Repeatability and reproducibility of various 4D Flow MRI postprocessing software programs in a multi-software and multi-vendor cross-over comparison study.

BACKGROUND: Different software programs are available for the evaluation of 4D Flow cardiovascular magnetic resonance (CMR). A good agreement of the results between programs is a prerequisite for the acceptance of the method. Therefore, the goal was to compare quantitative results from a cross-over comparison in individuals examined on two scanners of different vendors analyzed with four postprocessing software packages. METHODS: Eight healthy subjects (27 ± 3 years, 3 women) were each examined on two 3T CMR systems (Ingenia, Philips Healthcare; MAGNETOM Skyra, Siemens Healthineers) with a standardized 4D Flow CMR sequence. Six manually placed aortic contours were evaluated with Caas (Pie Medical Imaging, SW-A), cvi42 (Circle Cardiovascular Imaging, SW-B), GTFlow (GyroTools, SW-C), and MevisFlow (Fraunhofer Institute MEVIS, SW-D) to analyze seven clinically used parameters including stroke volume, peak flow, peak velocity, and area as well as typically scientifically used wall shear stress values. Statistical analysis of inter- and intrareader variability, inter-software and inter-scanner comparison included calculation of absolute and relative error (ER), intraclass correlation coefficient (ICC), Bland-Altman analysis, and equivalence testing based on the assumption that inter-software differences needed to be within 80% of the range of intrareader differences. RESULTS: SW-A and SW-C were the only software programs showing agreement for stroke volume (ICC = 0.96; ER = 3 ± 8%), peak flow (ICC: 0.97; ER = -1 ± 7%), and area (ICC = 0.81; ER = 2 ± 22%). Results from SW-A/D and SW-C/D were equivalent only for area and peak flow. Other software pairs did not yield equivalent results for routinely used clinical parameters. Especially peak maximum velocity yielded poor agreement (ICC ≤ 0.4) between all software packages except SW-A/D that showed good agreement (ICC = 0.80). Inter- and intrareader consistency for clinically used parameters was best for SW-A and SW-D (ICC = 0.56-97) and worst for SW-B (ICC = -0.01-0.71). Of note, inter-scanner differences per individual tended to be smaller than inter-software differences. CONCLUSIONS: Of all tested software programs, only SW-A and SW-C can be used equivalently for determination of stroke volume, peak flow, and vessel area. Irrespective of the applied software and scanner, high intra- and interreader variability for all parameters have to be taken into account before introducing 4D Flow CMR in clinical routine. Especially in multicenter clinical trials a single image evaluation software should be applied.

Comprehensive analysis of haemodynamics in patients with physiologically curved prostheses of the ascending aorta.

OBJECTIVES: This is a comprehensive analysis of haemodynamics after valve-sparing aortic root replacement (VSARR) with anatomically curved prosthesis (CP) compared to straight prosthesis (SP) and age-matched volunteers (VOL) using 4D flow MRI (time-resolved three-dimensional magnetic resonance phase-contrast imaging). METHODS: Nine patients with 90° CP, nine patients with SP, and twelve VOL were examined with 4D flow MRI. Analyses included various characteristic anatomical, qualitative and quantitative haemodynamic parameters. RESULTS: Grading of secondary flow patterns was lower in CP patients than in SP patients (P = 0.09) and more comparable to VOL, albeit not reaching statistical significance. However, it was easy to differentiate between VSARR patients and healthy volunteers: Patients more often had angular aortic arches (CP: 89%, SP: 100%; VOL: 17%; P ≤ 0.002), increased average curvature (CP: 0.17/cm [0.15, 0.18]; SP: 0.15/cm [0.14, 0.16]; VOL: 0.14/cm [0.13, 0.16]; P ≤ 0.007; values given as median [interquartile range]), and more secondary flow patterns (CP: 3 [2, 4] SP: 3 [2, 3] VOL: 2 [1, 2]; P < 0.01). Maximum circulation (CP: 142.7 cm2/s [116.1, 187.3]; SP: 101.8 cm2/s [77.7, 132.5]; VOL: 42.8cm2/s [39.3, 65.6]; P ≤ 0.002), maximum helicity density (CP: 9.6 m/s2 [9.3, 23.9]; SP: 9.7 m/s2 [8.6, 12.5]; VOL 4.9 m/s2 [4.2, 7.7]; P ≤ 0.007), and wall shear stress gradient (e.g., proximal ascending aorta CP: 0.97 N/m2 [0.54, 1.07]; SP: 1.08 N/m2 [0.74, 1.24]; VOL: 0.41 N/m2 [0.32, 0.60]; P ≤ 0.01) were increased in patients. One CP patient had a round aortic arch with physiological haemodynamic parameters. CONCLUSIONS: The restoration of physiological aortic configuration and haemodynamics was not fully achieved with the curved prostheses in our study cohort. However, there was a tendency towards improved haemodynamic conditions in the patients with curved prostheses overall but without statistical significance. A single patient with a CP and near-physiological configuration of the thoracic aorta underlines the importance of optimizing postoperative geometric conditions for allowing for physiological haemodynamics and cardiovascular energetics after VSARR.

