Differences in beginner and expert neurointerventionalists" heart rate variability during simulated neuroangiographies.

BACKGROUND: Likewise work experience, heart rate variability (HRV) has repeatedly been correlated with improved performance under real life and simulator conditions. Using HRV as a correlate of workload, it is meaningful to assess the impact of work experience. To understand the impact of work experience on HRV metrics, we examined differences in HRV among experts and beginners during simulated endovascular neuroradiological procedures. METHODS: Six inexperienced radiologists (beginners) and five experts in neurological endovascular intervention each performed 10 diagnostic angiographies on a Vascular Interventional System Trainer (VIST) simulator (Mentice AB, SW). Beyond total time, fluoroscopy time, and amount of contrast medium used, heart rate variability and the NASA-task load index were gathered as correlates of workload. The t-Test for independent samples as well as Mann-Whitney-U tests were applied for group-wise comparison between beginners and experts. Multivariate regression was used to assess the influence of age and expert status. RESULTS: Ten participants completed all scenarios; one participant only completed the first five scenarios. Accordingly, 105 simulations were analyzed (beginners N = 60; experts N = 45, respectively). The heart rate variability of experts and beginners significantly differed in three time domain HRV metrics (decreased RMSSD, NN50, pNN50 in experts; all p < 0.05) as well as with respect to its distribution in the frequency spectrum (LF/HF ratio; p < 0.001, increased high frequency components in experts). CONCLUSIONS: The HRV of beginners and expert neurointerventionalists significantly differed during simulated endovascular neuroradiological procedures. Experts presented decreased HRV, this could be a cardiovascular surrogate to the effort the subjects expend on their performance. It is in line with previous studies on vagal influences on the heart and cognitive-executive performance.

Dual-Layer Spectral Detector CT in Comparison with FDG-PET/CT for the Assessment of Lymphoma Activity.

PURPOSE: In patients with malignant lymphoma, disease activity is recommended to be assessed by FDG-PET/CT and the Deauville five-point scale (5-PS). The purpose of this study was to explore the potential of iodine concentration measured in contrast-enhanced dual-layer spectral detector CT (SDCT) as an alternative surrogate parameter for lymphoma disease activity by investigating its correlation with maximum standardized uptake values (SUVmax) and 5-PS. MATERIALS AND METHODS: 25 patients were retrospectively analyzed. Contrast-enhanced SDCT and FDG-PET/CT were performed in the same treatment interval within at most 3 months. CT attenuation values (AV), absolute iodine concentrations (aIC), and normalized iodine concentrations (nIC) of lymphoma lesions were correlated with SUVmax using Spearman's rank correlation coefficient. The performance of aIC and nIC to detect lymphoma activity (defined as 5-PS > 3) was determined using ROC curves. RESULTS: 60 lesions were analyzed, and 31 lesions were considered active. AV, aIC, and nIC all correlated significantly with SUVmax. The strongest correlation (Spearman ρ = 0.71; p < 0.001) and highest area under the ROC curve (AUROC) for detecting lymphoma activity were observed for nIC normalized to inferior vena cava enhancement (AUROC = 0.866). The latter provided sensitivity, specificity, and diagnostic accuracy of 87 %, 75 %, and 80 %, respectively, at a threshold of 0.20. ROC analysis for AV (AUROC = 0.834) and aIC (AUROC = 0.853) yielded similar results. CONCLUSION: In malignant lymphomas, there is a significant correlation between metabolic activity as assessed by FDG-PET/CT and iodine concentration as assessed by SDCT. Iodine concentration shows promising diagnostic performance for detecting lymphoma activity and may represent a potential imaging biomarker. KEY POINTS: · Iodine concentration correlates significantly with SUVmax in lymphoma patients. · Iodine concentration may represent a potential imaging biomarker for detecting lymphoma activity. · Normalization of iodine concentration improves diagnostic performance of iodine concentration. CITATION FORMAT: · Gehling K, Mokry T, Do TD et al. Dual-Layer Spectral Detector CT in Comparison with FDG-PET/CT for the Assessment of Lymphoma Activity. Fortschr Röntgenstr 2022; 194: 747 - 754.

Simulation Training in Neuroangiography-Validation and Effectiveness.

