Comparison of artery diameters in the Aachen minipig serving as a human intracranial in vivo model.

Minipigs are used as in vivo endovascular models, particularly in stroke and aneurysm research. However, detailed knowledge of the diameters of forelimb arteries that are commonly used as surrogates for human brain-supplying arteries are lacking. This study aimed to determine the diameters of forelimb and neck arteries in Aachen minipigs and to compare those to the diameters of human cerebral brain-supplying arteries in order to assess the validity of the Aachen minipig as a human intracranial in vivo model. We measured the diameters in the external carotid artery and eight different branches of the subclavian artery in 12 Aachen minipigs using angiographic imaging. Analysed arteries comprised the external carotid artery, axillary artery, brachial artery, subscapular artery first segment, subscapular artery second segment, external thoracic artery, caudal circumflex humeral artery, suprascapular artery and thoracodorsal artery. We compared these diameters to diameters of the following human brain-supplying arteries: terminal internal carotid artery (carotid-T and petrous segment), M1 segment of the middle cerebral artery, M2 segments of the middle cerebral artery, anterior cerebral artery, vertebral artery and basilar artery. Median diameters of porcine forelimb arteries ranged from 1.8 to 4.9 mm, and human brain supplying arteries ranged in diameter from 1.4 to 4.3 mm. Depending on the intended use, this allows porcine forelimb arteries to be selected which are statistically comparable to human brain-supplying vessels. In conclusion, we identified several equivalent arteries of the porcine subclavian branches that are comparable to human brain-supplying arteries. This may help to validate the minipig as a suitable in vivo model for neurovascular experiments.

Treatment practice of vasospasm during endovascular thrombectomy: an international survey.

BACKGROUND AND AIM: The clinical importance and management of vasospasm as a complication during endovascular stroke treatment (EVT) has not been well studied. We sought to investigate current expert opinions in neurointervention and therapeutic strategies of iatrogenic vasospasm during EVT. METHODS: We conducted an anonymous international online survey (4 April 2023 to 15 May 2023) addressing treatment standards of neurointerventionalists (NIs) practising EVT. Several illustrative cases of patients with vasospasm during EVT were shown. Two study groups were compared according to the NI's opinion regarding the potential influence of vasospasm on patient outcome after EVT using descriptive analysis. RESULTS: In total, 534 NI from 56 countries responded, of whom 51.5% had performed >200 EVT. Vasospasm was considered a complication potentially influencing the patient's outcome by 52.6% (group 1) whereas 47.4% did not (group 2). Physicians in group 1 more often added vasodilators to their catheter flushes during EVT routinely (43.7% vs 33.9%, p=0.033) and more often treated severe large-vessel vasospasm with vasodilators (75.3% vs 55.9%; p<0.001), as well as extracranial vasospasm (61.4% vs 36.5%, p<0.001) and intracranial medium-vessel vasospasm (27.1% vs 11.2%, p<0.001), compared with group 2. In case of a large-vessel vasospasm and residual and amenable medium-vessel occlusion during EVT, the study groups showed different treatment strategies. Group 2 continued the EVT immediately more often, without initiating therapy to treat the vasospasm first (9.6% vs 21.1%, p<0.001). CONCLUSION: There is disagreement among NIs about the clinical relevance of vasospasm during EVT and its management. There was a higher likelihood of use of preventive and active vasodilator treatment in the group that perceived vasospasm as a relevant complication as well as differing interventional strategies for continuing an EVT in the presence of a large-vessel vasospasm.

Platelet function testing using the Multiplate analyzer after administration of aspirin in Aachen minipigs.

Knowledge of platelet function in pigs and the effectiveness of antiplatelet therapy is important to ensure proper transferability from animal studies to humans. Our aim was to (1) characterize baseline platelet function of Aachen minipigs using the bedside Multiplate analyzer, (2) compare baseline platelet function with Göttingen minipigs, and (3) characterize platelet inhibition within the first 5 minutes after intravenous administration of acetylsalicylic acid (ASA). We characterized the baseline platelet function and hematological parameters in 9 Aachen minipigs. Historical data of 8 unmedicated Göttingen minipigs were used for comparison of baseline values. Platelet inhibition in Aachen minipigs was tested 1-5 minutes after intravenous administration of 500 mg ASA. Multiplate examinations included the following tests: ASPI test (to assess the effect of ASA), adenosine-diphosphate-test (ADP test) and thrombin receptor activating peptide test (TRAP test). Median values and interquartile range (IQR) of the Multiplate baseline tests in Aachen minipigs were as follows: ASPI: 39 U (IQR = 21-71), ADP: 70 U (IQR = 48-73), and TRAP: 8 U (IQR = 6-9), whereas the values in Göttingen minipigs were as follows: ASPI: 70.5 U (IQR = 60-78), ADP: 51 U (IQR = 45-66), and TRAP: 6.5 U (IQR = 4-8). ASPI values of Göttingen minipigs were significantly higher than those of Aachen minipigs (p = 0.046). Intravenous administration of ASA in Aachen minipigs resulted in significant platelet inhibition after 1 minute, which remained stable over a period of 5 minutes (p≤0.038). Aachen minipigs appeared to have a high variance in arachidonic acid-mediated platelet aggregation. In Aachen minipigs, intravenous ASA administration resulted in immediate platelet inhibition.

