ChatGPT: Evaluating answers on contrast media related questions and finetuning by providing the model with the ESUR guideline on contrast agents.

OBJECTIVE: This study aimed to assess the feasibility of GPT-4 for answering questions related to contrast media with and without the context of the European Society of Urogenital Radiology (ESUR) guideline on contrast agents. The overarching goal was to determine whether contextual enrichment by providing guideline information improves answers of GPT-4 for clinical decision-making in radiology. METHODS: A set of 64 questions, based on the ESUR guideline on contrast agents mirroring pertinent sections, was developed and posed to GPT-4 both directly and after providing the guideline using a plugin. Responses were graded by experienced radiologists for quality of information and accuracy in pinpointing information from the guideline as well as by radiology residents for utility, using Likert-scales. RESULTS: GPT-4's performance improved significantly with the guideline. Without the guideline, average quality rating was 3.98, which increased to 4.33 with the guideline (p = 0036). In terms of accuracy, 82.3% of answers matched the information from the guideline. Utility scores also reflected a significant improvement with the guideline, with average scores of 4.1 (without) and 4.4 (with) (p = 0.008) with a Fleiss´ Kappa of 0.44. CONCLUSION: GPT-4, when contextually enriched with a guideline, demonstrates enhanced capability in providing guideline-backed recommendations. This approach holds promise for real-time clinical decision-support, making guidelines more actionable. However, further refinements are necessary to maximize the potential of large language models (LLMs). Inherent limitations need to be addressed.

Contrast media for hysterosalpingography: systematic search and review providing new guidelines by the Contrast Media Safety Committee of the European Society of Urogenital Radiology.

OBJECTIVES: Hysterosalpingography (HSG) is widely used for evaluating the fallopian tubes; however, controversies regarding the use of water- or oil-based iodine-based contrast media (CM) remain. The aim of this work was (1) to discuss reported pregnancy rates related to the CM type used, (2) to validate the used CM in published literature, (3) to discuss possible complications and side effects of CM in HSG, and (4) to develop guidelines on the use of oil-based CM in HSG. METHODS: A systematic literature search was conducted for original RCT studies or review/meta-analyses on using water-based and oil-based CM in HSG with fertility outcomes and complications. Nine randomized controlled trials (RCTs) and 10 reviews/meta-analyses were analyzed. Grading of the literature was performed based on the Oxford Centre for Evidence-Based Medicine (OCEBM) 2011 classification. RESULTS: An approximately 10% higher pregnancy rate is reported for oil-based CM. Side effects are rare, but oil-based CM have potentially more side effects on the maternal thyroid function and the peritoneum. CONCLUSIONS: 1. HSG with oil-based CM gives approximately 10% higher pregnancy rates. 2. External validity is limited, as in five of nine RCTs, the CM used is no longer on the market. 3. Oil-based CM have potentially more side effects on the maternal thyroid function and on the peritoneum. 4. Guideline: Maternal thyroid function should be tested before HSG with oil-based CM and monitored for 6 months after. CLINICAL RELEVANCE STATEMENT: Oil-based CM is associated with an approximately 10% higher chance of pregnancy compared to water-based CM after HSG. Although side effects are rare, higher iodine concentration and slower clearance of oil-based CM may induce maternal thyroid function disturbance and peritoneal inflammation and granuloma formation. KEY POINTS: • It is unknown which type of contrast medium, oil-based or water-based, is the optimal for HSG. • Oil-based contrast media give a 10% higher chance of pregnancy after HSG, compared to water-based contrast media. • From the safety perspective, oil-based CM can cause thyroid dysfunction and an intra-abdominal inflammatory response in the patient.

Differences in neonatal gastric tubes during insertion into a 3D model in relation to risk of potential perforation.

