Zielsetzung Vergleich der retrograd transpedalen und der retrograd plantaren Technik zur Revaskularisierung von Unterschenkelarterien bei Patienten mit kritischer Extremitätenischämie, nach fehlgeschlagener antegrader Revaskularisierung, hinsichtlich Durchführbarkeit, Verfahrenssicherheit sowie technischen und klinischen Erfolg.

To develop and validate a deep learning–based algorithm for segmenting and quantifying the physiological and diseased aorta in computed tomography angiographies. CTA exams of the aorta of 191 patients (68.1 ± 14 years, 128 male), performed between 2015 and 2018, were retrospectively identified from our imaging archive and manually segmented by two investigators. A 3D U-Net model was trained on the data, which was divided into a training, a validation, and a test group at a ratio of 7:1:2. Cases in the test group (n = 41) were evaluated to compare manual and automatic segmentations. Dice similarity coefficient (DSC), mean surface distance (MSD), and Hausdorff surface distance (HSD) were extracted. Maximum diameter, effective diameter, and area were quantified and compared between both segmentations at eight anatomical landmarks, and at the maximum area of an aneurysms if present (n = 14). Statistics included error calculation, intraclass correlation coefficient, and Bland-Altman analysis. A DSC of 0.95 [0.94; 0.95] and an MSD of 0.76 [0.06; 0.99] indicated close agreement between segmentations. HSD was 8.00 [4.47; 10.00]. The largest absolute errors were found in the ascending aorta with 0.8 ± 1.5 mm for maximum diameter and at the coeliac trunk with − 30.0 ± 81.6 mm2 for area. Results for absolute errors in aneurysms were − 0.5 ± 2.3 mm for maximum diameter, 0.3 ± 1.6 mm for effective diameter, and 64.9 ± 114.9 mm2 for area. ICC showed excellent agreement (> 0.9; p < 0.05) between quantitative measurements. Automated segmentation of the aorta on CTA data using a deep learning algorithm is feasible and allows for accurate quantification of the aortic lumen even if the vascular architecture is altered by disease. • A deep learning–based algorithm can automatically segment the aorta, mostly within acceptable margins of error, even if the vascular architecture is altered by disease. • Quantifications performed in the segmentations were mostly within clinically acceptable limits, even in pathologically altered segments of the aorta.

BACKGROUND: Recent studies on the Endurant (TM) endografts mainly compared outcomes of the bimodular stent-graft to other manufacturer's endografts or reported results for cases outside manufacturer's instructions for use (IFU), while data on the experience of standard endovascular aortic repair (EVAR) of infrarenal abdominal aortic aneurysms (AAA) inside manufacturer's IFU comparing the bi- with the trimodular device is limited. METHODS: Inclusion criteria were: 1) infrarenal aneurysms (>50 mm diameter) treated by Endurant (TM) II (END II) or Endurant (TM) IIs (END IIs) stent-graft inside manufacturer's IFU; 2) available CTA with 1 mm reconstruction of the entire aorta prior to intervention. Endpoints comparing the devices included technical success, 30-day mortality, rate of complications (bleeding with conversion to open repair, stent-graft stenosis/occlusion, acute distal embolism, infection or postprocedural necessity of dialysis), endoleaks and reinterventions (5-year follow-up). Aneurysm sac diameters were compared between baseline preinterventional CTA and last post-interventional CTA. RESULTS: One hundred patients (90% male, mean age 74 years) treated with END II (N.=66) or END IIs (N.=34) were included. Technical success was 99%. One procedure-related active bleeding occurred ending up in surgical conversion (END II N.=1). 30d mortality was 0%. No initial type I/III endoleaks were present. Re-interventions were required in 19/100 (19%) of patients (END II N.=10; END IIs N.=9, P=0.17). The outcome of EVAR including technical success, 30d mortality, rate of complications, endoleaks and re-interventions showed no significant differences comparing END II/IIs. CONCLUSIONS: Five-year outcomes of EVAR show consistently safe and effective results for either END II or IIs device.

