The impact of injector-based contrast agent administration in time-resolved MRA

2017 ◽  
Vol 28 (5) ◽  
pp. 2246-2253 ◽  
Author(s):  
Johannes Budjan ◽  
Ulrike I. Attenberger ◽  
Stefan O. Schoenberg ◽  
Hubertus Pietsch ◽  
Gregor Jost
Keyword(s):  
Contrast Agent ◽  
Time Resolved ◽  
Contrast Agent Administration ◽  
The Impact

Structure–Relaxivity Mechanism of an Ultrasmall Ferrite Nanoparticle T1 MR Contrast Agent: The Impact of Dopants Controlled Crystalline Core and Surface Disordered Shell

Nano Letters ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 1115-1123
Author(s):  
Yuqing Miao ◽  
Huan Zhang ◽  
Jing Cai ◽  
Yimin Chen ◽  
Huijun Ma ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Crystalline Core ◽  
Ferrite Nanoparticle ◽  
The Impact

Surface Roughness Impact on Secondary Flow and Losses in a Turbine Exhaust Casing

2018 ◽  
Author(s):  
Isak Jonsson ◽  
Valery Chernoray ◽  
Borja Rojo
Keyword(s):  
Surface Roughness ◽  
Secondary Flow ◽  
Suction Side ◽  
Pressure Probe ◽  
Time Resolved ◽  
Pressure Distributions ◽  
Turbulence Decay ◽  
Inlet Swirl ◽  
High Level ◽  
The Impact

This paper experimentally addresses the impact of surface roughness on losses and secondary flow in a Turbine Rear Structure (TRS). Experiments were performed in the Chalmers LPT-OGV facility, at an engine representative Reynolds number with a realistic shrouded rotating low-pressure turbine (LPT). Outlet Guide Vanes (OGV) were manufactured to achieve three different surface roughnesses tested at two Reynolds numbers, Re = 235000 and Re = 465000. The experiments were performed at on-design inlet swirl conditions. The inlet and outlet flow of the TRS were measured in 2D planes with a 5-hole probe and 7-hole probe accordingly. The static pressure distributions on the OGVs were measured and boundary layer studies were performed at the OGV midspan on the suction side with a time-resolved total pressure probe. Turbulence decay was measured within the TRS with a single hot-wire. The results showed a surprisingly significant increase in the losses for the high level of surface roughness (25–30 Ra) of the OGVs and Re = 465000. The increased losses were primary revealed as a result of the flow separation on the OGV suction side near the hub. The loss increase was seen but was less substantial for the intermediate roughness case (4–8 Ra). Experimental results presented in this work provide support for the further development of more advanced TRS and data for the validation of new CFD prediction methods for TRS.

scholarly journals Contrast-Enhanced Magnetic Resonance Angiography Using a Novel Elastin-Specific Molecular Probe in an Experimental Animal Model

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Carolin Reimann ◽  
Julia Brangsch ◽  
Jan Ole Kaufmann ◽  
Lisa C. Adams ◽  
David C. Onthank ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Image Quality ◽  
Magnetic Resonance Angiography ◽  
Contrast Agent ◽  
Mr Angiography ◽  
Molecular Probe ◽  
Time Resolved ◽  
Clinical Dose ◽  
Contrast Enhanced ◽  
First Pass

Objectives. The aim of this study was to test the potential of a new elastin-specific molecular agent for the performance of contrast-enhanced first-pass and 3D magnetic resonance angiography (MRA), compared to a clinically used extravascular contrast agent (gadobutrol) and based on clinical MR sequences. Materials and Methods. Eight C57BL/6J mice (BL6, male, aged 10 weeks) underwent a contrast-enhanced first-pass and 3D MR angiography (MRA) of the aorta and its main branches. All examinations were on a clinical 3 Tesla MR system (Siemens Healthcare, Erlangen, Germany). The clinical dose of 0.1 mmol/kg was administered in both probes. First, a time-resolved MRA (TWIST) was acquired during the first-pass to assess the arrival and washout of the contrast agent bolus. Subsequently, a high-resolution 3D MRA sequence (3D T1 FLASH) was acquired. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were calculated for all sequences. Results. The elastin-specific MR probe and the extravascular imaging agent (gadobutrol) enable high-quality MR angiograms in all animals. During the first-pass, the probes demonstrated a comparable peak enhancement (300.6 ± 32.9 vs. 288.5 ± 33.1, p>0.05). Following the bolus phase, both agents showed a comparable intravascular enhancement (SNR: 106.7 ± 11 vs. 102.3 ± 5.3; CNR 64.5 ± 7.4 vs. 61.1 ± 7.2, p>0.05). Both agents resulted in a high image quality with no statistical difference (p>0.05). Conclusion. The novel elastin-specific molecular probe enables the performance of first-pass and late 3D MR angiography with an intravascular contrast enhancement and image quality comparable to a clinically used extravascular contrast agent.

