Technical aspects of the new BYCROSSTM atherectomy device - preliminary results after 28 patients.

Purpose: Technical aspects are crucial for the planning and performing of the atherectomy to treat peripheral arterial disease. This report illustrates the use of a novel atherectomy device and investigates the feasibility, efficacy, and safety procedures involved in performing the atherectomy on 28 patients. MATERIALS AND METHODS: We performed a prospective analysis of patients who underwent an atherectomy with the BYCROSSTM Atherectomy device between August 2022 and September 2023 at a tertiary referral centre. Patients with a lesion below the aortic bifurcation (vessel diameter ≥ 3mm) having a de novo or restenotic (stent-included) present were recruited. Major adverse events (MAE) are defined as amputation, death, myocardial infarction, or angiographic distal embolization that require a separate intervention. RESULTS: Of the 28 patients treated with the BYCROSS device, 23 were men with a mean age of 65.6 ± 9,6 years and a mean BMI of 24,6 ± 3.9 kg/m2. Most patients had a typical atherogenic risk profile as well as multiple preexisting comorbidities. In all patients, a symptomatic peripheral arterial disease (PAD) was the main reason for an intervention. The most common Rutherford category was 5 (12/28). The most common lesion region was the femoropopliteal segment (25/28) with 23 de novo stenosis. Mean lesion length was 218,0 ± 93,7 mm. The mean PACCS Score was 3,0 ± 1,0. Stenosis grade was by mean 99,3 ± 3,7%. Ankle Brachial Index (ABI) increased significantly after BYCROSS atherectomy (pre- 0,44 ± 0,43 vs. post-procedure 0,84 ± 0,30 P<0,001. Target lesion/vessel revascularization (TLR/TVR) within the first 30 days was 3,6% (1/28). 30-day MAE rate was 14,3% (vessel perforation in 3/28 patients, embolism in 1/28). There were no deaths, index limb amputations, or myocardial infarctions. CONCLUSION: The BYCROSSTM atherectomy system is a new device with numerous advantages in treating high-grade, calcifying stenosis and occlusion processes in PAD. Based on the above findings, the BYCROSSTM Atherectomy device represents a feasible, safe, and effective method for endovascular treatment of peripheral arterial disease.

Photon-counting detector CT - first experiences in the field of musculoskeletal radiology.

The introduction of photon-counting detector CT (PCD-CT) marks a remarkable leap in innovation in CT imaging. The new detector technology allows X-rays to be converted directly into an electrical signal without an intermediate step via a scintillation layer and allows the energy of individual photons to be measured. Initial data show high spatial resolution, complete elimination of electronic noise, and steady availability of spectral image data sets. In particular, the new technology shows promise with respect to the imaging of osseous structures. Recently, PCD-CT was implemented in the clinical routine. The aim of this review was to summarize recent studies and to show our first experiences with photon-counting detector technology in the field of musculoskeletal radiology.We performed a literature search using Medline and included a total of 90 articles and reviews that covered recent experimental and clinical experiences with the new technology.In this review, we focus on (1) spatial resolution and delineation of fine anatomic structures, (2) reduction of radiation dose, (3) electronic noise, (4) techniques for metal artifact reduction, and (5) possibilities of spectral imaging. This article provides insight into our first experiences with photon-counting detector technology and shows results and images from experimental and clinical studies. · This review summarizes recent experimental and clinical studies in the field of photon-counting detector CT and musculoskeletal radiology.. · The potential of photon-counting detector technology in the field of musculoskeletal radiology includes improved spatial resolution, reduction in radiation dose, metal artifact reduction, and spectral imaging.. · PCD-CT enables imaging at lower radiation doses while maintaining or even enhancing spatial resolution, crucial for reducing patient exposure, especially in repeated or prolonged imaging scenarios.. · It offers promising results in reducing metal artifacts commonly encountered in orthopedic or dental implants, enhancing the interpretability of adjacent structures in postoperative and follow-up imaging.. · With its ability to routinely acquire spectral data, PCD-CT scans allow for material classification, such as detecting urate crystals in suspected gout or visualizing bone marrow edema, potentially reducing reliance on MRI in certain cases.. Bette S, Risch F, Becker J et al. Photon-counting detector CT - first experiences in the field of musculoskeletal radiology. Fortschr Röntgenstr 2024; DOI 10.1055/a-2312-6914.

Radiomics-Based Machine Learning Model for Diagnosis of Acute Pancreatitis Using Computed Tomography.