Objective Thrombectomy of the aortoiliac segment remains a challenge for surgical and endovascular revision. This study aimed to evaluate the concept of percutaneous thrombectomy in patients with aortoiliac segment occlusions. Materials & Methods Eighteen patients with aortoiliac occlusion who underwent percutaneous thrombectomy were retrospectively identified using the local picture archive and divided into the stent-graft ( N = 10) and native vessels ( N = 8) groups. The procedure was performed by placing a 12–24 French sheath adjacent to the distal end of the occluded vessel segment. The occlusion was passed with a balloon catheter which was retracted after inflation, to deliver the thrombus into the sheath. Technical success (reperfusion of the vessel and no residual thrombus/stenosis < 30%), complications and primary arterial patency were assessed. Follow-up included computed tomography angiography and evaluation of the clinical situation via telephone. Results Technical success was achieved in 38% (7/18) of patients after percutaneous thrombectomy alone and in 100% after additional procedures. The most common complication was peripheral embolism (44%, 8/18), which was treated successfully in all cases and was linked to a mismatch between the sheath and target vessel of ≥ 1 mm ( P < .01). There were no significant differences in the incidence of complications between the two groups. Primary patency was 72% (13/18) with no significant difference between groups ( P = .94). Follow-up CT scans were available for 13/18 patients (72%), with a mean follow-up time of 270 ± 146 days. All patients were contacted via phone (follow-up time, 653 ± 264 days). Conclusion Percutaneous thrombectomy appears to be effective for revascularization of the aortoiliac segment, both in stent-grafts and in native vessels. The most common complication is peripheral embolism; however, the risk may be reduced by choosing an adequate sheath size.

BACKGROUND: This study investigates the frequency of functional stenoses (FS) after stent implantation into the femoropopliteal artery (FPA) detected on lateral angiograms with the knee flexed and evaluates the impact on additional treatment. METHODS: Retrospectively we identified 42 patients with stent-based revascularizations of the FPA in whom a final lateral digital subtraction angiography (DSA) with the knee in a flexed position (functional angiography [FA]) had been performed. In 32 patients' location, frequency and additional treatment of FS as well as stent-type. landing zones, angle of the knee-joint during FA and patency rates were evaluated. RESULTS: Mean lesion length was 12.9 +/- 20.16cm, 26/32 patients (81%) had a CTO. In 5/32 patients (15.6%) a FS was detected by FA: in three patients FS was located proximal and in two patients distal to a Supera (R) stent (Abbott Laboratories, Chicago, IL, USA). FS of the proximal landing zones were within the distal SFA (N.=2) or PI segment (N.=1) and FS of the distal landing zone were within the P3 segment (N.=2). In all three proximal FS additional overlapping stent implantation was performed. The distal FS went untreated in order to preserve the P3 segment for a bypass option. Mean angle of FA was 98.1 degrees +/- 31.7 degrees. Patency at 12 months did not differ between patients with (treated) FS (50%) and those without FS (72%) (P=0.240). CONCLUSIONS: Functional stenosis after stent-based revascularization of the FPA by use of a device with increased radial force occurs rather frequently. Proximal functional stenosis can be successfully treated by overlapping stent implantation. However, clinical relevance of functional stenosis needs further investigation.

PURPOSE:To evaluate the feasibility and accuracy of a radiation-free implantation of a thoracic aortic stent graft employing fiberoptic and electromagnetic tracking in an anthropomorphic phantom.MATERIALS AND METHODS:An anthropomorphic phantom was manufactured based on computed tomography (CT) angiography data from a patient. An aortic stent graft application system was equipped with a fiber Bragg gratings and 3 electromagnetic sensors. The stent graft was navigated in the phantom by 3 interventionalists using the tracking data generated by both technologies. One implantation procedure was performed. The technical success of the procedure was evaluated using digital subtraction angiography and CT angiography (before and after the intervention). Tracking accuracy was determined at various anatomical landmarks based on separately acquired fluoroscopic images. The mean/maximum errors were measured for the stent graft application system and the tip/end of the stent graft.RESULTS:The procedure resulted in technical success with a mean error below 3 mm for the entire application system and <2 mm for the position of the tip of the stent graft. Navigation/implantation and handling of the device were rated sufficiently accurate and on par with comparable, routinely used stent graft application systems.CONCLUSIONS:The study demonstrates successful stent graft implantation during a thoracic endovascular aortic repair procedure employing advanced guidance techniques and avoiding fluoroscopic imaging. This is an essential step in facilitating the implantation of stent grafts and reducing the health risks associated with ionizing radiation during endovascular procedures.

