Image Quality and Radiation Exposure in Abdominal Angiography: A Head-to-Head Comparison of Conventional Detector-Dose-Driven Versus Contrast-to-Noise Ratio-Driven Exposure Control at Various Source-to-Image Receptor Distances and Collimations in a Pilot Phantom and Animal Study.

OBJECTIVES: This phantom and animal pilot study aimed to compare image quality and radiation exposure between detector-dose-driven exposure control (DEC) and contrast-to-noise ratio (CNR)-driven exposure control (CEC) as functions of source-to-image receptor distance (SID) and collimation. MATERIALS AND METHODS: First, an iron foil simulated a guide wire in a stack of polymethyl methacrylate and aluminum plates representing patient thicknesses of 15, 25, and 35 cm. Fluoroscopic images were acquired using 5 SIDs ranging from 100 to 130 cm and 2 collimations (full field of view, collimated field of view: 6 × 6 cm). The iron foil CNRs were calculated, and radiation doses in terms of air kerma rate were obtained and assessed using a multivariate regression. Second, 5 angiographic scenarios were created in 2 anesthetized pigs. Fluoroscopic images were acquired at 2 SIDs (110 and 130 cm) and both collimations. Two blinded experienced readers compared image quality to the reference image using full field of view at an SID of 110 cm. Air kerma rate was obtained and compared using t tests. RESULTS: Using DEC, both CNR and air kerma rate increased significantly at longer SID and collimation below the air kerma rate limit. When using CEC, CNR was significantly less dependent of SID, collimation, and patient thickness. Air kerma rate decreased at longer SID and tighter collimation. After reaching the air kerma rate limit, CEC behaved similarly to DEC. In the animal study using DEC, image quality and air kerma rate increased with longer SID and collimation (P < 0.005). Using CEC, image quality was not significantly different than using longer SID or tighter collimation. Air kerma rate was not significantly different at longer SID but lower using collimation (P = 0.012). CONCLUSIONS: CEC maintains the image quality with varying SID and collimation stricter than DEC, does not increase the air kerma rate at longer SID and reduces it with tighter collimation. After reaching the air kerma rate limit, CEC and DEC perform similarly.

[Spontaneous retroperitoneal and rectus sheath hematomas and their interventional therapy: a review]. / Spontane retroperitoneale und Rektusscheidenhämatome und ihre interventionelle Therapie: ein Review.

BACKGROUND: Retroperitoneal and rectus sheath hemorrhage (RRSH) has been described as a potentially fatal condition with mortality rates of up to 30 % due to the risk of exsanguination in combination with often nonspecific clinical symptoms. Patients at risk are > 65 years of age as well as those receiving anticoagulation/antiplatelet medicine. Classifications based on etiology consist of trauma, surgery, and/or underlying vascular pathologies, though spontaneous occurrences without precipitating factors have been reported and are expected to increase with the high number of patients undergoing anticoagulant therapy. METHOD: Analysis, summary, and discussion of published review articles and expert recommendations. RESULTS: The most commonly described symptom during clinical examination is abdominal pain. However, depending on the volume loss, clinical symptoms may include signs of abdominal compartment and hemorrhagic shock. Computed tomography angiography (CTA) with high sensitivity and specificity for the presence of active bleeding plays an important role in the detection of RH and RSH. Therapy management is based on different pillars, which include surgical and interventional measures in addition to conservative measures (volume replacement, optimization of coagulation parameters). Due to its lower invasiveness with simultaneously high technical and clinical success rates, interventional therapy in particular has gained increasing importance. CONCLUSION: Diagnostic and therapeutic workup of the patients by an interdisciplinary team is essential for optimal patient care. In case of transcatheter arterial embolization, a standardized approach to the detection of bleeding sites within the vascular territory of the core hematoma appears to favorably influence success and patient outcome. KEY POINTS: · The clinical presentation of retroperitoneal and rectus sheath hematomas can be very heterogeneous and nonspecific. Quick diagnosis is essential due to the relatively high mortality rate (approx. 12-30 %).. · The main risk factors are age > 65 years and the intake of anticoagulants, the use of which has increased 2.5 times in the last 10 years. Coagulopathies, retroperitoneal masses, and hemodialysis are less common causes.. · Computed tomography angiography (CTA) has a high sensitivity and specificity for the presence of active bleeding and has replaced diagnostic subtraction angiography (DSA).. · Treatment should be performed in a multidisciplinary setting with the inclusion of internal medicine, radiology, and surgery. The main indications for embolization are the detection of active contrast extravasation on CTA and the presence of abdominal pain. In cases without active bleeding and with stable vital parameters, conservative treatment measures can be sufficient. Surgical treatment is often reserved for treatment-refractory bleeding with symptoms of abdominal compartment.. · A systematic standardized approach to the detection of bleeding on DSA seems to have advantages regarding technical and clinical success rates.. CITATION FORMAT: · Becker LS, Dewald CLA et al. Spontaneous retroperitoneal and rectus sheath hematomas and their interventional therapy: a review. Fortschr Röntgenstr 2024; 196: 163 - 175.

Classification of Diverticular Disease (CDD) - assessment of the intra- and interobserver agreement in abdominal CT scans.