In the early diagnostic workup of acute pancreatitis (AP), the role of contrast-enhanced CT is to establish the diagnosis in uncertain cases, assess severity, and detect potential complications like necrosis, fluid collections, bleeding or portal vein thrombosis. The value of texture analysis/radiomics of medical images has rapidly increased during the past decade, and the main focus has been on oncological imaging and tumor classification. Previous studies assessed the value of radiomics for differentiating between malignancies and inflammatory diseases of the pancreas as well as for prediction of AP severity. The aim of our study was to evaluate an automatic machine learning model for AP detection using radiomics analysis. Patients with abdominal pain and contrast-enhanced CT of the abdomen in an emergency setting were retrospectively included in this single-center study. The pancreas was automatically segmented using TotalSegmentator and radiomics features were extracted using PyRadiomics. We performed unsupervised hierarchical clustering and applied the random-forest based Boruta model to select the most important radiomics features. Important features and lipase levels were included in a logistic regression model with AP as the dependent variable. The model was established in a training cohort using fivefold cross-validation and applied to the test cohort (80/20 split). From a total of 1012 patients, 137 patients with AP and 138 patients without AP were included in the final study cohort. Feature selection confirmed 28 important features (mainly shape and first-order features) for the differentiation between AP and controls. The logistic regression model showed excellent diagnostic accuracy of radiomics features for the detection of AP, with an area under the curve (AUC) of 0.932. Using lipase levels only, an AUC of 0.946 was observed. Using both radiomics features and lipase levels, we showed an excellent AUC of 0.933 for the detection of AP. Automated segmentation of the pancreas and consecutive radiomics analysis almost achieved the high diagnostic accuracy of lipase levels, a well-established predictor of AP, and might be considered an additional diagnostic tool in unclear cases. This study provides scientific evidence that automated image analysis of the pancreas achieves comparable diagnostic accuracy to lipase levels and might therefore be used in the future in the rapidly growing era of AI-based image analysis.

Inpatient treatment of acute diverticulitis between 2010 and 2021 - A German nationwide study about long-term trends and effects of the SARS-CoV-2 pandemic.

AIM: The aims of this study were to analyse all hospitalizations for acute diverticulitis in Germany from 2010 to 2021 and to assess the effects of the first 2 years of the SARS-CoV-2 pandemic on hospitalizations for acute diverticulitis. METHOD: Using data from the German Federal Statistical Office, we analysed fully anonymized healthcare data of hospitalizations and treatment regimens with acute diverticulitis as the main diagnosis between 2010 and 2021. Logistic regression analyses for in-hospital mortality were performed. RESULTS: A total of 608,162 hospitalizations were included. While the number of hospitalizations constantly increased until 2019 (+52.4%), a relative decrease of 10.1% was observed between 2019 and 2020, followed by stable numbers of hospitalizations in 2021 (+1.1% compared with 2020). In-hospital mortality showed a relative decrease of 33.2% until 2019 and thereafter a relative increase of 26.9% in 2020 and of 7.5% in 2021. A 21.6% and a 19.3% drop in hospitalizations was observed during the first and second waves of the SARS-CoV-2 pandemic, mostly affecting hospitalizations for uncomplicated diverticulitis, with a corresponding 11.6% and 16.8% increase in admissions for complicated diverticulitis. Multivariable logistic regression analyses showed significantly higher in-hospital mortality for hospitalizations in which surgery (OR = 2.76) and CT (OR = 1.32) were given, as well as lower mortality for women (OR = 0.88), whereas percutaneous drainage was not associated with higher in-hospital mortality compared with conservative treatment (OR = 0.71). CONCLUSION: This study points out the long-term trends in inpatient treatment for acute diverticulitis and the in-hospital mortality risk factors of patients hospitalized for acute diverticulitis in a large nationwide cohort, as well as changes in these trends and factors resulting from the SARS-CoV-2 pandemic. These changes might be attributable to delayed diagnosis and thus more severe stages of disease as a result of containment measures.

Revascularization with BYCROSS atherectomy device- protocol of a prospective multicenter observational study.