Zielsetzung Die zur Navigation von endovaskulärem Fremdmaterial genutzte fluoroskopische Bildgebung birgt Gesundheitsrisiken. Strahlenfreie Trackingmethoden versprechen Abhilfe zu schaffen, müssen aber hohe klinische Anforderungen (z.B. Trackinggenauigkeit) erfüllen. Ziel der Studie war die strahlungsfreie Implantation eines thorakalen Aortenstentgrafts mittels einer neu entwickelten Kombination aus faseroptischen und elektromagnetischen (EM)-Sensoren im anthropomorphen Phantom.

Purpose Endovascular stents are medical devices, which are implanted in stenosed blood vessels to ensure sufficient blood flow. Due to a high rate of in-stent re-stenoses, there is the need of a noninvasive imaging method for the early detection of stent occlusion. The evaluation of the stent lumen with computed tomography (CT) and magnetic resonance imaging (MRI) is limited by material-induced artifacts. The purpose of this work is to investigate the potential of the tracer-based modality magnetic particle imaging (MPI) for stent lumen visualization and quantification. Methods In this in vitro study, 21 endovascular stents were investigated in a preclinical MPI scanner. Therefore, the stents were implanted in vessel phantoms. For the signal analysis, the phantoms were scanned without tracer material, and the signal-to-noise-ratio was analyzed. For the evaluation of potential artifacts and the lumen quantification, the phantoms were filled with diluted tracer agent. To calculate the stent lumen diameter a calibrated threshold value was applied. Results We can show that it is possible to visualize the lumen of a variety of endovascular stents without material induced artifacts, as the stents do not generate sufficient signals in MPI. The stent lumen quantification showed a direct correlation between the calculated and nominal diameter (r = 0.98). Conclusion In contrast to MRI and CT, MPI is able to visualize and quantify stent lumina very accurately.

PURPOSE:To compare retrograde plantar-arch and transpedal-access approach for revascularization of below-the-knee (BTK) arteries in patients with critical limb ischemia (CLI) after a failed antegrade approach. MATERIALS AND METHODS:Retrospectively we identified 811 patients who underwent BTK revascularization between 1/2014 and 1/2020. In 115/811 patients (14.2%), antegrade revascularization of at least 1 tibial artery had failed. In 67/115 (58.3%), patients retrograde access to the target vessel was achieved via the femoral access and the plantar-arch (PLANTAR-group); and in 48/115 patients (41.7%) retrograde revascularization was performed by an additional retrograde puncture (TRANSPEDAL-group). Comorbidities, presence of calcification at pedal-plantar-loop/transpedal-access-site, and tibial-target-lesion was recorded. Endpoints were technical success (PLANTAR-group: crossing the plantar-arch; TRANSPEDAL-group: intravascular placement of the pedal access sheath), procedural success [residual stenosis <30% after plain old balloon angioplasty (POBA)], and procedural complications limb salvage and survival. Correlations between calcification at access site/tibial-target-lesion and technical/procedural-success were tested. RESULTS:Technical success was achieved in 50/67 (75%) patients of the PLANTAR-group and in 39/48 (81%) patients of the TRANSPEDAL-group (p=0.1). Procedural success was obtained in 23/67 (34%) patients of the PLANTAR-group and in 25/48 (52%) patients of the TRANSPEDAL-group (p=0.04). In 14/49 (29%) cases with calcification at the pedal-plantar loop, technical success was not achieved (p=0.04), and in 33/44 (75%) patients with calcification at the tibial-target-lesion, procedural success was not attained (PLANTAR-group) (p=0.026). In the TRANSPEDAL-group, correlations between calcification at access site/tibial-target-lesion and technical/procedural-success were not observed (p=0.2/p=0.4). In the PLANTAR-group, minor complications occurred in 13/67 (19%) and in the TRANSPEDAL-group in 4/48 patients (8%) (p=0.08). Limb salvage at 12 (18) months was 90% (82%) (PLANTAR-group; 95%CI 15.771-18.061) and 84% (76%) (TRANSPEDAL-group; 95%CI 14.475-17.823) (Log-rank p=0.46). Survival at 12 (18) months was 94% (86%) (PLANTAR-group; 95%CI 16.642-18.337) and 85% (77%) (TRANSPEDAL; 95%CI 14.296-17.621) (Log-rank p=0.098). CONCLUSION:Procedural success was significantly higher using the transpedal-access approach. Calcifications at pedal-plantar loop and target-lesion significantly influenced technical/procedural failure using the plantar-arch approach. No significant difference between both retrograde techniques in terms of feasibility, safety, and limb salvage/survival was found.