MRI appearance of chronic subdural hematoma.

Objective: We aimed to describe the magnetic resonance imaging (MRI) characteristics of chronic subdural hematoma (cSDH) and to ascribe MRI patterns. Methods: A total of 20 patients having 27 subdural hematomas underwent contrast-enhanced (CE) MRI of the brain at our institution between April 2019 and May 2021. The images were independently evaluated by two experienced neuroradiologists with regard to imaging characteristics on T1w, T2w, T2*-GRE, FLAIR, diffusion-weighted magnetic resonance imaging (DWI), and CE images. Results: The signal characteristics of cSDH on T1- and T2-weighted images were rather heterogeneous. The majority of hematomas (74%) had internal septations. Surprisingly, contrast enhancement along the outer membrane adjacent to the cranium was noticed in all hematomas. There was also contrast enhancement along the inner membrane adjacent to the brain in more than one-third of the hematomas (37%). In approximately two-thirds of the cSDH (62%), there was a mass-like enhancement of the hematoma. Most hematomas (89%) were partially hypointense on T2*-GRE and/or susceptibility-weighted imaging (SWI). Restricted diffusion was detected in approximately one-third of the hematomas (33%). Conclusion: Consistent contrast enhancement along the outer membrane, triangular-shaped contrast enhancement at the borders of the cSDH, and infrequent enhancement of the inner membrane may help to distinguish cSDH from other entities such as empyema and tumors. Mass-like enhancement may refer to non-solid hematomas and could be an indicator for hematoma growth and a possible surrogate for successful endovascular embolization. Restricted diffusion in a subdural mass is not specific for empyema but may also be found in cSDH.

Can training on ex-vivo models increase neurointerventionalists' subjective self-confidence in the operating room?

In a changing learning environment where young neurointerventionalists spend less time in the operating room, computer simulators have been established as a new training model. Our aim was the comparison of silicone models and computer simulators, and the evaluation of their influence on subjective self-confidence of operators. Pre- and postquestionnaires of 27 participants and 9 tutors were evaluated after the participation in a three-days interventional stroke course using silicone models and computer simulators. Training on computer simulators was considered as more realistic and important before patient contact than training on silicone models. Participants rated their own abilities as significantly better after participation in the course and felt significantly better prepared for patient care. Training on computer simulators can increase the subjective self-confidence of trainees. We suggest a stepwise training program, comprising both ex-vivo and the porcine in-vivo model, finished by conventional operating room teaching, to prepare neuroradiologists for optimal patient care when performing interventions.

Seeing faces, when faces can't be seen: Wearing portrait photos has a positive effect on how patients perceive medical staff when face masks have to be worn.

INTRODUCTION: Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, wearing surgical face masks has become mandatory for healthcare staff in many countries when interacting with patients. Recently, it has been shown that wearing face masks impairs social interaction by diminishing a person's ability to read the emotion of their counterparts, an essential prerequisite to respond adequately in social situations. It is easily conceivable that this may have a tangible negative influence on the communication and relationship between patients and healthcare personnel. We therefore investigated whether it has an effect on how patients perceive healthcare professionals when physicians and nursing staff wear portrait photos with their smiling faces in addition to face masks. METHODS: During the study period of 16 days, the medical staff of our Department wore surgical face masks at all times during any kind of interaction with patients. In a pseudorandomized order, all members of our staff additionally affixed their portrait photos to their work clothes on 8 of the 16 days. After completion of their visit, 226 patients were interviewed anonymously in a cross-sectional study design using a questionnaire in which they rated the following three items: friendliness of staff, medical quality of treatment, and how well they felt taken care of during treatment in our Department. RESULTS: On days, on which staff wore photos, mean scores of the questionnaires were significantly higher than on non-photo days (p = 0.013; mean ± standard deviation = 92.8 ± 11.3 vs. 91.0 ± 12.6; median (range) = 97 (98) vs. 96 (76)). When analyzed separately, the increased scores were only significant for the item friendliness of staff (p = 0.009; mean ± standard deviation = 95.8 ± 6.3 vs. 92.2 ± 11.5; median (range) = 98 (39) vs. 97 (54)). CONCLUSION: Our study suggests that the use of portrait photos with smiling faces has a positive effect on how patients perceive healthcare staff.

Work satisfaction among neuroradiology staff after receiving follow up reports of thrombectomy stroke patients.

