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Purpose: To investigate the impact of positron emission tomography/computed tomography (PET/CT) on clinical management in patients with esophageal cancer and its link to overall survival (OS) in a real-world setting., Methods: A patient cohort with advanced esophageal cancer undergoing PET/CT was prospectively enrolled in a registry study between 04/2013 and 06/2019. Intended patient management prior and after PET/CT was documented based on standardized questionnaire data. Management changes after PET/CT were recorded including major changes concerning the treatment goal (curative vs. palliative) and minor changes (therapy adjustments). OS was analyzed for subgroups with squamous cell carcinomas (SCC) or adenocarcinomas (AC) and stratified for extent of metastatic disease and treatment goals., Results: 257 patients (53 female;65.5 ± 10.0 yr.) were included. After PET/CT, major changes of intended therapy were observed in 34/257 patients (13.2%), from curative to palliative (8.2%), palliative to curative (1.9%) and from "not finally determined" to a curative (1.9%) or palliative (1.2%) concept. Minor changes were found in 62/257 patients (24.1%). Invasive procedures and additional imaging were intended in 70/257 (27.2%) and 94/257 (36.6%) patients before PET/CT and 20/257 (7.8%) and 8/257 (3.1%) patients after PET/CT. Curative therapy concepts based on PET/CT were associated with a longer OS (3.5 yr.[95%CI 3.1-3.8 yr.]) as compared to palliative concepts (0.9 yr.[95%CI 0.6-1.2 yr.];p < 0.0001). Patients with SCC had a worse prognosis (2.4 yr.[95%CI 2.0-2.9 yr.]) as compared to patients with AC (3.2 yr.[95%CI 2.7-3.7 yr.];p = 0.01)., Conclusions: In patients with advanced esophageal cancer, PET/CT has a significant impact on clinical management by improving the selection of individualized treatment strategies and avoiding additional diagnostic procedures., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Purpose: To evaluate the potential of CT texture analysis parameters and metabolic characteristics of melanoma metastases in 18 F- FDG PET/CT to predict relevant mutations of tumour cells for targeted therapy in metastatic melanoma patients in correlation with histopathologic specimen., Material and Methods: 66 melanoma patients, examined with contrast-enhanced 18 F-FDG PET/CT before scheduled metastasectomy without any prior systemic therapy, were included in this single-centre retrospective analysis under IRB waiver. The largest, resected metastasis in each patient was assessed with CT texture analysis and semiquantitative 18 F-FDG PET parameters. Correlation between imaging parameters and histopathological mutations (BRAF- and NRAS- genes) were calculated., Results: Attenuation standard deviation (SD) within target lesion indicated a weak correlation with its SUV peak (rho -0.292, p 0.017). However, no correlation between CT texture analysis, metabolic 18 F-FDG PET parameters and tumour cell mutation could be established., Conclusion: CT texture parameters cannot replace the diagnostic value of 18 F- FDG PET/CT for metabolic information in melanoma patients. Discrimination between BRAF- and NRAS mutation status was not feasible with CT texture analysis in this exploratory study., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Purpose: To examine the potential effect of CT dose variation on radiomic features in vivo using simulated contrast-enhanced CT dose reduction in patients with non-small lung cell cancer (NSCLC)., Methods: In this retrospective study, we included 69 patients (25 females, 44 males, median age 66 years) with histologically proven NSCLC who underwent a whole contrast-enhanced body FDG-PET/CT for primary staging. To simulate different CT dose levels, we used an algorithm to simulate low-dose CT images based on a noise model derived from phantom experiments. The tumor lesions and reference regions in the paraspinal muscle were manually segmented to obtain three-dimensional regions of interest. Radiomic feature extraction was performed using the PyRadiomics toolbox. The median relative feature value deviation was assessed for each feature and each dose level., Results: The mean segmented tumor volume was 340 ml. T-stages of the primary tumors were primarily T3/4. For NSCLCs, the median relative feature value deviation in the lowest dose images varied for the calculated features from 52.2% to -49.5%. In general, dose-dependent deviations of feature values showed a monotonous increase or decrease with decreasing dose levels. Statistical analyses