RPS 701 - Imaging of the intestines with focus on Crohn's disease

Author Block: R. Guo¹, W. Zhou², G. Zhang², T. Wang², P. Hu¹, Q. Liang¹, P. Rong¹; ¹Changsha/CN, ²Shanghai/CN
Purpose: To investigate the clinical value of artificial intelligence iterative reconstruction (AIIR) in optimizing image spatial resolution and diagnostic performance of low-dose CT enterography (CTE) for patients with Crohn's disease (CD), compared with the routine hybrid iterative reconstruction (HIR).
Methods or Background: Forty patients with suspected CD were prospectively enrolled to receive low-dose CTE (80kVp, ref 120mAs) with ilecolonoscopy-guided biopsy as the reference. Images were reconstructed using the AIIR and HIR. Diagnosis of CD was made on a per-segment level. The diagnostic confidence was scored with a five-point scale (1=insufficient, 5=definitely confirmed). Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and edge rise slope (ERS) of the bowel wall were measured. Diagnostic image quality, including conspicuity of bowel wall enhancement, thickness, luminal narrowing, comb signs, and creeping fat signs, was evaluated with a five-point scale (1=poor, 5=excellent).
Results or Findings: There were 77 bowel segments confirmed with CD, of which 57 were detected on HIR images and 71 on AIIR images. AIIR images showed 124.3% higher SNR, 136.3% higher CNR, 68.4% higher ERS, and more conspicuous diagnostic imaging features (all p<0.001), indicating higher image spatial resolution than HIR. With higher spatial resolution, AIIR images showed better diagnostic performance for CD detection than HIR images (sensitivity: 88.7% vs 71.2%; accuracy: 92.9% vs 87.9%; specificity: 94.5% vs 94.5%; false-positive-rate: 13.4% vs 16.2%; false-negative-rate: 4.5% vs 10.9%). The diagnostic confidence was significantly improved by AIIR (4.5±0.6 vs 3.4±0.6, p<0.001).
Conclusion: AIIR improved the image spatial resolution of low-dose CTE and thus delivered higher diagnostic confidence and better diagnostic performance than HIR. Low-dose CTE with AIIR provides excellent image quality and reliable CD detection, making it a feasible option for follow-up examinations for CD patients.
Limitations: A single-centre study.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study received approval from the Institutional Review Board (R20230019).

Author Block: J. Rimola Gibert¹, C. Saavedra¹, N. Capozzi², I. De Kock³, A. R. Radmard⁴, M. Scharitzer⁵, M. C. Masamunt¹, I. Ordás¹, J. Dillman⁶; ¹Barcelona/ES, ²Bologna/IT, ³Ghent/BE, ⁴Tehran/IR, ⁵Vienna/AT, ⁶Cincinnati, OH/US
Purpose: Crohn's disease (CD) often requires multiple imaging evaluations. An abbreviated MR enterography (aMRE) protocol, without IV contrast, could improve patient experience and reduce costs. This study aims to compare inter-observer agreement for detecting CD activity and complications using conventional MRE protocol (cMRE) versus an abbreviated protocol (aMRE).
Methods or Background: Ten radiologists from six countries independently reviewed cMRE and aMRE exams from 80 CD patients, with imaging assessments separated by at least one month. The exams included both pre- and post-treatment images of CD patients. Interobserver agreement, Fleiss' Kappa statistics, and Gwet's concordance 1 (AC1), which corrects the prevalence dependence in categorizations, were calculated at the bowel segment and patient levels for the presence of different findings indicative of active inflammation and complications.
Results or Findings: Overall (n=80), the concordance for detecting disease activity was high and comparable between aMRE and cMRE: agreement was 0.83 (0.80-0.86) for aMRE vs. 0.84 (0.82-0.87) for cMRE; Kappa values were 0.41 (0.29-0.53) vs. 0.36 (0.23-0.49); and AC1 values were 0.76 (0.64-0.88) vs. 0.79 (0.69-0.89). Agreement for detecting active disease was similar across the small bowel and colon, as well as between pre-treatment (n=51) and post-treatment (n=29) MREs. For detecting strictures, agreement was 0.76 (0.73-0.78) for aMRE vs. 0.72 (0.68-0.75) for cMRE; Kappa values were 0.35 (0.24-0.46) vs. 0.34 (0.24-0.43); and AC1 values were 0.61 (0.47-0.74) vs. 0.50 (0.35-0.65). For penetrating complications, agreement was 0.81 (0.79-0.84) for aMRE vs. 0.85 (0.82-0.87) for cMRE; Kappa values were 0.47 (0.34-0.59) vs. 0.57 (0.45-0.69); and AC1 values were 0.71 (0.56-0.86) vs. 0.76 (0.63-0.90).
Conclusion: The interobserver agreement for detecting active CD and related complications using an aMRE protocol was comparable to that of the cMRE protocol that supports the adoption of abbreviated MRE protocols.
Limitations: None
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Local ethics committee approved the study with the code HCB/2021/0629