PURPOSE: Along with ultrasound, computed tomography (CT) is one of the imaging modalities of choice in patients with suspected diverticular disease (DD). Recently, a newer Classification of Diverticular Disease (CDD) has been proposed. However, its reliability in daily radiological practice has never been proven. Therefore, our aim was to evaluate the intra- and interobserver agreement of the CDD in abdominal CT scans. METHODS: In this retrospective study, 481 CT scans of patients with suspected DD were included. Two readers (one board-certified radiologist with 6 years of experience, one 3 rd year radiology resident) individually evaluated all CTs in two reading sessions using the CDD. A composite endpoint of a prior consensus reading, follow-up, and intraoperative findings served as the reference. Intra- and interobserver agreement were calculated using Cohen-k statistic. RESULTS: DD was present in 317 cases (66 %), mostly classified as CDD stage 0, 1b, and 2a (28 %, 30 %, und 14 %). Intraobserver agreement was almost perfect for both readers (kappa 0.93 and 0.88). Interobserver agreement was high and improved from substantial (kappa 0.77) in the first reading session to almost perfect (kappa 0.84) in the second reading session. The interobserver agreement was best for CDD types 0 (diverticulosis) and 2c (free perforated diverticulitis) (mean kappa 0.83 and 0.86) and poorest for CDD types 1a (diverticulitis without phlegmon) and 2b (covered diverticulitis with macroabscess) (mean kappa 0.17 and 0.38). Intra- and interobserver agreement of acute uncomplicated (CDD type 1) and acute complicated diverticulitis (CDD type 2) were substantial to almost perfect (mean kappa 0.63-0.86). Agreement with the reference was almost perfect for both observers (mean kappa 0.86 and 0.82). Administration of rectal contrast did not significantly improve the diagnosis. CONCLUSION: The CDD is a classification based on relatively clear imaging characteristics, which can be readily applied by radiologists with different expertise. In our study, the CDD had a high intra- and interobserver agreement, enabling a reliable therapy-related categorization of DD. KEY POINTS: · The Classification of Diverticular Disease (CDD) is an easy-to-use classification for diverticular disease based on relatively clear image features.. · The CDD can be applied equally by radiologists with different levels of experience in the clinical routine.. · The high intra- and interobserver agreement indicates high reliability in the therapy-relevant classification of diverticulitis on CT..

Regional Pulmonary Morphology and Function: Photon-counting CT Assessment.

Background Experience with functional CT in the lungs without additional equipment in clinical routine is limited. Purpose To report initial experience and evaluate the robustness of a modified chest CT protocol and photon-counting CT (PCCT) for comprehensive analysis of pulmonary vasculature, perfusion, ventilation, and morphologic structure in a single examination. Materials and Methods In this retrospective study, consecutive patients with clinically indicated CT for various known and unknown pulmonary function impairment (six subgroups) were included between November 2021 and June 2022. After administration of an intravenous contrast agent, inspiratory PCCT was followed by expiratory PCCT after a delay of 5 minutes. Advanced automated postprocessing was performed, and CT-derived functional parameters were calculated (regional ventilation, perfusion, late contrast enhancement, and CT angiography). Mean intravascular contrast enhancement in the mediastinal vessels and radiation dose were determined. Using analysis of variance, the mean values of lung volumes, attenuation, ventilation, perfusion, and late contrast enhancement were tested for differences between subgroups of patients. Results In 166 patients (mean age, 63.2 years ± 14.2 [SD]; 106 male patients), all CT-derived parameters could be acquired (84.7% success rate; 166 of 196 patients). At the inspiratory examination, mean density was 325 HU in the pulmonary trunk, 260 HU in the left atrium, and 252 HU in the ascending aorta. The mean dose-length product for inspiration and expiration was 110.32 mGy · cm and 109.47 mGy · cm, respectively; the mean CT dose index for inspiration and expiration was 3.22 mGy and 3.09 mGy, respectively (less than the mean total radiation dose of 8-12 mGy, which is diagnostic reference level). Significant differences (P < .05) between the subgroups were found for all assessed parameters. Visual inspection allowed for voxelwise assessment of morphologic structure and function. Conclusion The proposed PCCT protocol allowed for a dose-efficient and robust simultaneous evaluation of pulmonary morphologic structure, ventilation, vasculature, and parenchymal perfusion in a procedure requiring advanced software but no additional hardware. © RSNA, 2023.

Heparin reversal with protamine sulfate after Percutaneous Hepatic Perfusion (PHP): is less more?