OBJECTIVES: Perforation of esophagus or stomach is a potential complication during and after insertion of a gastric tube in neonates. The aim of this study was to analyze different types of gastric tubes in a three-dimensional (3D) model of neonatal esophagus and stomach regarding potential perforations. METHODS: A 3D model of esophagus and stomach was created based on computed tomography data of a term neonate. Three types of gastric tubes were inserted into the 3D model, the localization was examined by radioscopy and the behavior, stiffness and manageability of each gastric tube was evaluated. RESULTS: Insertion of gastric tubes with higher stiffness was easier. The rates of correct localization differed significantly between the gastric tubes with the highest rate of correct localization in the softest tube (48.5%) and the lowest rate in the tube with the highest stiffness (21.2%). Additionally, the softest tube showed the lowest rate of localization of its tip at the stomach wall. CONCLUSIONS: The study illustrates differences between various types of gastric tubes regarding stiffness, behavior and resiliency. Softer gastric tubes may be beneficial. These differences may be relevant in neonatal care of very immature and very sick infants.

Retrospective evaluation of interventional radiological treatments for chronic mesenteric ischemia in Germany based on a four-year period of the DeGIR Registry: comparison of outcomes with international quality standards.

PURPOSE: Endovascular treatment has emerged as the gold standard for managing chronic mesenteric ischemia (CMI) resulting from arterial stenosis or occlusion. This study aimed to assess the efficacy and complication rates of continuous interventional radiology treatment for CMI in Germany between 2018 and 2021, comparing these findings with international quality standards. MATERIALS AND METHODS: Data for CMI therapy with stenting and percutaneous transluminal angioplasty (PTA) was obtained from the quality management system of the German Interventional Radiological Society (DeGIR). A total of 3752 endovascular procedures for CMI performed from 2018 to 2021 were documented (PTA: n = 675; stenting: n = 3077). Data was analyzed for technical and clinical success rates, as well as major complication rates. RESULTS: Overall technical and clinical success rates for PTA and stenting procedures were 92.03 %/85.9 % and 98.76 %/96.62 %, respectively. The most common major complications were: arterial occlusion (PTA: 0.73 %; stenting: 0.63), major bleeding (PTA: 1.05 %; stenting: 0.68 %), aneurysm formation (PTA: 0.29 %; stenting: 0.72 %), stent dislodgment (PTA: 0 %; stenting: 0.06 %), and organ failure (PTA: 0.43 %; stenting: 0.96 %). Technical and clinical success rates were higher, while complication rates were lower than the corresponding threshold recommended by the Society of Interventional Radiology for the percutaneous management of chronic mesenteric ischemia. CONCLUSION: Treatment of CMI performed by interventional radiologists in Germany is safe and effective during daily and on-call shifts with results exceeding internationally accepted standards. KEY POINTS: · Treatment of CMI by interventional radiologists in Germany is effective and safe.. · The interventions are safe and effective regardless of whether they are performed during on-call shifts or the daily routine.. · The clinical and technical success rates favorably surpass the thresholds presented by SIR.. · Different major complications occurred in under 1.1 % of CMI interventions..

Assessment of Efficacy and Complications of Endovascular Interventions for Critical Limb Ischemia in Germany: A Nationwide Study.

PURPOSE: Endovascular interventional radiological procedures have become the mainstay for the treatment of critical limb ischemia (CLI) due to arterial stenosis or occlusion. Open surgical or endovascular procedures, such as percutaneous transluminal angioplasty (PTA) or stenting can be used as a treatment strategy. The aim is to evaluate the success and major complication rates of interventional radiology treatments for CLI in Germany in 2021, and to compare these results with internationally published data. MATERIALS AND METHODS: Data for PTA and stenting in CLI for 2021 was obtained from the quality management system of the German Society of Interventional Radiology (DeGIR). 16 393 PTA procedures, 701 stenting procedures, and 8110 combined procedures were documented for 2021. Data was analyzed for technical and clinical success rates, as well as major complication rates documented mainly as major bleeding, distal embolization, and aneurysm formation. RESULTS: PTA had technical and clinical success rates of 96.3 % and 92.33 %, respectively. Stenting had technical and clinical success rates of 98.7 % and 96.15 %, respectively. PTA and stenting combined had success rates of 98.71 % and 96.91 %, respectively. The major complications were mainly: major bleeding (PTA: 0.40 %; stenting: 1.28 %; PTA and stenting: 0.54 %), distal embolization (PTA: 0.48 %; stenting: 1 %; PTA and stenting: 0.96 %), and aneurysm formation (PTA: 0.19 %; stenting: 0.43 %; PTA and stenting: 0.19 %). All procedures showed high technical and clinical success rates, while the complication rates were low. CONCLUSION: Interventional radiologists in Germany perform effective and safe treatment for CLI, achieving outcomes that tend to surpass internationally published data. KEY POINTS: · German interventional radiologists provide safe and effective critical limb ischemia treatment.. · Major complications occurred at maximum in 1.28 % of cases.. · Outcomes tend to surpass international data, indicating strong performance..