CoRad-19 - Modular Digital Teaching during the SARS-CoV-2 Pandemic. / CoRad-19 ­ Modulare Digitale Lehre während der SARS-CoV-2-Pandemie.

PURPOSE: During the SARS-CoV-2 pandemic, higher education worldwide had to switch to digital formats. The purpose of this study was to evaluate CoRad-19, a digital teaching tool created by the German Radiological Society for medical students during the COVID-19 pandemic. MATERIALS AND METHODS: A total of 13 German-speaking universities implemented CoRad-19 in their curriculum and partially or completely replaced their classes with the online courses. Previous experience and contact with radiology and the participants' opinions regarding the medium of e-learning were surveyed using a custom questionnaire. The subjective level of knowledge regarding the individual modules was also surveyed before and after participation to measure learning effects. The data of 994 medical students from the participating sites were analyzed and compared intraindividually using the Friedman test. RESULTS: From 4/1/2020-10/1/2020, 451 complete data sets from a total of 994 surveys were included. E-learning was rated "very useful" both before and after course participation (4 [IQR 3-4], p = 0.527, r = 0.16). E-learning as a method was also rated as a "very good" medium both before and after participation (4 [IQR 3-4], p = 0.414, r = 0.17). After participation, participants rated radiology as particularly suitable for digital teaching (before: 3 [IQR 3-4] vs. after 4 [IQR 3-4], p = 0.005, r = 0.6). Significant learning gains were measurable in all course modules (p ≤ 0.009). Post-hoc analysis showed interest in radiology to increase significantly after course participation (p = 0.02). CONCLUSION: In the representative survey, significant learning effects were observed in all course modules. In addition, it should be particularly emphasized that the students' interest in radiology was increased by course participation. Thus, the German Radiological Society provided significant support to German-speaking medical faculties with respect to maintaining excellent education using CoRad-19. KEY POINT: · Co-Rad-19 course participation results in measurable subjective learning effects and increases student interest in radiology.. CITATION FORMAT: · Brendlin AS, Molwitz I, Oechtering TH et al. CoRad-19 - Modular Digital Teaching during the SARS-CoV-2 Pandemic. Fortschr Röntgenstr 2022; 194: 644 - 651.

Congenital Diaphragmatic Hernia Presenting with Tension Pneumothorax in a 3-Year-Old Boy.

We report the case of a 3-year-old boy who presented with an upper respiratory tract infection and severe dyspnea. A chest X-ray revealed a left-sided tension pneumothorax with mediastinal shift and suspected enterothorax. After thoracic computed tomography (CT) scan, a chest tube was inserted, which drained fluid which had the same consistency and color as the one derived from the nasogastric (NG) tube. The boy underwent diagnostic laparoscopy for suspected bowel perforation, which confirmed a left-sided Bochdalek hernia with herniation of the viscera into the chest. After repositioning of the herniated organs into the abdomen, a gastric perforation was identified and repaired. This case demonstrates that the cause of a tension pneumothorax in an infant may be a rare combination of congenital diaphragmatic hernia (CDH) and perforation of a visceral hollow organ.