PURPOSE: Percutaneous hepatic perfusion (PHP) is a palliative intraarterial therapy for unresectable hepatic malignancies. During PHP, high-dose melphalan is infused via the hepatic artery to saturate tumor in the liver with the chemotherapeutic substance. The venous hepatic blood is filtered by an extracorporeal melphalan specific filtration system. Blood clotting in the extracorporeal filter system is prevented by administering unfractionated heparin (UFH) in high doses, which might be reversed with protamine sulfate after the procedure. Aim of this retrospective two-center-study was to analyze the potential effect of UFH reversal with protamine sulfate on complication rates following PHP. MATERIALS AND METHODS: All patients receiving PHP treatment between 10/2014 and 04/2021 were classified according to their intraprocedural coagulation management: 92 patients/192 PHP received full UFH reversal with protamine (groupPROTAMINE); 13 patients/21 PHP in groupREDUCED_PROTAMINE received a reduced amount of protamine, and 28 patients/43 PHP did not receive UFH reversal with protamine (groupNO_PROTAMINE). Periinterventional clinical reports, findings and laboratory values were retrospectively evaluated. Complications and adverse events were classified according to Common Terminology Criteria for Adverse Events (CTCAEv5.0). RESULTS: Thromboembolic events were recorded after 10 PHP procedures (5%) in groupPROTAMINE, six of which (3%) were major events (CTCAE grade 3-5). No (0%) thromboembolic events were recorded in groupREDUCED_PROTAMINE and groupNO_PROTAMINE. Hemorrhagic events were registered after 24 PHP (13%) in groupPROTAMINE, two of which (1%) were major (CTCAE grade 3-4). In groupREDUCED_PROTAMINE, only minor bleeding events were recorded, and one major hemorrhagic event was documented in groupNO_PROTAMINE (2%). There was a significant difference between the percentage of post-interventional thrombopenia in groupPROTAMINE (39%) and groupREDUCED_PROTAMINE (14%) versus groupNO_PROTAMINE (23%) (p=.00024). In groupPROTAMINE one patient suffered from a severe anaphylactic shock after the administration of protamine. CONCLUSION: Our retrospective study implies that there might be a link between the practice of protamine sulfate administration to reverse the full hemodilutive effect of UFH after PHP and the post-interventional risk of thromboembolic events as well as clinically significant thrombopenia. Our data suggest that the standard use of protamine sulfate after PHP in low-risk patients without clinical signs of active bleeding should be critically re-evaluated.

Portal Vein Recanalization-Transjugular Intrahepatic Portosystemic Shunt (PVR-TIPS) with superior mesenteric vein access and balloon-assisted shunt placement.

BACKGROUND: To report the technique and outcome of ultrasound-guided percutaneous access to the superior mesenteric vein (SMV) for balloon-assisted portal vein recanalization-transjugular intrahepatic portosystemic shunt (PVR-TIPS) in a patient with chronic portal venous and splenic vein occlusion. CASE PRESENTATION: A 51-year-old, non-cirrhotic patient with severe portal hypertension was admitted for PVR-TIPS. Neither splenic nor hepatic access was feasible due to chronic portal and splenic vein occlusion. Percutaneous ultrasound-guided direct puncture of the SMV was performed to obtain access for balloon-assisted PVR-TIPS. The transmesenteric approach in combination with a balloon puncture technique for PVR-TIPS was successful, and no immediate complications were observed post-procedure. The subsequent follow-up exams showed patent TIPS and SMV without signs of intraabdominal hemorrhage. CONCLUSION: Percutaneous ultrasound-guided superior mesenteric vein access for balloon-assisted PVR-TIPS is a feasible option in cases where hepatic or splenic access is not.

Automated Classification of Free-Text Radiology Reports: Using Different Feature Extraction Methods to Identify Fractures of the Distal Fibula.

PURPOSE: Radiology reports mostly contain free-text, which makes it challenging to obtain structured data. Natural language processing (NLP) techniques transform free-text reports into machine-readable document vectors that are important for creating reliable, scalable methods for data analysis. The aim of this study is to classify unstructured radiograph reports according to fractures of the distal fibula and to find the best text mining method. MATERIALS & METHODS: We established a novel German language report dataset: a designated search engine was used to identify radiographs of the ankle and the reports were manually labeled according to fractures of the distal fibula. This data was used to establish a machine learning pipeline, which implemented the text representation methods bag-of-words (BOW), term frequency-inverse document frequency (TF-IDF), principal component analysis (PCA), non-negative matrix factorization (NMF), latent Dirichlet allocation (LDA), and document embedding (doc2vec). The extracted document vectors were used to train neural networks (NN), support vector machines (SVM), and logistic regression (LR) to recognize distal fibula fractures. The results were compared via cross-tabulations of the accuracy (acc) and area under the curve (AUC). RESULTS: In total, 3268 radiograph reports were included, of which 1076 described a fracture of the distal fibula. Comparison of the text representation methods showed that BOW achieved the best results (AUC = 0.98; acc = 0.97), followed by TF-IDF (AUC = 0.97; acc = 0.96), NMF (AUC = 0.93; acc = 0.92), PCA (AUC = 0.92; acc = 0.9), LDA (AUC = 0.91; acc = 0.89) and doc2vec (AUC = 0.9; acc = 0.88). When comparing the different classifiers, NN (AUC = 0,91) proved to be superior to SVM (AUC = 0,87) and LR (AUC = 0,85). CONCLUSION: An automated classification of unstructured reports of radiographs of the ankle can reliably detect findings of fractures of the distal fibula. A particularly suitable feature extraction method is the BOW model. KEY POINTS: · The aim was to classify unstructured radiograph reports according to distal fibula fractures.. · Our automated classification system can reliably detect fractures of the distal fibula.. · A particularly suitable feature extraction method is the BOW model.. CITATION FORMAT: · Dewald CL, Balandis A, Becker LS et al. Automated Classification of Free-Text Radiology Reports: Using Different Feature Extraction Methods to Identify Fractures of the Distal Fibula. Fortschr Röntgenstr 2023; 195: 713 - 719.

