Assessment of Brain Tumour Perfusion Using Early-Phase 18F-FET PET: Comparison with Perfusion-Weighted MRI.

PURPOSE: Morphological imaging using MRI is essential for brain tumour diagnostics. Dynamic susceptibility contrast (DSC) perfusion-weighted MRI (PWI), as well as amino acid PET, may provide additional information in ambiguous cases. Since PWI is often unavailable in patients referred for amino acid PET, we explored whether maps of relative cerebral blood volume (rCBV) in brain tumours can be extracted from the early phase of PET using O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET). PROCEDURE: Using a hybrid brain PET/MRI scanner, PWI and dynamic 18F-FET PET were performed in 33 patients with cerebral glioma and four patients with highly vascularized meningioma. The time interval from 0 to 2 min p.i. was selected to best reflect the blood pool phase in 18F-FET PET. For each patient, maps of MR-rCBV, early 18F-FET PET (0-2 min p.i.) and late 18F-FET PET (20-40 min p.i.) were generated and coregistered. Volumes of interest were placed on the tumour (VOI-TU) and normal-appearing brain (VOI-REF). The correlation between tumour-to-brain ratios (TBR) of the different parameters was analysed. In addition, three independent observers evaluated MR-rCBV and early 18F-FET maps (18F-FET-rCBV) for concordance in signal intensity, tumour extent and intratumoural distribution. RESULTS: TBRs calculated from MR-rCBV and 18F-FET-rCBV showed a significant correlation (r = 0.89, p < 0.001), while there was no correlation between late 18F-FET PET and MR-rCBV (r = 0.24, p = 0.16) and 18F-FET-rCBV (r = 0.27, p = 0.11). Visual rating yielded widely agreeing findings or only minor differences between MR-rCBV maps and 18F-FET-rCBV maps in 93 % of the tumours (range of three independent raters 91-94%, kappa among raters 0.78-1.0). CONCLUSION: Early 18F-FET maps (0-2 min p.i.) in gliomas provide similar information to MR-rCBV maps and may be helpful when PWI is not possible or available. Further studies in gliomas are needed to evaluate whether 18F-FET-rCBV provides the same clinical information as MR-rCBV.

Automated Brain Tumor Detection and Segmentation for Treatment Response Assessment Using Amino Acid PET.

Evaluation of metabolic tumor volume (MTV) changes using amino acid PET has become an important tool for response assessment in brain tumor patients. MTV is usually determined by manual or semiautomatic delineation, which is laborious and may be prone to intra- and interobserver variability. The goal of our study was to develop a method for automated MTV segmentation and to evaluate its performance for response assessment in patients with gliomas. Methods: In total, 699 amino acid PET scans using the tracer O-(2-[18F]fluoroethyl)-l-tyrosine (18F-FET) from 555 brain tumor patients at initial diagnosis or during follow-up were retrospectively evaluated (mainly glioma patients, 76%). 18F-FET PET MTVs were segmented semiautomatically by experienced readers. An artificial neural network (no new U-Net) was configured on 476 scans from 399 patients, and the network performance was evaluated on a test dataset including 223 scans from 156 patients. Surface and volumetric Dice similarity coefficients (DSCs) were used to evaluate segmentation quality. Finally, the network was applied to a recently published 18F-FET PET study on response assessment in glioblastoma patients treated with adjuvant temozolomide chemotherapy for a fully automated response assessment in comparison to an experienced physician. Results: In the test dataset, 92% of lesions with increased uptake (n = 189) and 85% of lesions with iso- or hypometabolic uptake (n = 33) were correctly identified (F1 score, 92%). Single lesions with a contiguous uptake had the highest DSC, followed by lesions with heterogeneous, noncontiguous uptake and multifocal lesions (surface DSC: 0.96, 0.93, and 0.81 respectively; volume DSC: 0.83, 0.77, and 0.67, respectively). Change in MTV, as detected by the automated segmentation, was a significant determinant of disease-free and overall survival, in agreement with the physician's assessment. Conclusion: Our deep learning-based 18F-FET PET segmentation allows reliable, robust, and fully automated evaluation of MTV in brain tumor patients and demonstrates clinical value for automated response assessment.

Digital participation of brain tumour patients in the assessment and treatment of communication disorders.