BACKGROUND: The BYCROSS™ device is a novel device intended for use in atherectomy of the peripheral arterial disease (PAD). With the BYCROSS™ atherectomy system, also prolonged calcifying lesions can be treated in a minimally invasive manner, which was previously reserved for bypass surgery. The aim of this study is to collect additional clinical data on safety and performance of the BYCROSS™ from patients undergoing revascularization of severely stenotic or occluded peripheral arterial vessels with the BYCROSS™. METHODS AND DESIGN: This is an investigator-initiated national prospective multicenter observational study in patients with PAD. Sixty patients (20 per center) with PAD with stenosis higher than 80% or complete occlusion (de novo or recurrent stenosis) of vessels below the aortic bifurcation (min 3 mm vessel diameter) will be recruited. Three vascular surgery centers are participating in the study. The primary efficacy endpoint is procedural success, defined as passage of the occlusion through the BYCROSS device, and safety outcomes, explicated as freedom from device-related serious adverse events (SADEs). Secondary endpoints include primary and secondary patency rates, change in Rutherford classification, and freedom from amputation at 3 and 12 months. DISCUSSION: The BYCROSS atherectomy system may be a novel device for the minimally invasive treatment of prolonged calcified lesions previously reserved for bypass surgery. This national prospective multicenter observational study could represent another step in demonstrating the efficancy and safety of this device for treatment of PAD. TRIAL REGISTRATION: #DRKS00029947 (who.int). PROTOCOL APPROVAL ID: #22-0047(Ethics Committee at Ludwig-Maximilians-University Munich).

Image Characteristics of Virtual Non-Contrast Series Derived from Photon-Counting Detector Coronary CT Angiography-Prerequisites for and Feasibility of Calcium Quantification.

In photon-counting detector CT (PCD-CT), coronary artery calcium scoring (CACS) can be performed using virtual non-contrast (VNC) series derived from coronary CT angiography (CCTA) datasets. Our study analyzed image characteristics of VNC series in terms of the efficacy of virtual iodine "removal" and image noise to determine whether the prerequisites for calcium quantification were satisfied. We analyzed 38 patients who had undergone non-enhanced CT followed by CCTA on a PCD-CT. VNC reconstructions were performed at different settings and algorithms (conventional VNCConv; PureCalcium VNCPC). Virtual iodine "removal" was investigated by comparing histograms of heart volumes. Noise was assessed within the left ventricular cavity. Calcium was quantified on the true non-contrast (TNC) and all VNC series. The histograms were comparable for TNC and all VNC. Image noise between TNC and all VNC differed slightly but significantly. VNCConv CACS showed a significant underestimation regardless of the reconstruction setting, while VNCPC CACS were comparable to TNC. Correlations between TNC and VNC were excellent, with a higher predictive accuracy for VNCPC. In conclusion, the iodine contrast can be effectively subtracted from CCTA datasets. The remaining VNC series satisfy the requirements for CACS, yielding results with excellent correlation compared to TNC-based CACS and high predicting accuracy.

Spontaneous Iliopsoas Muscle Hemorrhage-Predictors of Associated Mortality.

RATIONALE AND OBJECTIVES: Spontaneous iliopsoas muscle hemorrhage (SIPH) is a rare clinical condition associated with high mortality. In this work we aimed to retrospectively investigate the predictors of mortality in a single-institution cohort of consecutive SIPH patients. MATERIALS AND METHODS: Consecutive patients (n = 61, 30 men, 76 years [range 51-93]) with computed tomography (CT) confirmed diagnosis of SIPH were retrospectively included between January 2010 and April 2020. CT studies were assessed for signs of active bleeding, extramuscular retroperitoneal hematoma, visible sedimentation, and hematoma volume. Medication history, laboratory parameters, comorbidities, and disease management were also recorded. All parameters were subsequently examined with regard to their impact on outcome and survival. Univariate and multivariate Cox regressions were performed to identify variables associated with time to death. RESULTS: The overall mortality was 22.9%. A total of 77% of patients received anticoagulant therapy prior to the onset of SIPH. Active bleeding in contrast enhanced CT (CECT) was the only independent variable associated with shorter survival (p = 0.01, hazard ratio 7.05 [1.45-34.20]). Hematoma volume or extramuscular retroperitoneal hematoma had no significant influence on short-term mortality. CONCLUSION: Only active bleeding but not hematoma volume or extra-muscular bleeding is an independent risk factor for short-term mortality in patients with SIPH.

Typical Imaging Patterns in COVID-19 Infections of the Lung on Plain Chest Radiographs to Aid Early Triage.

