A comparative study of multi and single post labeling delay pseudocontinuous arterial spin labeling in patients with carotid artery stenosis

PURPOSE

Arterial Spin Labeling (ASL) allows for the non-invasive visualization of brain perfusion to detect abnormalities. In unilateral carotid artery stenosis, one hemisphere is less supplied with blood which results in a lower cerebral blood flow (CBF) compared to the healthy side. ASL can be performed time-resolved using multiple post labeling delay (PLD) times after labeling or static with a single delay, the latter allowing for a faster and more robust acquisition while bearing the risk of a falsely set delay resulting in unusable images. The purpose of this study is to compare the performance of multi-PLD and single-PLD ASL in patients with unilateral carotid artery stenosis both as means of diagnosis and therapeutic follow-up examination.

METHODS

ASL perfusion data of 17 patients with known unilateral carotid artery stenosis was used to compare the diagnostic performance of the multi-PLD and single-PLD approach. Comparisons were made based on the CBF values and the added benefit of arrival time maps showing slower blood flow in multi-PLD ASL which might be overlooked in the individual delay images both before and after therapy.

RESULTS

Both the multi-PLD and the single-PLD data could identify the side of the stenosis with hemispheric differences in each approach (p < 0.001) and depict the normalization of CBF after therapy (p > 0.05). There were no differences between the individual methods (p > 0.05).

CONCLUSION

In this work, we could show that multi-PLD ASL in patients with unilateral carotid artery stenosis is beneficial as it provides both CBF and arrival time maps, however when only a single-PLD acquisition is available, this appears sufficient in a clinical setting to investigate the presence of a unilateral stenosis.

9-Month observational Dia-Vacc study of vaccine type influence on SARS-CoV-2 immunity in dialysis and kidney transplant patients

BACKGROUND

SARS-CoV-2mRNA vaccination related seroconversion rates are reduced in dialysis and kidney transplant patients.

METHODS

We evaluated nine months follow up data in our observational Dia-Vacc study exploring specific cellular (interferon-γ release assay) or/and humoral immune responses after 2x SARS-CoV-2mRNA vaccination in 880 participants including healthy medical personnel (125-MP), dialysis patients (595-DP), kidney transplant recipients (111-KTR), and apheresis patients (49-AP) with positive seroconversion (de novo IgA or IgG antibody positivity by ELISA) after eight weeks.

FINDINGS

Nine months after first vaccination, receptor binding domain (RBD) antibodies were still positive in 90 % of MP, 86 % of AP, but only 55 %/48 % of DP/KTR, respectively. Seroconversion remained positive in 100 % of AP and 99·2 % of MP, but 86 %/81 % of DP/KTR, respectively. Compared to MP, DP but not KTR or AP were at risk for a strong RBD decline, while KTR kept lowest RBD values over time. By multivariate analysis, BNT162b2mRNA versus 1273-mRNA vaccine type was an independent risk factor for a strong decline of RBD antibodies. Within the DP group, only time on dialysis was another (inverse) risk factor for the DP group. Compared to humoral immunity, T-cell immunity decline was less prominent.

INTERPRETATION

While seroconverted KTR reach lowest RBD values over time, DP are at specific risk for a strong decline of RBD antibodies after successful SARS-CoV-2mRNA vaccination, which also depends on the vaccine type being used. Therefore, booster vaccinations for DP should be considered earlier compared to normal population.

Risk of strong antibody decline in dialysis and transplant patients after SARS-CoV-2mRNA vaccination: Six months data from the observational Dia-Vacc study

Background

Vulnerable dialysis and kidney transplant patients show impaired seroconversion rates compared to medical personnel eight weeks after SARS-CoV-2mRNA vaccination.

Methods

We evaluated six months follow up data in our observational Dia-Vacc study exploring specific cellular (interferon-γ release assay) or/and humoral immune responses after 2x SARS-CoV-2mRNA vaccination in 1205 participants including medical personnel (125 MP), dialysis patients (970 DP) and kidney transplant recipients (110 KTR) with seroconversion (de novo IgA or IgG antibody positivity by ELISA) after eight weeks.

Findings

Six months after vaccination, seroconversion remained positive in 98% of MP, but 91%/87% of DP/KTR (p = 0·005), respectively. Receptor binding domain-IgG (RBD-IgG) antibodies were positive in 98% of MP, but only 68%/57% of DP/KTR (p < 0·001), respectively. Compared to MP, DP and KTR were at risk for a strong IgG or RBD-IgG decline (p < 0·001). Within the DP but not KTR group male gender, peritoneal dialysis, short time on dialysis, BNT162b2mRNA vaccine, immunosuppressive drug use and diabetes mellitus were independent risk factors for a strong decline of IgG or RBD antibodies. The percentage of cellular immunity decline was similar in all groups.

