Is spin echo T1 or T2?
Historically, spin echo was the first sequence to be used. It has been a benchmark for all subsequent developments, namely in terms of contrast. The 180° rephasing pulse gives a « true T2 » signal rather than a T2*signal.
What is spin echo images?
In magnetic resonance, a spin echo is the refocusing of spin magnetisation by a pulse of resonant electromagnetic radiation. Modern nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) make use of this effect.
What does T1 and T2 mean on MRI?
The most common MRI sequences are T1-weighted and T2-weighted scans. T1-weighted images are produced by using short TE and TR times. The contrast and brightness of the image are predominately determined by T1 properties of tissue. Conversely, T2-weighted images are produced by using longer TE and TR times.
What is spin echo pulse sequence in MRI?
Spin-echo pulse sequences are one of the earliest developed and still widely used (in the form of fast spin echo) of all MRI pulse sequences. The pulse sequence timing can be adjusted to give T1-weighted, proton density, and T2-weighted images.
What is the difference between spin echo and fast spin echo?
Fast spin echo offers increased resolution in a comparable time to conventional spin echo by increased number of excitations and finer matrix size, thus improving the signal-to-noise ratio and spatial resolution, respectively.
What is T2 used for?
Clinical applications. T2*-weighted sequences are used to detect deoxygenated hemoglobin, methemoglobin, or hemosiderin in lesions and tissues.
What is spin echo used for?
The “spin-echo” pulse sequence [9,10,11] is used to obtain a signal by means of a 90º excitation pulse and a 180º inversion pulse, which were sent to the nuclei of hydrogen atoms of the tissues present in the region to be analyzed (Figure 2).
What are T1 images?
T1 images can be thought of as a map of proton energy within fatty tissues of the body. Fatty tissues include subcutaneous fat (SC fat) and bone marrow of the vertebral bodies. Cerebrospinal fluid (CSF) contains no fat – so it appears black on T1-weighted images.
What is the difference between spin echo and gradient echo?
How does a gradient echo differ from a spin echo? A spin echo (SE) is produced by pairs of radiofrequency (RF) pulses, whereas a gradient echo (GRE) is produced by a single RF pulse in conjunction with a gradient reversal.
What is turbo factor in MRI?
(TSE TF) The turbo factor is the number of echoes acquired after each excitation. This is a measure of the scan time acceleration, e.g. at turbo factor 3 the scan time is 3 times faster as a SE sequence with comparable parameters.