Das Schülerlabor als Ort authentischer Wissenschaftsvermittlung? Entwicklung und Validierung eines Fragebogens zur Erfassung der Authentizitätswahrnehmung der Wissenschaftsvermittlung im Schülerlabor

Im vorliegenden Beitrag wird ein Fragebogen zur mehrdimensionalen Erfassung der Wahrnehmung von Authentizität in der Wissenschaftsvermittlung (FEWAW) vorgestellt. Die Entwicklung des Messinstruments mit den Authentizitätsdimensionen Vermittler, Ort, Vorgehen und Innovation erfolgte auf der Grundlage theoretischer Modelle zur Wahrnehmung von Authentizität der Wissenschaftsvermittlung. In einer Validierungsstudie mit N = 337 Schülerinnen und Schülern im Alfried Krupp-Schülerlabor der Ruhr-Universität Bochum konnte die faktorielle Struktur mittels konfirmatorischer Faktorenanalysen bestätigt werden. Die internen Konsistenzen der vier Dimensionen sind zufriedenstellend (Cronbachs α ≥ 0,81). Außerdem konnte die Messinvarianz des Instruments für das Geschlecht sowie die Klassenstufe bestätigt werden. Die Zusammenhänge der Authentizitätsdimensionen mit Außenkriterien, wie z. B. epistemologischen Überzeugungen, liefern weitere Hinweise auf die Validität des Messinstruments. Insgesamt stellt der FEWAW ein geeignetes Instrument für die mehrdimensionale Erfassung der Authentizitätswahrnehmung in der Wissenschaftsvermittlung dar.

Rise of extremity fractures and sport accidents in children at 8-12 years and increase of admittance via the resuscitation room over a decade

Introduction

In an emergency department, the majority of pediatric trauma patients present because of minor injuries. The aim of this study was to evaluate temporal changes in age-related injury pattern, trauma mechanism, and surgeries in pediatric patients.

Methods

This retrospective study included patients < 18 years of age following trauma from 01/2009 to 12/2018 at a level I trauma center. They were divided into two groups: group A (A: 01/2009 to 12/2013) and group B (B: 01/2014 to 12/2018). Injury mechanism, injury pattern, and surgeries were analyzed. As major injuries fractures, dislocations, and organ injuries and as minor injuries contusions and superficial wounds were defined.

Results

23,582 patients were included (58% male, median age 8.2 years).

There was a slight increase in patients comparing A (n = 11,557) and B (n = 12,025) with no difference concerning demographic characteristics.

Significant more patients (A: 1.9%; B: 2.4%) were admitted to resuscitation room, though the number of multiple injured patients was not significantly different.

In A (25.5%), major injuries occurred significantly less frequently than in B (27.0%), minor injuries occurred equally. Extremity fractures were significantly more frequent in B (21.5%) than in A (20.2%), peaking at 8–12 years.

Most trauma mechanisms of both groups were constant, with a rising of sport injuries at 8–12 years.

Conclusion

Although number of patients increases only slightly over a decade, there was a clear increase in major injuries, particularly extremity fractures, peaking at 8–12 years. At this age also sport accidents significantly increased.

At least, admittance to resuscitation room rose but without an increase of multiple injured patients.

Correction of Motion Artifacts Using a Multiscale Fully Convolutional Neural Network

BACKGROUND AND PURPOSE

Motion artifacts are a frequent source of image degradation in the clinical application of MR imaging (MRI). Here we implement and validate an MRI motion-artifact correction method using a multiscale fully convolutional neural network.

MATERIALS AND METHODS

The network was trained to identify motion artifacts in axial T2-weighted spin-echo images of the brain. Using an extensive data augmentation scheme and a motion artifact simulation pipeline, we created a synthetic training dataset of 93,600 images based on only 16 artifact-free clinical MRI cases. A blinded reader study using a unique test dataset of 28 additional clinical MRI cases with real patient motion was conducted to evaluate the performance of the network.

RESULTS

Application of the network resulted in notably improved image quality without the loss of morphologic information. For synthetic test data, the average reduction in mean squared error was 41.84%. The blinded reader study on the real-world test data resulted in significant reduction in mean artifact scores across all cases (P < .03).