Interpretation

Both vulnerable DP and KTR groups are at risk for a strong decline for IgG and RBD antibodies. In KTR, antibody titres peak at a markedly lower level and accelerated antibody decline is mixed with a delayed/increasing IgG, RBD-IgG, or cellular immune response in a 16% fraction of patients. In both populations, immune monitoring should be used for early timing of additional booster vaccinations.

Funding

This study was funded by the Else Kröner Fresenius Stiftung, Bad Homburg v. d. H., grant number Fördervertrag EKFS 2021_EKSE.27.

Individualized arterial spin labeling background suppression by rapid T1 mapping during acquisition

Objective

Arterial spin labeling blood perfusion signal relies on the difference between a label and a control image. Background suppression pulses are commonly used to improve the contrast, yet these are based on estimates of tissue relaxation times. The aim of this study is to improve the perfusion contrast by individualizing the timing of these background suppression pulses by means of T1 mapping.

Methods

The optimized timing of the background suppression pulses is obtained by rapid T1 mapping employing the variable flip angle technique. Ten healthy volunteers were included in this study. To compare the results, visual grading and the Wilcoxon signed-rank test was used comparing three categories of image quality.

Results

The readers confirmed that the images of the proposed method generally show a higher signal-to-background ratio and cortical structures are better visible. Noise was mostly comparable to the standard method. Relative blood flow was statistically significant higher in the modified method.

Conclusion

The individually optimized background suppression pulses improve the image appearance and allow for a better visualization of cortical structures. The proposed technique however prolongs scan time, which can be seen as negative result, yet needs to be further evaluated.

Key Points

• Background suppression timing in ASL can vary.

• Both the label and control condition can be modified for T1 mapping.

• Adapting the pulse timing improves the signal-to-background ratio.

Pulse-shape discrimination against low-energy Ar-39 beta decays in liquid argon with 4.5 tonne-years of DEAP-3600 data

The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from 39 Ar beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator: the prompt-fraction, which considers the fraction of the scintillation signal in a narrow and a wide time window around the event peak, and the log-likelihood-ratio, which compares the observed photon arrival times to a signal and a background model. We furthermore use two algorithms to determine the number of photons detected at a given time: (1) simply dividing the charge of each PMT pulse by the mean single-photoelectron charge, and (2) a likelihood analysis that considers the probability to detect a certain number of photons at a given time, based on a model for the scintillation pulse shape and for afterpulsing in the light detectors. The prompt-fraction performs approximately as well as the log-likelihood-ratio PSD algorithm if the photon detection times are not biased by detector effects. We explain this result using a model for the information carried by scintillation photons as a function of the time when they are detected.

FAP imaging in rare cancer entities-first clinical experience in a broad spectrum of malignancies

PURPOSE

⁶⁸ Ga-FAPI (fibroblast activation protein inhibitor) is a rapidly evolving and highly promising radiotracer for PET/CT imaging, presenting excellent results in a variety of tumor entities, particularly in epithelial carcinomas. This retrospective analysis sought to evaluate the potential and impact of FAPI-PET/CT in rare cancer diseases with respect to improvement in staging and therapy, based on tracer uptake in normal organs and tumors.

MATERIAL AND METHODS

Fifty-five patients with rare tumor entities, defined by a prevalence of 1 person out of 2000 or less, received a ⁶⁸ Ga-FAPI-PET/CT scan. Fourteen women and 41 men (median age 60) were included within the following subgroups: cancer of unknown primary (n = 10), head and neck cancer (n = 13), gastrointestinal and biliary-pancreatic cancer (n = 17), urinary tract cancer (n = 4), neuroendocrine cancer (n = 4), and others (n = 7). Tracer uptake was quantified by standardized uptake values SUVmax and SUVmean and the tumor-to-background ratio (TBR) was determined (SUVmax tumor/SUVmean organ).

RESULTS

In 20 out of 55 patients, the primary tumor was identified and 31 patients presented metastases (n = 88), characterized by a high mean SUVmax in primary (10.1) and metastatic lesions (7.6). The highest uptake was observed in liver metastases (n = 6) with a mean SUVmax of 9.8 and a high TBR of 8.7, closely followed by peritoneal carcinomatosis (n = 16) presenting a mean SUVmax of 9.8 and an excellent TBR of 29.6. In terms of the included subgroups, the highest uptake regarding mean SUVmax was determined in gastrointestinal and biliary-pancreatic cancer with 9.8 followed closely by urinary tract cancer with 9.5 and head and neck cancer (9.1).