Author Block: N. Bogveradze, K. Kranz, T. Traub-Weidinger, C. Primas, A. Macher-Beer, W. Reinisch, T. Mang, M. Hacker, M. Scharitzer; Vienna/AT
Purpose: To evaluate the global and regional inflammatory burden in patients with Crohn’s Disease (CD) using FDG PET/MR enterography (PET/MRE), in correlation with histopathological findings and relevant biomarkers.
Methods or Background: Patients with CD undergoing PET/MRE and ileocolonoscopy were included in this retrospective study between 2016-2021. Eight intestinal segments were manually segmented, and the uncorrected total lesion glycolysis values (TLG) were summed to calculate global CD activity score (GCDAS). GCDAS and highest SUVmax/ patient were correlated with clinical biomarkers (fecal calprotectin [FC], serum C-reactive protein [CRP], peripheral blood leukocyte counts, Harvey-Bradshaw index [HBI]) to evaluate global inflammation. For assessing regional inflammation, SUVmax was correlated with histopathological disease activity. Comparisons were made using Spearman's coefficient and Wilcoxon-W tests.
Results or Findings: In 41 patients (mean age, 40 years ±14 (SD), 26 men), the highest segmental SUVmax correlated significantly with FC (r= 0.443 p < 0.004) and CRP (r = 0.645, p < 0.001). The GCDAS correlated significantly with CRP (r = 0.498, p = 0.01) but not with FC (p = 0.49), leukocyte counts (p=0.56) or HBI (p = 0.518). SUVmax values significantly correlated with grading of active inflammation in corresponding histopathological samples (r = 0.515, p < 0.001) and were higher in segments with severe histopathological inflammation (4.7, 95% CI: 3.8-5.6) compared to segments with moderate (3.3, 95% CI: 2.6-4.1) or without active inflammation (2.0, 95% CI: 1.8-2.0).
Conclusion: SUVmax was found to be a reliable biomarker for assessing global inflammatory burden and correlated well with histopathological segmental activity. Furthermore, SUVmax enabled grading of active inflammation. GCDAS showed good correlation with CRP, but not with FC and may therefore be less useful for quantifying global disease burden.
Limitations: Retrospective study design
Funding for this study: N/A
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ek 1356/2023

Author Block: A. Valenti, F. Maccioni, L. Busato, L. Bottino, A. Longhi, C. Catalano; Rome/IT
Purpose: Perianal fistulas are severe complications of pediatric Crohn’s disease (CD), due to a high risk of demolitive surgery. MRI is the gold standard for scoring intestinal and perianal CD. The purpose of this study was to stage severity and activity of both lesions using MRI scores in pediatric CD.
Methods or Background: A retrospective study was performed on 186 pediatric patients. Inclusion criteria were: proven CD, intestinal and perianal disease, complete MRI. Forty patients were finally included. MR Enterography (MRE) and high-resolution MRI (HRMRI) of the perianal region were used to analyze intestinal and perianal disease. The MEGS score was applied to assess the severity of intestinal disease, the Parks’ classification and MAGNIFI-CD score to classify perianal disease and quantify its activity. Correlations between location and activity of intestinal and perianal lesions were investigated.
Results or Findings: Simple perianal fistulas (Parks A and B) were found in 82.5% of patients, whereas complex fistulas (Parks C-E or a combination of them) in 17.5 %. Jejunal, ileal and colonic lesions were found in 22,5%, 80% and 35%, variably associated. Considering colorectal lesions only, 70% were left-sided. Disease of the left colon was associated with a more extensive disease, > 25 cm in length (p < 0.001), and a more severe activity, MEGS grade 3. Correlations were found between left-sided colonic lesions and severe fistulas, and between MAGNIFI-CD and MEGS scores both grade 3 (p<0.05).
Conclusion: The perianal fistulizing phenotype in pediatric patients is correlated with the severity of intestinal inflammation and with left-sided colonic disease.
Limitations: We used two differente MRI scanners to obtoin our data.
Funding for this study: No funding.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: We have received the approvation of the ethics commitee of our Hospital