PURPOSE: To evaluate imaging patterns of a COVID-19 infection of the lungs on chest radiographs and their value in discriminating this infection from other viral pneumonias. MATERIALS AND METHODS: All 321 patients who presented with respiratory impairment suspicious for COVID-19 infection between February 3 and May 8, 2020 and who received a chest radiograph were included in this analysis. Imaging findings were classified as typical for COVID-19 (bilateral, peripheral opacifications/consolidations), non-typical (findings consistent with lobar pneumonia), indeterminate (all other distribution patterns of opacifications/consolidations), or none (no opacifications/consolidations). The sensitivity, specificity, as well as positive and negative predictive value for the diagnostic value of the category "typical" were determined. Chi² test was used to compare the pattern distribution between the different types of pneumonia. RESULTS: Imaging patterns defined as typical for COVID-19 infections were documented in 35/111 (31.5 %) patients with confirmed COVID-19 infection but only in 4/210 (2 %) patients with any other kind of pneumonia, resulting in a sensitivity of 31.5 %, a specificity of 98.1 %, and a positive and negative predictive value of 89.7 % or 73 %, respectively. The sensitivity could be increased to 45.9 % when defining also unilateral, peripheral opacifications/consolidations with no relevant pathology contralaterally as consistent with a COVID-19 infection, while the specificity decreases slightly to 93.3 %. The pattern distribution between COVID-19 patients and those with other types of pneumonia differed significantly (p < 0.0001). CONCLUSION: Although the moderate sensitivity does not allow the meaningful use of chest radiographs as part of primary screening, the specific pattern of findings in a relevant proportion of those affected should be communicated quickly as additional information and trigger appropriate protective measures. KEY POINTS: · COVID-19 infections show specific X-ray image patterns in 1/3 of patients.. · Bilateral, peripheral opacities and/or consolidations are typical imaging patterns.. · Unilateral, peripheral opacities and/or consolidations should also raise suspicion of COVID-19 infection.. CITATION FORMAT: · Kasper J, Decker J, Wiesenreiter K et al. Typical Imaging Patterns in COVID-19 Infections of the Lung on Plain Chest Radiographs to Aid Early Triage. Fortschr Röntgenstr 2021; 193: 1189 - 1196.

Author Correction: Predictors for success in renal denervation-a single centre retrospective analysis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Predictors for success in renal denervation-a single centre retrospective analysis.

Renal denervation (RDN) is one of the most frequently used invasive methods for the treatment of arterial hypertension. However, recent randomized sham-controlled studies raised concern about the efficacy and predictability of response. We retrospectively analyzed outcomes of patients, who underwent RDN in our hypertension center between November 2010 and April 2014 and report here outcomes twelve months after procedure based on 24-hours ambulatory blood pressure monitoring. We defined ten-mm Hg decrease in office systolic blood pressure (SBP) as a cut-off for response and looked for possible predictors of this response using binary multiple regression analysis. 42 patients were included. Their mean age was 59.6 ± 9.2 years and 24% were female. Baseline office SBP and diastolic blood pressure (DBP) were 164.1 ± 20.3 and 91.8 ± 12.4 mm Hg respectively. Mean 24 h-SBP significantly decreased from 149.8 ± 13.3 mm Hg to 141.2 ± 14.6 mm Hg. Mean 24 h-DBP significantly decreased from 83.3 ± 11.7 mm Hg to 78.8 ± 11.2 mm Hg. A higher level of mean 24 h-DBP and office DBP was shown to be predictive for response in office BP and a higher level of mean 24 h-DBP for response in 24 h-SBP and 24 h-DBP. Further properly designed randomized trials are warranted to confirm this finding as well as further investigate the role of diabetes mellitus and arterial stiffness in RDN.

Apparent migration of implantable port devices: normal variations in consideration of BMI.

PURPOSE: To evaluate the extent of normal variation in implantable port devices between supine fluoroscopy and upright chest x-ray in relation to body mass index (BMI) based on three different measurement methods. METHODS: Retrospectively, 80 patients with implanted central venous access port systems from 2012-01-01 until 2013-12-31 were analyzed. Three parameters (two quantitative and one semi-quantitative) were determined to assess port positions: projection of port capsule to anterior ribs (PCP) and intercostal spaces, ratio of extra- and intravascular catheter portions (EX/IV), normalized distance of catheter tip to carina (nCTCD). Changes were analyzed for males and females and normal-weight and overweight patients using analysis of variance with Bonferroni-corrected pairwise comparison. RESULTS: PCP revealed significantly greater changes in chest x-rays in overweight women than in the other groups (p<0.001, F-test). EX/IV showed a significantly higher increase in overweight women than normal-weight women and men and overweight men (p<0.001). nCTCD showed a significantly greater increase in overweight women than overweight men (p = 0.0130). There were no significant differences between the other groups. Inter- and intra-observer reproducibility was high (Cronbach alpha of 0.923-1.0) and best for EX/IV. CONCLUSIONS: Central venous port systems show wide normal variations in the projection of catheter tip and port capsule. In overweight women apparent catheter migration is significantly greater compared with normal-weight women and with men. The measurement of EX/IV and PCP are straightforward methods, quick to perform, and show higher reproducibility than measurement of catheter tip-to-carina distance.