Introduction: Communication deficits have a severe impact on our social interactions and health-related quality of life. Subtle communication deficits are frequently overlooked or neglected in brain tumour patients, due to insufficient diagnostics. Digital tools may represent a valuable adjunct to the conventional assessment or therapy setting but might not be readily suitable for every patient. Methods: This article summarises results of three surveys on the readiness for telemedicine among (a) patients diagnosed with high-grade glioma, (b) matched controls, and (c) speech and language therapists. The respective surveys assessed the motivation for participation in telemedical assessments and supposed influencing factors, and the use potential of digital assessment and therapy technologies in daily routine, with a spotlight on brain tumour patients and the future prospects of respective telemedical interventions. Respondents included 56 high-grade glioma patients (age median: 59 years; 48% males), 73 propensity-score matched neurologically healthy controls who were instructed to imagine themselves with a severe disease, and 23 speech and language therapists (61% <35 years; all females). Results and discussion: The vast majority of the interviewed high-grade glioma (HGG) patients was open to digitisation, felt well-equipped and sufficiently skilled. The factorial analysis showed that digital offers would be of particular interest for patients in reduced general health condition (p = 0.03) and those who live far from specialised treatment services (p = 0.03). The particular motivation of these subgroups seemed to outweigh the effects of age, equipment and internet skills, which were only significant in the control cohort. The therapists' survey demonstrated a broad consensus on the need for improving the therapy access of brain tumour patients (64%) and strengthening their respective digital participation (78%), although digitisation seems to have yet hardly entered the therapists' daily practise. In summary, the combined results of the surveys call for a joint effort to enhance the prerequisites for digital participation of patients with neurogenic communication disorders, particularly in the context of heavily burdened HGG patients with limited mobility.

The economic crisis during the COVID-19 pandemic has a negative effect on tax compliance: Results from a scenario study in Austria.

In a scenario study with 1200 Austrian taxpayers, we examined how tax compliance is affected by the economic crisis related to the COVID-19 pandemic. Moreover, we investigated the potential of trust in government, attitude towards taxes, and justice perceptions in mitigating potential effects. The results suggest a strong effect of the economic environment on tax compliance. Specifically, tax compliance was lower in scenarios where the pandemic had a negative effect on the economy than in scenarios with no negative effect. However, for individuals with a positive attitude towards taxes, compliance was not lower in a negative economic environment than in pre-COVID-19 times. Moreover, we found that taxpayers who were not affected economically, taxpayers with a positive attitude towards taxes, and taxpayers with a low propensity to take risks generally indicated higher levels of tax compliance. Exploratory analyses indicate that taxpayers who change their compliance behavior in response to the economic environment are, on average, younger, less educated, more strongly affected economically, and more uncertain about their current economic situation than taxpayers with stable compliance levels. Policy interventions should target these groups to strengthen tax compliance in times of crisis.

Clinical routine assessment of palliative care symptoms and concerns and caregiver burden in glioblastoma patients: an explorative field study.

The implementation of self-reported outcome measurements into clinical routine was tested to help facilitate early access to palliative care (PC) for glioblastoma (GBM)-patients. Measures detail PC symptoms and concerns and caregiver burden. Between January 2014 and December 2016, a total of 337 GBM-patients were discussed during meetings of the neuro-oncology tumor board to examine further treatment options. Each patient, along with their caregivers, was requested to participate in self-assessment using the palliative outcome scale (POS) and the Zarit Burden Interview (ZBI). Analyses encompassed summary statistics, non-parametric tests, visual graphic analysis, content analysis and assessing the utilization of the specialized PC consulting service (SPCCS). Ninety-five (28%) GBM-patients and 71 (21%) caregivers completed the self-assessment. Of these, 20 patients and 12 caregivers repeated the assessment at least once more during follow-up. POS total scores were similar in the group of patients with initial diagnosis [10 (0-31)] and those with later disease stages like recurrent diagnosis [9 (0-25)], but ZBI total scores differed [14 (0-51) vs. 24 (2-62)]. Single item analysis demonstrated that anxiety and worries about the future predominated. Caregivers were torn between high engagement in caring and feeling overburdened. Still, requests for the SPCCS showed no increase. Actual implementation of measures like POS and ZBI for detecting PC concerns and caregiver burden with GBM-patients in the field remains challenging as indicated by the limited response rate and lack of increased requests for the SPCCS. Modified clinical routines including strengthening awareness of PC, and allowing proxy-assessment might help to overcome barriers.

O-(2-18F-fluoroethyl)-L-tyrosine PET for evaluation of brain metastasis recurrence after radiotherapy: an effectiveness and cost-effectiveness analysis.