CONCLUSION

Due to excellent tumor visualization and, thereby, sharp contrasts in terms of high TBRs in primary and metastatic lesions in different rare malignancies, ⁶⁸ Ga-FAPI-PET/CT crystallizes as a powerful and valuable imaging tool, particularly with respect to epithelial carcinomas, and therefore an enhancement to standard diagnostics imaging methodologies. The realization of further and prospective studies is of large importance to confirm the potential of FAP imaging in oncology.

Humoral and cellular immunity to SARS-CoV-2 vaccination in renal transplant versus dialysis patients: A prospective, multicenter observational study using mRNA-1273 or BNT162b2 mRNA vaccine

Background

Dialysis and kidney transplant patients are vulnerable populations for COVID-19 related disease and mortality.

Methods

We conducted a prospective study exploring the eight week time course of specific cellular (interferon-γ release assay and flow cytometry) or/and humoral immune responses (ELISA) to SARS-CoV-2 boost vaccination in more than 3100 participants including medical personnel, dialysis patients and kidney transplant recipients using mRNA vaccines BNT162b2 or mRNA-1273.

Results

SARS-CoV-2-vaccination induced seroconversion efficacy in dialysis patients was similar to medical personnel (> 95%), but markedly impaired in kidney transplant recipients (42%). T-cellular immunity largely mimicked humoral results. Major risk factors of seroconversion failure were immunosuppressive drug number and type (belatacept, MMF-MPA, calcineurin-inhibitors) as well as vaccine type (BNT162b2 mRNA). Seroconversion rates induced by mRNA-1273 compared to BNT162b2 vaccine were 97% to 88% (p < 0.001) in dialysis and 49% to 26% in transplant patients, respectively. Specific IgG directed against the new binding domain of the spike protein (RDB) were significantly higher in dialysis patients vaccinated by mRNA-1273 (95%) compared to BNT162b2 (85%, p < 0.001). Vaccination appeared safe and highly effective demonstrating an almost complete lack of symptomatic COVID-19 disease after boost vaccination as well as ceased disease incidences during third pandemic wave in dialysis patients.

Conclusion

Dialysis patients exhibit a remarkably high seroconversion rate of 95% after boost vaccination, while humoral response is impaired in the majority of transplant recipients. Immunosuppressive drug number and type as well as vaccine type (BNT162b2) are major determinants of seroconversion failure in both dialysis and transplant patients suggesting immune monitoring and adaption of vaccination protocols.

The novel Mechanical Ventilator Milano for the COVID-19 pandemic

This paper presents the Mechanical Ventilator Milano (MVM), a novel intensive therapy mechanical ventilator designed for rapid, large-scale, low-cost production for the COVID-19 pandemic. Free of moving mechanical parts and requiring only a source of compressed oxygen and medical air to operate, the MVM is designed to support the long-term invasive ventilation often required for COVID-19 patients and operates in pressure-regulated ventilation modes, which minimize the risk of furthering lung trauma. The MVM was extensively tested against ISO standards in the laboratory using a breathing simulator, with good agreement between input and measured breathing parameters and performing correctly in response to fault conditions and stability tests. The MVM has obtained Emergency Use Authorization by U.S. Food and Drug Administration (FDA) for use in healthcare settings during the COVID-19 pandemic and Health Canada Medical Device Authorization for Importation or Sale, under Interim Order for Use in Relation to COVID-19. Following these certifications, mass production is ongoing and distribution is under way in several countries. The MVM was designed, tested, prepared for certification, and mass produced in the space of a few months by a unique collaboration of respiratory healthcare professionals and experimental physicists, working with industrial partners, and is an excellent ventilator candidate for this pandemic anywhere in the world.

Improved cancer detection in Waldeyer's tonsillar ring by 68Ga-FAPI PET/CT imaging

Purpose

In cancer of unknown primary (CUP), positron emission tomography/computed tomography (PET/CT) with the glucose analog [¹⁸F]FDG represents the standard imaging approach for localization of the malignant primary. Frequently, however, [¹⁸F]FDG PET/CT cannot precisely distinguish between small occult tumors and chronic inflammation, especially in Waldeyer’s tonsillar ring. To improve the accuracy for detecting primary tumors in the Waldeyer’s tonsillar ring, the novel PET tracer [⁶⁸Ga]Ga-FAPI-4 for specific imaging of fibroblast activation protein (FAP) expression was used as a more specific target for cancer imaging.

Methods

Eight patients with suspicion of a malignant tumor in Waldeyer’s tonsillar ring or a CUP syndrome were examined. PET/CT scans with [¹⁸F]-FDG and [⁶⁸Ga]Ga-FAPI-4 were performed for pre-operative tumor localization. After surgical resection, histopathological and immunohistochemical results were compared to PET/CT findings.

