Multi Echo Sequence
Multi Echo Sequence - Related Videos
01:06
Echo
0 Views •
2023
The human ear cannot distinguish between two sources of sound if they happen to reach within a specific time interval, typically 0.1 seconds apart. More than this, and they are perceived as separate sources. Imagine the sound is reflected back to the ears. Assuming that the source is very close to the human, the difference between hearing the two sounds—the emitted sound and the reflected sound—may be more than the minimum time for perceiving distinct sounds. If this is the case, then the...
02:51
Multi-species Conserved Sequences
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2021
Next-generation sequencing technologies have created large genomic databases of a variety of animals and plants. Ever since the human genome project was completed, scientists studied the genome of primates, mammals, and other phylogenetically distant living beings. Such large-scale studies have provided new insights into the evolutionary relationship between organisms. Although the genome of each species varies greatly from each other, a few sequences are highly conserved. Such conserved DNA...
10:00
Gradient Echo Quantum Memory in Warm Atomic Vapor
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Cited by 2 •
2013
The gradient echo memory is a protocol for storing optical quantum states of light in atomic ensembles. Quantum memory is a key element of a quantum repeater, which can extend the range of quantum key distribution. We outline the operation of the scheme when implemented in a 3-level atomic ensemble.
16:31
Echo Particle Image Velocimetry
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Cited by 10 •
2012
An echo particle image velocimetry (EPIV) system capable of acquiring two-dimensional fields of velocity in optically opaque fluids or through optically opaque geometries is described, and validation measurements in pipe flow are reported.
08:11
Ultrasound Tissue Characterization of Human Achilles Tendon by Stability Quantification of Echo Patterns
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2025
Ultrasound is the approach most commonly adopted in the clinical setting for the assessment of the size and structure of the Achilles tendon. To expand the Achilles tendon assessment in a more comprehensive manner, the ultrasound tissue characterization (UTC) approach has recently been proposed and validated in clinical studies.
FAQs
Each echo captures the remaining transverse magnetization at a particular echo time. Comparing signal measurements across these times shows how rapidly phase coherence is lost through T2 or T2* relaxation. Because tissues and materials can exhibit different decay behavior, the resulting signal pattern provides contrast that may reveal compositional or magnetic differences not apparent in a single measurement.
Measurements at multiple echo times describe the signal decay rather than capturing it at only one point. Early and later echoes therefore contribute different information about the relaxation process. This broader sampling supports fitting procedures that estimate relaxation behavior and helps distinguish tissues or materials whose magnetic properties produce different rates of signal loss.
The acquired signal values are analyzed as a series related to transverse relaxation. Fitting those measurements estimates relaxation characteristics and converts the observed decay into maps. These maps provide spatially distributed quantitative information, allowing investigators to assess tissue composition or magnetic changes and to compare findings more systematically than relying only on conventional image appearance.
The sequence can sample signal decay associated with either T2 or T2* relaxation, depending on the acquisition and readout. T2 reflects transverse signal loss, while T2* represents the decay behavior measured when additional magnetic-field-related effects influence phase coherence. Selecting and interpreting the relevant decay measure helps characterize different magnetic behaviors in tissues or materials.
The examination begins with a radiofrequency excitation or readout period that produces multiple echoes. The scanner records signal measurements at their respective echo times, creating a decay series for each spatial location. Researchers then analyze or fit these measurements to generate relaxation maps, which can be reviewed for tissue composition or susceptibility-related changes.
A multi-echo approach is useful when the goal extends beyond visual contrast to quantitative tissue assessment. It can support evaluation of composition, iron, or other susceptibility-related changes, including abnormalities that may be subtle on conventional single-echo images. Its repeated measurements also make it valuable for research studies and comparisons over time.
In medicine, the technique can produce quantitative relaxation maps that aid disease characterization and assessment of tissue changes. It is also relevant when investigators need to monitor abnormalities longitudinally, because repeated quantitative measurements can support comparisons across examinations. These outputs complement conventional imaging by providing information about tissue composition and magnetic behavior.