The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Automated processing and visualization of vessel trees

Zsfassung in dt. SpracheDie automatisierte Verarbeitung und Visualisierung von vaskulären Strukturen ist ein gebräuchlicher Ablauf im Bereich der medizinischen Bildverarbeitung. Maximum Intensity Projection (MIP) und Curved Planar Reformation (CPR) sind gut etablierte und robuste Methoden für den klinischen Einsatz. Im Falle verkalkter Gefäßwände verhindern visuelle Verdeckungen das Erkunden des Inneren der Adern, bei der Anwendung von MIP. CPR hingegen erlaubt einen Schnitt entlang der Mittelachse und somit die Darstellung des Querschnitts. Als Erweiterung der Idee von CPR wird eine neuartige automatische Methode zur Visualisierung von Blutgefäßen vorgestellt. Diese funktioniert auch mit mehreren Mittelachsen von Adern, welche nicht notwendigerweise verbunden sein müssen, oder gar eine Baumstruktur vorweisen. Beliebig komplexe vaskuläre Strukturen werden im Volumen als Punktemengen dargestellt und weiters kann man optional, um die Tiefenwahrnehmung zu erhöhen, Okklusion-Halos hinzufügen. Nach der Durchführung einer Merkmalsextraktion im Scale-Raum, werden die Mittelachsen der Adern automatisch aus dem Datenvolumen extrahiert. Dem Benutzer wird die Möglichkeit gegeben das finale Bild zu justieren und die gewünschten Adern, mit Hilfe von visuellen Abfragen anhand der Mausbewegung, zu selektieren. Darüber hinaus wird eine Kombination mit der kürzlich veröffentlichten Visualisierungstechnik namens Maximum Intensity Difference Accumulation (MIDA) vorgestellt. Diese Technik hat die Vorteile des Direkten Volumen Renderings (DVR), nämlich Verdeckungs- und Tiefeninformationen, allerdings benötigt sie keine explizite Angabe einer Transferfunktion. In der vorliegenden Arbeit wird die Anwendung der erwähnten Technik auf große Datensätze gezeigt, welche sowohl für die Feststellung von Embolien, speziell Lungenembolien, als auch für die Diagnose von peripheren Verschlusskrankheiten geeignet ist.Automated processing and visualization of vascular structures is a common task in medical imaging. Maximum Intensity Projection (MIP) and Curved Planar Reformation (CPR) are well established and robust methods for clinical use. In case of calcified vessel walls, occlusion prevents exploring the inside of the vessels when using MIP. CPR allows to cut a single vessel along its centerline and to visualize the lumen. Extending the idea of CPR, a novel automatic method for vessel visualization is proposed. It works with multiple vessel centerlines that do not necessarily need to be connected into a tree structure. Arbitrarily complex vascular structures are rendered in the volume as point sets and optionally, occlusion halos are created around them to enhance depth perception. Vessel centerlines are automatically extracted from a volumetric data-set after performing feature extraction in a scale-space. The user is provided with the ability to control the final image and he or she can visually select the desired centerlines with visual queries by stroking with the mouse. Furthermore, a combination with the recent Maximum Intensity Difference Accumulation (MIDA) visualization technique is presented, which has the advantages of Direct Volume Rendering (DVR) such as occlusion and depth cues, but does not require an explicit transfer function specification. It is demonstrated how the proposed technique can be applied to large data-sets, particularly to data featuring peripheral arterial occlusive diseases or in order to detect possible embolisms as presented on a pulmonary data-set.8

Multipath Curved Planar Reformations of Peripheral CT Angiography : Diagnostic Accuracy and Time Efficiency