Results

Histopathology revealed a palatine or lingual tonsil carcinoma in all patients. In case of lymph node metastases smaller than 7 mm in size, the [¹⁸F]FDG PET/CT detection rate of cervical lymph node metastases was higher than that of [⁶⁸Ga]FAPI PET/CT, while both tracers identified the primary tumors in all eight cases. The size of the primary and the lymph node metastases was directly correlated to the respective FAP expression, as detected by immunohistochemistry. The mean SUV_max for the primary tumors was 21.29 ± 7.97 for ¹⁸F-FDG and 16.06 ± 6.29 for ⁶⁸Ga-FAPI, respectively (p = 0.2). The mean SUV_max for the healthy contralateral tonsils was 8.38 ± 2.45 for [¹⁸F]FDG and 3.55 ± 0.47 for [⁶⁸Ga]FAPI (p < 0.001). The SUV_max ratio of [⁶⁸Ga]FAPI was significantly different from [¹⁸F] FDG (p = 0.03). Mean TBR_max for the [⁶⁸Ga]Ga-FAPI-4 tracer was markedly higher in comparison to [¹⁸F]FDG (10.90 vs. 4.11).

Conclusion

Non-invasive imaging of FAP expression by [⁶⁸Ga]FAPI PET/CT resulted in a better visual detection of the malignant primary in CUP, as compared to [¹⁸F]FDG imaging. However, the detection rate of lymph node metastases was inferior, presumably due to low FAP expression in small metastases. Nevertheless, by offering a detection method for primary tumors with the potential of lower false positive rates and thus avoiding biopsies, patients with CUP syndrome may benefit from [⁶⁸Ga]FAPI PET/CT imaging.

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

[18F]-florbetaben PET/CT Imaging in the Alzheimer's Disease Mouse Model APPswe/PS1dE9

BACKGROUND

Positron-emission-tomography (PET) using 18F labeled florbetaben allows noninvasive in vivo-assessment of amyloid-beta (Aβ), a pathological hallmark of Alzheimer's disease (AD). In preclinical research, [¹⁸F]-florbetaben-PET has already been used to test the amyloid-lowering potential of new drugs, both in humans and in transgenic models of cerebral amyloidosis. The aim of this study was to characterize the spatial pattern of cerebral uptake of [¹⁸F]-florbetaben in the APPswe/ PS1dE9 mouse model of AD in comparison to histologically determined number and size of cerebral Aβ plaques.

METHODS

Both, APPswe/PS1dE9 and wild type mice at an age of 12 months were investigated by smallanimal PET/CT after intravenous injection of [¹⁸F]-florbetaben. High-resolution magnetic resonance imaging data were used for quantification of the PET data by volume of interest analysis. The standardized uptake values (SUVs) of [¹⁸F]-florbetaben in vivo as well as post mortem cerebral Aβ plaque load in cortex, hippocampus and cerebellum were analyzed.

RESULTS

Visual inspection and SUVs revealed an increased cerebral uptake of [¹⁸F]-florbetaben in APPswe/ PS1dE9 mice compared with wild type mice especially in the cortex, the hippocampus and the cerebellum. However, SUV ratios (SUVRs) relative to cerebellum revealed only significant differences in the hippocampus between the APPswe/PS1dE9 and wild type mice but not in cortex; this differential effect may reflect the lower plaque area in the cortex than in the hippocampus as found in the histological analysis.

CONCLUSION

The findings suggest that histopathological characteristics of Aβ plaque size and spatial distribution can be depicted in vivo using [¹⁸F]-florbetaben in the APPswe/PS1dE9 mouse model.

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.

First Results from the DEAP-3600 Dark Matter Search with Argon at SNOLAB

This Letter reports the first results of a direct dark matter search with the DEAP-3600 single-phase liquid argon (LAr) detector. The experiment was performed 2 km underground at SNOLAB (Sudbury, Canada) utilizing a large target mass, with the LAr target contained in a spherical acrylic vessel of 3600 kg capacity. The LAr is viewed by an array of PMTs, which would register scintillation light produced by rare nuclear recoil signals induced by dark matter particle scattering. An analysis of 4.44 live days (fiducial exposure of 9.87 ton day) of data taken during the initial filling phase demonstrates the best electronic recoil rejection using pulse-shape discrimination in argon, with leakage <1.2×10^{-7} (90% C.L.) between 15 and 31  keV_{ee}. No candidate signal events are observed, which results in the leading limit on weakly interacting massive particle (WIMP)-nucleon spin-independent cross section on argon, <1.2×10^{-44}  cm^{2} for a 100  GeV/c^{2} WIMP mass (90% C.L.).