Prevalence of burnout among German radiologists: a call to action.

OBJECTIVES: In the presence of escalating global concerns regarding physician burnout, this study aims to analyze the prevalence and associated factors of burnout among radiologists in Germany. METHODS: A comprehensive online survey, inclusive of 73 targeted questions including a German-modified version of the Maslach Burnout Inventory, was distributed among all members of the German Radiological Society and the German Interventional Radiological Society between May and August 2023. The survey encompassed aspects of employment, workload, well-being, and coping mechanisms. Data from 172 completed surveys were analyzed, with correlations explored via crosstabs and the Pearson-chi-square test. RESULTS: In total, 76.7% of participating radiologists were identified to be burnt out. The prevalence was significantly associated with increased workload, reduced sleep quality, suboptimal working conditions, reduced job satisfaction, and the negative interplay between work, family life, and health. Median work satisfaction was described as "satisfied" while median workload was assessed as "frequently overwhelming of work." A total of 41.9% of respondents noted facing daily time pressure. Radiologists' concerns about work interfering with private family life were voiced by approximately 70%, and 73.3% highlighted the perceived negative effects on their health. CONCLUSION: The pronounced prevalence of burnout among German radiologists demonstrates an urgent, unmet need for comprehensive interventions and systemic changes. Our findings act as a catalyst for initiating targeted, multifaceted strategies and dialogs, essential for fostering a resilient and effective healthcare ecosystem. Further large-scale systematic studies should follow to analyze the findings in broad. CLINICAL RELEVANCE STATEMENT: Consistent with other countries, there is a high prevalence of burnout among radiologists in Germany. A call for further investigation is recommended to help mitigate adverse outcomes associated with physician burnout. KEY POINTS: • The prevalence of burnout has yet not been evaluated for German radiologists. • German radiologists have a high prevalence of burnout. • Steps must be implemented to engage this problem to prevent worsening.

A New Iterative Metal Artifact Reduction Algorithm for Both Energy-Integrating and Photon-Counting CT Systems.

OBJECTIVES: The aim of this study was to introduce and evaluate a new metal artifact reduction framework (iMARv2) that addresses the drawbacks (residual artifacts after correction and user preferences for image quality) associated with the current clinically applied iMAR. MATERIALS AND METHODS: A new iMARv2 has been introduced, combining the current iMAR with new modular components to remove residual metal artifacts after image correction. The postcorrection image impression is adjustable with user-selectable strength settings. Phantom scans from an energy-integrating and a photon-counting detector CT were used to assess image quality, including a Gammex phantom and anthropomorphic phantoms. In addition, 36 clinical cases (with metallic implants such as dental fillings, hip replacements, and spinal screws) were reconstructed and evaluated in a blinded and randomized reader study. RESULTS: The Gammex phantom showed lower HU errors compared with the uncorrected image at almost all iMAR and iMARv2 settings evaluated, with only minor differences between iMAR and the different iMARv2 settings. In addition, the anthropomorphic phantoms showed a trend toward lower errors with higher iMARv2 strength settings. On average, the iMARv2 strength 3 performed best of all the clinical reconstructions evaluated, with a significant increase in diagnostic confidence and decrease in artifacts. All hip and dental cases showed a significant increase in diagnostic confidence and decrease in artifact strength, and the improvements from iMARv2 in the dental cases were significant compared with iMAR. There were no significant improvements in the spine. CONCLUSIONS: This work has introduced and evaluated a new method for metal artifact reduction and demonstrated its utility in routine clinical datasets. The greatest improvements were seen in dental fillings, where iMARv2 significantly improved image quality compared with conventional iMAR.