Author Block: L. Busato, F. Maccioni, A. Valenti, L. Bottino, A. Iori, U. La Rocca, C. Catalano; Rome/IT
Purpose: Acute gastrointestinal Graft-versus-Host disease (GI-a GVHD) is one of the most severe complications stem cell transplantation, occurring when the transplanted immune cells attack the host's intestinal tissues. Aim of this study was to evaluate the efficacy of MRI biomarkers in the diagnosis and staging of acute gastrointestinal GI-aGVHD, currently based on clinical and endoscopic criteria only.
Methods or Background: Thirty-five patients with clinical suspicion of GI-aGVHD were retrospectively and prospectively analysed, , 21/35 retrospectively , 14/35 prospectively, both separately and in conjunction. In these patients we investigated 15 MRI biomarkers suggestive of bowel inflammation and GVHD severity. A diagnostic score was tested, based on the most relevant GVHD biomarkers: small bowel involvement, T2 and post-contrast bowel wall stratification, ascites , oedema of the retroperitoneal and declivous tissues.
Results or Findings: GI -GVHD was confirmed by biopsy in 13/35 patients (37%). Analysing the 6 key biomarkers (diagnostic score), MRI showed 88.2% and sensitivity 100%specificity. In addition to these siw biomarkers, wall stiffness and mesenteric oedema appeared useful for differentiating GVHD from non-GVHD patients. Most commonly affected segments were the proximal, middle and distal ileum (82.3%). Considering all the 15 MRI Biomarkers, MRI showed high predictive value on disease severity and mortality, superior to the clinical score.
Conclusion: MRI is a noninvasive and accurate tool for the diagnosis of GI-GVHD,which can provide crucial information and implement current clinical and endoscopic criteria.
Limitations:
The small number of patients, due to the low prevalence of this disease.
Limitations: The small number of patients, due to the low frequence of the disease.
Funding for this study: No funding
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Our study has been approved by the ethics committee of our hospital

Author Block: R. Martín-Márquez¹, E. Gutiérrez Dorta², D. J. L. Ruiz¹, J. Mesa¹; ¹Córdoba/ES, ²Ourense/ES
Purpose: To evaluate the profitability of Magnetic Resonance Enterography (MRE) in different clinical contexts, determining if it is both clinically and cost-effective, optimizing resources and improving patient care.
To establish a protocol for performing MRE in various clinical scenarios.
Methods or Background: A retrospective study of 615 patients who underwent MRE at Reina Sofía Hospital (Córdoba, Spain) over one year. Patients were divided into two groups: patients with known inflammatory bowel disease (IBD) and those without IBD history.
Variables included the reason for the examination, clinical unit, patient presentation, and findings from MRE, colonoscopy, and intestinal biopsy. A descriptive analysis was performed, and differences were assessed with chi-square or Student's t-tests (p<0.05).
Diagnostic indices of MRE were compared to colonoscopy (sensitivity, specificity, positive predictive value (PPV), negative predictive value(NPV)).
Results or Findings: A total of 242 (39.3%) patients had a history of IBD, while 373(60.7%) did not. Pathological findings were seen in 68.2% of IBD patients versus 23.3% without IBD (p<0.05). 9.1% of IBD patients with normal colonoscopy had pathological findings on MRE, compared to 10.4% without IBD (p>0.05). Among those with elevated fecal calprotectin, MRE detected more findings in IBD patients (86.4% vs. 18.8%; p<0.05). Diarrhea occurred in 8.7% of IBD patients and 37.3% of non-IBD patients, with MRE findings in 52.4% and 16.5%, respectively (p<0.05).
Diagnostic indices of MRE: IBD group: Sensitivity 70.6%, Specificity 90.9%, PPV 92.3%, NPV 66.7%. Non-IBD group: S 43.2%, E 89.5%, PPV 70.7%, NPV 73%.
Conclusion: Our study highlights the importance of MRE in IBD patients and the need to optimize its use in non-IBD patients, especially with negative colonoscopies.
Limitations: The main limitations of this study are its retrospective design, which may lead to missing information, and the lack of long-term follow-up.
Funding for this study: No
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: There is no additional information.