Introduction: 3D printing has a wide range of applications in medicine. In surgery, this technique can be used for preoperative planning of complex procedures, production of patient specific implants, as well as training. However, accuracy evaluations of 3D vascular models are rare. Objectives: Aim of this study was to investigate the accuracy of patient-specific 3D-printed aortic anatomies. Methods: Patients suffering from aorto-iliac aneurysms and with indication for treatment were selected on the basis of different anatomy and localization of the aneurysm in the period from January 1st 2014 to May 27th 2016. Six patients with aorto-iliac aneurysms were selected out of the database for 3D-printing. Subsequently, computed tomography (CT) images of the printed 3D-models were compared with the original CT data sets. Results: The mean deviation of the six 3D-vascular models ranged between -0.73 mm and 0.14 mm compared to the original CT-data. The relative deviation of the measured values showed no significant difference between the 3D-vascular and the original patient CT-data. Conclusion: Our results showed that 3D printing has the potential to produce patient-specific 3D vascular models with reliable accuracy. This enables the use of such models for the development of new endovascular procedures and devices. (C) 2020 Elsevier GmbH. All rights reserved.

Background This study aimed to assess the error of different registration techniques and imaging modalities for fusion imaging of the aorta in a standardized setting using a anthropomorphic body phantom. Materials and methods A phantom with the 3D printed vasculature of a patient suffering from an infrarenal aortic aneurysm was constructed. Pulsatile flow was generated via an external pump. CTA/MRA of the phantom was performed, and a virtual 3D vascular model was computed. Subsequently, fusion imaging was performed employing 3D-3D and 2D-3D registration techniques. Accuracy of the registration was evaluated from 7 right/left anterior oblique c-arm angulations using the agreement of centerlines and landmarks between the phantom vessels and the virtual 3D virtual vascular model. Differences between imaging modalities were assessed in a head-to-head comparison based on centerline deviation. Statistics included the comparison of means ± standard deviations, student’s t-test, Bland-Altman analysis, and intraclass correlation coefficient for intra- and inter-reader analysis. Results 3D-3D registration was superior to 2D-3D registration, with the highest mean centerline deviation being 1.67 ± 0.24 mm compared to 4.47 ± 0.92 mm. The highest absolute deviation was 3.25 mm for 3D-3D and 6.25 mm for 2D-3D registration. Differences for all angulations between registration techniques reached statistical significance. A decrease in registration accuracy was observed for c-arm angulations beyond 30° right anterior oblique/left anterior oblique. All landmarks (100%) were correctly positioned using 3D-3D registration compared to 81% using 2D-3D registration. Differences in accuracy between CT and MRI were acceptably small. Intra- and inter-reader reliability was excellent. Conclusion In the realm of registration techniques, the 3D-3D method proved more accurate than did the 2D-3D method. Based on our data, the use of 2D-3D registration for interventions with high registration quality requirements (e.g., fenestrated aortic repair procedures) cannot be fully recommended. Regarding imaging modalities, CTA and MRA can be used equivalently.

Purpose To evaluate heating of a redilatable stent for the treatment of aortic coarctation in neonates and small children in the new imaging modality magnetic particle imaging and established magnetic resonance imaging. Materials and Methods The cobalt-chromium stent (BabyStent, OSYPKA AG, Rheinfelden, Germany) has a stent design which allows for redilatation and adjustment of the diameter from 6 to 16 mm for a use in aortic coarctation. The stent loses its radial integrity while opening at predetermined breaking points at a diameter of 14 mm or 16 mm, respectively. We measured the temperature increase in the stent at different diameters during 7-min magnetic particle imaging and magnetic resonance imaging scans with fiber optic thermometers under static conditions surrounded by air. In magnetic particle imaging, stents with diameters from 6 to 16 mm were tested while in magnetic resonance imaging only stents with diameters of 6 mm and 14 mm were investigated exemplarily. Result In magnetic particle imaging, the measured temperature differences increased up to 4.7 K with growing diameters, whereas the opened stents with discontinuous struts at 14 and 16 mm showed only minimal heating of max. 0.5 K. In contrast to magnetic particle imaging, our measurements showed no heating of the stents during magnetic resonance imaging under identical conditions. Conclusion The BabyStent did show only slight heating in magnetic particle imaging and no detectable temperature increase in magnetic resonance imaging .