CONCLUSIONS

Retrospective correction of motion artifacts using a multiscale fully convolutional network is promising and may mitigate the substantial motion-related problems in the clinical MRI workflow.

A simulation platform using 3D printed neurovascular phantoms for clinical utility evaluation of new imaging technologies

Modern 3D printing technology allows rapid prototyping of vascular phantoms based on an actual human patient with a high degree of precision. Using this technology, we present a platform to accurately simulate clinical views of neuro-endovascular interventions and devices. The neuro-endovascular interventional phantom has a 3D printed cerebrovasculature model derived from a patient CT angiogram and embedded inside a human skull providing bone attenuation. Acrylic layers were placed underneath and on top of the skull, simulating entrance and exit tissue attenuation and also simulating forward scatter. The 3D model was connected to a pulsatile flow loop for simulating interventions using clinical devices such as catheters and stents. To validate the x-ray attenuation and establish clinical accuracy, the automatic exposure selection by a clinical c-arm system for the phantom was compared with that for a commercial anthropomorphic head phantom (SK-150, Phantom Labs). The percentage difference between automatic exposure selection for the neuro-intervention phantom and the SK-150 phantom was under 10%. By changing 3D printed models, various patient diseased anatomies can be simulated accurately with the necessary x-ray attenuation. Using this platform various interventional procedures were performed using new imaging technologies such as a high-resolution x-ray fluoroscope and a dose-reduced region-of-interest attenuator and differential temporally filtered display for enhanced interventional imaging. Simulated clinical views from such phantom-based procedures were used to evaluate the potential clinical performance of such new technologies.

High energy probe for detecting lymph node metastases with 18F-FDG in patients with head and neck cancer

Aim of this study was to validate a newly developed high energy probe (positron emission probe, PEP) optimised for localising PET tracers in vivo. Patients and methods: Physical investigations included determination of full width at half maximum (FWHM) values at a distance of 1 cm and angular resolution using different point sources. Values obtained with the new probe were compared to those of a conventional gamma probe (CGP). Additionally, PET studies were performed in 36 patients (6 women, 30 men) with proven head and neck cancer and suspected lymph node metastases (Axis, Marconi/Philips) after administering 250–320 MBq 18F-FDG. Subsequent to PET investigations 18F-FDG uptake in cervical regions was measured using the PEP. PEP investigations were carried out bilaterally in 5 lymph node (LN) levels (Robbins’ classification of the neck). Results of probe studies were correlated with visual and semiquantitative PET evaluations, US and histological findings. Results: FWHM of the new probe was 7 mm (CGP 22 mm) at 662 keV (137Cs) and angular resolution resulted in 8° (CGP 60°). In 29 out of 36 patients LN metastases were suspected due to ultrasound investigations. After neck dissection, histology confirmed LN metastases in 21 patients. Sensitivity (sens.) of US amounted to 95% and specificity to 40%. In 18/21 patients LN metastases were detected by PET (sens. 86%). PET scans failed to diagnose the LN status correctly in 6/36 patients (accuracy 83%). Employing the PEP probe in 20/21 patients LN metastases were identified (sens. 95%), and LN status was determined accurately in 29/36 patients (accuracy 81%). Tumour/ background ratios of PEP measurement and results of semiquantitative PET analyses were comparable. Conclusions: PEP measurement is a promising method for preoperative planning of the extent of neck dissection in patients with head and neck cancer and further for radioguided localising PET tracer accumulation during surgery.

Towards predicting the encoding capability of MR fingerprinting sequences

Sequence optimization and appropriate sequence selection is still an unmet need in magnetic resonance fingerprinting (MRF). The main challenge in MRF sequence design is the lack of an appropriate measure of the sequence's encoding capability. To find such a measure, three different candidates for judging the encoding capability have been investigated: local and global dot-product-based measures judging dictionary entry similarity as well as a Monte Carlo method that evaluates the noise propagation properties of an MRF sequence. Consistency of these measures for different sequence lengths as well as the capability to predict actual sequence performance in both phantom and in vivo measurements was analyzed. While the dot-product-based measures yielded inconsistent results for different sequence lengths, the Monte Carlo method was in a good agreement with phantom experiments. In particular, the Monte Carlo method could accurately predict the performance of different flip angle patterns in actual measurements. The proposed Monte Carlo method provides an appropriate measure of MRF sequence encoding capability and may be used for sequence optimization.

