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Purpose To evaluate technical feasibility and safety of common endovascular visceral interventions using a vascular robotic platform through preclinical study. Material and Methods The CorPath GRX Robotic System (Corindus Inc, Waltham, Massachusetts) was tested in an anesthetized pig for its ability to navigate various commercially available devices in the abdominal vasculature and to perform routine endovascular visceral procedures. After manually placing a guiding catheter in the celiac trunk, several visceral branches were probed with microcatheters and -wires under robotic assistance, and embolization with liquids (lipiodol), detachable coils and plugs were performed. Furthermore, the origin of the celiac trunk was stented before accessing the left hypogastric artery for pelvic embolization. Results All procedures were performed with technical success and without any complications. Navigating the catheters and wires via the steering console proved intuitive. Coil, plug and stent deployment were exclusively controlled by remote with remarkable precision and stability. Conclusion Robotic-assisted visceral embolization and stenting as well as pelvic embolization using the CorPath GRX System is feasible and safe. Application of the platform in the abdominal vasculature is demonstrated for the first time. Considering the precision and the potential for reducing the operator’s radiation exposure, further research in this area is highly encouraged to enable translation into clinical practice.

Background Complication rates in percutaneous transhepatic biliary drainage (PTBD) are non-uniform and vary considerably. In addition, the impact of peri-procedural risk factors is under-investigated. Purpose To compare success and complication rates of PTBD in patients with and without accompanying technical risk factors. Material and Methods A single-center retrospective study was conducted from January 2004 to December 2016. Patients receiving PTBD due to biliary obstruction or biliary leakage were included. Technical risk factors (non-distended bile ducts, ascites, obesity, anasarca, non-compliance) were assessed. Complications were classified according to the Society of Interventional Radiology. Results In total, 372 patients were included (57.3% men, 42.7% women; mean age = 66 years). Overall, 466 PTBDs were performed. Of the patients, 70.1% presented with malignancy and biliary obstruction; 26.8% had benign biliary obstruction; 3.1% had biliary leakage. Technical risk factors were reported in 57 (15.3%) patients. Overall technical success of initial PTBD was 98.7%, primary technical success was 97.9%. In patients with non-dilatated bile ducts, primary technical success was 68.2%. Overall complication rate was 15.0% (8.1% major complications, 6.9% minor complications). Neither major nor minor complications were more frequent in patients with technical risk factors ( P > 0.05). In left-sided PTBD, hemorrhage was more frequent ( P = 0.015). Patients with malignancy were significantly more affected by drainage-related complications ( P = 0.004; odds ratio = 2.03). The mortality rate was 0.5% (n = 2). Conclusion PTBD is a safe and effective method for the treatment of biliary obstruction and biliary leaks. Complication rates are low, even in procedures with risk factors.

To evaluate whether a 3 D proton density-weighted fat-suppressed sequence (PDwFS) of the knee is able to replace multiplanar 2D-PDwFS.52 patients (26 men, mean age: 41.9 ± 14.5years) underwent magnetic resonance imaging (MRI) of the knee at 3.0 Tesla using a T/R-coil. The imaging protocol included 3 planes of 2D-PDwFS (acquisition time (AT): 6:40 min; voxel sizes: 0.40 - 0.63 × 0.44 - 0.89 × 3mm³) and a 3D-PDwFS (AT: 6:31 min; voxel size: 0.63 × 0.68 × 0.63mm³). Homogeneity of fat suppression (HFS), artifacts, and image sharpness (IS) were evaluated on a 5-point scale (5[excellent] - 1[non-diagnostic]). The sum served as a measure for the overall image quality (OIQ). Contrast ratios (CR) compared to popliteal muscle were calculated for the meniscus (MEN), anterior (ACL) and posterior cruciate ligaments (PCL). In 13 patients who underwent arthroscopic knee surgery, two radiologists evaluated the presence of meniscal, ligamental and cartilage lesions to estimate the sensitivity and specificity of lesion detection.The CR was higher in the ACL, PCL and MEN in 3D- PDwFS compared to 2D-PDwFS (p 0.01 for ACL and PCL; p = 0.07 for MEN). Compared to 2 D images, the OIQ was rated higher in 3D-PDwFS images (p 0.01) due to fewer artifacts and HFS despite the lower IS (p 0.01). The sensitivity and specificity of lesion detection in 3D- and 2D-PDwFS were similar.Compared to standard multiplanar 2D-PDwFS knee imaging, isotropic high spatial resolution 3D-PDwFS of the knee at 3.0 T can be acquired with high image quality in a reasonable scan time. Multiplanar reformations in arbitrary planes may serve as an additional benefit of 3D-PDwFS.• 3D-PDwFS of the knee is acquired with high image quality• 3D-PDwFS can be achieved in only one measurement with a reasonable scan time• 3D-PDwFS with the advantage of multiplanar reformation may replace 2D-PD-weighted knee MRI Citation Format: • Homsi R, Gieseke J, Luetkens JA et al. Three-Dimensional Isotropic Fat-Suppressed Proton Density-Weighted MRI at 3 Tesla Using a T/R-Coil Can Replace Multiple Plane Two-Dimensional Sequences in Knee Imaging. Fortschr Röntgenstr 2016; 188: 949 - 956.

