RESUMO
The worldwide increasing population density in major urban centres poses great challenges for transportation systems. Air taxi services could be a solution to this growing problem by bringing the existing transportation system to the three dimensional space. This paper analyzes the challenges and requirements of developing a vertiport intended for the use of air taxis at Cologne Bonn Airport. This research was conducted with the information available at the time of writing, for which a basis scenario is defined for the Cologne Bonn Airport where important aspects of an air taxi service are determined such as passenger demand and possible vehicles. The main aspects analysed were the requirements on the vertiport infrastructure and its location, as well as the requirements on passenger processing. For the defined basis scenario, results show that the preferential locations to develop a vertiport at Cologne Bonn Airport are the roof top levels of parking garages P2 and P3. Furthermore, it is shown that given the estimated passenger demand, a very high utilization factor of the defined infrastructure is to be expected. This paper provides a starting point for the development of an air taxi service at Cologne Bonn Airport. Further research is needed in key issues such as the financial aspects of an air taxi service, its integration into the current operating scenario of the Cologne Bonn Airport and the approval process for an air taxi service and the vertiport itself.
RESUMO
PURPOSE: To compare magnetic resonance angiography (MRA) at 3 Tesla (3T) and digital subtraction angiography (DSA) for the detection and characterization of unruptured intracranial aneurysms (UIA). MATERIALS AND METHODS: This study has been approved by our local ethical committee. From February to August 2010, 40 consecutive patients with UIA contemporarily underwent MRA at 3T including time-of-flight (TOF-MRA) and contrast enhanced (CE-MRA) techniques and DSA. MR images were independently reviewed by 3 radiologists and DSA images were reviewed by 2 radiologists together. Interobserver and intertechnique agreements were assessed for aneurysm detection and characterization including maximal diameter, neck width and the presence of a bleb or a branch arising from the sac. RESULTS: DS angiography revealed 56 aneurysms. Mean sensitivity and positive predictive value of MRA were 91.4% and 93.4% respectively. For UIA < 3 mm and those ≥ 3 mm, MRA had a mean sensitivity of 74.1% and 100% respectively. Intertechnique and interobserver agreements were substantial for the measurement of UIA maximal diameter (mean κ, 0.607 and 0.601 respectively) and were moderate and fair for neck width measurement respectively (mean κ, 0.456 and 0.285 respectively). For bleb detection, intertechnique and interobserver agreements were fair and slight respectively (mean κ, 0.312 and 0.116 respectively) whereas both were slight for detection of branches arising from the sac (mean κ, 0.151 and 0.070 respectively). CONCLUSION: MR angiography at 3T has a high sensitivity for the detection of UIA. However, it remains significantly inferior to DSA for morphological characterization of UIA.