PURPOSE We aimed to examine lesion characteristics influencing technical outcome and periprocedural peripheral embolization (PPE) during percutaneous mechanical rotational thrombectomy (PMT) of long femoropopliteal artery and bypass occlusions. METHODS Retrospectively, 65 consecutive patients (43 male patients, mean age 70±12 years; Rutherford category I-III), undergoing PMT (Rotarex®, Straub Medical AG) with acutely/subacutely occluded femoropopliteal arteries/bypasses were included. Occlusions (mean length, 217±98 mm) were treated by PMT followed by percutaneous transluminal angioplasty (PTA) plus drug-coated balloon or PTA plus stenting/stentgrafting. Technical success was defined as residual stenosis <30%. Follow-up included duplex ultrasound and ankle-brachial index (ABI) after 12 months. Endpoints were technical success, complications, improvement of Rutherford category, ABI, and patency (re-stenosis <50%). The influence of lesion length, duration, and thrombus density (measured in preinterventional computed tomography angiography) on technical success and PPE was analyzed. RESULTS Technical success was 18% (12/65) after PMT alone, 92% (60/65) after additional means. Four patients (6%) underwent bypass surgery and one patient (2%) amputation. PPE occurred in 11% (7/65). During the 12-month follow-up, three patients (5%) were lost to follow-up. ABI increased from baseline 0.5±0.12 to 0.81±0.14 (p = 0.001) and Rutherford category increased by at least one level in 57 patients at 12-month follow-up (clinical success, 88%). At 12 months, primary patency was 57.4% (95% CI, 45.8%-68.9%) and secondary patency was 75.0% (95% CI, 59.8%-72.3%). As risk factors for PPE, we identified lesion length >200 mm (15%; 6/39; OR 4.5; 95% CI, 0.5-40; p = 0.014) and thrombus density ≤45 HU (20%; 2/10; OR 3.0; 95% CI, 0.2-38.9; p = 0.05). No significant relation between risk factors and technical success was found. CONCLUSION PMT followed by PTA or implantation of stent (grafts) appears to be effective and safe for revascularization of acute/subacute long occlusions. Thrombus density <45 HU and lesion length above 20 cm represent risk factors for PPE during PMT.

Nichtinvasive bildgebende Verfahren haben in den aktuellen Leitlinien der European Society of Cardiology (ESC) eine zentrale Bedeutung bei der Diagnostik des chronischen Koronarsyndroms (CCS), während die Rolle einer primären invasiven Koronarangiographie in diesem Zusammenhang zunehmend in Frage gestellt wird. Die vorliegende Übersichtsarbeit bietet eine Zusammenfassung der wichtigsten diagnostischen Strategien aus Sicht der Radiologie. Der diagnostische Algorithmus orientiert sich an der Vortestwahrscheinlichkeit (VTW) für das Vorliegen eines CCS, die anhand von Alter, Geschlecht und Symptomen abgeschätzt werden kann. Wichtig ist dabei, dass die VTW in den aktuellen Leitlinien im Vergleich zu älteren Empfehlungen deutlich gesunken ist, und diese Veränderung hat Auswirkungen auf die Auswahl des am besten geeigneten bildgebenden Verfahrens. Bei Patienten mit niedriger VTW (>5 % und <15 %) und ohne vordiagnostizierte koronare Herzerkrankung (KHK) kann mit einer unauffälligen computertomographischen Angiographie (CTA) der Koronargefäße ein CCS sicher ausgeschlossen werden. Bei Patienten mit erhöhter VTW (>15 %) oder einer bereits vordiagnostizierten KHK sollte primär eine nichtinvasive funktionelle Bildgebung zur Ischämiediagnostik eingesetzt werden. Die exzellente Sensitivität (89 %) und Spezifität (87 %), die hohe prognostische Relevanz und die fehlende Strahlenexposition machen die Perfusions-Stress-Magnetresonanztomographie (MRT) zur funktionellen Methode der ersten Wahl. Radiologen sollten die Empfehlungen der aktuellen Leitlinien kennen und sich für die Etablierung der koronaren CTA und Perfusions-Stress-MRT in der klinischen Routine einsetzen.