Magnetic Resonance Fingerprinting with short relaxation intervals

PURPOSE

The aim of this study was to investigate a technique for improving the performance of Magnetic Resonance Fingerprinting (MRF) in repetitive sampling schemes, in particular for 3D MRF acquisition, by shortening relaxation intervals between MRF pulse train repetitions.

MATERIAL AND METHODS

A calculation method for MRF dictionaries adapted to short relaxation intervals and non-relaxed initial spin states is presented, based on the concept of stationary fingerprints. The method is applicable to many different k-space sampling schemes in 2D and 3D. For accuracy analysis, T₁ and T₂ values of a phantom are determined by single-slice Cartesian MRF for different relaxation intervals and are compared with quantitative reference measurements. The relevance of slice profile effects is also investigated in this case. To further illustrate the capabilities of the method, an application to in-vivo spiral 3D MRF measurements is demonstrated.

RESULTS

The proposed computation method enables accurate parameter estimation even for the shortest relaxation intervals, as investigated for different sampling patterns in 2D and 3D. In 2D Cartesian measurements, we achieved a scan acceleration of more than a factor of two, while maintaining acceptable accuracy: The largest T₁ values of a sample set deviated from their reference values by 0.3% (longest relaxation interval) and 2.4% (shortest relaxation interval). The largest T₂ values showed systematic deviations of up to 10% for all relaxation intervals, which is discussed. The influence of slice profile effects for multislice acquisition is shown to become increasingly relevant for short relaxation intervals. In 3D spiral measurements, a scan time reduction of 36% was achieved, maintaining the quality of in-vivo T1 and T2 maps.

CONCLUSIONS

Reducing the relaxation interval between MRF sequence repetitions using stationary fingerprint dictionaries is a feasible method to improve the scan efficiency of MRF sequences. The method enables fast implementations of 3D spatially resolved MRF.

Clinical outcome after alternative treatment of scaphoid fractures and nonunions

PURPOSE

Achieving stable fixation of scaphoid fractures and nonunions continues to be a challenge. Compression screw fixation has been the current standard surgical procedure. However, in some cases, bone healing cannot be achieved and requires further revision. Recent series reintroduced volar plating as valid option for stable fixation. The aim of the study was to review clinical outcome of alternative scaphoid treatment.

METHODS

From 2011 to 2014, nine patients with scaphoid fracture were treated by Headless Compression Screw (HCS) and seven patients with scaphoid nonunion by HCS or volar mini condylar plate with bone graft. The average age was 34.4 years and the average time to follow-up was 19.3 months. From 1996 to 1998, 38 patients with scaphoid nonunion were treated using compression screw (S-group) or volar mini condylar plate (P-group) with bone graft. The average age was 39.6 years and the average time to follow-up was 26.2 months.

RESULTS

The union rate was 100%. For scaphoid fractures, the mean Modified Mayo Wrist Score (MMWS) was 94.1 and the DASH score 7.4. From 2011 to 2014, the MMWS was 87.9 and the DASH score 7 in scaphoid nonunions. In the period between 1996 and 1998, the MMWS was 67.2 in the P-group and 58.6 in the S-group, and the DASH score 16.8 and 28.2.

CONCLUSIONS

Our study demonstrated that appropriate application of the HCS was able to produce very satisfactory results in scaphoid fractures and nonunions. In our opinion, however, the method of scaphoid plate osteosynthesis can achieve a higher degree of stability, particularly rotational stability, in case of multifragmentary avascular scaphoid nonunions.