Vessel Wall Enhancement in Unruptured Intracranial Aneurysms: An Indicator for Higher Risk of Rupture? High-Resolution MR Imaging and Correlated Histologic Findings

BACKGROUND AND PURPOSE

Recent studies have suggested that wall enhancement of unruptured intracranial aneurysms in high-resolution MR imaging might serve as an imaging biomarker for higher risk of rupture. Histologic studies have revealed a possible association among inflammatory processes, degeneration, and destabilization of the aneurysm wall preceding rupture. Understanding the histologic condition underlying aneurysm wall enhancement could be an important step toward assessing the value of this method for risk stratification. We present our observations of aneurysm wall enhancement in MR vessel wall imaging and underlying histologic changes.

MATERIALS AND METHODS

We reviewed records of patients with an unruptured middle cerebral artery aneurysm who underwent MR vessel wall imaging before aneurysm clipping. Contrast enhancement of the aneurysm wall was dichotomized into either none/faint or strong. Histologic analysis included myeloperoxidase stain for detection of inflammatory cell invasion and CD34 stain for assessment of neovascularization and vasa vasorum.

RESULTS

Thirteen aneurysms were included. Five aneurysms showed strong wall enhancement. Among these, myeloperoxidase staining revealed inflammatory cell infiltration in 4. Three showed neovascularization. In 2 aneurysms, vasa vasorum were present. Seven aneurysms did not show wall enhancement; 1 had only mild enhancement. None of these bore evidence of inflammatory cell invasion or neovascularization, and they all lacked vasa vasorum.

CONCLUSIONS

Wall enhancement in MR vessel wall imaging is associated with inflammatory cell invasion, neovascularization, and the presence of vasa vasorum. Enhancement does not occur when histologic signs of inflammation are absent. Our results support the hypothesis that MR vessel wall imaging could provide valuable information for risk stratification.

The Pituitary-Thyroid Axis and Prolactin Secretion in Hemodialysis Patients in Two Endemic Regions of Eastern Germany

Introduction Endocrine disorders of the pituitary axes are frequent in patients with hemodialysis (CKD5D). The aim of this multicenter study (Leipzig (L), Quedlinburg and Blankenburg in the Harz region (Hz)) in CKD5D patients was to evaluate influences of CKD5D related factors, morphological and biochemical parameters, and serum iodine and prolactin concentrations on the pituitary-thyroid axis.

Patients and Methods 170 patients (L n=58; Hz n=112) were included in this prospective, non-interventional, cross-sectional study. Mann-Whitney-U-test and bivariate correlation analyses with Spearman-Rho test (r correlation coefficient) were used in statistical analysis.

Results TSH was higher in patients with prolactin concentrations>370 mIU/l (p=0.013), in patients with high flux membranes (p=0.0013) and in patients with longer dialysis vintage (p=0.04). Median iodine serum concentrations were slightly elevated in the Leipzig cohort (p=0.001) and correlated with fT4 (p<0.001, r=0.43) and albumin (p=0.001, r=0.245) but not with morphological signs. Albumin was correlated with fT3 (p<0.001, r=0.339) and fT4 (p<0.001, r=0.421). Prolactin was correlated with residual excretion rate (p=0.001, r=- 0.303) and thyroid volume (p=0.027, r=0.217).

Conclusions In the assessment of the thyroid status in CKD5D patients, the synopsis of the clinical and nutritional status, comorbidities, ultrasound of the thyroid gland and laboratory results is necessary for further intervention with hormone replacement. Standardized reference values of the pituitary-thyroid axis should be critically evaluated and are still lacking in CKD5D.

Point-of-Care Diagnostic Device for Traumatic Pneumothorax: Low Sensitivity of the Unblinded PneumoScan™

BACKGROUND

Traumatic Pneumothorax (PTX) is a potentially life-threatening injury. It requires a fast and accurate diagnosis and treatment, but diagnostic tools are limited. A new point-of-care device (PneumoScan) based on micropower impulse radar (MIR) promises to diagnose a PTX within seconds. In this study, we compare standard diagnostics with PneumoScan during shock-trauma-room management.

PATIENTS AND METHODS

Patients with blunt or penetrating chest trauma were consecutively included in the study. All patients were examined including clinical examination with auscultation (CE) and supine chest radiography (CXR). In addition, PneumoScan-readings and thoracic ultrasound scan (US) were performed. Computed tomography (CT) served as gold standard.