BACKGROUND AND PURPOSE: During a period of 6 months, we provided our entire neuroradiological staff including physicians, radiographers, and researchers with systematic feedback via email on the further clinical course of stroke patients who underwent mechanical thrombectomy. We analyzed the effects of this feedback on work satisfaction, work meaningfulness and valuation of the therapy among our staff. METHODS: Our staff completed two self-reported questionnaires before and after the period of six months with systematic feedback. RESULTS: Employees with higher work meaningfulness and higher work satisfaction valuated endovascular stroke therapy as more useful (p<0.001). A good clinical outcome was regarded more motivating than a good interventional outcome (p<0.001). Receiving systematic feedback did not increase work satisfaction (p = 0.318) or work meaningfulness (p = 0.178). Radiographers valuated the usefulness of interventional therapy the worst of all employees (p≤ 0.017). After the feedback period, 75% of radiographers estimated stroke as a more severe disease than before. Also, their desire for feedback decreased significantly (p = 0.007). Primarily patient cases with unfavorable outcomes were remembered by the staff. CONCLUSIONS: Systematic email feedback does not per se enhance work satisfaction or work meaningfulness among employees. However, receiving feedback is educative for the staff. Evaluating work satisfaction and the perception of treatment may help to identify unexpected issues and may therefore help to find specific measures that increase work satisfaction and motivation.

Is the detectability of the spot sign on CT angiography depending on slice thickness and reconstruction type?

OBJECTIVE: The spot sign is a validated imaging marker widely used in CT angiography (CTA) to detect active bleeding and a higher risk of hematoma expansion in patients with intracerebral hemorrhage (ICH). The aim of this study was to investigate the detectability of spot signs on thin multiplanar projection reconstruction (MPR) images compared to thicker maximum intensity projection (MIP) images. METHODS: In this retrospective analysis, we assessed imaging data of 146 patients with primary hypertensive/microangiopathic ICH who received emergency non-contrast computed tomography (NCCT) and CTA. Two experienced radiologists, blinded to each other, evaluated images of thin (1 mm) MPR images and thick (3 mm) MIP images on the presence of spot signs and performed a consensus reading. Kappa tests were used for data comparison. RESULTS: In total, spot signs were observed in 27 cases (=18.5 %) in both thin MPR and thick MIP slices. Detectability of the spot sign did not differ in 1 mm MPR images and 3 mm MIP images (Cohen's kappa, 1.0; p = 0.00). Also, when the readings of the two radiologists were analyzed separately, results for MPR and MIP slices were similar (MPR: Cohen's kappa, 0.81, p = 0.00; MIP: Cohen's kappa, 0.74; p = 0.00). CONCLUSION: No significant difference in the detectability of the spot sign could be demonstrated when comparing 1 mm MPR images with 3 mm MIP images.

Adjustment of Stent Retriever Length to Clot Extent Affects First-Pass Reperfusion in Endovascular Treatment of Acute Ischemic Stroke.

BACKGROUND: Stent retriever technology has evolved, and significantly longer devices have become available for mechanical thrombectomy (MT) of large cerebral vessel occlusions in ischemic stroke. We hypothesized that increased stent retriever length may improve the rate of complete angiographic reperfusion and decrease the respective number of attempts, resulting in a better clinical outcome. METHODS: Retrospective analysis of patients with large vessel occlusion in the anterior and posterior circulation treated with stent retriever MT. The study group was dichotomized into short (20 mm) and long (>20 mm) retrievers using propensity matching. In the anterior circulation, the clot burden score was evaluated. Primary end points were first-pass modified thrombolysis in cerebral infarction (mTICI) 3 reperfusion and first-pass mTICI ≥ 2b reperfusion, and the secondary end point was functional independence (defined as modified Rankin Scale score 0-2) at discharge and 90 days. RESULTS: Overall, 394 patients were included in the analysis. In the anterior circulation, short stent retrievers had a significantly higher rate of first-pass reperfusion in cases with low clot burden (mTICI 3: 27% vs. 17%; p = 0.009; mTICI ≥ 2b: 42 vs. 30%; p = 0.005) and in middle cerebral artery occlusions (mTICI ≥ 2b: 51 vs. 41%; p = 0.024). Higher rates of favorable outcome at discharge and 90 days were observed for the short stent retriever group (p < 0.001). CONCLUSION: Stent retriever length should be adjusted to clot burden score and vessel occlusion site.

Transcript and metabolite profiling for the evaluation of tobacco tree and poplar as feedstock for the bio-based industry.

The global demand for food, feed, energy and water poses extraordinary challenges for future generations. It is evident that robust platforms for the exploration of renewable resources are necessary to overcome these challenges. Within the multinational framework MultiBioPro we are developing biorefinery pipelines to maximize the use of plant biomass. More specifically, we use poplar and tobacco tree (Nicotiana glauca) as target crop species for improving saccharification, isoprenoid, long chain hydrocarbon contents, fiber quality, and suberin and lignin contents. The methods used to obtain these outputs include GC-MS, LC-MS and RNA sequencing platforms. The metabolite pipelines are well established tools to generate these types of data, but also have the limitations in that only well characterized metabolites can be used. The deep sequencing will allow us to include all transcripts present during the developmental stages of the tobacco tree leaf, but has to be mapped back to the sequence of Nicotiana tabacum. With these set-ups, we aim at a basic understanding for underlying processes and at establishing an industrial framework to exploit the outcomes. In a more long term perspective, we believe that data generated here will provide means for a sustainable biorefinery process using poplar and tobacco tree as raw material. To date the basal level of metabolites in the samples have been analyzed and the protocols utilized are provided in this article.