PURPOSE: Simulators are increasingly used in the training of endovascular procedures; however, for the use of the Mentice vascular interventional system trainer (VIST) simulator in neuroradiology, the validity of the method has not yet been proven. The study was carried out to test the construct validity of such a simulator by demonstrating differences between beginner and expert neurointerventionalists and to evaluate whether a training effect can be demonstrated in repeated cases for different levels of experience. METHODS: In this study 4 experts and 6 beginners performed 10 diagnostic angiographies on the VIST simulator (Mentice AB, Gothenburg, Sweden). Of the cases four were non-recurring, whereas three were repeated once and ten subjects performed all tasks. Additionally, another expert performed only five non-recurring cases. The simulator recorded total time, fluoroscopy time, amount of contrast medium and number of material changes. Furthermore, gaze direction and heart rate were recorded, and subjects completed a questionnaire on workload. RESULTS: Beginners and experts showed significant differences in total duration time, fluoroscopy time and amount of contrast agent (all p < 0.05). Gaze direction, dwell time and heart rate were similar between both groups. Only beginners improved during training with respect to total duration time, fluoroscopy time and amount of contrast agent. If a case was previously known to them, the total duration and fluoroscopy time were significantly shortened (p < 0.001). CONCLUSION: This study demonstrated both the construct validity of a diagnostic neuroangiography simulator as well as a significant training effect for beginners. Therefore, in particular beginner neurointerventionalists should use such simulation tools more extensively in their initial training.

Simulation Training in Neuroangiography: Transfer to Reality.

PURPOSE: Endovascular simulation is an established and validated training method, but there is still no proof of direct patient's benefit, defined as lower complication rate. In this study, the impact of such a training was investigated for rehearsal of patient-specific cases as well as for a structured simulation curriculum to teach angiographer novices. MATERIALS AND METHODS: A total of 40 patients undergoing a diagnostic neuroangiography were randomized in a training and control group. In all training group patients, the angiographer received a patient-anatomy-specific rehearsal on a high-fidelity simulator prior to the real angiography. Radiation exposure, total duration, fluoroscopy time and amount of contrast agent of the real angiography were recorded. Silent cerebral ischemia was counted by magnetic resonance diffusion-weighted imaging (DWI). Additionally, the first 30 diagnostic neuroangiographies of six novices were compared (ntotal = 180). Three novices had undergone a structured simulation curriculum; three had acquired angiographic skills without simulation. RESULTS: No differences were found in the number of DWI lesions or in other quality measures of the angiographies performed with and without patient-specific rehearsal. A structured simulation curriculum for angiographer novices reduced fluoroscopy time significantly and radiation exposure. The curriculum had no influence on the total duration of the examination, the amount of contrast medium or the number of catheters used. CONCLUSION: There was no measurable benefit of patient-anatomy-specific rehearsal for an unselected patient cohort. A structured simulation-based curriculum to teach angiographic skills resulted in a reduction of fluoroscopy time and radiation dose in the first real angiographies of novice angiographers. LEVEL OF EVIDENCE: Level 4, part 1: randomized trial, part 2: historically controlled study.

Simulation in Angiography - Experiences from 5 Years Teaching, Training, and Research. / Simulation in der Angiografie ­ Erfahrungen aus 5 Jahren Lehre, Ausbildung und Forschung.

PURPOSE: The example of university radiology/neuroradiology illustrates how high-tech angiography simulators can be used meaningfully in teaching, clinical training and research. MATERIALS AND METHODS/TECHNICAL BASICS: A VIST LAB simulator (Mentice, Gothenburg, Sweden), which has been continuously developed both in terms of software and hardware, has been in use since 2013. Recently, the simulator has been integrated into the angiography suite Azurion (Philips, Amsterdam, Netherlands). RESULTS/AREAS OF APPLICATION: In student education there is the possibility for intensive examination of cerebrovascular diseases and their therapy in small group lessons. The training of beginners in diagnostic and interventional angiography begins mandatorily on the simulator. Research questions are the proof of validity and the training effect, but also the influence on patient safety and the possible cost reduction of an intervention. CONCLUSION: As a result of continuous further development in recent years, simulators are now very well suited for both student teaching and beginner medical training. In the future, even experienced interventionalists could benefit from further technical advances, which should also be driven by academic research. Possible effects would be the reduction of examination times, complications and costs. KEY POINTS: · Angiography simulators are useful in teaching students, medical training and research.. · Linking a simulator to an angiography suite increases the degree of reality even further.. · Real patient cases can be practiced and thus patient safety can be increased.. · Future developments should also increase the benefit for experienced interventionalists.. · Integration of simulators into certification programs (e. g. DEGIR) is to be targeted in the future.. CITATION FORMAT: · Kreiser K, Gehling K, Zimmer C. Simulation in Angiography - Experiences from 5 Years Teaching, Training, and Research. Fortschr Röntgenstr 2019; 191: 547 - 552.