Therapy control in a patient with an inflammatory abdominal aneurysm: potential pitfalls in PET/CT imaging

We present a case of inflammatory abdominal arterial aneurysms, which demonstrates the potential usefulness of PET/CT with F-FDG in long-term monitoring of this disease, but also demonstrates potential pitfalls in abdominal arterial aneurysm imaging with PET/CT. Imaging may be challenged as the initial presentation prior to therapy may mimic an infected aneurysm. Follow-up images may be mistaken for vascular graft infection or persistent disease

Vascular graft infections

Vascular graft infections are rare complications after surgical and endovascular treatment of aortic diseases. This condition is characterized by complexity in diagnosis and medico-surgical management. Moreover, even if properly treated, morbidity and mortality rates are high. Although several advances have been made over the years and guidelines of treatment have been published, there is still debate on the optimal care for this disease. With local microbiological patterns and multiresistant strains conditioning antimicrobial treatment as well as several surgical debridement techniques in the armamentarium, it is difficult to offer recommendations that can be generalized for every single case. In this review, we aim at describing thoracic and abdominal vascular graft infections and providing current information on diagnosis, medical treatment, and surgical management

Full Wafer Redistribution and Wafer Embedding as Key Technologies for a Multi-Scale Neuromorphic Hardware Cluster

Together with the Kirchhoff-Institute for Physics(KIP) the Fraunhofer IZM has developed a full wafer redistribution and embedding technology as base for a large-scale neuromorphic hardware system. The paper will give an overview of the neuromorphic computing platform at the KIP and the associated hardware requirements which drove the described technological developments. In the first phase of the project standard redistribution technologies from wafer level packaging were adapted to enable a high density reticle-to-reticle routing on 200mm CMOS wafers. Neighboring reticles were interconnected across the scribe lines with an 8{\mu}m pitch routing based on semi-additive copper metallization. Passivation by photo sensitive benzocyclobutene was used to enable a second intra-reticle routing layer. Final IO pads with flash gold were generated on top of each reticle. With that concept neuromorphic systems based on full wafers could be assembled and tested. The fabricated high density inter-reticle routing revealed a very high yield of larger than 99.9%. In order to allow an upscaling of the system size to a large number of wafers with feasible effort a full wafer embedding concept for printed circuit boards was developed and proven in the second phase of the project. The wafers were thinned to 250{\mu}m and laminated with additional prepreg layers and copper foils into a core material. After lamination of the PCB panel the reticle IOs of the embedded wafer were accessed by micro via drilling, copper electroplating, lithography and subtractive etching of the PCB wiring structure. The created wiring with 50um line width enabled an access of the reticle IOs on the embedded wafer as well as a board level routing. The panels with the embedded wafers were subsequently stressed with up to 1000 thermal cycles between 0C and 100C and have shown no severe failure formation over the cycle time.Comment: Accepted at EPTC 201

In-vivo flow simulation in coronary arteries based on computed tomography datasets: feasibility and initial results

The purpose of this paper was to non-invasively assess hemodynamic parameters such as mass flow, wall shear stress (WSS), and wall pressure with computational fluid dynamics (CFD) in coronary arteries using patient-specific data from computed tomography (CT) angiography. Five patients (two without atherosclerosis, three with atherosclerosis) underwent retrospectively electrocardiogram (ECG) gated 16-detector row CT using ECG-pulsing and geometric models of coronary arteries were reconstructed for CFD analysis. Blood flow was considered laminar, incompressible, Newtonian, and pulsatile. The mass flow, WSS, and wall pressure were quantified and flow patterns were visualized. The wall pressure continuously decreased towards distal segments and showed pressure drops in stenotic segments. In coronary segments without atherosclerotic wall changes, WSS remained low, even during phases of high flow velocity, whereas in atherosclerotic vessels, the WSS was elevated already at low flow velocities. Stenoses and post-stenotic dilatations led to flow acceleration and rapid deceleration, respectively, including a distortion of flow. Areas of high WSS and high flow velocities were found adjacent to plaques, with values correlating with the degree of stenosis. CFD provided detailed mass flow measurements. CFD analysis is feasible in normal and atherosclerotic coronary arteries and provides the rationale for further investigation of the links between hemodynamic parameters and the significance of coronary stenose

Flow and wall shear stress in end-to-side and side-to-side anastomosis of venous coronary artery bypass grafts

<p>Abstract</p> <p>Purpose</p> <p>Coronary artery bypass graft (CABG) surgery represents the standard treatment of advanced coronary artery disease. Two major types of anastomosis exist to connect the graft to the coronary artery, i.e., by using an end-to-side or a side-to-side anastomosis. There is still controversy because of the differences in the patency rates of the two types of anastomosis. The purpose of this paper is to non-invasively quantify hemodynamic parameters, such as mass flow and wall shear stress (WSS), in end-to-side and side-to-side anastomoses of patients with CABG using computational fluid dynamics (CFD).</p> <p>Methods</p> <p>One patient with saphenous CABG and end-to-side anastomosis and one patient with saphenous CABG and side-to-side anastomosis underwent 16-detector row computed tomography (CT). Geometric models of coronary arteries and bypasses were reconstructed for CFD analysis. Blood flow was considered pulsatile, laminar, incompressible and Newtonian. Peri-anastomotic mass flow and WSS were quantified and flow patterns visualized.</p> <p>Results</p> <p>CFD analysis based on in-vivo CT coronary angiography data was feasible in both patients. For both types of CABG, flow patterns were characterized by a retrograde flow into the native coronary artery. WSS variations were found in both anastomoses types, with highest WSS values at the heel and lowest WSS values at the floor of the end-to-side anastomosis. In contrast, the highest WSS values of the side-to-side anastomosis configuration were found in stenotic vessel segments and not in the close vicinity of the anastomosis. Flow stagnation zones were found in end-to-side but not in side-to-side anastomosis, the latter also demonstrating a smoother stream division throughout the cardiac cycle.</p> <p>Conclusion</p> <p>CFD analysis of venous CABG based on in-vivo CT datasets in patients was feasible producing qualitative and quantitative information on mass flow and WSS. Differences were found between the two types of anastomosis warranting further systematic application of the presented methodology on multiple patient datasets.</p