What are the different types of spin echo of magnetic resonance imaging (MRI)? What are the fundamental characteristics features of T1, T2 and STIR echo sequences?
The following are the different types of spin echo of magnetic resonance imaging (MRI):
Single echo spin echo
Simplest for of SE pulse sequence
consist of 90° pulse, 180º pulse and then echo
Multi echo spin echo: As long as T2 relaxation has not completely destroyed the MR signal it is possible to stimulate the system with addition 180 pulses and generate additional echoes is progressively due to T2 decay. Uniformly diminishes in size.
Fast (Turbo) Spin Echo (FSE): echoes are not uniformly diminishing in size with increasing TE multi echo SE as expected.
The fundamental characteristics of :
STIR echo sequence
Short TR (500-700ms)
short TE (15-40 ms)
Long TR (2000-4000MS)
Long TE (50-90msec)
Fat suppression method
Excellent soft tissue contrast c superior display of anatomy
sensitive to inflammatory, ischemic or neoplastic alteration in tissue.
short T1 inversion recovery(STIR)
High signal to noises ratio
vitreous/CSF : bright
reduces/eliminates chemical shifts artifarts by removing fat signal from image.
Inversion time (TI)=140 m sec can be huled individuals
CSF vitreous mucous : bright