Our aim was to retrospectively evaluate the occurrence of respiratory motion artefacts in patients undergoing dynamic liver magnetic resonance (MR) either with gadoxetate disodium or gadobutrol. Two hundred and thirty liver MR studies (115 with gadobutrol, 115 with gadoxetate disodium) were analysed. Respiratory motion artefacts on dynamic 3D T1-weighted MR images (pre-contrast, arterial, venous, and late-dynamic phase) were assessed using a five-point rating scale. Severe motion was defined as a score ≥ 4. Mean motion scores were compared with the Mann-Whitney-U-test. The chi-squared-test was used for dichotomous comparisons. Mean motion scores for gadoxetate disodium and gadobutrol showed no relevant differences for each phase of the dynamic contrast series (pre-contrast: 1.85 ± 0.70 vs. 1.88 ± 0.57, arterial: 1.85 ± 0.81 vs. 1.87 ± 0.74, venous: 1.82 ± 0.67 vs. 1.74 ± 0.64, late-dynamic: 1.75 ± 0.62 vs. 1.79 ± 0.63; p = 0.469, 0.557, 0.382 and 0.843, respectively). Severe motion artefacts had a similar incidence using gadoxetate disodium and gadobutrol (11/460 [2.4 %] vs. 7/460 [1.5 %]; p = 0.341). Gadoxetate disodium is associated with equivalent motion scores compared to gadobutrol in dynamic liver MRI. In addition, both contrast agents demonstrated a comparable and acceptable rate of severe respiratory motion artefacts. • Gadobutrol and gadoxetate disodium showed comparable motion scores in dynamic phase imaging. • The incidence of severe motion artefacts was pronounced in arterial phase imaging. • Adverse respiratory side effects were not recorded in 115 examinations with gadoxetate disodium.

Objectives To investigate the impact of aortic valve calcification and brain morphology on acute peri-procedural cerebrovascular events (CVEs) in patients undergoing transcatheter aortic valve implantation (TAVI). Background Aortic valve calcification and stenosis can be assessed with echocardiography. Cerebral magnetic resonance imaging (MRI) depicts and quantifies morphological signs of hypoperfusion and vascular embolism, which is of special interest in patients with severe aortic stenosis. Furthermore, subjects who undergo TAVI are prone to suffer of clinically silent peri-procedural CVEs. Methods A total of 119 patients referred to TAVI were investigated for aortic valve calcification using trans-esophageal echocardiography. Cerebral MRI prior to and immediate after implantation was performed in all patients using a dedicated scan protocol. Prior to TAVI, brain morphology was characterized. Post TAVI, brains were investigated for the onset of acute peri-procedural CVEs using diffusion weighted imaging (DWI). Results Seventy-eight patients (65.5%) revealed acute peri-procedural CVEs on MRI after TAVI with a favor of the left hemisphere (57.5%). The degree of valve calcification was associated with peri-procedural CVEs. Patients with a high WML burden had an increased risk for CVEs ((OR) 2.36 (95% CI: 1.09–5.15; P = 0.037)), especially when distributed periventricular ((OR: 3.27; 95% CI: 1.47–7.26; P = 0.0038)). Conclusion In patients undergoing TAVI, the degree of aortic valve calcification and periventricular WML burden were correlated with acute peri-procedural CVEs. Future studies are needed to evaluate their independent value for the long-term clinical outcome.

Objectives To intraindividually compare gadoxetate disodium and gadofosveset trisodium regarding vessel contrast, image quality and vessel delineation in dynamic contrast-enhanced liver MRI at 3.0 T. Methods Twelve patients underwent 3.0 T MRI twice (24 examinations) with a single dose of gadoxetate disodium and gadofosveset trisodium, respectively. Signal intensity in abdominal vessels and tissue was determined. Vessel-to-background ratio (VBR) was calculated for each vessel and dynamic phase. All images were evaluated by two radiologists regarding image quality, vessel delineation and anatomic variants or pathologies with digital subtraction angiography as the standard of reference. Results Gadofosveset trisodium demonstrated a significantly higher VBR compared to gadoxetate disodium (arterial phase: 0.57 ± 0.12 [SD] vs. 0.46 ± 0.19; portal venous phase: 0.51 ± 0.11 vs. 0.37 ± 0.14; equilibrium phase: 0.48 ± 0.10 vs. 0.31 ± 0.13; p ≤ 0.01). Image quality and vessel delineation were rated equal or better for gadofosveset trisodium in all cases. These differences were not significant for most vessel segments. All anatomic variants were correctly identified by both readers for both contrast agents. Conclusions Although gadofosveset trisodium provides a significantly higher vessel contrast at 3.0 T, gadoxetate disodium is equivalent by qualitative measurements. Thus, gadoxetate-enhanced liver MRI at 3.0 T enables reliable assessment of the upper abdominal vasculature with the additional benefit of hepatobiliary imaging.