Intraarterial embolizations in life-threatening spontaneous retroperitoneal and rectus sheath hemorrhage (SRRSH): a three-center experience.

PURPOSE: To retrospectively evaluate the technical and clinical success of interventional treatments employed in three University medical centers and to develop work-flow recommendations for intra-arterial embolizations in patients with life-threatening spontaneous retroperitoneal and rectus sheath hemorrhage (SRRSH). MATERIALS AND METHODS: Retrospective evaluation of all patients with contrast-enhanced CT and digital subtraction angiography (DSA) for SRRSH from 01/2018 to 12/2022, amounted to 91 interventions in 83 patients (45f, 38m) with a mean age of 68.1 ± 13.2 years. Analysis of the amount of bleeding and embolized vessels, choice of embolization material, technical success, and 30-day mortality was performed. RESULTS: Pre-interventional contrast-enhanced CT demonstrated active contrast extravasation in 79 cases (87%). DSA identified a mean of 1.4 ± 0.88 active bleeds in all but two interventions (98%), consisting of 60 cases with a singular and 39 cases of >1 bleeding artery, which were consecutively embolized. The majority of patients underwent embolization with either n-butyl-2-cyanoacrylate (NBCA; n=38), coils (n=21), or a combination of embolic agents (n=23). While the technical success rate was documented at 97.8%, 25 patients (30%) died within 30 days after the initial procedure, with mortality rates ranging from 25 to 86% between the centers, each following different diagnostic algorithms. CONCLUSION: Embolotherapy is a safe therapy option with high technical success rates in patients with life-threatening SRRSH. To maximize clinical success and survival rates, we propose a standardized approach to angiography as well as a low threshold for re-angiography.

Photon-counting CT of elbow joint fractures: image quality in a simulated post-trauma setting with off-center positioning.

BACKGROUND: Photon-counting detector computed tomography (PCD-CT) has the potential to provide superior image quality compared to energy-integrating detector computed tomography (EID-CT). We compared the two systems for elbow imaging in off-center arm positioning, 90° flexion, and cast fixation in a simulated post-trauma setting. METHODS: The institutional review board approved the study protocol. In a cadaver study, an olecranon fracture was artificially created in ten whole arm specimens. Two different scanning positions were evaluated: (a) arm overhead; and (b) arm on top of the abdomen of a whole-body phantom. The ultra-high resolution mode with three dose protocols and two reconstruction kernels was applied. Two blinded radiologists independently evaluated fracture and trabecular bone delineation. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and cortical sharpness measurements were performed. Cohen κ correlations, Mann-Whitney U and Wilcoxon signed rank tests were used. A p value lower than 0.05 was considered statistically significant. RESULTS: Dose-equivalent PCD-CT scans were rated better for fracture and trabecular bone evaluation (p < 0.001). SNR, CNR, and cortical sharpness were higher for all diagnostic (Br76) PCD-CT images (p < 0.001). The arm position had less effect on image quality in the PCD-CT compared to the EID-CT. The use of a sharp bone kernel (Br89) improved image quality ratings for PCD-CT. In the low-dose scan mode, PCD-CT resulted in more diagnostic scans (75%) compared to EID-CT (19%). CONCLUSIONS: PCD-CT provided superior objective and subjective image quality for fracture and trabecular bone structures delineation of the elbow compared to EID-CT in a typical post-trauma setting. KEY POINTS: • Photon-counting detector computed tomography (PCD-CT) preserved high image quality in elbow imaging with off-center positions. • PCD-CT was advantageous for bone evaluation in trauma elbows. • PCD-CT ultra-high-resolution mode and very sharp reconstruction kernels facilitated higher image quality.

Impact of the COVID-19 Pandemic on Interventional Radiology in Germany. / Auswirkung der COVID-19-Pandemie auf die Interventionelle Radiologie in Deutschland.

PURPOSE: To investigate the effect of the ongoing COVID-19 pandemic on interventional radiology (IR) in Germany in 2020 and 2021. MATERIALS UND METHODS: This retrospective study is based on the nationwide interventional radiology procedures documented in the quality register of the German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR-QS-Register). The nationwide volume of interventions in the pandemic years 2020 and 2021 was compared with the pre-pandemic period (Poisson-test, Mann-Whitney test). The aggregated data were additionally evaluated by intervention type with differentiated consideration of the temporal epidemiological infection occurrence. RESULTS: During the two pandemic years 2020 and 2021, the number of interventional procedures increased by appr. 4 % compared to the same period of the previous year (n = 190 454 and 189 447 vs. n = 183 123, respectively, p < 0.001). Only the first pandemic wave in spring 2020 (weeks 12-16) showed a significant temporary drop in the number of interventional procedures by 26 % (n = 4799, p < 0.05). This primarily involved interventions that were not immediately medically urgent, such as pain treatments or elective arterial revascularization. In contrast, interventions in the field of interventional oncology, such as port catheter implantations and local tumor ablations, remained unaffected. The decline of the first wave of infection was accompanied by a rapid recovery and a significant, partly compensatory, 14 % increase in procedure numbers in the second half of 2020 compared to the same period of the previous year (n = 77 151 vs. 67 852, p < 0.001). Subsequent pandemic waves had no effect on intervention numbers. CONCLUSION: The COVID-19 pandemic in Germany led to a significant short-term decrease in interventional radiology procedures in the initial phase. A compensatory increase in the number of procedures was observed in the subsequent period. This reflects the adaptability and robustness of IR and the high demand for minimally invasive radiological procedures in medical care. KEY POINTS: · The study shows the nationwide pandemic-related effects on interventional radiology in Germany.. · In quantitative terms, the ongoing pandemic caused a significant, temporary decline in intervention cases only in the initial phase.. · Subsequent waves of infections had no effect on the scope of services provided by interventional radiology.. · Short-term deficits, especially in elective interventions, could be partially compensated.. CITATION FORMAT: · Schmidbauer M, Busjahn A, Paprottka P et al. Impact of the COVID-19 Pandemic on Interventional Radiology in Germany. Fortschr Röntgenstr 2023; 195: 597 - 604.