Author Block: S. Martin, J. Pancholi, S. Liong; Manchester/UK
Purpose: This service evaluation compares the diagnostic yield and utilisation trends of non-contrast versus contrast-enhanced magnetic resonance enterography (MRE) for small bowel (SB) evaluation in a cohort of patients without a diagnosis of inflammatory bowel disease or clear gastrointestinal symptom aetiology.
Methods or Background: A retrospective review of all 1,012 MREs performed across four hospitals in Greater Manchester, United Kingdom, between 1 January and 31 December 2023, identified 208 undiagnosed patients. Among these, 92(44.2%) underwent non-contrast and 116(57.8%) underwent contrast-enhanced MRE. Diagnostic yield was assessed by reviewing MRE reports and correlating findings with colonoscopic histopathology results (within 6 weeks of MRE) and faecal calprotectin levels (FC, within 12 weeks of MRE).
Results or Findings: SB abnormalities were observed in a similar minority of patients in both the contrast (14/116 [12.1%]) and non-contrast (5/92 [5.4%], p=0.15) groups. Of 45 patients with colonoscopies completed within 6 weeks of MRE, 22 had terminal ileum (TI) biopsies available (non-contrast: n=8; contrast-enhanced: n=14). Compared with TI biopsies, contrast-enhanced MRE has sensitivity of 100% (95%CI 15.8-100%) and specificity of 83.3%(95%CI 51.5-97.9%), whereas non-contrast MRE has sensitivity of 100%(95%CI 2.5-100%) and specificity of 100%(95%CI 59-100%). Contrast-enhanced MRE has positive predictive value (PPV) of 50%(95%CI 22-78%) and accuracy of 85.7(95%CI 57.2-98.2%). Non-contrast MRE has PPV 100%(95%CI 2.5-100%) and accuracy of 100%(95%CI 63.1-100%). FC was available for 27 patients, but there was no clear relationship between FC levels and MRE results.
Conclusion: Contrast enhancement did not significantly alter the diagnostic yield of small bowel pathology in our cohort and is known to require longer acquisition and reporting times, impacting service capacity. Non-contrast MRE has high sensitivity and specificity for diagnosis of SB pathology.
Limitations: Retrospective design. Small number of patients with histopathology and FC available.
Funding for this study: None.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Ethics approval was not required as this was an educational project and retrospective service evaluation.