Objectives To compare diagnostic performance and time efficiency between 3D multipath curved planar reformations (mpCPRs) and axial images of CT angiography for the pre-interventional assessment of peripheral arterial disease (PAD), with digital subtraction angiography as the standard of reference. Methods Forty patients (10 females, mean age 72 years), referred to CTA prior to endovascular treatment of PAD, were prospectively included and underwent peripheral CT angiography. A semiautomated toolbox was used to render mpCPRs. Twenty-one arterial segments were defined in each leg; for each segment, the presence of stenosis > 70% was assessed on mpCPRs and axial images by two readers, independently, with digital subtraction angiography as gold standard. Results Both readers reached lower sensitivity (Reader 1: 91 vs. 94%, p = 0.08; Reader 2: 89 vs. 93%, p = 0.03) but significantly higher specificity (Reader 1: 94 vs. 89%, p < 0.01; Reader 2: 96 vs. 95%, p = 0.01) with mpCPRs than with axial images. Reader 1 achieved significantly higher accuracy with mpCPRs (93 vs. 91%, p = 0.02), and Reader 2 had similar overall accuracy in both evaluations (94 vs. 94%, p = 0.96). Both readers read mpCPRs significantly faster than axial images (Reader 1: 5′45″ based on mpCPRs vs. 7′40″ based on axial images; Reader 2: 4′41″ based on mpCPRs vs. 6′57″ based on axial images; p < 0.01). Conclusions mpCPRs are a promising 3D reformation technique that facilitates a fast assessment of PAD with high diagnostic accuracy.(VLID)357824

Novel software-derived workflow in extracranial–intracranial bypass surgery validated by transdural indocyanine green videoangiography

BACKGROUND:The introduction of image-guided methods to bypass surgery has resulted in optimized preoperative identification of the recipients and excellent patency rates. However, the recently presented methods have also been resource-consuming. In the present study, we have reported a cost-efficient planning workflow for extracranial-intracranial (EC-IC) revascularization combined with transdural indocyanine green videoangiography (tICG-VA). METHODS:We performed a retrospective review at a single tertiary referral center from 2011 to 2018. A novel software-derived workflow was applied for 25 of 92 bypass procedures during the study period. The precision and accuracy were assessed using tICG-VA identification of the cortical recipients and a comparison of the virtual and actual data. The data from a control group of 25 traditionally planned procedures were also matched. RESULTS:The intraoperative transfer time of the calculated coordinates averaged 0.8 minute (range, 0.4-1.9 minutes). The definitive recipients matched the targeted branches in 80%, and a neighboring branch was used in 16%. Our workflow led to a significant craniotomy size reduction in the study group compared with that in the control group (P = 0.005). tICG-VA was successfully applied in 19 cases. An average of 2 potential recipient arteries were identified transdurally, resulting in tailored durotomy and 3 craniotomy adjustments. Follow-up patency results were available for 49 bypass surgeries, comprising 54 grafts. The overall patency rate was 91% at a median follow-up period of 26 months. No significant difference was found in the patency rate between the study and control groups (P = 0.317). CONCLUSIONS:Our clinical results have validated the presented planning and surgical workflow and support the routine implementation of tICG-VA for recipient identification before durotomy

Single-stage bone resection and cranioplastic reconstruction: Comparison of a novel software-derived PEEK workflow with the standard reconstructive method

The combined resection of skull-infiltrating tumours and immediate cranioplastic reconstruction predominantly relies on freehand-moulded solutions. Techniques that enable this procedure to be performed easily in routine clinical practice would be useful. A cadaveric study was developed in which a new software tool was used to perform single-stage reconstructions with prefabricated implants after the resection of skull-infiltrating pathologies. A novel 3D visualization and interaction framework was developed to create 10 virtual craniotomies in five cadaveric specimens. Polyether ether ketone (PEEK) implants were manufactured according to the bone defects. The image-guided craniotomy was reconstructed with PEEK and compared to polymethyl methacrylate (PMMA). Navigational accuracy and surgical precision were assessed. The PEEK workflow resulted in up to 10-fold shorter reconstruction times than the standard technique. Surgical precision was reflected by the mean 1.1 ± 0.29 mm distance between the virtual and real craniotomy, with submillimetre precision in 50%. Assessment of the global offset between virtual and actual craniotomy revealed an average shift of 4.5 ± 3.6 mm. The results validated the ‘elective single-stage cranioplasty’ technique as a state-of-the-art virtual planning method and surgical workflow. This patient-tailored workflow could significantly reduce surgical times compared to the traditional, intraoperative acrylic moulding method and may be an option for the reconstruction of bone defects in the craniofacial region