40 research outputs found
Vessel-profile comparison.
<p>Top: SWI, NLM-SWI, IR-SWI and MIR-SWI axial brain slices (from left to right respectively) in a healthy volunteer. The red lines represent the domain used to plot the in-plane profiles of the voxel intensities perpendicular to a small right frontal vein. Bottom: the comparison of the corresponding in-plane profiles of the SWI (green line), NLM-SWI (yellow line), IR-SWI (cyan line) and MIR-SWI (dotted red line) voxel intensities shows that MIR-SWI, IR-SWI and NLM-SWI schemes enhance the SNR of the parenchyma (depicted by the line plateau) compared to the SWI vessel profile, but only the MIR-SWI does not introduce a detrimental blurring between the vessel and surrounding tissues.</p
Spectroscopic Characterization of the 3+ and 2+ Oxidation States of Europium in a Macrocyclic Tetraglycinate Complex
The
3+ and 2+ oxidation states of europium have drastically different
magnetic and spectroscopic properties. Electrochemical measurements
are often used to probe Eu<sup>III/II</sup> oxidation state changes,
but a full suite of spectroscopic characterization is necessary to
demonstrate conversion between these two oxidation states in solution.
Here, we report the facile conversion of an europium(III) tetraglycinate
complex into its Eu<sup>II</sup> analogue. We present electrochemical,
luminescence, electron paramagnetic resonance, UV–visible,
and NMR spectroscopic data demonstrating complete reversibility from
the reduction and oxidation of the 3+ and 2+ oxidation states, respectively.
The Eu<sup>II</sup>-containing analogue has kinetic stability within
the range of clinically approved Gd<sup>III</sup>-containing complexes
using an acid-catalyzed dissociation experiment. Additionally, we
demonstrate that the 3+ and 2+ oxidation states provide redox-responsive
behavior through chemical-exchange saturation transfer or proton relaxation,
respectively. These results will be applicable to a wide range of
redox-responsive contrast agents and Eu-containing complexes
Results of different denoising pipelines on SWI image generation.
<p>Axial brain mIPs (corresponding to a volume of 20 mm) at the level of the lateral ventricles of SWI-100Hz (a), SWI (b), NLM-SWI (c), IR-SWI (d), MNLM-SWI (e), MNLM-HP-SWI (f), and MIR-SWI (g) images. The number of phase mask multiplications is set to 4. Enhanced visibility of venous structures without loss of tissue contrast is evident in (g) compared to (b-f).</p
Influence of different denoising pipelines on high-pass filtered phase images.
<p>Argument of the phase mask function (somehow equivalent to high-pass filtered phase) in the following pipelines: SWI-100Hz (a), SWI (b), IR-SWI (c), MNLM-SWI (d), MNLM-HP-SWI (e) and MIR-SWI (f). The tissues outside the brain were masked in order to focus on the denoising results. The image obtained with MIR-SWI scheme shows good noise suppression while preserving brain structures compared to both MNLM-SWI and MNLM-HP-SWI images.</p
The effect of the <i><b>n</b></i> values on SWI images in subject #1.
<p>mIPs of the same targeted volume of 20 mm at varying <i>n</i> values. In reference to the SWI-100Hz image, MIR-SWI shows both satisfactory noise removal and better vessel enhancement at increasing <i>n</i> values compared to the other SWI schemes.</p
Depiction of the smooth muscle FiberArea% algorithm.
<p>Smooth muscle micrographs (200× magnification, 1260×1400 resolution) of embryonic gizzard at incubation day 14 (<b>A</b>) and incubation day 17 (<b>B</b>). Four muscle bundles are randomly chosen in each micrograph and the results of the FiberArea% algorithm are shown in right corner.</p
Bar graph of VB-CNRs at different <i>n</i> values in subject #1.
<p>VB-CNR analysis performed on the same veins of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126835#pone.0126835.g004" target="_blank">Fig 4a</a> (AS: anterior septal vein, TS: thalamostriate vein, IC: internal cerebral vein, LA: lateral atrial vein, SC: sylvian cortical vein) as they appeared in the three rightmost columns of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126835#pone.0126835.g006" target="_blank">Fig 6</a>. From each vein, the triplets of bars with the same color correspond to the images with <i>n</i> value of 6, 7 and 8, from left to right, respectively. Among the denoising schemes under evaluation, only MIR-SWI (red bars) consistently showed increased VB-CNR in all selected veins.</p
VB-CNR analysis in subject #1.
<p>SWI-100HZ axial brain mIP (a) corresponding to a volume of 20 mm shows the five venous ROIs we used for the quantitative evaluation of the MIR-SWI denoising scheme. Green lines represent the veins used for VB-CNR analysis while cyan lines are the background counterparts positioned on neighbooring tissues (anterior septal vein, AS; thalamostriate vein, TS; internal celebral vein, IC; lateral atrial vein, LA; silvian cortical vein, SC). The VB-CNR bar graph of each vein (b) shows an overall higher contrast between veins and background of the MIR-SWI (red bars) compared to the other schemes.</p
Semiquantitative visual assessment.
<p>Frequency histogram of the semiquantitative scores for the display of the brain structures of the MNLM-SWI (gray), MNLM-HP-SWI (orange), SWI (green), NLM-SWI (yellow), IR-SWI (cyan) and MIR-SWI (red) images. Score values from 1 to 5 indicate increasing overall image quality (see text).</p