Oliver Dudeck

Prior to radioembolization (RE) of hepatic tumors, many centers prophylactically occlude the cystic artery (CA) during evaluation angiography (EVA) to prevent radiation-induced cholecystitis. There is no conclusive evidence for the protective effect of CA embolization and it bears the risk of inducing ischemic cholecystitis. The aim of this study is to evaluate the justification for CA embolization by comparing clinical and morphologic imaging parameters between patients undergoing coil occlusion of the cystic artery (COCA) and those with uncoiled CA (UCCA). Retrospective comparison of 37 patients with UCCA versus 68 patients with COCA in terms of clinical findings (CRP, leukocyte count, body temperature, upper abdominal pain) and morphologic imaging parameters associated with cholecystitis (gallbladder (GB) wall thickness, free fluid in GB bed, bremsstrahlung SPECT) after EVA, after RE, and at 6-week follow-up. At none of the 3 time points (EVA, RE, 6-week follow-up) was there any significant difference in CRP, leukocyte count, body temperature, or upper abdominal pain between the UCCA and COCA group. There was also no significant difference between the two groups with regard to GB wall thickness, fluid in the GB bed, and bremsstrahlung in SPECT. One patient of the UCCA group and two patients of the COCA developed cholecystitis requiring treatment. Comparison of clinical and imaging findings between patients with and without CA embolization prior to RE identified no predictors of radiogenic or ischemic cholecystitis after RE. Our study provides no evidence for a benefit of prophylactic CA embolization before RE.

To evaluate the efficacy and safety of a novel retrograde transvenous embolization technique of peripheral arteriovenous malformations (AVMs) using Onyx. We conducted a retrospective analysis of all patients who underwent transvenous retrograde Onyx embolization of peripheral AVMs with dominant venous outflow over a 29-month period. The embolization is aimed at retrograde filling of the nidus after building a solid plug in the dominant venous outflow (push-through). Classification, clinical signs, technical aspects, clinical and technical success rates, and complications were recorded. Short-term outcome was assessed. 11 Symptomatic patients (8 female; mean age 31.4 years) were treated at our Vascular Anomalies Center with this method between January 2012 and May 2014. The AVMs were located on the upper extremity (n = 3), pelvis (n = 2), buttock (n = 2), and lower extremity (n = 4). Retrograde embolization was successfully carried out after preparatory transarterial-flow reduction in eight cases (73 %) and venous-flow reduction with Amplatzer Vascular Plugs in four cases (36 %). Complete devascularization (n = 10; 91 %) or 95 % devascularization (n = 1; 9 %) led to complete resolution (n = 8; 73 %) or improvement of clinical symptoms (n = 3; 27 %). One minor complication occurred (pain and swelling). During a mean follow-up time of 8 months, one clinically asymptomatic recurrence of AVM was detected. Initial results suggest that retrograde transvenous Onyx embolization of peripheral AVMs with dominant venous outflow is a safe and effective novel technique with a low complication rate.

Objectives: The objective of this study was to compare the parameter maps of a new flat-panel detector application for time-resolved perfusion imaging in the angiography room (FD-CTP) with computed tomography perfusion (CTP) in an experimental tumor model. Materials and Methods: Twenty-four VX2 tumors were implanted into the hind legs of 12 rabbits. Three weeks later, FD-CTP (Artis zeego; Siemens) and CTP (SOMATOM Definition AS +; Siemens) were performed. The parameter maps for the FD-CTP were calculated using a prototype software, and those for the CTP were calculated with VPCT-body software on a dedicated syngo Multi-Modality Workplace. The parameters were compared using Pearson product-moment correlation coefficient and linear regression analysis. Results: The Pearson product-moment correlation coefficient showed good correlation values for both the intratumoral blood volume of 0.848 (P < 0.01) and the blood flow of 0.698 (P < 0.01). The linear regression analysis of the perfusion between FD-CTP and CTP showed for the blood volume a regression equation y = 4.44x + 36.72 (P < 0.01) and for the blood flow y = 0.75x + 14.61 (P < 0.01). Conclusions: This preclinical study provides evidence that FD-CTP allows a time-resolved (dynamic) perfusion imaging of tumors similar to CTP, which provides the basis for clinical applications such as the assessment of tumor response to locoregional therapies directly in the angiography suite.

