaminepentaacetic acid (DTPA)-octreotide ((111)In-DTPA-OC) as a basis for implementing (64)Cu-DOTATATE as a routine., Methods: We prospectively enrolled 112 patients with pathologically confirmed NETs of gastroenteropancreatic or pulmonary origin. All patients underwent both PET/CT with (64)Cu-DOTATATE and SPECT/CT with (111)In-DTPA-OC within 60 d. PET scans were acquired 1 h after injection of 202 MBq (range, 183-232 MBq) of (64)Cu-DOTATATE after a diagnostic contrast-enhanced CT scan. Patients were followed for 42-60 mo for evaluation of discrepant imaging findings. The McNemar test was used to compare the diagnostic performance., Results: Eighty-seven patients were congruently PET- and SPECT-positive. No SPECT-positive cases were PET-negative, whereas 10 false-negative SPECT cases were identified using PET. The diagnostic sensitivity and accuracy of (64)Cu-DOTATATE (97% for both) were significantly better than those of (111)In-DTPA-OC (87% and 88%, respectively, P = 0.017). In 84 patients (75%), (64)Cu-DOTATATE identified more lesions than (111)In-DTPA-OC and always at least as many. In total, twice as many lesions were detected with (64)Cu-DOTATATE than with (111)In-DTPA-OC. Moreover, in 40 of 112 cases (36%) lesions were detected by (64)Cu-DOTATATE in organs not identified as disease-involved by (111)In-DTPA-OC., Conclusion: With these results, we demonstrate that (64)Cu-DOTATATE is far superior to (111)In-DTPA-OC in diagnostic performance in NET patients. Therefore, we do not hesitate to recommend implementation of (64)Cu-DOTATATE as a replacement for (111)In-DTPA-OC., (© 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

Atherosclerosis is a major cause of global morbidity and mortality that could benefit from novel targeted therapeutics. Recent studies have shown efficient and local drug delivery with nanoparticles, although the nanoparticle targeting mechanism for atherosclerosis has not yet been fully elucidated. Here we used in vivo and ex vivo multimodal imaging to examine permeability of the vessel wall and atherosclerotic plaque accumulation of fluorescently labeled liposomal nanoparticles in a rabbit model. We found a strong correlation between permeability as established by in vivo dynamic contrast enhanced magnetic resonance imaging and nanoparticle plaque accumulation with subsequent nanoparticle distribution throughout the vessel wall. These key observations will enable the development of nanotherapeutic strategies for atherosclerosis.