New perspectives in unresectable cholangiocarcinoma? Evaluation of chemosaturation with percutaneous hepatic perfusion as a palliative treatment option.

Cholangiocarcinoma (CCA) are the second most common primary liver tumors and carry a dismal prognosis. Chemosaturation with percutaneous hepatic perfusion (PHP) is a palliative, intra-arterial therapeutic approach that provides a high dose chemotherapy of the liver with reduced systemic exposure. Aim of this retrospective, monocentric study was to analyze PHP as a palliative treatment for unresectable CCA. Toxicity, adverse events and complications were classified using the Common Terminology Criteria for Adverse Events (CTCAE v5.0). Overall response rate (ORR) and disease control rate (DCR) were evaluated according to the Response Evaluation Criteria in Solid Tumors (RECIST1.1). Median overall survival (mOS), median progression-free survival (mPFS) and hepatic mPFS (mhPFS) were computed using Kaplan-Meier estimation. In total 17 patients were treated with 42 PHP between 10/2014 and 09/2020. No significant complications occurred during the interventions. mOS was 27.6 (interquartile range (IQR) 16.5-37) months from first diagnosis and 9.9 (IQR 3.8-21) months from first PHP. mPFS was 4 (IQR 2-7) and mhPFS was 4 (IQR 3-10) months. ORR was 25% and DCR 75%. Significant, but transient hematotoxicity was frequent with grade 3/4 thrombopenia after 50%, leukopenia after 26% and anaemia after 21% of the interventions. An increase of transaminases (AST increase after 21% and ALT increase after 14% of the PHP) developed more often than a deterioration of the liver synthesis capacity. Salvage treatment with PHP has the potential to prolong life in selected patients with unresectable, refractory cholangiocarcinoma. The interventional procedure is safe. Post-interventional toxicity is frequent but manageable.

Fully Integrated Laser Guidance for CT-Based Punctures: A Study in Phantoms and Patients.

PURPOSE: To test the hypothesis of equal or even superior applicability and accuracy of a fully integrated, laser-based computed tomography (CT) navigation system compared with conventional CT guidance for percutaneous interventions. MATERIALS AND METHODS: CT-guided punctures were first performed in phantoms. Four radiologists with different experience levels (2 residents (L.B., C.D.) and 2 board-certified radiologists (B.M., K.R.) performed 48 punctures using both conventional image-guided and laser-guided approaches. Subsequently, 12 punctures were performed in patients during a clinical pilot trial. Phantom targets required an in-plane or a single-/double-angulated, out-of-plane approach. Planning and intervention time, control scan number, radiation exposure, and accuracy of needle placement (measured by deviation of the needle tip to the designated target) were assessed for each guidance technique and compared (Mann-Whitney U test and t test). Patient interventions were additionally analyzed for applicability in a clinical setting. RESULTS: The application of laser guidance software in the phantom study and in 12 human patients in a clinical setting was both technically and clinically feasible in all cases. The mean planning time (P = .009), intervention time (P = .005), control scan number (P < .001), and radiation exposure (P = .013) significantly decreased for laser-navigated punctures compared with those for conventional CT guidance and especially in punctures with out-of-plane-trajectories. The accuracy significantly increased for laser-guided interventions compared with that for conventional CT (P < .001). CONCLUSIONS: Interventional radiologists with differing levels of experience performed faster and more accurate punctures for out-of-plane trajectories in the phantom models, using a new, fully integrated, laser-guided CT software and demonstrated excellent clinical and technical success in initial clinical experiments.

Identification of Relevant Attributes for Liver Cancer Therapies (IRALCT): a maximum-difference-scaling analysis.

The Identification of Relevant Attributes for Liver Cancer Therapies (IRALCT) project is intended to provide new insights into the relevant utility attributes regarding therapy choices for malignant primary and secondary liver tumors from the perspective of those who are involved in the decision-making process. It addresses the potential value of taking patients' expectations and preferences into account during the decision-making and, when possible, adapting therapies according to these preferences. Specifically, it is intended to identify the relevant clinical attributes that influence the patients', medical laymen's, and medical professionals' decisions and compare the three groups' preferences. We conducted maximum difference (MaxDiff) scaling among 261 participants (75 physicians, 97 patients with hepatic malignancies, and 89 medical laymen) to rank the importance of 14 attributes previously identified through a literature review. We evaluated the MaxDiff data using count analysis and hierarchical Bayes estimation (HB). Physicians, patients, and medical laymen assessed the same 7 attributes as the most important: probability (certainty) of a complete removal of the tumor, probability of reoccurrence of the disease, pathological evidence of tumor removal, possible complications during the medical intervention, welfare after the medical intervention, duration and intensity of the pain, and degree of difficulty of the medical intervention. The cumulative relative importance of these 7 attributes was 88.3%. Our results show that the physicians', patients', and medical laymen's preferences were very similar and stable.Trial registration DRKS-ID of the study: DRKS00013304, Date of Registration in DRKS: 2017/11/16.