Medical students' general and radiology-specific motivation: Correlations, stability and associations with learning strategies and ability beliefs.

PURPOSE: This study investigated general and subject-specific motivational beliefs from the perspectives of self-determination theory (i.e. intrinsic, identified, introjected, and extrinsic motivation) and achievement goal theory (i.e. mastery, performance-approach, and -avoidance goal orientation including the respective classroom goal structures), their interrelations, their stability over time, and their associations with desirable outcomes (i.e. deep-level learning strategies, self-concept of ability). It was hypothesized that motivational beliefs are interrelated but demonstrate a distinct correlational pattern depending on whether they were assessed as general or subject-specific motivation. In addition, motivational beliefs were hypothesized to relate to learning strategies and ability beliefs. METHODS: Medical students (n = 146) participated in this longitudinal study with measurement points at the beginning and end of a semester. The questionnaire included established motivational scales to assess motivational beliefs and desirable outcomes. Measurement models were tested using confirmatory factor analyses; correlations of scale means were investigated to assess the nomological network of motivational beliefs. RESULTS: As expected, intrinsic and identified motivation were associated with mastery goal orientation and with desirable outcome variables, such as the use of deep-level learning strategies. General and subject-specific motivation exhibited distinct correlational patterns. Motivation was relatively stable over time. Results did not confirm the factor structure of classroom goal structure. CONCLUSIONS: The study emphasizes the benefit of a subject-specific conceptualization of motivation and the need for a careful adaptation of theoretical constructs from the secondary school context to make them fruitful for the promotion of medical students' motivation. Medical teachers can use established motivational interventions (e.g. using an individual frame of reference for feedback) to support students' adaptive motivational beliefs (e.g. self-determined motivation, mastery goals). Given the subject specificity of motivation, it seems beneficial to promote adaptive motivation in the respective medical specialty regardless of students' general motivational characteristics.

Analytical interference of intravascular contrast agents with clinical laboratory tests: a joint guideline by the ESUR Contrast Media Safety Committee and the Preanalytical Phase Working Group of the EFLM Science Committee.

The Contrast Media Safety Committee of the European Society of Urogenital Radiology has, together with the Preanalytical Phase Working Group of the EFLM Science Committee, reviewed the literature and updated its recommendations to increase awareness and provide insight into these interferences.

Feasibility of GPT-3 and GPT-4 for in-Depth Patient Education Prior to Interventional Radiological Procedures: A Comparative Analysis.

PURPOSE: This study explores the utility of the large language models, GPT-3 and GPT-4, for in-depth patient education prior to interventional radiology procedures. Further, differences in answer accuracy between the models were assessed. MATERIALS AND METHODS: A total of 133 questions related to three specific interventional radiology procedures (Port implantation, PTA and TACE) covering general information as well as preparation details, risks and complications and post procedural aftercare were compiled. Responses of GPT-3 and GPT-4 were assessed for their accuracy by two board-certified radiologists using a 5-point Likert scale. The performance difference between GPT-3 and GPT-4 was analyzed. RESULTS: Both GPT-3 and GPT-4 responded with (5) "completely correct" (4) "very good" answers for the majority of questions ((5) 30.8% + (4) 48.1% for GPT-3 and (5) 35.3% + (4) 47.4% for GPT-4). GPT-3 and GPT-4 provided (3) "acceptable" responses 15.8% and 15.0% of the time, respectively. GPT-3 provided (2) "mostly incorrect" responses in 5.3% of instances, while GPT-4 had a lower rate of such occurrences, at just 2.3%. No response was identified as potentially harmful. GPT-4 was found to give significantly more accurate responses than GPT-3 (p = 0.043). CONCLUSION: GPT-3 and GPT-4 emerge as relatively safe and accurate tools for patient education in interventional radiology. GPT-4 showed a slightly better performance. The feasibility and accuracy of these models suggest their promising role in revolutionizing patient care. Still, users need to be aware of possible limitations.

