Fast spin echo

Most clinical examinations apply robust spin-echo or fast spin-echo sequences. These types of sequences provide tissue contrast changes by variation of the chosen repetition time TR (time interval between succeeding RF excitations) and echo time TE (time delay between RF excitation and signal acquisition). 

Fig. 5. Standard fast spin-echo imaging of the pelvis and the lower leg. Typical contrasts between musculature and other tissues are demonstrated. Bl = bladder, Fe = femur. Gluteus = gluteus muscle. Original recording parameters matrix 192 x 256, slice thickness 6 mm, a-c field of view (fov) = 380 mm, d-f fov = 180 mm. (a) and (d) Proton density weighting TR = 5000 ms, TE = 12 ms. (b) and (e) Ti-weighting TR = 500 ms, TE = 12 ms. (c) and (f) 7 2-weighting TR = 5000 ms, TE = 100 ms.

Anatomical localization is performed by acquiring three sets of orthogonal T2-weighted fast spin echo (FSE) images (see Table 1 for parameters). 

The symbol denotes convolution. Thus, the effect of varying TE and TR in pulse sequences on resolution can be followed by a PSF analysis.Robson et al have outlined an experimental method for measuring the PSF. Different schemes for the phase encoding employed in pulse sequences can lead to different fe-space weighting functions and thus affect resolution. Zhou et al analyzed three different fc-space sampling schemes and the corresponding PSFs for a fast spin echo sequence in order to... 

Ricci, P.E., et al., A comparison of fast spin-echo, fluid-attenuated inversion-recovery, and diffusion-weighted MR imaging in the first 10 days after cerebral infarction. AJNR Am J Neuroradiol, 1999. 20(8) p. 1535-42. 

Electrodes are left externalized to confirm their position by MRI. Scans are performed using 1.5 T Edge equipment software version 9.3 (Marconi Medical Systems, Cleveland, Ohio), using T2 weighted fast spin echo sequence (echo time 11 ms repetition time 4070 msec field of view 16.0 cm 256 x 256 matrix). Sections are oriented parallel and perpendicular to the AC-PC line for axial and frontal views, and parallel to the midsagittal plane for sagittal sections [Velasco et al, 2000b, 2002]. 

Katayama M, Masui T, Kobayashi S et al (2001) Fat-suppressed T2-weighted MRI of the liver comparison of respiratory-triggered fast spin-echo, breath-hold singleshot fast spin-echo, and breath-hold fast-recovery fast spin-echo sequences. J Magn Reson Imaging 14 439-449... 

Tien, R.D., and Felsberg, G.J. 1995. The hippocampus in status epUepticus demonstration of signal intensity and morphologic changes with sequential fast spin-echo MR imaging. Radiology 194(l) 249-256... 

Fig. 9.5 Magnetic resonance imaging of the brain T2-weighted images using FLAIR (fluid attenuated inversion recovery) and FSE (fast spin echo) reveal enhanced signal intensity representing white matter abnormalities...

TSE, turbo spin echo also known as FSE, fast spin echo TR, repetition time TE, time to echo TI, time for inversion coronal oblique, parallel to the long axis of the uterus axial oblique, parallel to the short axis of the uterus TRUFISP, fast induction steady state potential gradient sequence (Siemens Medical, Germany). 

Ascher SM, O Malley J, Semelka RC, Patt RH, Rajan S, Thomasson D (1999) T2-weighted MRI of the uterus fast spin echo vs. breath-hold fast spin echo. J Magn Reson Imaging 9 384-390... 

Masui T, Katayama M, Kobayashi S, Sakahara H, Ito T, Nozaki A (2001) T2-weighted MRl of the female pelvis comparison of breath-hold fast-recovery fast spin-echo and nonbreath-hold fast spin-echo sequences. J Magn Reson Imaging 13 930-937... 

Lefevre N, Naouri JF, Bohu Y, Klouche S, Herman S (2014) Partial tears of the anterior cruciate ligament diagnostic performance of isotropic three-dimensional fast spin echo (3D-FSE-Cube) MRI. Eur J Orthop Surg Traumatol 24 85-91... 

Tl Weighted Spin Echo Sequences 62 T2 Weighted Spin Echo Sequences 64 Proton Density Imaging 64 Fast Spin Echo Techniques 64... 

The sequences may obscure sclerosis or marrow oedema due to poor marrow fat contrast compared to TlWl or fat saturated proton density fast spin echo (FS PD FSE) sequences. 

T2 or proton density fast spin echo fat suppressed (PD FSE FS) are useful for evaluating marrow oedema, articular cartilage, ligaments, tendons, synovium and meniscal morphology. They are a commonly used sequence for all appendicular joint imaging. TE values are typically less than 60 ms and TR values greater than or equal to 3000 ms. TE values are around 40-50 ms to optimise image quality. 

Fig. 8.16. Periostitis ofthe tibia. Axial T2 fast spin echo fat saturated image. The child had sustained an open injury 4 months previously when he ran into a bush. The tibia has a low signal thickened cortex. There is extensive high/intermediate signal fluid collection surrounding almost the entire circumference of the tibia, as well as extensive subcutaneous oedema. At surgery, there was shown to be a large subperiosteal abscess...

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