Work and Training Conditions of German Residents and Young Radiologists in Interventional Radiology - A Nationwide Survey.

With the increasing need for minimally invasive procedures based on lower complication rates, higher patient acceptance, and technical developments, there is a growing focus on the sound interventional training of young radiologists. This survey aimed to analyze the current situation in interventional radiology (IR) training in Germany to detect shortcomings and identify areas for improvement.From November 1-30, 2020, an online questionnaire was distributed to representative radiological associations and societies with the request to forward it to radiology residents and radiologists < 40 years. The 44 questions covered six distinct areas from personal working conditions to the characterization of the IR department, training conditions, role of women in IR, and attendance at congresses/external training.A total of 330 participants completed the questionnaire. 77 % of participants expressed a high interest in IR, and 47 % could even imagine subspecializing in interventional radiology. Most institutions provided the necessary learning conditions and infrastructure. The rate of overall satisfaction with IR training conditions was 45 % (vs. a dissatisfaction rate of 39 %). However, females showed a lower satisfaction rate with their training environment than male participants (28 % vs. 51 %; P = 0.06). Positive correlations with work satisfaction were found for the presence and duration of the IR rotation, the number of partly independently/mentored performed interventions, and structured feedback. Moreover, the need for a structured training curriculum was expressed by 67 % of participants.Radiological residents and young radiologists expressed a high interest in interventional radiology, and they rate the infrastructure of German hospitals regarding IR as sufficient. However, they expressed the need for consistent IR rotations and better-structured resident and postgraduate education (curricula & interviews).Interest in interventional radiology among radiological residents and young radiologists in Germany is high, but satisfaction with interventional radiology training leaves room for improvement. The most frequently mentioned aspects that can improve IR training were · organized rotations of at least 6 months. · structured curriculums with face-to-face feedback. · structured guidance by senior interventionists during procedures. CITATION FORMAT: · Sieren M, Katoh M, Mahnken AH et al. Work and Training Conditions of German Residents and Young Radiologists in Interventional Radiology - A Nationwide Survey. Fortschr Röntgenstr 2022; 194: 1346 - 1357.

Effectuality study of a 3D motion correction algorithm in C-arm CTs of severely impaired image quality during transarterial chemoembolization.

BACKGROUND: To evaluate effectivity of a 3D-motion correction algorithm in C-Arm CTs (CACT) with limited image quality (IQ) during transarterial chemoembolization (TACE). METHODS: From 1/2015-5/2021, 644 CACTs were performed in patients during TACE. Of these, 27 CACTs in 26 patients (18 m, 8f; 69.7 years ± 10.7 SD) of limited IQ were included. Post-processing of the original raw-data sets (CACTOrg) included application of a 3D-motion correction algorithm and bone segmentation (CACTMC_no_bone). Four radiologists (R1-4) compared the images by choosing their preferred dataset and recommending repeat acquisition in case of severe IQ-impairment. R1,2 performed additional grading of intrahepatic vessel visualization, presence/extent of movement artifacts, and overall IQ. RESULTS: R1,2 demonstrated excellent interobserver agreement for overall IQ (ICC 0.79,p < 0.01) and the five-point vessel visualization scale before and after post-processing of the datasets (ICC 0.78,p < 0.01). Post-processing caused significant improvement, with overall IQ improving from 2.63 (CACTOrg) to 1.39 (CACTMC_no_bone;p < 0.01) and a decrease in the mean distance of identifiable, subcapsular vessels to the liver capsule by 4 mm (p < 0.01). This proved especially true for datasets with low parenchymal and high hepatic artery contrast. A good interobserver agreement (ICC = 0.73) was recorded concerning the presence of motion artifacts, with significantly less discernible motion after post-processing (CACTOrg:1.31 ± 1.67, CACTMC_no_bone:1.00 ± 1.34, p < 0.01). Of the 27 datasets, ≥ 23 CACTMC_no_bone were preferred, with identical datasets chosen by the readers to show benefit from the algorithm. CONCLUSION: Application of a 3D-motion correction algorithm significantly improved IQ in diagnostically limited CACTs during TACE, with the potential to decrease repeat acquisitions.

Tantalum-specific contrast-to-noise ratio or conventional detector dose-driven exposure control in angiography: radiation dose and image quality evaluation in a porcine model.