Acute adrenal insufficiency: an aide-memoire of the critical importance of its recognition and prevention

Adrenal crisis is a life-threatening emergency that causes significant excess mortality in patients with adrenal insufficiency. Delayed recognition by medical staff of an impending adrenal crisis and failure to give timely hydrocortisone therapy within the emergency department continue to be commonly encountered, even in metropolitan teaching hospitals. Within the authors' institutions, several cases of poorly handled adrenal crises have occurred over the last 2 years. Anecdotal accounts from members of the Addison's support group suggest that these issues are common in Australia. This manuscript is a timely reminder for clinical staff on the critical importance of the recognition, treatment and prevention of adrenal crisis. The manuscript: (i) outlines a case and the clinical outcome of sub-optimally managed adrenal crisis, (ii) summarises the clinical features and acute management of adrenal crisis, (iii) provides recommendations on the prevention of adrenal crisis and (iv) provides guidance on the management of 'sick days' in patients with adrenal insufficiency.

Resting myocardial blood flow quantification using contrast-enhanced magnetic resonance imaging in the presence of stenosis: A computational fluid dynamics study

PURPOSE

The extent to which atherosclerotic plaques affect contrast agent (CA) transport in the coronary arteries and, hence, quantification of myocardial blood flow (MBF) using magnetic resonance imaging (MRI) is unclear. The purpose of this work was to evaluate the influence of plaque induced stenosis both on CA transport and on the accuracy of MBF quantification.

METHODS

Computational fluid dynamics simulations in a high-detailed realistic vascular model were employed to investigate CA bolus transport in the coronary arteries. The impact of atherosclerosis was analyzed by inserting various medium- to high-grade stenoses in the vascular model. The influence of stenosis morphology was examined by varying the stenosis shapes but keeping the area reduction constant. Errors due to CA bolus transport were analyzed using the tracer-kinetic model MMID4.

RESULTS

Dispersion of the CA bolus was found in all models and for all outlets, but with a varying magnitude. The impact of stenosis was complex: while high-grade stenoses amplified dispersion, mild stenoses reduced the effect. Morphology was found to have a marked influence on dispersion for a small number of outlets in the post-stenotic region. Despite this marked influence on the concentration-time curves, MBF errors were less affected by stenosis. In total, MBF was underestimated by -7.9% to -44.9%.

CONCLUSIONS

The presented results reveal that local hemodynamics in the coronary vasculature appears to have a direct impact on CA bolus dispersion. Inclusion of atherosclerotic plaques resulted in a complex alteration of this effect, with both degree of area reduction and stenosis morphology affecting the amount of dispersion. This strong influence of vascular transport effects impairs the accuracy of MRI-based MBF quantification techniques and, potentially, other bolus-based perfusion measurement techniques like computed tomography perfusion imaging.

Local hyperthermia, hyperfractionated radiation, and cisplatin in preirradiated recurrent lymph node metastases of recurrent head and neck cancer

Large tumor size is a negative prognostic variable for attaining complete regression (CR) with local hyperthermia (HT) and radiotherapy (RT). Such poor prognosis lesions (i.e., >7 cm(2) or >14 cm(3)) have an expected CR rate of similar to 30+/-8%. To improve on this result we added cisplatin to HT and RT with standard fractionation (std Fx) in an earlier study, and observed a 19% CR rate in head and neck (H&N) patients. We now report the results of a second generation trial combining HT, cisplatin (40 mg/m(2)) and hyperfractionated RT in a series of 13 pretreated poor prognosis H&N patients. Therapy encompassed 44 triple modality sessions and was well tolerated: toxicity included one episode of grade-3 skin reaction and one grade 1 leukopenia. Although the overall remission rate was 92%, the CR rate was only 8%; this resulted in early closure of this trial concluding that hyperfractionated RT had no (over std Fx RT) benefit in this combined modality approach.