BACKGROUND: Conventional MRI is the standard method to diagnose recurrence of brain metastases after radiation. However, following radiation therapy, reactive transient blood-brain barrier alterations with consecutive contrast enhancement can mimic brain metastasis recurrence. Recent studies have suggested that O-(2-18F-fluoroethyl)-L-tyrosine (FET) PET improves the correct differentiation of brain metastasis recurrence from radiation injury. Based on published evidence and clinical expert opinion, we analyzed effectiveness and cost-effectiveness of the use of FET PET in addition to MRI compared with MRI alone for the diagnosis of recurrent brain metastases. METHODS: A decision-tree model was designed to compare the 2 diagnostic strategies from the perspective of the German Statutory Health Insurance (SHI) system. Effectiveness was defined as correct diagnosis of recurrent brain metastasis and was compared between FET PET with MRI and MRI alone. Costs were calculated for a baseline scenario and for a more expensive scenario. Robustness of the results was tested using sensitivity analyses. RESULTS: Compared with MRI alone, FET PET in combination with MRI increases the rate of correct diagnoses by 42% (number needed to diagnose of 3) with an incremental cost-effectiveness ratio of €2821 (baseline scenario) and €4014 (more expensive scenario) per correct diagnosis. The sensitivity analyses confirmed the robustness of the results. CONCLUSIONS: The model suggests that the additional use of FET PET with conventional MRI for the diagnosis of recurrent brain metastases may be cost-effective. Integration of FET PET has the potential to avoid overtreatment with corresponding costs as well as unnecessary side effects.

A Modeling and Simulation Framework for Adverse Events in Erlotinib-Treated Non-Small-Cell Lung Cancer Patients.

Treatment with erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor used for treating non-small-cell lung cancer (NSCLC) and other cancers, is frequently associated with adverse events (AE). We present a modeling and simulation framework for the most common erlotinib-induced AE, rash, and diarrhea, providing insights into erlotinib toxicity. We used the framework to investigate the safety of high-dose erlotinib pulses proposed to limit acquired resistance while treating NSCLC. Continuous-time Markov models were developed using rash and diarrhea AE data from 39 NSCLC patients treated with erlotinib (150 mg/day). Exposure and different covariates were investigated as predictors of variability. Rash was also tested as a survival predictor. Models developed were used in a simulation analysis to compare the toxicities of different regimens, including the previously mentioned pulsed strategy. Probabilities of experiencing rash or diarrhea were found to be highest early during treatment. Rash, but not diarrhea, was positively correlated with erlotinib exposure. In contrast with some common understandings, radiotherapy decreased transitioning to higher rash grades by 81% (p < 0.01), and experiencing rash was not correlated with positive survival outcomes. Model simulations predicted that the proposed pulsed regimen (1600 mg/week + 50 mg/day remaining week days) results in a maximum of 20% of the patients suffering from severe rash throughout the treatment course in comparison to 12% when treated with standard dosing (150 mg/day). In conclusion, the framework demonstrated that radiotherapy attenuates erlotinib-induced rash, providing an opportunity to use radiotherapy and erlotinib together, and demonstrated the tolerability of high-dose pulses intended to address acquired resistance to erlotinib.

Echocardiographic assessment of global longitudinal right ventricular function in patients with an acute inferior ST elevation myocardial infarction and proximal right coronary artery occlusion.

Right ventricular (RV) myocardial infarction (MI) is a frequent concomitant of an acute inferior MI. We set out to determine the diagnostic value of speckle tracking echocardiography in comparison with cardiac magnetic resonance (CMR) for RV stunning and scar prediction. 55 patients (66 ± 11 years) with an acute inferior ST elevation MI who underwent percutaneous coronary intervention (PCI) of an occlusion in the proximal right coronary artery were prospectively enrolled. An echocardiography was done on the day of presentation and on the 5th day thereafter. A CMR was subsequently performed 1 month after the MI. The CMR was used to differentiate between the group with RV scar (n = 26) and without RV scar (n = 29). RV peak systolic longitudinal strain (RV-LS) at presentation determined RV scar (-21.1 ± 5.1% vs. -9.9 ± 4.6%, p < 0.0001). The RV-LS correlated with the scar extent (r = 0.83, p < 0.0001). RV-LS > -15.8% had a sensitivity of 92% and a specificity of 83% in RV scar prediction (AUC 0.93). RV-LS was superior to TAPSE and TDI in determining the presence of RV scar. According to RV-LS values at presentation and on the 5th day, 3 subgroups were defined: G1-normal deformation (RV-LS <-20%), G2-RV stunning (baseline RV-LS >-20%, 5th day RV-LS <-20%) and G3-persistent RV dysfunction (unchanged RV-LS > -20%). In G1, there was neither RV scar nor clinically relevant hypotension. In G2, 58% of patients developed RV scar and 36% had hypotension. In the G3, 83% developed RV scar and 55% had hypotension. The myocardial deformation analysis could provide an early prediction of RV scar. It allowed the patients to be divided into subgroups with normal RV function, stunning and persistent RV dysfunction.