revealed significant differences between the dose levels in 91% of features., Conclusions: We examined the effects of simulated CT dose reduction on the values of radiomic features in primary NSCLC and showed significant deviations of varying degrees in numerous feature classes. This is a theoretical indicator of potential influence under real conditions, which should be taken into account in clinical use., Competing Interests: Declaration of Competing Interest This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors confirm that the article is not under consideration for publication elsewhere. Neither the authors nor authors’ institutions have conflicts of interest., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Purpose: To define the most appropriate imaging parameters in combined Fluorodeoxyglucose (FDG) PET/CT reflecting the inflammatory burden in large vessel vasculitis., Methods: Two readers retrospectively graded disease extent and activity in 17 LVV patients using visual and quantitative scores in FDG PET and contrast enhanced CT. Visual PET scores were assessed corresponding to FDG-uptake vs. liver uptake (score 0-3). CT visual scoring referred to the affected vessel extent (score 1-5). Quantitative PET scores relied on normalized SUV ratios. For quantitative CT evaluation vessel wall thickness was correlated with FDG- uptake. Imaging scores were correlated with Erythrocyte Sedimentation Rate (ESR) and C-reactive protein (CRP). Intraclass correlation coefficients (ICC) were measured for interreader reliability., Results: Visual PET scores showed stronger correlation with CRP (ρ 0.640, 0.541 for reader I and II, respectively) than with ESR levels (ρ 0.477, 0.447). Quantitative PET showed strongest correlation with CRP using liver as reference tissue. Visual CT scores did neither correlate with ESR nor with CRP levels (ESR: ρ 0.085, 0.294 with p 0.743, 0.252; CRP: ρ 0.322, 0.395 with p 0.208, 0.116). Quantitative CT evaluation correlated with ESR levels in one reader (ρ 0.505, -0.026), however no correlation between quantitative CT measures and quantitative PET scores was found. Best ICC between readers was 0.994 for highest SUV avg vessel/highest SUV avg liver., Conclusions: Visual and quantitative PET scores were superior to CT scores with best ICC and strongest correlations between quantitative PET score and inflammation markers especially when using vessel to liver ratios., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Rationale of this study was the evaluation of the diagnostic value of computed tomography (CT) in the detection of bone marrow infiltration in comparison to PET/CT. Fifty patients (age 61 ± 15.12 years) with metastatic malignant melanoma underwent 18F-FDG-PET/CT, including contrast-enhanced CT. 2 readers evaluated the CT images in consensus for bone and bone marrow lesions focusing on lesion location, type and size. PET/CT was used as reference standard to estimate sensitivity, specificity, negative and positive predictive value. Moreover, the bone marrow density was estimated in the long bones and the sacral bone. Serum hamoglobin, thrombocyte level and S100 protein were correlated with the presence or absence of bone and bone marrow lesions. According to PET/CT as standard of reference, of 594 bone and medullary lesions 495 were considered malignant. Of these 77.8% were medullary, 20.4% lytic, 1% sclerotic and 0.8% mixed lytic/sclerotic. Contrast-enhanced CT yielded a lesion-based sensitivity of 36.8% and a specificity of 87.9% (PPV 93.8%; NPV 21.8%). Patient-based sensitivity and specificity were 78.8% and 82.4%, respectively. Of the missed lesions, most were medullary (95.8%). A disseminated bone marrow involvement (defined as >10 bone marrow lesions or diffuse infiltration of a whole body segment) was described in 11 cases, in 6 cases the disseminated involvement was underestimated or missed on CT. In cases with disseminated bone marrow involvement the bone marrow density was significantly higher in the humerus (p=0.04), but not in the femur or sacral bone (p=0.06). Multivariate analysis revealed no isolated effect of bone metastases on S100 serum and hemoglobin level, but both were significantly altered in patients with disseminated bone marrow involvement (p<0.05). In conclusion, the diagnostic value of computed tomography for the detection of bone marrow metastases in patients with melanoma, is limited. Especially in cases with disseminated bone marrow involvement about 50% of the cases were missed or underestimated., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Introduction: PET quantification using the standard uptake value (SUV) is very prone to variations by technical factors of the scanner system and patient specific characteristics. Aim of the study was to investigate the reproducibility of SUV values between different measures and different reconstruction algorithms in a PET/CT scanner of the newest generation., Methods: The time-of-flight PET datasets of 27 consecutive oncological patients were reconstructed with OSEM3D in two different matrix sizes (200 × 200 and 400 × 400) as well as in a matrix size of 400 × 400 and additional point-spread-reconstruction. The standardized uptake values SUVmax, SUVmean and SUVpeak in 60 lesions were compared concerning their variability in the three reconstructions., Results: The addition of point-spread-reconstruction causes a significant increase of SUV values in comparison to OSEM 3D. SUVpeak showed the highest reproducibility between the different reconstruction algorithms. The variability of SUVmax and SUVmean increases in small lesions <5 ml, while SUVpeak remains more stable., Conclusion: SUVmax, SUVmean and SUVpeak can be used for PET quantification in principle. However, quantification of small lesions is difficult. SUVpeak is the most robust method when using varying reconstruction methods, especially in small lesions., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Objectives: The present work illustrates the current state of image quality and diagnostic accuracy in a new hybrid BrainPET/MR., Materials and Methods: 50 patients with intracranial masses, head and upper neck tumors or neurodegenerative diseases were examined with a hybrid BrainPET/MR consisting of a conventional 3T MR system and an MR-compatible PET insert. Directly before PET/MR, all patients underwent a PET/CT examination with either [18F]-FDG, [11C]-methionine or [68Ga]-DOTATOC. In addition to anatomical MR scans, functional sequences were performed including diffusion tensor imaging (DTI), arterial spin labeling (ASL) and proton-spectroscopy. Image quality score of MR imaging was evaluated using a 4-point-scale. PET data quality was assessed by evaluating FDG-uptake and tumor delineation with [11C]-methionine and [68Ga]-DOTATOC. FDG uptake quantification accuracy was evaluated by means of ROI analysis (right and left frontal and temporo-occipital lobes). The asymmetry indices and ratios between frontal and occipital ROIs were compared., Results: In 45/50 patients, PET/MR examination was successful. Visual analysis revealed a diagnostic image quality of anatomical MR imaging (mean quality score T2 FSE: 1.27±0.54; FLAIR: 1.38±0.61). ASL and proton-spectroscopy was possible in all cases. In DTI, dental artifacts lead to one non-diagnostic dataset (mean quality score DTI: 1.32±0.69; ASL: 1.10±0.31). PET datasets of PET/MR and PET/CT offered comparable tumor delineation with [11C]-methionine; additional lesions were found in 2/8 [(68)Ga]-DOTATOC-PET in the PET/MR. Mean asymmetry index revealed a high accordance between PET/MR and PET/CT (1.5±2.2% vs. 0.9±3.6%; mean ratio (frontal/parieto-occipital) 0.93±0.08 vs. 0.96±0.05), respectively., Conclusions: The hybrid BrainPET/MR allows for molecular, anatomical and functional imaging with uncompromised MR image quality and a high accordance of PET results between PET/MR and PET/CT. These results justify the application of this technique in further clinical studies and may contribute to the transfer into whole-body PET/MR systems., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To assess early high-resolution computer tomographic (CT) signs of invasive pulmonary aspergillosis (IPA) in non-HIV immunosuppressed patients and their potential association with patient's outcome, including frequency and severity of pulmonary hemorrhage, taking also in consideration the impact of other known risk factors contributory to IPA., Material and Methods: A retrospective review of serial CT scans was performed in 45 immunocompromised patients with a total of 46 episodes of invasive pulmonary aspergillosis. All patients underwent CT beginning with the day they showed clinical or laboratory signs of infection. Serial follow-up CT included more than two, up to 12 CT examinations. Patient's outcome was judged by clinical and radiological follow-up and classified as survival, death by IPA, or death unrelated to IPA. The influence of patient's age, underlying disease, hematopoietic stem cell transplantation, neutropenia, graft versus host disease, and antifungal therapy onset was also statistically considered., Results: Three main CT