Myxoid liposarcomas represent a heterogeneous group of soft tissue tumors in which prognosis is dependent on differentiation. To identify magnetic resonance imaging (MRI) criteria to distinguish low-grade from high-grade myxoid liposarcomas. MR images of 30 histologically proven myxoid liposarcomas were retrospectively reviewed. Tumors were evaluated according to size, localization, tumor border, and structure as well as tumor composition. These imaging criteria were correlated with histopathological findings. Nineteen myxoid liposarcomas were histologically classified as low-grade myxoid liposarcomas, whereas 11 were considered high-grade myxoid liposarcomas. Mean tumor volume of low-grade myxoid liposarcomas (710.1 ± 960.1 ccm) was significantly smaller as compared to high-grade myxoid liposarcomas (2737.0 ± 3423.7 ccm; P = 0.04). In addition to necrotic areas, three tumor components – fatty, myxoid, as well as contrast-enhancing non-fatty, non-myxoid – could be identified. The mean fraction of fatty tumor areas in low-grade myxoid liposarcomas was 10 ± 11% as compared to 6 ± 4% for high-grade myxoid liposarcomas (P = 0.66). Myxoid components accounted for 88 ± 16% in low-grade myxoid liposarcomas, but only for 45 ± 25% in high-grade myxoid liposarcomas (P < 0.0001). The non-fatty, non-myxoid tumor fraction was significantly higher in high-grade myxoid liposarcomas (50 ± 25%) as compared to low-grade myxoid liposarcomas (2 ± 9%; P < 0.0001). A proportion of > 5% of this tumor fraction was found to be a precise unique predictor for high-grade myxoid liposarcomas with a sensitivity of 100% and a specificity of 95%. Tumor components with contrast-enhancing non-fatty, non-myxoid imaging features were predominantly found in high-grade myxoid liposarcomas, which may histologically resemble round cell clusters.

Background: Most cholangiocarcinomas (CCA) are locally advanced and unresectable at the time of diagnosis. Currently, chemotherapy combining gemcitabine with a platinum agent is the recommended first-line treatment regimen for advanced biliary tract cancer. However, median overall survival is only approximately 1 year. As the hepatic tumor burden is the limiting factor for the prognosis of these patients, local tumor control is essential. Methods: We present and discuss the current evidence for such therapy options for patients with CCA. Results: Local and locoregional therapies have been shown to be well tolerated and can contribute to tumor control in the context of a comprehensive oncologic treatment strategy, and may prolong survival of patients with advanced CCA. Unfortunately, only few high-quality clinical trials are available. Conclusion: Randomized prospective clinical trials enrolling larger numbers of patients need to be carried out to elucidate the precise value of these treatments alone as well as in combination with systemic chemotherapy.

To assess the potential of a steerable microcatheter in a comparative preclinical trial. A total of 100 small target vessels of the lower limbs with a maximum diameter of 3 mm were prospectively randomized to catheterize with either the preshaped torqueable Direxion™ (J tip shape; Boston Scientific, Natick, MA) or a similarly steam-shaped Renegade™ microcatheter (Boston Scientific) in a porcine model. Catheterization was first performed in combination with a microguidewire and afterwards without. No significant differences were found for the mean vessel diameter in the Direxion (1.53 ± 0.44 mm; n = 50) or Renegade (1.62 ± 0.43 mm; n = 50; p = 0.35) group. Guidewire-assisted catheterization was successful in all target vessels, whereas access was achieved in most cases with the guidewire alone. However, when it became necessary to steer the Direxion actively, this was regarded as key to obtain vessel access in three of four target vessels (75 %). Vessel catheterization without guidewire was significantly more successful with the Direxion (88 %; n = 44) compared with the Renegade (32 %; n = 16; p < 0.0001). In addition, this catheterization technique was also significantly faster with the Direxion compared with guidewire-assisted vessel catheterization with the Renegade (16.1 ± 14.4 sec compared with 27.1 ± 24.7 sec; p = 0.011). The Direxion microcatheter demonstrated unique steerability characteristics, which makes it a promising new tool especially for complex coaxial endovascular procedures.