The diagnostic reading of follow-up low-dose whole-body computed tomography (WBCT) examinations in patients with multiple myeloma (MM) is a demanding process. This study aimed to evaluate the diagnostic accuracy and benefit of a novel software program providing rapid-subtraction maps for bone lesion change detection. Sixty patients (66 years ± 10 years) receiving 120 WBCT examinations for follow-up evaluation of MM bone disease were identified from our imaging archive. The median follow-up time was 292 days (range 200–641 days). Subtraction maps were calculated from 2-mm CT images using a nonlinear deformation algorithm. Reading time, correctly assessed lesions, and disease classification were compared to a standard reading software program. De novo clinical reading by a senior radiologist served as the reference standard. Statistics included Wilcoxon rank-sum test, Cohen’s kappa coefficient, and calculation of sensitivity, specificity, positive/negative predictive value, and accuracy. Calculation time for subtraction maps was 84 s ± 24 s. Both readers reported exams faster using subtraction maps (reader A, 438 s ± 133 s; reader B, 1049 s ± 438 s) compared to PACS software (reader A, 534 s ± 156 s; reader B, 1486 s ± 587 s; p < 0.01). The course of disease was correctly classified by both methods in all patients. Sensitivity for lesion detection in subtraction maps/conventional reading was 92%/80% for reader A and 88%/76% for reader B. Specificity was 98%/100% for reader A and 95%/96% for reader B. A software program for the rapid-subtraction map calculation of follow-up WBCT scans has been successfully tested and seems suited for application in clinical routine. Subtraction maps significantly facilitated reading of WBCTs by reducing reading time and increasing sensitivity. • A novel algorithm has been successfully applied to generate motion-corrected bone subtraction maps of whole-body low-dose CT scans in less than 2 min. • Motion-corrected bone subtraction maps significantly facilitate the reading of follow-up whole-body low-dose CT scans in multiple myeloma by reducing reading time and increasing sensitivity.

To evaluate technical success, safety and efficacy of post-dilatation of an interwoven nitinol stent using a paclitaxel-coated balloon (PCB) for revascularization of complex femoro-popliteal lesions. Thirty patients (26 male, mean age 70 ± 7 years) suffering from peripheral artery disease (PAD) (Rutherford category II–III) underwent revascularization of chronic total occlusions (n = 22, 73%) or severe stenosis (n = 8, 27%) of the femoro-popliteal segment. Mean lesion length was 251 ± 85 mm. Lesions were treated by pre-dilatation (POBA), implantation of a helical interwoven stent and post-dilatation with a PCB. Technical success was defined as residual stenosis < 30%. Follow-up included clinical visits, duplex ultrasound and ABI at 6 and 12 months. Endpoints were patency (re-stenosis < 50%), complications, improvement of Rutherford category and ABI. Regarding patency two sub-groups were compared: long-(“LL”; < 25 cm, n = 12, mean 175 ± 38 mm) and ultra-long lesions (“ULL”; ≥ 25 cm, n = 13, mean 322 ± 43 mm). Technical success was 100%. In 1/30 patients (3.3%), a minor complication occurred (embolism). The overall primary and secondary patency rates at 12 months were 80.0% (95% CI 72.5–96.9%) and 92.0% (95% CI 84.7–100%). In the LL-sub-group, primary patency was 100%, and in the ULL-sub-group, primary patency was 61.5% (95% CI 51.8–92.3%) (p = 0.056), and secondary patency 84.6% (95% CI 71.3–100%), respectively. Rutherford category increased by at least one category in 92% of patients, ABI increased from 0.52 ± 0.13 (baseline) to 0.9 ± 0.14 (12 months) (p = 0.001). Five patients underwent target lesion revascularization during follow-up (bypass: n = 1, endovascular: n = 4). No death was observed during follow-up. Post-dilatation of an interwoven nitinol stent using a paclitaxel-coated-balloon proved to be safe and effective with promising outcomes in long- and ultra-long lesions up to 12 months of follow-up.