findings were identified: small nodules (<1cm) 43% (20/46), large nodules 21% (10/46) and consolidations, either in patchy+/-segmental 26% (12/46), or peribronchial distribution+/-tree in bud 9% (4/46). In 11 patients (24%) we found a combination of two or more of these signs: 9 (19%) patients presented concurrent small nodules accompanied by reticulation, tree in bud or peribronchial infiltrates, while 2 (4%) patients showed large pulmonary nodules accompanied by large consolidations. An accompanying "halo" sign was observed in 38 patients (82%). Crescent sign followed by cavitation was encountered in 29 patients (63%). Two patients succumbed to massive pulmonary bleeding caused by IPA. Twenty-one patients (15/46) deceased in this series, 12 of them succumbed to IPA, 1 died from cerebral invasive aspergillosis, while in 9 patients the cause of death was not primarily IPA. Manifest pulmonary hemorrhage occurred in 19% (9/46) of IPA episodes., Conclusion: Initial CT findings of invasive pulmonary aspergillosis consist mainly of small nodules or patchy consolidations, showing in 82% of cases an early halo sign. Serious pulmonary hemorrhage was an infrequent clinical complication in our series, with an attributable mortality of 4.3%. IPA-related lethality was 26%, in our cohort. None of the early HRCT signs seemed to predict outcome.

Objective: The goal of this study was to establish the feasibility of a low-dose whole-body multidetector row-CT (MDCT) protocol in the diagnosis of multiple myeloma (MM), as an alternative to conventional X-ray imaging, which is currently still state-of-the-art in these patients, with emphasis on the comparison of image resolution on axial and multiplanar reformatted (MPR) scans and reduction of radiation dose., Material and Methods: 100 patients with known MM, or monoclonal gammopathy of unknown significance (MGUS) underwent unenhanced whole-body MDCT on a 16-slice scanner in a randomised fashion, using a 16 x 1.5 mm collimation and four different energy parameters (40, 50, 60 and 70 mAs). Three different reconstruction algorithms were used in every patient (B40f, B50f and B60f kernel). CT scans were reviewed independently by two radiologists, with regard to correct classification into one of the three known MM stages, and recognition of fracture risk. Thereafter, axial and MPR images were evaluated in consensus by both readers, with respect to image resolution. Diagnosis of osteolytic lesions was performed on the basis of axial and multiplanar reformatted images, whereas the assessment of spinal misalignment and fracture was done only on MPR images. The distribution of image resolution categories (very good, good, sufficient, insufficient for diagnosis) was evaluated depending on following parameters: current time product, patient's weight, bone density and reconstruction algorithm. The effective radiation dose was determined with the aid of an anthropomorphic Alderson Rando-Phantom, using a tube current time product of 40 mAs, and then extrapolating it on all current time products applied in this study on a commercially available software program WinDose (Institute of Medical Physics, Erlangen, Germany)., Results: In all 100 patients, image resolution was diagnostic, regardless of scanning parameters, enabling correct classification of multiple myeloma patients. Image quality of MPR images was either equal or inferior to correspondent axial images in the delineation of smaller lytic lesions, because of the use of non-isotropic voxel size. However, they proved accurate in diagnosing fracture and spine misalignment. A strong dependency of image resolution on bone density was observed, with reduced quality in patients with either diffuse skeleton infiltration or concurrent osteoporosis. Spatial resolution was also dependent on the reconstruction algorithm and energy level (mAs) used, as well as on patient's weight, but their influence was low within the given ranges. A middle-frequency reconstruction algorithm (B50f kernel) proved beneficial for all energy protocols. The interobserver agreement was excellent (kappa = 0.95) for classification of MM-patients. Effective radiation dose of MDCT calculated at a tube current time product of 40 mAs was 1.7-fold higher than the mean radiation dose of conventional X-ray (4.1 mSv versus 2.4 mSv)., Discussion: Our study shows that whole-body low-dose MDCT investigational protocols are appropriate for the diagnosis of lytic bone changes and for assessment of fracture risk in multiple myeloma patients, representing a serious alternative to current standards.