RESULTS

CT scan revealed PTX in 11 patients. PneumoScan detected two PTX correctly but missed nine. 15 false-positive results were found by PneumoScan, leading to a sensitivity of 20% and specificity of 80%. Six PTX were detected through CE (sensitivity: 54,5%). CXR detected four (sensitivity: 27,3%) and thoracic US two PTX correctly (sensitivity: 25%).

CONCLUSION

The unblinded PneumoScan prototype did not confirm the promising results of previous studies. The examined standard diagnostics and thoracic US showed rather weak sensitivity as well. Until now, there is no appropriate point-of-care tool to rule out PTX.

[Coma in the emergency room]

Coma of unknown origin (CUO) is a frequent unspecific emergency symptom associated with a high mortality. A fast diagnostic work-up is essential given the wide spectrum of underlying diagnoses that are made up of approximately 50% primary central nervous system (CNS) pathologies and approximately 50% extracerebral, almost exclusively internal medical causes. Despite the high mortality associated with this symptom, there are currently no generally accepted management guidelines for adult patients presenting with CUO. We propose an interdisciplinary standard operating procedure (SOP) for patients with acute CUO as has been established in our maximum care hospital. The SOP is triggered by simple triage criteria that are sufficient to identify CUO patients before arrival in hospital. The in-hospital response team is led by a neurologist. Collaboration with nursing staff, internal medicine, anesthesiology, neurosurgery and trauma surgery is organized along structured pathways that include standardized laboratory tests, including cerebrospinal fluid (CSF), toxicology, computed tomography (CT) and CT angiography imaging (CTA). Our data suggest that neurologists and internists need to be placed at the beginning of the diagnostic work-up. Imaging should not just be carried out depending on the clinical syndrome because sensitivity, specificity and inter-rater reliability of the latter are not sufficient and because in many cases, multiple pathologies can be detected that could each explain CUO alone. Clinical examination, imaging and laboratory testing should be regarded as components of an integrative diagnostic approach and the final aetiological classification should only be made after the diagnostic work-up is complete.

Quantitative Phase-Contrast MR Angiography to Measure Hemodynamic Changes in Idiopathic Intracranial Hypertension

BACKGROUND AND PURPOSE

Idiopathic intracranial hypertension is a syndrome of raised intracranial pressure of unknown etiology. Few MR imaging-based studies have investigated arterial and venous blood flow in these patients. Results are inconclusive, and to our knowledge, no comparison of the hemodynamic parameters before and after CSF pressure reduction has been published. The aim of this study was to assess the short-term effects of normalizing CSF pressure on intracranial flow to better understand the pathophysiology of idiopathic intracranial hypertension.

MATERIALS AND METHODS

In this study, we performed quantitative MR imaging-derived flow measurements of brain-supplying arteries and draining veins/dural sinuses to visualize hemodynamic changes in patients with idiopathic intracranial hypertension before and after therapy by lumbar puncture in comparison with a healthy control group.

RESULTS

We found differences in patients before and after lumbar puncture in the calculated resistance and pulsatility indices in the superior sagittal sinus. Venous pulsatility showed a negative correlation with CSF pressure in untreated patients. Additionally, there was a trend toward lower flow in the superior sagittal sinus in patients compared with healthy controls. Flow in the internal jugular veins was significantly reduced by lumbar puncture, and the resistance and pulsatility indices differed in patients and controls. The arterial flow was not influenced by pressure normalization.

CONCLUSIONS

The results of the present study indicate that venous but not arterial blood flow differs in patients compared with controls and that calculating resistance and pulsatility indices may contribute to assessing short-term hemodynamic changes in patients with diagnosed idiopathic intracranial hypertension before and after CSF diversion.

Combined Analysis of Neutrino and Antineutrino Oscillations at T2K

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×10^{20} protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135  μ-like events, and 7.471×10^{20} protons on target in antineutrino mode, which yielded 4 e-like and 66  μ-like events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ_{CP} spans the range (-3.13, -0.39) for normal mass ordering. The CP conservation hypothesis (δ_{CP}=0, π) is excluded at 90% C.L.

MR Imaging of Individual Perfusion Reorganization Using Superselective Pseudocontinuous Arterial Spin-Labeling in Patients with Complex Extracranial Steno-Occlusive Disease

BACKGROUND AND PURPOSE

Patients with multiple stenoses or occlusions of the extracranial arteries require an individualized diagnostic approach. We evaluated the feasibility and clinical utility of a novel MR imaging technique for regional perfusion imaging in this patient group.