Waiting times between examinations with intravascularly administered contrast media: a review of contrast media pharmacokinetics and updated ESUR Contrast Media Safety Committee guidelines.

The pharmacokinetics of contrast media (CM) will determine how long safe waiting intervals between successive CT or MRI examinations should be. The Contrast Media Safety Committee has reviewed the data on pharmacokinetics of contrast media to suggest safe waiting intervals between successive contrast-enhanced imaging studies in relation to the renal function of the patient. CLINICAL RELEVANCE STATEMENT: Consider a waiting time between elective contrast-enhanced CT and (coronary) angiography with successive iodine-based contrast media administrations in patients with normal renal function (eGFR > 60 mL/min/1.73 m2) of optimally 12 h (near complete clearance of the previously administered iodine-based contrast media) and minimally 4 h (if clinical indication requires rapid follow-up). KEY POINTS: • Pharmacokinetics of contrast media will guide safe waiting times between successive administrations. • Safe waiting times increase with increasing renal insufficiency. • Iodine-based contrast media influence MRI signal intensities and gadolinium-based contrast agents influence CT attenuation.

Analytical interference of intravascular contrast agents with clinical laboratory tests: a joint guideline by the ESUR Contrast Media Safety Committee and the Preanalytical Phase Working Group of the EFLM Science Committee.

The Contrast Media Safety Committee of the European Society of Urogenital Radiology has, together with the Preanalytical Phase Working Group of the EFLM Science Committee, reviewed the literature and updated its recommendations to increase awareness and provide insight into these interferences. CLINICAL RELEVANCE STATEMENT: Contrast Media may interfere with clinical laboratory tests. Awareness of potential interference may prevent unwanted misdiagnosis. KEY POINTS: • Contrast Media may interfere with clinical laboratory tests; therefore awareness of potential interference may prevent unwanted misdiagnosis. • Clinical Laboratory tests should be performed prior to radiological imaging with contrast media or alternatively, blood or urine collection should be delayed, depending on kidney function.

Safe use of contrast media in myasthenia gravis: systematic review and updated European Society of Urogenital Radiology Contrast Media Safety Committee guidelines.

OBJECTIVES: It is uncertain whether modern iodine-based or gadolinium-based contrast media (CM) administration can lead to increased symptoms in patients with myasthenia gravis. METHODS: A systematic search in Medline was conducted for studies describing the symptomatology of myasthenia gravis patients before and after receiving intravenous (IV) CM and having a matched control group of myasthenia gravis patients who did not receive IV CM. RESULTS: Three retrospective studies were selected with a total of 374 myasthenia gravis patients who received iodine-based CM and a total of 313 myasthenia gravis patients who underwent unenhanced CT and served as controls. Pooling of the data from the three retrospective studies showed that in 23 of 374 patients, increased symptoms after iodine-based CM administration were described (6.1%). Increased symptomatology also occurred in 11 of 313 patients after unenhanced CT (3.5%). When looking more deeply into the data of the three studies, conflicting results were found, as two articles did not find any relationship between CM and myasthenia gravis symptoms. The remaining study only found a significant increase in symptomatology within 1 day after CT scanning: seven patients (6.3%) in the contrast-enhanced CT group and one patient (0.6%) in the unenhanced CT group (p = 0.01). CONCLUSIONS: There is limited evidence on the relationship between CM and myasthenia gravis symptoms. In the vast majority of myasthenia gravis patients, CM are safe. Probably, in less than 5% of the patients, iodine-based CM administration may lead to increased severity of the symptoms within the first 24 h after administration. CLINICAL RELEVANCE STATEMENT: Be aware that intravenous administration of iodine-based contrast media can lead to an increase of symptoms in patients with myasthenia gravis within the first 24 h. This can probably happen in less than 5% of the patients. KEY POINTS: • It is unclear whether modern contrast media can lead to increased symptoms in myasthenia gravis patients after intravenous administration. • There seems to be a small risk of increased myasthenia gravis symptoms within 24 h after intravenous administration of iodine-based contrast media, probably in less than 5% of the administrations. • Gadolinium-based contrast media are safe for patients with myasthenia gravis.