Toward online reconstruction of quantitative susceptibility maps: superfast dipole inversion

Magnetic susceptibility is an intrinsic tissue property that recently became measureable in vivo by a magnetic-resonance based technique called quantitative susceptibility mapping (QSM). Although QSM may be performed without additional acquisition time, for example, in the course of the well-established susceptibility weighted imaging, the applicability of QSM is currently hampered by the numerical complexity and computational cost associated with the reconstruction procedure. This work introduces a novel QSM framework called superfast dipole inversion which allows rapid online reconstruction of susceptibility maps from wrapped raw gradient-echo phase data. The algorithm relies on the extension and combination of several recent algorithms involving the precalculation of convolution kernels and the correction of inversion artifacts. Reconstruction of three-dimensional high resolution susceptibility maps of the human brain was achieved with superfast dipole inversion in less than 20 s on a conventional workstation computer. Thus, superfast dipole inversion opens the door to an implementation of QSM on MR scanner hardware as well as to the routine reconstruction of large cohorts of datasets.

Quantitative susceptibility mapping for investigating subtle susceptibility variations in the human brain

Quantitative susceptibility mapping (QSM) is a novel magnetic resonance-based technique that determines tissue magnetic susceptibility from measurements of the magnetic field perturbation. Due to the ill-posed nature of this problem, regularization strategies are generally required to reduce streaking artifacts on the computed maps. The present study introduces a new algorithm for calculating the susceptibility distribution utilizing a priori information on its regional homogeneity derived from gradient echo phase images and analyzes the impact of erroneous a priori information on susceptibility map fidelity. The algorithm, Homogeneity Enabled Incremental Dipole Inversion (HEIDI), was investigated with a special focus on the reconstruction of subtle susceptibility variations in a numerical model and in volunteer data and was compared with two recently published approaches, Thresholded K-space Division (TKD) and Morphology Enabled Dipole Inversion (MEDI). HEIDI resulted in susceptibility maps without streaking artifacts and excellent depiction of subtle susceptibility variations in most regions. By investigating HEIDI susceptibility maps acquired with the volunteers' heads in different orientations, it was demonstrated that the apparent magnetic susceptibility distribution of human brain tissue considerably depends on the direction of the main magnetic field.

Quantitative susceptibility mapping (QSM) as a means to measure brain iron? A post mortem validation study

Quantitative susceptibility mapping (QSM) is a novel technique which allows determining the bulk magnetic susceptibility distribution of tissue in vivo from gradient echo magnetic resonance phase images. It is commonly assumed that paramagnetic iron is the predominant source of susceptibility variations in gray matter as many studies have reported a reasonable correlation of magnetic susceptibility with brain iron concentrations in vivo. Instead of performing direct comparisons, however, all these studies used the putative iron concentrations reported in the hallmark study by Hallgren and Sourander (1958) for their analysis. Consequently, the extent to which QSM can serve to reliably assess brain iron levels is not yet fully clear. To provide such information we investigated the relation between bulk tissue magnetic susceptibility and brain iron concentration in unfixed (in situ) post mortem brains of 13 subjects using MRI and inductively coupled plasma mass spectrometry. A strong linear correlation between chemically determined iron concentration and bulk magnetic susceptibility was found in gray matter structures (r = 0.84, p < 0.001), whereas the correlation coefficient was much lower in white matter (r = 0.27, p < 0.001). The slope of the overall linear correlation was consistent with theoretical considerations of the magnetism of ferritin supporting that most of the iron in the brain is bound to ferritin proteins. In conclusion, iron is the dominant source of magnetic susceptibility in deep gray matter and can be assessed with QSM. In white matter regions the estimation of iron concentrations by QSM is less accurate and more complex because the counteracting contribution from diamagnetic myelinated neuronal fibers confounds the interpretation.

[Skeletal tuberculosis of the distal radius during pregnancy]

We present a case of a pregnant woman (32nd gestational week) that suffered from a chronic non-healing wound at the distal radius. Skeletal tuberculosis was finally diagnosed and treated successfully with staged surgical therapy combined with appropriate medication. One year after surgical treatment, the outcome of the mother was excellent and the baby did not suffer from any disease related to operative procedures or pharmacotherapy. Operative treatment of skeletal tuberculosis (especially osteoarticular and vertebral tuberculosis) in combination with tuberculostatic therapy during pregnancy and lactation seem to be the appropriate treatment with minimal risk for the child and excellent outcome for the mother.