MATERIALS AND METHODS

Superselective pseudocontinuous arterial spin-labeling with a circular labeling spot enabling selective vessel labeling was added to routine imaging in a prospective pilot study in 50 patients (10 women, 70.05 ± 10.55 years of age) with extracranial steno-occlusive disease. Thirty-three had infarct lesions. DSC-MR imaging was performed in 16/50 (32%), and cerebral DSA, in 12/50 patients (24%). Vascular anatomy and the distribution of vessel stenoses and occlusions were defined on sonography and TOF-MRA. Stenoses were classified according to the NASCET criteria. Infarct lesions and perfusion deficits were defined on FLAIR and DSC-MR imaging, respectively. Individual perfusion patterns were defined on the superselective pseudocontinuous arterial spin-labeling maps and were correlated with vascular anatomy and infarct lesion localization.

RESULTS

The superselective pseudocontinuous arterial spin-labeling imaging sequence could be readily applied by trained technicians, and the additional scan time of 12.7 minutes was well-tolerated by patients. The detected vessel occlusions/stenoses and perfusion patterns corresponded between cerebral DSA and superselective pseudocontinuous arterial spin-labeling maps in all cases. Perfusion deficits on DSC-CBF maps significantly correlated with those on superselective pseudocontinuous arterial spin-labeling maps (Pearson r = 0.9593, P < .01). Individual collateral recruitment patterns were not predictable from the vascular anatomy in 71% of our patients.

CONCLUSIONS

Superselective pseudocontinuous arterial spin-labeling is a robust technique for regional brain perfusion imaging, suitable for the noninvasive diagnostics of individual perfusion patterns in patients with complex cerebrovascular disease.

Measurement of Coherent π^{+} Production in Low Energy Neutrino-Carbon Scattering

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

Measurement of Muon Antineutrino Oscillations with an Accelerator-Produced Off-Axis Beam

T2K reports its first measurements of the parameters governing the disappearance of ν[over ¯]_{μ} in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν[over ¯]_{μ} beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν[over ¯]_{μ} survival probability is expected to be minimal. Using a data set corresponding to 4.01×10^{20} protons on target, 34 fully contained μ-like events were observed. The best-fit oscillation parameters are sin^{2}(θ[over ¯]_{23})=0.45 and |Δm[over ¯]_{32}^{2}|=2.51×10^{-3}  eV^{2} with 68% confidence intervals of 0.38-0.64 and 2.26-2.80×10^{-3}  eV^{2}, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ν_{μ} disappearance parameters measured by T2K.

[Diffusion Weighted Magnetic Resonance Imaging and its Application in Ophthalmology]

The value of diffusion-weighted magnet resonance imaging (DWI-MRI) has been demonstrated for an ever growing range of clinical indications. DWI is sensitive to the diffusion of water molecules and probes their random displacement within tissue. DWI provides both qualitative and quantitative information on tissue characteristics, e.g. tissue cellularity. This review provides an overview of diffusion-weighted imaging and its emerging applications in ophthalmology. The basic physics and technical foundations of DWI are introduced. The emerging applications of DWI are surveyed, particularly in diseases of the eye, orbit and optical nerve.

Removal of Soluble Fms-Like Tyrosine Kinase-1 by Dextran Sulfate Apheresis in Preeclampsia

Preeclampsia is a devastating complication of pregnancy. Soluble Fms-like tyrosine kinase-1 (sFlt-1) is an antiangiogenic protein believed to mediate the signs and symptoms of preeclampsia. We conducted an open pilot study to evaluate the safety and potential efficacy of therapeutic apheresis with a plasma-specific dextran sulfate column to remove circulating sFlt-1 in 11 pregnant women (20-38 years of age) with very preterm preeclampsia (23-32 weeks of gestation, systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, new onset protein/creatinine ratio >0.30 g/g, and sFlt-1/placental growth factor ratio >85). We evaluated the extent of sFlt-1 removal, proteinuria reduction, pregnancy continuation, and neonatal and fetal safety of apheresis after one (n=6), two (n=4), or three (n=1) apheresis treatments. Mean sFlt-1 levels were reduced by 18% (range 7%-28%) with concomitant reductions of 44% in protein/creatinine ratios. Pregnancy continued for 8 days (range 2-11) and 15 days (range 11-21) in women treated once and multiple times, respectively, compared with 3 days (range 0-14) in untreated contemporaneous preeclampsia controls (n=22). Transient maternal BP reduction during apheresis was managed by withholding pre-apheresis antihypertensive therapy, saline prehydration, and reducing blood flow through the apheresis column. Compared with infants born prematurely to untreated women with and without preeclampsia (n=22 per group), no adverse effects of apheresis were observed. In conclusion, therapeutic apheresis reduced circulating sFlt-1 and proteinuria in women with very preterm preeclampsia and appeared to prolong pregnancy without major adverse maternal or fetal consequences. A controlled trial is warranted to confirm these findings.