Author Block: J. Brodersen¹, S. R. Rafaelsen², M. Agerbæk Jue¹, T. Knudsen¹, J. Keldsen³, M. D. Jensen¹; ¹Esbjerg/DK, ²Vejle/DK, ³Odense/DK
Purpose: The aim of this study was to evaluate intestinal ultrasound (IUS), magnetic resonance imaging enterocolonography (MREC), panenteric capsule endoscopy (PCE) and faecal calprotectin (FC) for determining response to medical treatment in patients with ileocolonic CD
Methods or Background: This prospective, blinded, multicentre study included patients with endoscopically active CD. Patients were scheduled for IC, MREC, IUS, PCE and FC before and 12 weeks after medical treatment. The vascularity within the affected bowel wall areas was assessed according to the Limberg score. The Simple Ultrasound Score for Crohn’s Disease (SUS-CD) was used for activity assessment. A > 50% reduction of the Simple Endoscopic Score for Crohn’s Disease (SES-CD) with IC defined treatment response as gold standard.
Results or Findings: From 2018 to 2024, 50 patients completed the pre- and post-treatment evaluation with IC, and endoscopic response was achieved in 25 (50.0%). PCE was omitted in 12 (24.0%) patients because of stricturing CD. All activity scores decreased in patients achieving endoscopic response: The Simple Ultrasound Score for Crohn’s Disease 2.2 vs. 6.1 (P < 0.001), Magnetic Resonance Index of Activity 29.0 vs. 37.1 (P = 0.05), SES-CD with PCE 3.1 vs. 12.8 (P < 0.001) and FC 115.3 vs. 1339.9 mg/kg (P < 0.001). The sensitivity and specificity of IUS, MREC, PCE and FC was 80.0% (95% CI 56.3-94.3) / 77.8% (52.4-93.6), 65.2% (42.7-83.6) / 87.0% (66.4-97.2), 87.5% (61.7-98.4) / 86.7% (59.5-98.3) and 90.0% (68.3-98.8) / 86.4% (65.1-97.1), respectively.
Conclusion: IUS, PCE and FC are equally effective for determining endoscopic response in patients with active CD. MREC is insufficient for determining endoscopic response.
Limitations: First, the sample size is limited. Second, IC served as gold standard for treatment response, which may favour modalities assessing mucosal inflammation (PCE and FC).
Funding for this study: The study was initiated by the investigators without funding from medical imaging companies or the capsule endoscope manufacturer.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the Local Ethics Committee of Southern Denmark (S-20170188). All patients gave informed consent before participation. The study was registered: NCT03435016.

Author Block: Y. Ke, R. Zhang, H. Cai, Q. Zeng, S-T. Feng, Z. Peng, X. Li; Guangzhou/CN
Purpose: Psychological distress may affect bowel disease activity in patients with Crohn's disease (CD). However, limited studies have investigated its correlation with trans-/peri-intestinal alterations in CD. Therefore, we aimed to investigate the relationship between psychological distress and intestinal abnormalities identified by magnetic resonance enterography (MRE), and to explore their underlying association using blood neurotransmitters.
Methods or Background: 105 CD patients and 46 healthy controls (HCs) were prospectively recruited. CD patients underwent MRE and provided blood samples for 19 serum neurotransmitters measurement. All participants completed State-Trait Anxiety Inventory (including STAI-Trait and State scores), Beck Depression Inventory (BDI), and Perceived Stress Scale (PSS) questionnaires to assess psychological distress. Correlation analysis, multivariable logistic regression, and causal mediation analyses were employed to investigate the relationship between psychological distress and MRE features.
Results or Findings: Psychological scores of CD patients, including STAI-Trait, PSS, and BDI scores, were significantly higher than HCs (all P<0.001). Among them, STAI-Trait score was significantly correlated with stricture (r=0.505), mural T2WI hyperintensity (r=0.466), perianal diseases (r=0.359), and perienteric effusion (r=0.340) (all P<0.05). Multivariable logistic regression analysis indicated that STAI-Trait score significantly influenced the odds of perienteric effusion (OR: 1.124; 95% CI: 1.007-1.255; P=0.036). In causal mediation analysis, a direct effect of STAI-Trait score on perienteric effusion (P=0.04) was observed; STAI-Trait score and tryptophan had a combined effect on perienteric effusion (P=0.06), approaching statistical significance. Negative correlation between tryptophan level and perienteric effusion (r=-0.220, P<0.05) was also found.
Conclusion: Psychological state is associated with MRE-detectable intestinal morphological changes, and neurotransmitters may serve as mediators in establishing this connection.
Limitations: This was a single-center study with small sample size. To enhance reliability and validity, future investigations should consider conducting multicenter studies with larger sample sizes.
Funding for this study: This study was financially supported by National Natural Science Foundation of China (82070680, 82270693, 82271958, 82471948, and 82072002).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the institutional ethics review board of our hospital (No. [2021]215-2).

