Thorsten Plum

Magnetic Resonance-Guided Angioplasty With Delivery of Contrast-Media Doped Solutions to the Vessel Wall : An Experimental Study in Swine

Objectives:To assess the feasibility of magnetic resonance (MR)-guided delivery of a solution containing contrast-medium and immediate online monitoring of its distribution to the vessel wall during MR-guided angioplasty in peripheral arteries. Materials and Methods:In 3 pigs, the feasibility of MR-guided atraumatic delivery of a solution containing contrast-medium and tissue dye (0.05 mmol/mL Gd-DTPA, 3% Evans blue dye) into the vessel wall of the iliac arteries was tested using a permeable balloon catheter (8 mm). Catheter placement was monitored using a steady-state free precession real-time imaging sequence. Additionally, in 5 pigs, surgically created bilateral stenoses in the external iliac artery were dilatated with the porous balloon. In these animals, contrast-enhanced MR angiography was performed before and after the interventions to assess the degree of the stenosis. In all animals, the vessel wall was delineated before and after dilatation using a T1-weighted gradient echo (GE) sequence. Results:In the 3 animals without stenosis, contrast medium was successfully applied to the vessel wall. On the GE images, the normalized signal intensity of the vessel wall was 0.95 ± 0.015 arbitrary units (a. u.) prior and 2.15 ± 0.105 a. u. after the intervention (P < 0.01). In the animals with stenosis, MR angiography performed before and after the intervention demonstrated successful dilatation of 9 of the 10 stenoses. Before the intervention, 7 stenoses were severe (76%–99%) and 3 moderate (50%–75%), and after the intervention, 4 stenoses were completely removed and 5 mild (<50%). Also in these 5 animals, the solution was visible in the vessel wall of the arteries on the T1-weighted GE MR images (normalized signal intensity prior the intervention 1.33 ± 0.16 a. u. and 2.97 ± 0.23 after angioplasty; P < 0.05). Histology demonstrated the distribution of the Evans blue dye within the vessel wall in all animals. Conclusions:MR-guided delivery of a contrast-medium containing solution and immediate online assessment of its distribution to the vessel wall during angioplasty in peripheral arteries is feasible.

A simulation-based case study for powertrain efficiency improvement by automated driving functions

An increasing level of driving automation and a successive electrification of modern powertrains enable a higher degree of freedom to improve vehicle fuel efficiency and reduce pollutant emissions. Currently, both domains themselves, driving automation as well as powertrain electrification, face the challenge of a rising development complexity with extensive use of virtual testing environments. However, state-of-the-art virtual testing environments typically strictly focus on just one domain and neglect the other. This paper shows the results of a simulation-based case study considering both domains simultaneously. The influence of energy saving automated functionalities on a conventional, a hybrid, and a pure electric powertrain is investigated for a carefully selected inner-city driving scenario. The vehicle simulation models for the different powertrain configurations are calibrated using test bench results and vehicle measurements. A model predictive acceleration controller is developed for realizing the speed optimization function. By considering traffic conditions such as traffic light schedules and a preceding vehicle as the boundary conditions, unnecessary accelerations and decelerations are avoided to reduce the energy demand. The case study is realized by applying this function to the three powertrains variants. As a final result, a clear difference in energy demand is observed: the hybrid powertrain benefits the most in terms of energy demand reduction in the given use case. The results clearly underscore that in future vehicle development programs, the powertrain and the real-world driving functionalities have to be optimized simultaneously to minimize the energy demand during everyday vehicle operation.

Elektrische Zusatzaufladung - neue Freiheitsgrade durch höhere Bordnetzspannungen

Die elektrisch angetriebene Aufladung ist bereits seit vielen Jahren immer wieder Gegenstand von Untersuchungen im Fahrzeugsektor. Sowohl Fahrzeughersteller als auch Zulieferer haben verschiedene Konzepte vorgestellt. Dem Konzept des elektrisch angetriebenen Verdichters in Kombination mit einem Abgasturbolader (TC) werden hierbei die grosten Erfolgschancen eingeraumt.

Vehicle speed trajectory optimization under limits in time and spatial domains

Among various aspects for predictive vehicle energy management optimization, driving speed profile optimization is a key factor for reducing energy consumption. Focus of this article is to optimize the speed trajectory of the vehicle along a given route, to reduce the energy consumption without sacrificing the overall travel time, which is a typical trade-off with energy consumption.

MRT des Innenohrs, Darstellung anatomischer Details bei 3T im Vergleich zu 1,5T

Ziele: Vergleich der Darstellbarkeit anatomischer Details des Innenohrs bei 3 und 1,5 T mittels einer stark T2-gewichteten turbo Spin-echo Sequenz (TSE). Methode: Bei 15 gesunden Probanden und 15 Patienten wurde bei 3 T und 1,5 T eine stark T2-gewichtete 3D TSE in axialer Schichtorientierung durchgefuhrt (Parameter 3T: TR/TE 2500/200ms, Matrix 368×512, FOV 160mm2, Messzeit 5.42min; 1,5T: TR/TE 2000/500ms, Matrix 128×128, FOV 90mm2, Messzeit 5,46min, seitengetrennte Untersuchung). Die Sichtbarkeit anatomischer Strukturen sowie pathologischer Veranderungen wurden von zwei Radiologen im Konsensus mittels einer nicht parametrischen 4 Punkteskale (0: nicht sichtbar; 1: sichtbar; 2: diagnostische Bildqualitat; 3: sehr gute Darstellung) beurteilt. Ergebnis: Kleine anatomische Strukturen wie der Modiolus, die Lamina spiralis und die Nervenaste im inneren Gehorgang konnten bei 3 T signifikant besser dargestellt werden (p<0.01). Fur die Sichtbarkeit grosere Strukturen wie Vestibulum und Bogengange ergaben sich nur geringe Unterschiede mit etwas besserer Darstellung bei 3T. Bei insgesamt 5 Patienten wurden pathologische Veranderungen gefunden. Diese waren bei beiden Feldstarken erkennbar, wurden jedoch bei 3T mit etwas besserer Bildqualitat dargestellt. Schlussfolgerung: Die Untersuchung des Innenohrs bei 3T erlaubt eine im Vergleich zu 1,5 T bessere Darstellung anatomischer Details, bei gleichzeitig deutlich kurzerer Messzeit. Korrespondierender Autor: Krombach GA Klinik fur Radiologische Diagnostik, Universitatsklinikum Aachen, RWTH-Aachen, Pauwelsstrasse 30, 52074 Aachen E-Mail: krombach@rad.rwth-aachen.de