Hepatopulmonary shunting after surgical, interventional and systemic therapy in patients with liver malignancies scheduled for radioembolization.

BACKGROUND: Hepatopulmonary shunts (HPS) lead to radiation exposure of the lungs in patients undergoing radioembolization (RE) of malignant liver tumors. PURPOSE: To retrospectively analyze how HPS is affected by prior systemic or local therapy of the liver. MATERIAL AND METHODS: The percentage HPS was calculated from SPECT/CT scans obtained after technetium-99 m macroaggregated albumin administration into hepatic arteries in 316 patients evaluated for RE. RESULTS: Patients with partial liver resection (n = 80) did not differ in HPS from the remaining patient population (n = 236) (HPS (median [range]) = 10.2 [2.1-48.3]resection% vs. 8.9 [2.3-32.9]no resection%; P = 0.527). In patients undergoing sequential RE, HPS was significantly higher in the liver lobe treated second (n = 10; HPS = 6.4 [2.1-10.2]firstlobe/session% vs. 12.0 [2.0-24.6]second lobe/session%; P = 0.019). (Chemo-)embolization (n = 19; HPS = 11.0 [2.8-48.3]%) or transcutaneous ablation (n = 63; HPS = 8.8 [3.0-32.9]%) had no effect on HPS compared to patients without prior interventions (no (chemo-)embolization: n = 297; HPS = 9.3 [2.1-47.3]%; P = 0.489; no ablation: n = 253; HPS = 9.5 [2.1-48.3]%; P = 0.382). Pretreatment with sorafenib (HPS = 9.5 [2.3-35.9]yes% vs. 10.2 [2.8-42.0]no%; P = 0.777) orbevacizumab (HPS = 10.7 [2.1-30.6]yes% vs. 9.0 [3.9-23.3]no%; P = 0.870) had no effect on HPS. CONCLUSION: Sequential RE results in an increase in the HPS in the contralateral liver lobe at the time of the second RE session. Other investigated therapy do not affect HPS.

Anatomic variants of arteries often coil-occluded prior to hepatic radioembolization.

BACKGROUND: Prior to radioembolization (RE) treatment of malignant liver lesions, many interventionalists occlude the right gastric artery (RGA), the cystic artery (CA), and the gastroduodenal artery (GDA) to prevent radioactive microspheres from entering non-target vessels. PURPOSE: To systematically analyze anatomic variants of arteries that are important to know for the interventional radiologist performing RE of the liver. MATERIAL AND METHODS: The computed tomography (CT) angiographies and conventional angiographies of 166 patients evaluated for RE were retrospectively analyzed for the presence of anatomic variants of the RGA, GDA, and CA. RESULTS: The RGA was found to arise from the left hepatic artery in 42% of cases, from the proper hepatic artery in 40%, from the GDA in 10%, from the right hepatic artery in 4%, and from the common hepatic artery in 3% of cases. The GDA originated in the common hepatic artery in 97% of cases, in the left hepatic artery in 2%, and in the celiac trunk in 1% of cases. The CA arose from the right hepatic artery in 96% of cases and from the GDA in 2% of cases; in 2% of our study population, the gallbladder was supplied by small branches from the liver parenchyma. CONCLUSION: Variant anatomy of the RGA is common, while it is quite rare for the GDA and CA. Knowledge of the variations of liver supplying arteries helps the interventionalist to embolize necessary vessels prior to RE.

Hepatopulmonary shunting in patients with primary and secondary liver tumors scheduled for radioembolization.