Radiology meets archaeology: digital restoration and 3D printing using CT data. / Radiologie trifft Archäologie: Restaurierung und 3D-Druck anhand von CT-Daten.

AIM: Archaeological objects are often recovered in blocks since highly porous materials and unstable and highly decayed objects cannot always be uncovered undamaged or time and resources for classic uncovering are lacking. Therefore, clinical computed tomography (CT) combined with freely available software solutions should be tested as a simple and fast method for visualizing and analyzing archaeological finds as an alternative to time-consuming restoration. MATERIALS AND METHODS: As an example, a block with a shield boss was selected from a block excavation and examined by means of CT. Using the freely available software 3D-Slicer (https://www.slicer.org/), the shield boss and handle were segmented in the surrounding soil with different tools. They were then digitally reconstructed and then restored using Meshmixer (Autodesk Inc., San Francisco, CA). A 3D print was generated based on the reconstructed model of the shield boss. RESULTS: The individual steps of CT examination of the block recovery, segmentation, reconstruction, and 3D printing were successfully performed. Based on the restored fragments of the shield boss, it was possible to date the object and to determine the initial properties of the find non-destructively without classic restoration. CONCLUSION: Radiological imaging combined with digital reconstruction and 3D printing makes it possible to determine decisive characteristics of the archaeological find before it is uncovered and restored, which is a time-consuming process. This opens up new opportunities for cooperation between radiology and archaeology for the evaluation and analysis of archaeological finds. KEY POINTS: · "The transfer of medical technology, digital image processing and 3D printing to archaeology has been demonstrated.". · "The digital restoration and reconstruction of archaeological objects using CT images is possible.". · "Medical imaging could make a significant contribution to the investigation and reconstruction of archaeological objects.". CITATION FORMAT: · Frohwerk E, Dürr A, Fiebich M et al. Radiology meets archaeology: digital restoration and 3D printing using CT data. Fortschr Röntgenstr 2023; DOI: 10.1055/a-2206-5741.

The Subdiaphragmatic Angle Of The Gastric Tube In Neonates - A Potential Predictor For Perforations?

BACKGROUND: Traumatic subdiaphramatic perforation of esophagus or stomach in neonates represents a rare clinical complication following the insertion of a gastric tube and is associated with high morbidity and mortality. The aim of the present study was to evaluate whether the angle of the gastric tube depicted on a plain radiograph may serve as a diagnostic tool to predict subdiaphragmatic traumatic (or iatrogenic) perforation. PATIENTS AND METHODS: Thoraco-abdominal radiographs of 128 preterm and term neonates without perforation and 15 neonates with perforation of the esophagogastric junction or the stomach were retrospectively analysed. RESULTS: The angle of the gastric tube increases with postnatal age (p=0.0380). In the control group, the angle of the gastric tube varied between 13° and 48° (median: 31°), whereas the values ranged from -31° to 42° (median: 11°) in neonates with subdiaphragmatic perforation. Perforation should thus be suspected in cases with an angle of<20° (sensitivity: 93.3%; specificity: 91.4%). Moreover, an unusual localization of the tip beyond the gastric bubble is highly indicative of perforation. DISCUSSION: The present study emphasizes the importance of verifying the correct course of an inserted gastric tube. CONCLUSIONS: In daily clinical practice, an angle of<20° should be followed by thorough physical examination, abdominal ultrasound and if applicable contrast medium examinations to exclude perforation.

Feasibility of the chick chorioallantoic membrane model for preclinical studies on tumor radiofrequency ablation.