BACKGROUND:Noninvasive imaging modalities are of central importance in the diagnosis of chronic coronary syndrome (CCS) in the current guidelines of the European Society of Cardiology (ESC), while the role of primary invasive coronary angiography in this context is increasingly being questioned. This review provides a summary of the most important diagnostic strategies from the radiology perspective. METHODOLOGICAL ISSUE:The diagnostic algorithm is guided by the pretest probability (PTP) for the presence of CCS, which can be estimated based on age, sex, and symptoms. It is important to note that PTP in the current guidelines has decreased significantly compared to older recommendations and this change has an impact on the selection of the most appropriate imaging technique. STANDARD RADIOLOGICAL METHODS:In patients with low PTP (>5% and <15%) and without prediagnosed coronary artery disease (CAD), CCS can be safely ruled out with inconspicuous computed tomography angiogram (CTA) of the coronary vessels. In patients with increased PTP (>15%) or prediagnosed CAD, noninvasive functional imaging should be primarily used to detect ischemia. PERFORMANCE AND METHODICAL INNOVATIONS:The excellent sensitivity (89%), specificity (87%) and high prognostic relevance make stress perfusion cardiovascular magnetic resonance (CMR) imaging the functional method of first choice. Technical innovations and the use of artificial intelligence-based methods for image analysis could contribute to further improve its accuracy in the future. PRACTICAL RECOMMENDATIONS:Radiologists should be aware of the recommendations of the current guidelines and work towards the establishment of coronary CTA and stress perfusion CMR in clinical routine.

Introduction - Over the last two decades, endovascular therapy has become an integral part of vascular surgery. One of the most difficulty in learning and performing this minimally invasive therapy is the fact, the vascular surgeon has to mentally overlay the three-dimensional vascular tree with the two-dimensional angiographic scene. While endovascular techniques are improving, the imaging during the procedure is still dependent on contrast agents and X-Rays with their known disadvantages. Looking at actual development trends towards radiation free localization of endovascular tools, the visualization and proper integration of this spatial information will become a key technology. Methods - We report the development of a real-time navigation software, which allows a three-dimensional view of the vascular system without any need of radiation. We used a vascular phantom model (Blue phantom FAST Trauma Full Torso Ultrasound Training Model) and an augmented reality (AR) headset (Microsoft HoloLens) to display the vascular structures in the field of view of the surgeon. Using simple landmark-based surface registration of a CT scan and marching cubes segmentation of the vessel tree, it is straightforward to visualize both the surface and the vessels in the AR display. Using a magnetic tracking system (i.e. AURORA, Northern Digital Inc.) it is possible to also display the position and orientation of a catheter inside the vessels. Results - Our preliminary results of the virtual real time navigation in endovascular procedures are promising. The presented technique allows a three-dimensional holographic view of the vascular system without any need of radiation. Using extrinsic landmark-based calibrations, the virtual objects are precisely aligned with the real world, resulting in a convincing holographic illusion. The prototype also offers the possibility of intervention planning and simulation, which in turn will lead to a reduced learning curve and therefore increased patient safety. Conclusion - The "virtual angioscope" may improve intraoperative visualization, placement of guide-wires and stents. It may reduce the amount of contrast agents and exposure to X-rays.

To evaluate feasibility, safety and efficacy of fusion imaging in order to guide endovascular revascularization of iliac steno-occlusive disease.

Background: Standard endovascular aortic repair (EVAR) is frequently performed with few data regarding utilization of 2D-3D fusion imaging (FI). Purpose: To evaluate a) feasibility and safety of 2D-3D FI to guide limb deployment during EVAR and b) efficacy of this technique compared to standard use of digital subtraction angiography (DSA) for guidance. Materials and Methods: Iliac limb deployment by guidance of 2D-3D FI (FUSION group, n=22 limbs) during EVAR was compared to (STANDARD group, n=23 limbs). Retrospectively, we analyzed feasibility (success-rate) and safety (patency of hypogastric artery; type Ib/III endoleak) of FI for limb deployment (FUSION group). Total contrast (ml) and median dose area product (mGy*cm2) per group to visualize the iliac bifurcation were compared. Results: In the FUSION group, limb deployment was performed in 19/22 limbs (86.4%) and all hypogastric arteries were patent at the end of the procedure. Median volumes of contrast per bifurcation were 13.0 ml (RANGE 13–13ml) in the STANDARD and 2.2ml (RANGE 0–13ml) in the FUSION group (p=0.002); median dose area products per bifurcation were 11951mGy*cm2 and 2593.1mGy*cm2 (p=0.001), respectively. Conclusion: Fusion imaging for guidance of limb deployment during standard EVAR is safe and feasible in the majority of procedures and can significantly reduce contrast volume and radiation exposure even if compared with optimal preparation by predicting optimal C-arm positions. Therefore, FI should be used whenever possible