This study was designed to identify parameters on CT angiography (CTA) of type II endoleaks following endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA), which can be used to predict the subsequent need for reinterventions. We retrospectively identified 62 patients with type II endoleak who underwent early CTA in mean 3.7 ± 1.9 days after EVAR. On the basis of follow-up examinations (mean follow-up period 911 days; range, 373–1,987 days), patients were stratified into two groups: those who did (n = 18) and those who did not (n = 44) require reintervention. CTA characteristics, such as AAA, endoleak, as well as nidus dimensions, patency of the inferior mesenteric artery, number of aortic branch vessels, and the pattern of endoleak appearance, were recorded and correlated with the clinical outcome. Univariate and receiver operating characteristic curve regression analyses revealed significant differences between the two groups for the endoleak volume (surveillance group: 1391.6 ± 1427.9 mm³; reintervention group: 3227.7 ± 2693.8 mm³; cutoff value of 2,386 mm³; p = 0.002), the endoleak diameter (13.6 ± 4.3 mm compared with 25.9 ± 9.6 mm; cutoff value of 19 mm; p p = 0.001), as well as a “complex type” endoleak pattern (13.6 %, n = 6 compared with 44.4 %, n = 8; p = 0.02). Early CTA can predict the future need for reintervention in patients with type II endoleak. Therefore, treatment decision should be based not only on aneurysm enlargement alone but also on other imaging characteristics.

To evaluate the effectiveness of proximal embolization of the gastroduodenal artery (GDA) using the Amplatzer Vascular Plug 4 (AVP 4) compared with pushable coils to avoid hepaticoenteric collaterals of the GDA stump, which may serve as pathways for nontarget embolization. One hundred thirty-four patients scheduled for 90-yttrium radioembolization (Y-90 RE) using either plugs (n = 67) or standard coils (n = 67) for GDA occlusion were retrospectively analyzed. Parameters recorded were length of the perfused GDA stump, distance device to the GDA origin, perfused proximal side branches after embolization, and durability of vessel occlusion at Y-90 RE. Length of the residually perfused GDA stump was 3.89 ± 2.86 mm for the AVP 4, which was significantly shorter compared with 5.78 ± 3.85 mm for coils (p = 0.005). Distance of the plug to the GDA origin was 1.41 ± 2.60 mm, which was also significantly shorter than 4.73 ± 3.44 mm for coils (p < 0.001). This resulted in significantly fewer patients with residually perfused side branches in the AVP 4 group (n = 2; 3.0 %) compared with the coil group (n = 18; 26.9 %; p < 0.001). At Y-90 RE, no GDA reperfusion was found after plug embolization compared with 2 cases after coil embolization (3.0 %; p = 0.156). Only one patient had a radiation-induced duodenal ulcer after coil embolization, whereas no Y-90-related toxicity was identified after plug embolization. Use of the AVP 4 for embolization of the GDA allowed an optimal proximal and more effective target vessel occlusion compared with coil embolization, which can avoid complications caused by extrahepatic gastrointestinal deposition of Y-90 microspheres by way of residually perfused proximal side branches.

Zugänge: Vorbereitung zur Intervention, Lagerung Punktionstechniken: retrograde/antegrade transfemorale, transpopliteale & transpedale Punktionen Tips & Tricks zur antegraden Punktion, insb. bei adipösen Pat. Tips & Tricks zur retrograden transpedalen Punktion Rekanalisationstechniken: Technik der intraluminalen Rekanalisation Technik der Rekanalisation über die tibiale Fußarkade Technik der subintimalen Rekanalisation im Unterschenkel Technik der antegrad transfemoralen – retrograd transpedalen Rekanalisation SAFARI-Technik (subintimal arterial flossing with antegrade-retrograde intervention) Lernziele: Den Kursteilnehmern sollen grundlegende und fortgeschrittene Punktions- und Rekanalisationstechniken bei Patienten mit pAVK der Unterschenkel-versorgenden Gefäße Schritt für Schritt aufgezeigt und an illustrativen Fallbeispielen erläutert werden. Korrespondierender Autor: Dudeck O Universitätsklinikum Magdeburg, Klinik für Radiologie und Nuklearmedizin, Leipziger Strasse 44, 39120 Magdeburg E-Mail: oliver.dudeck@med.ovgu.de