A System for Accurate Deployment of Unconstrained Triple-Fenestrated Aortic Arch Endografts

Purpose: To achieve accurate rotational orientation and the axial position of unconstrained triple-fenestrated physician-modified endografts upon deployment in the aortic arch during total arch thoracic endovascular aortic repair (TA-TEVAR). Materials and Methods: Following a detailed study of reconstructed computerized tomography angiography images of patients’ arch anatomy, customized, sealable fenestrations with radio-opaque margins are created onsite on Valiant Captivia (Medtronic) endografts, transposing the arch branch ostial anatomic interrelationship onto the endograft precisely. Radio-opaque figure-of-8 markers, indicating the 12 o’clock (superior) position, are attached to the endograft on the surface and brought up to the surface under the endograft cover during resheathing. Resheathing without any twist in the endograft is achieved by lining up the welds in each endograft stent segment in a straight line. The fluoroscopic working view for arch endograft delivery and deployment is the left anterior oblique view that is orthogonal to the plane of the arch, which, in turn, is the right anterior oblique view in which parts of a stiff indwelling guidewire in the ascending and descending aorta precisely overlap. During introduction in the working view, the endograft delivery system is rotated in the descending thoracic aorta so that the 12 o’clock figure-of-8 markers are viewed on the edge and situated at the outer aortic curvature; continued advancement into the arch without any further rotation will ensure superior orientation of the figure-of-8 markers and, consequently, correct endograft rotational orientation. Proper axial endograft positioning requires locating the left common carotid artery (LCCA) fenestration just proximal to a taut externalized LCCA-femoral guidewire loop marking the posterior limit of the LCCA ostium. After endograft deployment during rapid cardiac pacing, the target arch branches are cannulated through their respective fenestrations using hydrophilic 0.035-inch guidewires that are externalized via distal sheaths to create femoral-arch branch (through-and-through) loops over which covered fenestrated stents are introduced and deployed. Results: This technique was used successfully in 31 consecutive patients undergoing TA-TEVAR; systemic blood pressure was obtained in all arch branches immediately after endograft deployment, indicating adequate blood flow. All arch branches were successfully cannulated and stented. Conclusion: This system enables accurate deployment of unconstrained triple-fenestrated arch endografts simply and reliably during TA-TEVAR.

Structural and functional characterization of the pore-forming domain of pinholin S2168

Pinholin S2168 triggers the lytic cycle of bacteriophage φ21 in infectedEscherichia coli. Activated transmembrane dimers oligomerize into small holes and uncouple the proton gradient. Transmembrane domain 1 (TMD1) regulates this activity, while TMD2 is postulated to form the actual “pinholes.” Focusing on the TMD2 fragment, we used synchrotron radiation-based circular dichroism to confirm its α-helical conformation and transmembrane alignment. Solid-state15N-NMR in oriented DMPC bilayers yielded a helix tilt angle of τ = 14°, a high order parameter (Smol= 0.9), and revealed the azimuthal angle. The resulting rotational orientation places an extended glycine zipper motif (G40xxxS44xxxG48) together with a patch of H-bonding residues (T51, T54, N55) sideways along TMD2, available for helix–helix interactions. Using fluorescence vesicle leakage assays, we demonstrate that TMD2 forms stable holes with an estimated diameter of 2 nm, as long as the glycine zipper motif remains intact. Based on our experimental data, we suggest structural models for the oligomeric pinhole (right-handed heptameric TMD2 bundle), for the active dimer (right-handed Gly-zipped TMD2/TMD2 dimer), and for the full-length pinholin protein before being triggered (Gly-zipped TMD2/TMD1-TMD1/TMD2 dimer in a line).

A performance study of the suitability of Adaptive boosting in Red Acne detection

<p><em>AdaBoost along with HaarCascades have been well received for its accuracy and performance in primarily Facial Recognition applications. However, they are known to perform poorly with objects which have a different rotational orientation or for objects whose shapes are largely variant . In this paper, we apply Adaptive Cascading technique to a specific dermatological application of detecting red acne which are largely shaped variant outgrowths on the skin and to identify its suitability in the detection of acne. Based on the outcome it would be declared if Viola-Jones based Adaptive Boosting is well suited for dermatological processing of skin diseases.</em></p>

Intra-operative imaging in trauma surgery

The reconstruction of anatomical joint surfaces, limb alignment and rotational orientation are crucial in the treatment of fractures in terms of preservation of function and range of motion. To assess reduction and implant position intra-operatively, mobile C-arms are mandatory to immediately and continuously control these parameters. Usually, these devices are operated by OR staff or radiology technicians and assessed by the surgeon who is performing the procedure. Moreover, due to special objectives in the intra-operative setting, the situation cannot be compared with standard radiological image acquisition. Thus, surgeons need to be trained and educated to ensure correct technical conduct and interpretation of radiographs. It is essential to know the standard views of the joints and long bones and how to position the patient and C-arm in order to acquire these views. Additionally, the operating field must remain sterile, and the radiation exposure of the patient and staff must be kept as low as possible. In some situations, especially when reconstructing complex joint fractures or spinal injuries, complete evaluation of critical aspects of the surgical results is limited in two-dimensional views and fluoroscopy. Intra-operative three-dimensional imaging using special C-arms offers a valuable opportunity to improve intra-operative assessment and thus patient outcome. In this article, common fracture situations in trauma surgery as well as special circumstances that the surgeon may encounter are addressed. Cite this article: EFORT Open Rev 2018;3:541-549. DOI: 10.1302/2058-5241.3.170074

Determining the Rotational Orientation of Directional Deep Brain Stimulation Leads Employing Flat-Panel Computed Tomography

BACKGROUND Directional deep brain stimulation (DBS) constitutes an emerging technology that allows selective stimulation of target structures via partitioned electrode contacts. In order to effectively perform target-tailored stimulation, knowledge of the rotational orientation of the segmented leads is imperative. OBJECTIVE To develop a universally applicable and reliable method for determination of lead orientation angles in DBS using flat-panel computed tomography (fpCT). METHODS A binary template of directional leads DB-2202-30 (Boston Scientific, Natick, Massachusetts) and 6170 (Abbott, Plano, Texas) was imported into the 2-dimensional raw data set of a conventional fpCT scan. The template was aligned with and manually rotated around the predetermined lead trajectory. The overall orientation of the segmented lead can be deduced by transferring position and orientation of the lead orientation marker into the 3-dimensional volume. Accuracy of the method was investigated by two raters in a phantom study. RESULTS Accuracy were 5.4° ± 4.1° (range: 0.4°-11.9°) for rater 1 and 5.2° ± 3.0° (range: 0.3°-10.2°) for rater 2, when investigating DB-2202-30. For 6170 observed deviations were 2.5° ± 1.7° (range: 0.2°-5.2°) and 4.3° ± 3.6° (range: 0.2°-11.2°) for raters 1 and 2, respectively. CONCLUSION fpCT imaging constitutes a precise and accurate means to determine the rotational orientation of directional leads. The approach is universally transferable to different electrode designs as the template can easily be adjusted to the electrodes’ specific measures. The approach is independent from polar implantation angles owing to fpCT- and methodological features.