scholarly journals Phase contrast coronary blood velocity mapping with both high temporal and spatial resolution using triggered Golden Angle rotated Spiral k‐t Sparse Parallel imaging (GASSP) with shifted binning

2021 ◽  
Author(s):  
Dan Zhu ◽  
Gabriele Bonanno ◽  
Allison G. Hays ◽  
Robert G. Weiss ◽  
Michael Schär
Keyword(s):  
Spatial Resolution ◽  
Phase Contrast ◽  
Parallel Imaging ◽  
Blood Velocity ◽  
Velocity Mapping ◽  
Golden Angle ◽  
Temporal And Spatial

On Improving Temporal and Spatial Resolution of 3D Contrast-enhanced Body MR Angiography with Parallel Imaging

Radiology ◽  
2004 ◽  
Vol 231 (3) ◽  
pp. 893-899 ◽  
Author(s):  
Qun Chen ◽  
Carla V. Quijano ◽  
Vu M. Mai ◽  
Saravanan K. Krishnamoorthy ◽  
Wei Li ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Mr Angiography ◽  
Parallel Imaging ◽  
Contrast Enhanced ◽  
Temporal And Spatial

scholarly journals Achieving high spatial and temporal resolution with perfusion MRI in the head and neck region using golden-angle radial sampling

2020 ◽  
Author(s):  
Andrea Tomppert ◽  
Wolfgang Wuest ◽  
Marco Wiesmueller ◽  
Rafael Heiss ◽  
Markus Kopp ◽  
...  
Keyword(s):  
Image Quality ◽  
Head And Neck ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Neck Region ◽  
Head And Neck Region ◽  
Golden Angle ◽  
Edge Sharpness ◽  
Temporal And Spatial ◽  
Golden Angle Radial

Abstract Objectives Conventional perfusion-weighted MRI sequences often provide poor spatial or temporal resolution. We aimed to overcome this problem in head and neck protocols using a golden-angle radial sparse parallel (GRASP) sequence. Methods We prospectively included 58 patients for examination on a 3.0-T MRI using a study protocol. GRASP (A) was applied to a volumetric interpolated breath-hold examination (VIBE) with 135 reconstructed pictures and high temporal (2.5 s) and spatial resolution (0.94 × 0.94 × 3.00 mm). Additional sequences of matching temporal resolution (B: 2.5 s, 1.88 × 1.88 × 3.00 mm), with a compromise between temporal and spatial resolution (C: 7.0 s, 1.30 × 1.30 × 3.00 mm) and with matching spatial resolution (D: 145 s, 0.94 × 0.94 × 3.00 mm), were subsequently without GRASP. Instant inline-image reconstructions (E) provided one additional series of averaged contrast information throughout the entire acquisition duration of A. Overall diagnostic image quality, edge sharpness and contrast of soft tissues, vessels and lesions were subjectively rated using 5-point Likert scales. Objective image quality was measured as contrast-to-noise ratio in D and E. Results Overall, the anatomic and pathologic image quality was substantially better with the GRASP sequence for the temporally (A/B/C, all p < 0.001) and spatially resolved comparisons (D/E, all p < 0.002 except lesion edge sharpness with p = 0.291). Image artefacts were also less likely to occur with GRASP. Differences in motion, aliasing and truncation were mainly significant, but pulsation and fat suppression were comparable. In addition, the contrast-to-noise ratio of E was significantly better than that of D (pD-E < 0.001). Conclusions High temporal and spatial resolution can be obtained synchronously using a GRASP-VIBE technique for perfusion evaluation in head and neck MRI. Key Points • Golden-angle radial sparse parallel (GRASP) sampling allows for temporally resolved dynamic acquisitions with a very high image quality. • Very low-contrast structures in the head and neck region can benefit from using the GRASP sequence. • Inline-image reconstruction of dynamic and static series from one single acquisition can replace the conventional combination of two acquisitions, thereby saving examination time.

scholarly journals MR phase-contrast velocity mapping methods for measuring venous blood velocity in the deep veins of the calf

