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What is echo time in simple words?
The echo time (TE) refers to the time between the application of the radiofrequency excitation pulse and the peak of the signal induced in the coil. It is measured in milliseconds.
What is the echo time in MRI?
Time to Echo (TE) is the time between the delivery of the RF pulse and the receipt of the echo signal. Tissue can be characterized by two different relaxation times – T1 and T2. T1 (longitudinal relaxation time) is the time constant which determines the rate at which excited protons return to equilibrium.
What are TR and TE?
TR and TE are basic pulse sequence parameters and stand for repetition time and echo time respectively. They are typically measured in milliseconds (ms). The echo time (TE) represents the time from the center of the RF-pulse to the center of the echo.
What is a echo MRI?
EchoMRI™ is an international research instruments company that develops, manufactures and markets NMR and CT-based whole body composition and tissue characterization equipment.
What do you understand by ECH?
noun, plural ech·oes. a repetition of sound produced by the reflection of sound waves from a wall, mountain, or other obstructing surface. a sound heard again near its source after being reflected.
What is an echo signal?
In audio signal processing and acoustics, an echo is a reflection of sound that arrives at the listener with a delay after the direct sound. The delay is directly proportional to the distance of the reflecting surface from the source and the listener.
What does T1 and T2 mean?
T1 and T2 are technical terms applied to different MRI methods used to generate magnetic resonance images. Specifically, T1 and T2 refers to the time taken between magnetic pulses and the image is taken. These different methods are used to detect different structures or chemicals in the central nervous system.
What is spin echo sequence?
The spin echo sequence is made up of a series of events : 90° pulse – 180° rephasing pulse at TE/2 – signal reading at TE. This series is repeated at each time interval TR (Repetition time). With each repetition, a k-space line is filled, thanks to a different phase encoding.
What is RF pulse in MRI?
90 RF pulse rotates the net magnetization vector to transverse plane . 180 RF pulse rotates the net magnetization to –Z direction. RF pulse can disturb the protons and transfer energy only when tuned to the precession frequency of the spinning electrons. This phenomenon is called resonance.
What is gradient echo used for?
The gradient echo is generated by the frequency-encode gradient, except that it is used twice in succession, and in opposite directions: it is used in reverse at first to enforce transverse dephasing of spinning protons and then right after, it is used as a readout gradient (like in spin-echo MRI) to re-align the …