PURPOSE: In patients undergoing transarterial radioembolization (RE) of malignant liver tumors, hepatopulmonary shunts (HPS) can lead to nontarget irradiation of the lungs. This study aims at analyzing the HPS fraction in relation to liver volume, tumor volume, tumor-to-liver volume ratio, tumor vascularity, type of tumor, and portal vein occlusion. MATERIALS AND METHODS: In the presented retrospective study the percentage HPS fraction was calculated from SPECT/CT after infusion of Tc-99m macroaggregated albumin (Tc-99m MAA) into the proper hepatic artery of 233 patients evaluated for RE. RESULTS: HPS fractions correlate very weakly with liver volume (r=0.303), tumor volume (r=0.345), and tumor-to-liver volume ratio (r=0.340). Tumors with strong contrast enhancement (HPSmedian(range)=11.7%(46.3%); n=73) have significantly larger shunt fractions than tumors with little enhancement (HPS=8.3%(16.4%); n=61; p<0.001). Colorectal cancer metastases (HPS=10.6%(28.6%); n=68) and hepatocellular cancers (HPS=11.7%(39.4%); n=63) have significantly larger HPS fractions than metastases from breast cancer (HPS=7.4%(16.7%); n=40; p=0.012 and p=0.001). Patients with compression (HPS=13.9%(43.7%); n=33) or tumor thrombosis (HPS=15.8% (31.2%); n=33) of a major portal vein branch have significantly higher degrees of shunting than patients with normal portal vein perfusion (HPS=8.1% (47.0%); n=167; both p<0.001). The shunt fraction is largest in patients with HCC and thrombosis or occlusion of a major portal vein branch (HPS=16.6% (31.0%); n=32). CONCLUSION: The degree of hepatopulmonary shunting depends on the type of liver tumor, tumor vascularity, and portal vein perfusion. There is little to no correlation of HPS with liver volume, tumor volume, or tumor-to-liver volume ratio.

Impaired hepatic Gd-EOB-DTPA enhancement after radioembolisation of liver malignancies.

INTRODUCTION: To evaluate the uptake of the liver-specific magnetic resonance imaging (MRI) contrast agent gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) by functional liver parenchyma after radioembolisation (RE) of hepatic malignancies. METHODS: Uptake of Gd-EOB-DTPA prior to RE versus 60+/-24d and 126+/-32d after RE was compared in a group of 33 patients with primary or secondary hepatic malignancies. In patients who underwent single-lobe treatment, left and right lobes were compared 59+/-24 days after RE. Gd-EOB-DTPA uptake was determined as follows: ratio of mean signal intensity in liver parenchyma to muscle in Gd-EOB-DTPA-enhanced T1-weighted MRI was subtracted from ratio of mean intensity in liver parenchyma to muscle in unenhanced T1-weighted MRI. RESULTS: Gd-EOB-DTPA uptake in liver parenchyma was 0.845+/-0.29 before RE, 0.615+/-0.38 (P = 0.0022) at day 60+/-24, and 0.739+/-0.30 at day 126+/-32 after RE. In cases of single-lobe treatment, Gd-EOB-DTPA uptake was 0.581+/-0.256 for treated and 0.828+/-0.32 (P = 0.0164) for untreated hepatic lobes. CONCLUSIONS: Uptake of Gd-EOB-DTPA by liver parenchyma is impaired after RE, indicating dysfunction of the local hepatic system. These findings suggest that Gd-EOB-DTPA-enhanced MRI has the potential to be used for monitoring liver damage after RE.

Clinical practice in radioembolization of hepatic malignancies: a survey among interventional centers in Europe.

OBJECTIVES: A survey was conducted to give an overview about the practice of radioembolization in malignant liver tumors by European centers. METHODS: A questionnaire of 23 questions about the interventional center, preinterventional patient evaluation, the radioembolization procedure and aftercare were sent to 45 European centers. RESULTS: The response rate was 62.2% (28/45). The centers performed 1000 (median = 26) radioembolizations in 2009 and 1292 (median = 40) in 2010. Most centers perform preinterventional evaluation and radioembolization on an inpatient basis. An arterioportal shunt not amendable to preinterventional embolization is considered a contraindication. During preinterventional angiography, the gastroduodenal artery is embolized by 71%, the right gastric artery by 59%, and the cystic artery by 41%. In case of bilobar disease, yttrium-90 microspheres are infused into the common hepatic artery (14%) or separately into left and right hepatic artery (86%). 33% prefer a time interval between right and left liver lobe radioembolization to prevent radiation induced liver disease. 43% of the respondents do not prescribe prophylactic medication after radioembolization. In case of iatrogenic manipulation to the biliary duct system most centers perform radioembolization with prophylactic antibiotics. CONCLUSIONS: Despite standardization of the procedure, there are some differences in how radioembolization of liver tumors is performed in Europe.