BACKGROUND: The aim of this animal study was to compare the fluoroscopic image quality (IQ) and radiation dose between a tantalum (Ta)-specific contrast-to-noise ratio-driven exposure control (Ta-CEC) and a detector dose-driven exposure control (DEC) in abdominal angiography. METHODS: Nine angiography scenarios were created in seven anaesthetised pigs using Ta-based embolisation material during percutaneous liver and kidney intervention. Fluoroscopic images were acquired using three DEC protocols with different dose levels and Ta-CEC protocols with different IQ levels, sampled in small steps. Polymethyl-methacrylate and aluminium plates were used to simulate attenuation of three water equivalent thicknesses (WET). Three blinded readers evaluated the IQ of DEC and dose equivalent Ta images and selected the Ta-IQ equivalent image corresponding to the DEC image. RESULTS: Interobserver agreement for the IQ assessment was 0.43 for DEC, 0.56 for Ta-CEC and for the assessment of incident air kerma at the interventional reference point (Ka,r) for the Ta-IQ equivalent image 0.73. The average IQ of the dose equivalent Ta images was superior compared to the DEC images (p < 0.001) and also for every WET (26, 31, or 36 cm) and dose level (p ≤ 0.022). The average Ka,r for the Ta-IQ equivalent images was 59 ± 16% (mean ± standard deviation) lower compared to the DEC images (p < 0.001). CONCLUSIONS: Compared to DEC, Ta-CEC significantly improved the fluoroscopic depiction of Ta, while maintaining the Ka,r. Alternatively, the Ka,r can be significantly reduced by using Ta-CEC instead of DEC, while maintaining equivalent IQ.

Impact of the COVID 19 Pandemic on Radiological Imaging in Germany. / Auswirkung der COVID-19-Pandemie auf die radiologische Bildgebung in Deutschland.

PURPOSE: To analyze the impact of the COVID-19 pandemic in 2020 on the radiological imaging volume in Germany. MATERIALS UND METHODS: In this retrospective multicenter study, we analyzed CT and MRI examinations of 7 radiology institutes across Germany from January to December 2020. The imaging volume was compared to 2019 (Wilcoxon-Mann-Whitney test). Modality, patient service locations, and examined body parts were assessed in consideration of time periods of the pandemic. In addition, correlation with the incidence of SARS-CoV-2 cases and associated death was performed (Spearman-test). RESULTS: In total, in 2020, imaging volume declined by 4 % (n = 8314) compared with 2019 (p < 0.05). The hard lockdown during the first pandemic wave (calendar week 12-16, March 22 - April 19) revealed the highest decrease with 29 % (n = 894, p < 0.01), with the greatest decrease in CT (36 % vs. MRI 26 %), outpatients (38 %, p < 0.01), and imaging of the spine and extremities (51-72 %, < 0.05 - p < 0.01). Examinations referred from the emergency department (-13 %, p < 0.05) and CT of the chest (-16 %, p < 0.05) were least affected. With the end of the first wave, gradual normalization of the imaging volume was observed and persisted until the end of the observation period. A reduction of imaging volume negatively correlated with the incidence of SARS-CoV-2-positive cases and associated deaths (r = 0.28 and 0.49, p < 0.05 and p < 0.001). CONCLUSION: The COVID-19 pandemic was associated with a significant temporary decline in imaging volume. After the first lockdown period, a quick recovery was observed with radiologic imaging examinations steadily approaching prior-year figures. KEY POINTS: · This study assesses the impact of dynamic pandemic activity on radiological imaging in a multicenter analysis in Germany.. · The COVID-19 pandemic was associated with a temporary decline in CT and MRI scans.. · Relaxation of restrictions was associated with fast normalization of imaging volumes to prior-year levels, which persisted until the end of the year.. · Significant catch-up effects were not observed.. CITATION FORMAT: · Schmidbauer M, Grenacher L, Juchems MS et al. Impact of the COVID 19 Pandemic on Radiological Imaging in Germany. Fortschr Röntgenstr 2022; 194: 625 - 633.

The Value of C-Arm Computed Tomography in Addition to Conventional Digital Subtraction Angiography in the Diagnostic Work-up of Patients with Suspected Chronic Thromboembolic Pulmonary Hypertension: An Update of 300 Patients.

RATIONALE AND OBJECTIVES: To assess the value and possible benefit of combined C-arm computed tomography (CACT) and conventional digital subtraction angiography (DSA) of the pulmonary arteries in the diagnostic work-up of patients with suspected chronic thromboembolic pulmonary hypertension (CTEPH). MATERIALS AND METHODS: We evaluated 308 pulmonary artery angiographies of 308 consecutive patients with suspected CTEPH. Seven patients were excluded because of incomplete imaging. Thus, 301 datasets were included in our study. The pulmonary artery segments and their subsegmental branching were independently evaluated by two readers (R1, R2) using both, DSA and CACT for optimal image quality. Subsequently, the diagnostic findings were compared. Inter-modality and inter-observer agreement were calculated. Consensus reading was done and correlated to a standard of reference, representing the overall consensus of both modalities. Fisher's exact test and Cohen's Kappa were applied. RESULTS: A total of 5719 pulmonary segments were evaluated of which only 28 segments (0.4%) were rated to be nondiagnostic on both, CACT and DSA. Overall, 5640 (98.6%) and 5600 (97.9%) pulmonary segments were rated to be diagnostic in DSA and CACT, respectively. The main causes of nondiagnostic image quality were motion artifacts on both, CACT (R1:81, R2:50) and DSA (R1:60, R2:48). Interobserver agreement was excellent for DSA (κ = 0.9) and CACT (κ = 0.91) and intermodality agreement was substantial (R1: κ = 0.69, R2: κ = 0.77). Compared to standard of reference, the intermodality agreement for CACT was excellent (κ = 0.96), whereas it was inferior for DSA (κ = 0.75), due to the higher number of pathologic findings in CACT read as normal on DSA. CONCLUSION: CACT of the pulmonary arteries can provide additional information to DSA during CTEPH work-up. Moreover, the combination of CACT and DSA can minimize the portion of non-diagnostic examinations, therefore being a reasonable combination to optimize the diagnostic work-up.