scholarly journals Measurement of arteriolar blood volume in brain tumors using MRI without exogenous contrast agent administration at 7T

2016 ◽  
Vol 44 (5) ◽  
pp. 1244-1255 ◽  
Author(s):  
Yuankui Wu ◽  
Shruti Agarwal ◽  
Craig K. Jones ◽  
Andrew G. Webb ◽  
Peter C.M. van Zijl ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Contrast Agent ◽  
Blood Volume ◽  
Contrast Agent Administration ◽  
Exogenous Contrast Agent

Effect of Rotor-Stator Configuration in the Generation of Vortical Scales and Wake Mixing in Single Stage Axial Fans: Part II — Assessment of Vortex Sound Sources

2013 ◽  
Author(s):  
Mónica Galdo Vega ◽  
Jesus Manuel Fernandez Oro ◽  
Katia María Argüelles Díaz ◽  
Carlos Santolaria Morros
Keyword(s):  
Deep Understanding ◽  
Operating Conditions ◽  
Axial Fan ◽  
Noise Sources ◽  
Sound Sources ◽  
Time Resolved ◽  
Vortex Sound ◽  
Starting Point ◽  
Axial Fans ◽  
The Impact

This second part is devoted to the identification of vortex sound sources in low-speed turbomachinery. As a starting point, the time-resolved evolution of the vortical motions associated to the wake shear layers (reported in the first part of the present study) is employed to obtain vorticity distributions in both blade-to-blade and traverse locations throughout the axial fan stage. Following, the Powell analogy for generation of vortex sound is revisited to obtain the noise sources in the nearfield region of the fan. Both numerical and experimental databases presented previously are now post-processed to achieve a deep understanding of the aeroacoustic behavior of the vortical scales present in the flow. A LES simulation at midspan, using a 2.5D scheme, allows an accurate description of the turn-out time of the shedding vortices, within high-density meshes in the blades and vanes passages, and a correct modeling of the dynamics of turbulence. Besides, thermal anemometry has been employed with a two-wire probe to measure the planar flow in the midspan sections of the fan. Statistical procedures and signal conditioning of velocity traces have confirmed experimentally the unsteady flow patterns devised in the numerical model. The comparison of the rotor-stator and the stator-rotor configurations provides the influence of the wake mixing and the nucleation of turbulent spots in the distribution of the Powell source terms. Moreover, the relation between the turbomachine configuration and the generation of vortex sound can be established, including the impact of the operating conditions and the contributions of the interaction mechanisms.

Assessment of the impact of oxidation processes on indoor air pollution using the new time-resolved INCA-Indoor model

2015 ◽  
Vol 122 ◽  
pp. 521-530 ◽  
Author(s):  
Maxence Mendez ◽  
Nadège Blond ◽  
Patrice Blondeau ◽  
Coralie Schoemaecker ◽  
Didier A. Hauglustaine
Keyword(s):  
Air Pollution ◽  
Indoor Air ◽  
Indoor Air Pollution ◽  
Time Resolved ◽  
Oxidation Processes ◽  
The Impact ◽  
New Time

Surface Nanobubbles Studied by Time-Resolved Fluorescence Microscopy Methods Combined with AFM: The Impact of Surface Treatment on Nanobubble Nucleation

Langmuir ◽  
2016 ◽  
Vol 32 (43) ◽  
pp. 11155-11163 ◽  
Author(s):  
Nicole Hain ◽  
Daniel Wesner ◽  
Sergey I. Druzhinin ◽  
Holger Schönherr
Keyword(s):  
Fluorescence Microscopy ◽  
Surface Treatment ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
The Impact

scholarly journals Left ventricle volume measurements in cardiac micro-CT: The impact of radiation dose and contrast agent

2008 ◽  
Vol 32 (3) ◽  
pp. 239-250 ◽  
Author(s):  
Cristian T. Badea ◽  
Arthur W. Wetzel ◽  
Nilesh Mistry ◽  
Stuart Pomerantz ◽  
Demian Nave ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Left Ventricle ◽  
Contrast Agent ◽  
Micro Ct ◽  
Left Ventricle Volume ◽  
Volume Measurements ◽  
Ventricle Volume ◽  
The Impact
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