2011 ◽  
Vol 34 (3) ◽  
pp. 634-644 ◽  
Author(s):  
Iain T. Pierce ◽  
Peter D. Gatehouse ◽  
X. Yun Xu ◽  
David N. Firmin
Keyword(s):  
Phase Contrast ◽  
Venous Blood ◽  
Blood Velocity ◽  
Velocity Mapping

scholarly journals Time Resolved 3D MRA. Applications for Interventional Neuroradiology

2006 ◽  
Vol 12 (3) ◽  
pp. 223-231 ◽  
Author(s):  
CP Stracke ◽  
E. Spuentrup ◽  
P. Reinacher ◽  
A. Thron ◽  
T. Krings
Keyword(s):  
Spatial Resolution ◽  
Parallel Imaging ◽  
Three Dimensional ◽  
Interventional Neuroradiology ◽  
Structural Mri ◽  
Vascular Lesion ◽  
Whole Body ◽  
Time Resolved ◽  
Hemodynamic Characteristics ◽  
Temporal And Spatial

The decision for endovascular treatment of cranial dural AV fistulae and angiomas and their follow-up after treatment is usually based on conventional DSA. New techniques of magnetic resonance angiography (MRA) facilitate high temporal and spatial resolution images. The purpose of this study was to evaluate the applicability and clinical use of a newly developed 3D dynamic MRA protocol on a 3T scanner for neurointerventional planning and decision-making. Using a 3T whole body scanner, a three-dimensional dynamic contrast enhanced MRA sequence with parallel imaging, and intelligent k-space readout (Keyhole and “CENTRA” k-space filling) was added to structural MRI and time-of-flight MRA in seven patients. DSA was performed in each patient following MR examination. In all patients MRA allowed the identification and correct classification of the vascular lesion. Hemodynamic characteristics and venous architecture were clearly demonstrated. Larger feeding arteries could be identified in all cases. Smaller feeding vessels were overlooked in dynamic MRA and only depicted in conventional DSA High temporal and spatial resolution 3D MRA may correctly identify and classify fistulae and angiomas and help to reduce the number of pre- or post-interventional invasive diagnostic angiograms.

In operando visualization of electrolyte stratification dynamics in lead-acid battery using phase-contrast X-ray imaging

2020 ◽  
Vol 56 (66) ◽  
pp. 9553-9556
Author(s):  
Daiko Takamatsu ◽  
Tatsumi Hirano ◽  
Akio Yoneyama ◽  
Takayuki Kimura ◽  
Motoko Harada ◽  
...  
Keyword(s):  
Real Time ◽  
Spatial Resolution ◽  
Phase Contrast ◽  
Lead Acid Battery ◽  
X Ray ◽  
X Ray Imaging ◽  
Real Time Visualization ◽  
Temporal And Spatial ◽  
In Operando ◽  
Lead Acid

Real-time visualization of electrolyte stratification dynamics under lead-acid battery operation with high temporal and spatial resolution by phase-contrast X-ray imaging.

scholarly journals Semi-automated classification of colonial Microcystis by FlowCAM imaging flow cytometry in mesocosm experiment reveals high heterogeneity during seasonal bloom

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yersultan Mirasbekov ◽  
Adina Zhumakhanova ◽  
Almira Zhantuyakova ◽  
Kuanysh Sarkytbayev ◽  
Dmitry V. Malashenkov ◽  
...  
Keyword(s):  
Machine Learning ◽  
Flow Cytometry ◽  
Spatial Resolution ◽  
Mesocosm Experiment ◽  
Imaging Flow Cytometry ◽  
Leibler Divergence ◽  
Temporal And Spatial ◽  
High Level ◽  
Training Sets