Phantom study for comparison between computed tomography- and C-Arm computed tomography-guided puncture applied by residents in radiology. / Phantomstudie zum Vergleich zwischen Computertomografie- und C-Arm-Computertomografie-gesteuertem Punktionsverfahren bei Anwendung durch Weiterbildungsassistenten in der Radiologie.

PURPOSE: Comparison of puncture deviation and puncture duration between computed tomography (CT)- and C-arm CT (CACT)-guided puncture performed by residents in training (RiT). METHODS: In a cohort of 25 RiTs enrolled in a research training program either CT- or CACT-guided puncture was performed on a phantom. Prior to the experiments, the RiT's level of training, experience playing a musical instrument, video games, and ball sports, and self-assessed manual skills and spatial skills were recorded. Each RiT performed two punctures. The first puncture was performed with a transaxial or single angulated needle path and the second with a single or double angulated needle path. Puncture deviation and puncture duration were compared between the procedures and were correlated with the self-assessments. RESULTS: RiTs in both the CT guidance and CACT guidance groups did not differ with respect to radiologic experience (p = 1), angiographic experience (p = 0.415), and number of ultrasound-guided puncture procedures (p = 0.483), CT-guided puncture procedures (p = 0.934), and CACT-guided puncture procedures (p = 0.466). The puncture duration was significantly longer with CT guidance (without navigation tool) than with CACT guidance with navigation software (p < 0.001). There was no significant difference in the puncture duration between the first and second puncture using CT guidance (p = 0.719). However, in the case of CACT, the second puncture was significantly faster (p = 0.006). Puncture deviations were not different between CT-guided and CACT-guided puncture (p = 0.337) and between the first and second puncture of CT-guided and CACT-guided puncture (CT: p = 0.130; CACT: p = 0.391). The self-assessment of manual skills did not correlate with puncture deviation (p = 0.059) and puncture duration (p = 0.158). The self-assessed spatial skills correlated positively with puncture deviation (p = 0.011) but not with puncture duration (p = 0.541). CONCLUSION: The RiTs achieved a puncture deviation that was clinically adequate with respect to their level of training and did not differ between CT-guided and CACT-guided puncture. The puncture duration was shorter when using CACT. CACT guidance with navigation software support has a potentially steeper learning curve. Spatial skills might accelerate the learning of image-guided puncture. KEY POINTS: · The CT-guided and CACT-guided puncture experience of the RiTs selected as part of the program "Researchers for the Future" of the German Roentgen Society was adequate with respect to the level of training.. · Despite the lower collective experience of the RiTs with CACT-guided puncture with navigation software assistance, the learning curve regarding CACT-guided puncture may be faster compared to the CT-guided puncture technique.. · If the needle path is complex, CACT guidance with navigation software assistance might have an advantage over CT guidance.. CITATION FORMAT: · Meine TC, Hinrichs JB, Werncke T et al. Phantom study for comparison between computed tomography- and C-Arm computed tomography-guided puncture applied by residents in radiology. Fortschr Röntgenstr 2022; 194: 272 - 280.

The impact of the field of view (FOV) on image quality in MDCT angiography of the lower extremities.

OBJECTIVES: To evaluate the impact of the reconstructed field-of-view (FOV) on image quality in computed-tomography angiography (CTA) of the lower extremities. METHODS: A total of 100 CTA examinations of the lower extremities were acquired on a 2 × 192-slice multidetector CT (MDCT) scanner. Three different datasets were reconstructed covering both legs (standard FOV size) as well as each leg separately (reduced FOV size). The subjective image quality was evaluated for the different vessel segments (femoral, popliteal, crural, pedal) by three readers using a semi-quantitative Likert scale. Additionally, objective image quality was assessed using an automated image quality metric on a per-slice basis. RESULTS: The subjective assessment of the image quality showed an almost perfect interrater agreement. The image quality of the small FOV datasets was rated significantly higher as compared to the large datasets for all patients and vessel segments (p < 0.05) with a tendency towards a higher effect in smaller vessels. The difference of the mean scores between the group with the large FOV and small FOV was 0.68 for the femoral level, 0.83 for the popliteal level, 1.12 for the crural level, and 1.08 for the pedal level. The objective image quality metric also demonstrated a significant improvement of image quality in the small FOV datasets. CONCLUSIONS: Side-separated reconstruction of each leg in CTA of the lower extremities using a small reconstruction FOV significantly improves image quality as compared to a standard reconstruction with a large FOV covering both legs. KEY POINTS: • In CT angiography of the lower legs, the side-separated reconstruction of each leg using a small field-of-views improves image quality as compared to a standard reconstruction covering both legs. • The side-separated reconstruction can be readily implemented at every commercially available CT scanner. • There is no need for additional hardware or software and no additional burden to the patient.