A Short Introduction to Arterial Spin Labeling and its Application to Flow Territory Mapping

Arterial spin labeling (ASL) is an emerging method for the assessment of perfusion in various diseases of the brain. In ASL, the magnetization of arterial blood water spins is manipulated in a complete non-invasive way before flowing into the tissue of interest. This allows absolute quantification of cerebral blood flow, thereby, presenting an alternative to contrast-enhanced methods based on computed tomography or magnetic resonance imaging. Furthermore, its potential application for flow territory mapping can provide additional information of the individual configuration of intracerebral blood flow. This article gives a brief overview of the basic ASL methodology and its approaches to image individual perfusion territories. Additionally, the utilization of ASL in a variety of cerebrovascular diseases is presented to provide examples of potential applications of (territorial) ASL in clinical routine.

Measurement of the inclusive electron neutrino charged current cross section on carbon with the T2K near detector

The T2K off-axis near detector ND280 is used to make the first differential cross-section measurements of electron neutrino charged current interactions at energies ∼1  GeV as a function of electron momentum, electron scattering angle, and four-momentum transfer of the interaction. The total flux-averaged ν(e) charged current cross section on carbon is measured to be ⟨σ⟩(ϕ)=1.11±0.10(stat)±0.18(syst)×10⁻³⁸ cm²/nucleon. The differential and total cross-section measurements agree with the predictions of two leading neutrino interaction generators, NEUT and GENIE. The NEUT prediction is 1.23×10⁻³⁸ cm²/nucleon and the GENIE prediction is 1.08×10⁻³⁸ cm²/nucleon. The total ν(e) charged current cross-section result is also in agreement with data from the Gargamelle experiment.

[In vivo MR microscopy of the human eye]

MR microscopy using an ultra high-field MR system is a novel non-invasive imaging technique to explore the human eye without optical distortions. This review aims to provide an insight into the technique. Normal MR microscopic anatomy of the human eye in vivo is demonstrated and clinical applications of MR microscopy are discussed.

Precise measurement of the neutrino mixing parameter θ23 from muon neutrino disappearance in an off-axis beam

New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57×10(20) protons on target, T2K has fit the energy-dependent νμ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin(2)(θ23) is 0.514(-0.056)(+0.055) (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm32(2)=(2.51±0.10)×10(-3)  eV(2)/c(4) (inverted hierarchy: Δm13(2)=(2.48±0.10)×10(-3)  eV(2)/c(4)). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.

Observation of electron neutrino appearance in a muon neutrino beam

The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm(32)(2) and a CP violating phase δ(CP). In this neutrino oscillation scenario, assuming |Δm(32)(2)|=2.4×10(-3)  eV(2), sin(2)θ(23)=0.5, and Δm322>0 (Δm(32)(2)<0), a best-fit value of sin(2)2θ(13)=0.140(-0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at δ(CP)=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ(13) from reactor experiments, some values of δ(CP) are disfavored at the 90% C.L.

Requirement for a structured algorithm in cardiac arrest following major trauma: epidemiology, management errors, and preventability of traumatic deaths in Berlin

BACKGROUND

Despite continuous innovation in trauma care, fatal trauma remains a significant medical and socioeconomic problem. Traumatic cardiac arrest (tCA) is still considered a hopeless situation, whereas management errors and preventability of death are neglected. We analyzed clinical and autopsy data from tCA patients in an emergency-physician-based rescue system in order to reveal epidemiologic data and current problems in the successful treatment of tCA.

MATERIAL AND METHODS

Epidemiological and autopsy data of all unsuccessful tCPR cases in a one-year-period in Berlin, Germany (n=101, Group I) and clinical data of all cases of tCPR in a level 1 trauma centre in an 6-year period (n=52, Group II) were evaluated. Preventability of traumatic deaths in autopsy cases (n=22) and trauma-management failures were prospectively assessed.

RESULTS

In 2010, 23% of all traumatic deaths in Berlin received tCPR. Death after tCPR occurred predominantly prehospital (PH;74%) and only 26% of these patients were hospitalized. Of 52 patients (Group II), 46% required tCPR already PH and 81% in the emergency department (ED). In 79% ROSC was established PH and 53% in the ED. The survival rate after tCPR was 29% with 27% good neurological outcome. Management errors occurred in 73% PH; 4 cases were judged as potentially or definitive preventable death.

CONCLUSION

Trauma CPR is beyond routine with the need for a tCPR-algorithm, including chest/pericardial decompression, external pelvic stabilization and external bleeding control. The prehospital trauma management has the highest potential to improve tCPR and survival. Therefore, we suggested a pilot prehospital tCPR-algorithm.