BACKGROUND: We evaluated the feasibility of a chick chorioallantoic membrane (CAM) tumor model for preclinical research on tumor radiofrequency ablation (RFA). METHODS: Fertilized chicken eggs were incubated and divided into five cohorts: RFA for 30 s (n = 5), RFA for 60 s (n = 5), RFA for 120 s (n = 4), sham (n = 8), and controls (n = 6). Xenografting using pancreatic neuroendocrine tumor cells of the BON-1 cell line was performed on embryonic day (ED) 8. The RFA was performed on ED 12. Survival, stereomicroscopic observations, and histological observations using hematoxylin-eosin (H&E) and Ki67 staining were evaluated. RESULTS: The survival rates in the 30-s, 60-s, and 120-s, sham and control cohort were 60%, 60%, 0%, 100%, and 50%, respectively. Signs of bleeding and heat damage were common findings in the evaluation of stereomicroscopic observations. Histological examination could be performed in all but one embryo. Heat damage, bleeding, thrombosis, and leukocyte infiltration and hyperemia were regular findings in H&E-stained cuts. A complete absence of Ki67 staining was recorded in 33.3% and 50% of embryos in the 30-s and 60-s cohorts that survived until ED 14, respectively. CONCLUSIONS: The CAM model is a feasible and suiting research model for tumor RFA with many advantages over other animal models. It offers the opportunity to conduct in vivo research under standardized conditions. Further studies are needed to optimize this model for tumor ablations in order to explore promising but unrefined strategies like the combination of RFA and immunotherapy. RELEVANCE STATEMENT: The chick chorioallantoic membrane model allows in vivo research on tumor radiofrequency ablation under standardized conditions that may enable enhanced understanding on combined therapies while ensuring animal welfare in concordance with the "Three Rs." KEY POINTS: • The chorioallantoic membrane model is feasible and suiting for tumor radiofrequency ablation. • Radiofrequency ablation regularly achieved reduction but not eradication of Ki67 staining. • Histological evaluation showed findings comparable to changes in humans after RFA. • The chorioallantoic membrane model can enable studies on combined therapies after optimization.

Safety and efficacy of interventional treatment of acute limb ischemia in Germany 2021.

PURPOSE: Interventional procedures have become a mainstay in the therapy of acute limb ischemia caused by embolism or arterial thrombosis. Treatment options include pharmacological thrombolysis (PT) and mechanical thrombectomy (MT). The aim of this study was to evaluate success and major complication rates of interventional radiological treatments of arterial embolism and thrombosis in Germany in 2021 and to compare their results with accepted international quality standards. MATERIALS AND METHODS: Data for PT and MT for 2021 was obtained from the quality management system of the German interventional radiological society (DeGIR). 2431 PT and 1582 MT procedures were documented for 2021, with 459 combinations of PT and MT. Data was analysed for technical and clinical success rates, as well as major complication rates such as intracranial bleeding, major bleeding, distal embolization, aneurysm formation, organ-failure and cardiac-decompensation. RESULTS: PT alone had technical and clinical success rate of 90.21% and 81.08%, respectively. MT alone had technical and clinical success rates of 97.41% and 95.39%, respectively. MT&PT had technical and clinical success rates of 91.07% and 84.75%, respectively. Major complications were: distal embolization (PT:2.02%; MT:1.74%; PT&MT:2.61%), major bleeding (PT:0.94%; MT:1.14%; PT&MT:0.87%), aneurysm formation (PT:0.33%;MT: 1.14%;PT&MT: 0%), intracranial bleeding (PT:0.16%;MT:0%;PT&MT:0.22%), cardiac-decompensation (PT:0.21%;MT: 0.06%;PT&MT:0%) and organ-failure (PT:0%;MT:0.06%;PT&MT:0.22%). Technical and clinical success rates were higher, while complication rates were lower than the corresponding threshold recommended by the Society of Interventional Radiology for percutaneous management of acute lower-extremity ischemia. CONCLUSION: Treatment of arterial embolism and thrombosis performed by interventional radiologists in Germany is effective and safe with outcomes exceeding internationally accepted standards.

A nonlinear scaling-based normalized metal artifact reduction to reduce low-frequency artifacts in energy-integrating and photon-counting CT.