Author Block: R. Zhang, X. Shen, Y. Wang, J. Lin, L. Huang, W. He, S-T. Feng, X. Li; Guangzhou/CN
Purpose: There is considerable recent interest in the role of brain-gut axis in the pathogenesis and manifestations of Crohn’s disease (CD). We developed a multimodal neuroimaging-based model to characterize the neurophenotype of CD patients and predict intestinal disease progression, using multi-omics data to demonstrate its validity.
Methods or Background: This prospective study enrolled 109 CD patients who underwent baseline tests (including multimodal neuroimaging, psychological scales, MR enterography, ileocolonoscopy) and fecal/blood samples collection within one week. The neurophenotype of patients with different intestinal inflammation levels was characterized using a radiomics model, developed from 13 out of 13,870 neuroimaging features. This neurophenotype in predicting disease progression during follow-up was evaluated using Kaplan-Meier curves and Cox regression analysis. Multi-omics data (including fecal microbiome, fecal/blood metabolomics, intestinal/blood-brain-barrier permeability, and blood neurotransmitter) were used to elucidate how this neurophenotype reflecting brain-gut interactions.
Results or Findings: The model enabled accurate characterization of neurophenotypes in patients with different intestinal inflammation levels in training and test cohorts (AUC=0.824-0.842, both P<0.05). Neurophenotype was the most important predictor of disease progression (HR=29.05, P=0.033), surpassing psychological traits (HR=0.95-1.09, all P>0.05). Multi-omics analysis revealed that elevated intestinal inflammation was correlated with increased intestinal permeability and specific gut microbiota (e.g., Enterococcus) and metabolites (e.g., caproic acid), which collectively contributed to high-risk neurophenotype (all P<0.05). High-risk neurophenotype subsequently associated with intestinal disease progression by establishing correlations with six blood neurotransmitters (e.g., tryptophan) (all P<0.05).
Conclusion: The neurophenotype varies among CD patients with different intestinal inflammation levels and can predict intestinal disease progression. Multi-omics data offer biological evidence to support its validity.
Limitations: This was a single-centre study, and the potential mechanisms underlying the brain-gut axis in our study have yet to be validated.
Funding for this study: This study was financially supported by National Natural Science Foundation of China (82070680, 82270693, 82271958, 82072002, 82170537, and 82222010), Guangdong Basic and Applied Basic Research Foundation (2023B1515020070 and 2023A1515011097), 2023 SKY Imaging Research Fund of the Chinese International Medical Foundation (Z-2014-07-2301), and National Key R&D Program of China (2023YFC2507300).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the institutional ethics review board of The First Affiliated Hospital of Sun Yat-sen University (No. [2021]215-2)

Author Block: E. Höhne¹, V. Schäfer², S. Petzinna², A. Wittek², J. Gotta¹, P. Reschke¹, F. Recker²; ¹Frankfurt/DE, ²Bonn/DE
Purpose: Point-of-care ultrasound (POCUS) is increasingly important in clinical settings, leading to a growing demand for comprehensive ultrasound training in medical education. This study marks the University of Bonn's first attempt to integrate ultrasound courses and handheld devices into the regular curriculum for final-year medical students and assess their utilization.
Methods or Background: Forty students in their practical year received a handheld ultrasound device for four months and were invited to participate in eight optional ultrasound courses, where they acquired and rated images using a developed rating system. At the end of the tertial, they could complete a voluntary survey on equipment usage.
Results or Findings: Participation in the optional ultrasound courses was positive, with the Introduction and FAST module attracting the most participants (29). Lung images received the highest average rating (18.82 out of possible 23 points, SD ± 4.30), while aorta and vena cava images scored lowest (16.62, SD ± 1.55). The overall mean score for all images was 17.47 (SD ± 2.74). Only 21 students responded to the survey, and 67% used the device independently four times or fewer during the tertial.
Conclusion: The study aimed to enhance improving students' ultrasound skills, but device usage was unexpectedly low, with most students using it only once a month or less. This raises concerns about resource justification, prompting future initiatives to focus on technical improvements, better login data access, and closer monitoring of usage and progress to emphasize practical ultrasound training in medical education.
Limitations: This study's limitations include a small sample size, single-institution focus, incomplete usage data, and low response rates, which hinder the generalizability and reliability of the findings regarding ultrasound device integration into student routines.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The local ethics committee of the Uuniversity of Bonn approved the study (253/23-EP) .