AbstractA machine learning approach was employed to detect and quantify Microcystis colonial morphospecies using FlowCAM-based imaging flow cytometry. The system was trained and tested using samples from a long-term mesocosm experiment (LMWE, Central Jutland, Denmark). The statistical validation of the classification approaches was performed using Hellinger distances, Bray–Curtis dissimilarity, and Kullback–Leibler divergence. The semi-automatic classification based on well-balanced training sets from Microcystis seasonal bloom provided a high level of intergeneric accuracy (96–100%) but relatively low intrageneric accuracy (67–78%). Our results provide a proof-of-concept of how machine learning approaches can be applied to analyze the colonial microalgae. This approach allowed to evaluate Microcystis seasonal bloom in individual mesocosms with high level of temporal and spatial resolution. The observation that some Microcystis morphotypes completely disappeared and re-appeared along the mesocosm experiment timeline supports the hypothesis of the main transition pathways of colonial Microcystis morphoforms. We demonstrated that significant changes in the training sets with colonial images required for accurate classification of Microcystis spp. from time points differed by only two weeks due to Microcystis high phenotypic heterogeneity during the bloom. We conclude that automatic methods not only allow a performance level of human taxonomist, and thus be a valuable time-saving tool in the routine-like identification of colonial phytoplankton taxa, but also can be applied to increase temporal and spatial resolution of the study.

Potential of Arabic documentary sources for reconstructing past climate in the western Mediterranean region from AD 680 to 1815

The Holocene ◽  
2021 ◽  
pp. 095968362110332
Author(s):  
Yassin Meklach ◽  
Chantal Camenisch ◽  
Abderrahmane Merzouki ◽  
Ricardo Garcia Herrera
Keyword(s):  
Spatial Resolution ◽  
Mediterranean Region ◽  
Climate Extremes ◽  
Western Mediterranean ◽  
Historical Documents ◽  
Atmospheric Conditions ◽  
Documentary Sources ◽  
Drought Conditions ◽  
Temporal And Spatial ◽  
Climate Proxies

Archival records and historical documents offer direct observation of weather and atmospheric conditions and have the highest temporal and spatial resolution, and precise dating, of the available climate proxies. They also provide information about variables such as temperature, precipitation and climate extremes, as well as floods, droughts and storms. The present work studied Arab-Islamic documentary sources covering the western Mediterranean region (documents written by Arab-Islamic historians that narrate social, political and religious history) available for the period AD 680–1815. They mostly provide information on hydrometeorological events. In Iberia the most intense droughts were reported during AD 747–753, AD 814–822, AD 846–847, AD 867–874 and AD 914–915 and in the Maghreb AD 867–873, AD 898–915, AD 1104–1147, AD 1280–1340 and AD 1720–1815 had prevalent drought conditions. Intense rain episodes are also reported.

scholarly journals Visualization Ability of Phase-Contrast Synchrotron-Based X-Ray Imaging Using an X-Ray Interferometer in Soft Tissue Tumors

2021 ◽  
Vol 20 ◽  
pp. 153303382110101
Author(s):  
Thet-Thet Lwin ◽  
Akio Yoneyama ◽  
Hiroko Maruyama ◽  
Tohoru Takeda
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Spatial Resolution ◽  
Phase Contrast ◽  
Soft Tissue Tumors ◽  
X Ray ◽  
3 Dimensional ◽  
Computed Tomography Images ◽  
X Ray Imaging ◽  
X Ray Computed

Phase-contrast synchrotron-based X-ray imaging using an X-ray interferometer provides high sensitivity and high spatial resolution, and it has the ability to depict the fine morphological structures of biological soft tissues, including tumors. In this study, we quantitatively compared phase-contrast synchrotron-based X-ray computed tomography images and images of histopathological hematoxylin-eosin-stained sections of spontaneously occurring rat testicular tumors that contained different types of cells. The absolute densities measured on the phase-contrast synchrotron-based X-ray computed tomography images correlated well with the densities of the nuclear chromatin in the histological images, thereby demonstrating the ability of phase-contrast synchrotron-based X-ray imaging using an X-ray interferometer to reliably identify the characteristics of cancer cells within solid soft tissue tumors. In addition, 3-dimensional synchrotron-based phase-contrast X-ray computed tomography enables screening for different structures within tumors, such as solid, cystic, and fibrous tissues, and blood clots, from any direction and with a spatial resolution down to 26 μm. Thus, phase-contrast synchrotron-based X-ray imaging using an X-ray interferometer shows potential for being useful in preclinical cancer research by providing the ability to depict the characteristics of tumor cells and by offering 3-dimensional information capabilities.

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