BACKGROUND: Metal within the scan plane can cause severe artifacts when reconstructing X-ray computed tomography (CT) scans. Both in clinical use and recent research, normalized metal artifact reduction (NMAR) has established as the reference method for correcting metal artifacts, but NMAR introduces inconsistencies within the sinogram, which can cause additional low-frequency artifacts after image reconstruction. PURPOSE: This paper introduces an extension to NMAR by applying a nonlinear scaling function (NLS-NMAR) to reduce low-frequency artifacts, which get introduced by the reconstruction of interpolation-edge-related sinogram inconsistencies in the normalized sinogram domain. METHODS: After linear interpolation of the metal trace, an NLS function is applied in the prior-normalized sinogram domain to reduce the impact of the interpolation edges during filtered backprojection. After sinogram denormalization and image reconstruction, the low frequencies of the NLS image are combined with different high frequencies to restore anatomic details. An anthropomorphic dental phantom with removable metal inserts was utilized on two different CT systems to quantitatively assess the artifact reduction performance in terms of HU deviations and the root-mean-square-error within relevant regions of interest. Clinical dental examples were assessed to qualitatively demonstrate the problem of the interpolation-related blooming as well as to demonstrate the performance of the NLS function to reduce respective artifacts. To quantitatively prove HU consistency, HU values were assessed in central ROIs in the clinical cases. In addition, single clinical cases of a hip replacement and pedicle screws in the spine are shown to demonstrate the method's results in other body regions. RESULTS: The NLS-NMAR can minimize the effect of interpolation-related sinogram inconsistencies and thus reduce resulting hyperdense blooming artifacts. In the phantom results, the reconstructions with the NLS-NMAR-corrected low frequencies demonstrate the lowest error. In the qualitative assessment of the clinical data, the NLS-NMAR shows a tremendous enhancement in image quality, also performing best within all assessed images series. CONCLUSION: The NLS-NMAR provides a small yet effective extension to conventional NMAR by reducing low-frequency hyperdense metal trace-interpolation-related artifacts in computed tomography.

pTEVAR of an aorto-esophageal fistula in esophageal cancer: Case report and review of the literature.

An aorto-esophageal fistula (AEF) is a rare and life-threatening situation, associated with aneurysms, foreign bodies, infiltrating tumors, and radiotherapy. The ideal management is unclear. Open surgery of AEF has a high mortality and morbidity. Thoracic endovascular aortic repair (TEVAR) of an AEF is an effective and safe emergency treatment for these patients. We describe a case of AEF due to esophageal cancer successfully treated the first time by total percutaneous TEVAR (pTEVAR). A 70-year-old male patient presented with massive hematemesis at the emergency department. The patient had a known history of esophageal cancer previously treated by radiochemotherapy which was completed 3 days before. Emergency upper gastrointestinal endoscopy failed to stop the bleeding. Subsequent contrast-enhanced computed tomography revealed an aorto-esophageal fistula and emergency pTEVAR was performed. The bleeding stopped directly after stent graft placement and the patient was discharged after 10 days later. He died 3 months after pTEVAR from cancer progression. pTEVAR is an effective and safe treatment option for AEF. It can be applied as a first-line treatment and offers the potential to improve survival in the emergency setting.

How to Xenograft Cancer Cells on the Chorioallantoic Membrane of a Fertilized Hen's Egg and Its Visualization by PET/CT and MRI.

The chorioallantoic membrane (CAM) of fertilized hen's eggs represents a unique and alternative model for cancer research. The CAM model provides an optimal platform for xenografting cancer cell lines and studying essential key factors. Tumor size and growth as well as angiogenesis can be investigated to evaluate the response of therapies and strategies against cancer. Preclinical imaging represented by magnetic resonance imaging and positron emission tomography/computed tomography can generate detailed anatomical and functional information and reveal excellent metabolic sensitivity. In the following, a guideline is introduced in order to find a simplified entrance to the CAM model in combination with modern preclinical imaging techniques. Finally, the presented procedures are additionally completed by histological studies in the form of hematoxylin and eosin as well as immunohistochemical staining.