Gradient-recalled echo

Figure Bl.14.2. Gradient-recalled echo pulse sequence. The echo is generated by deliberately dephasing and refocusing transverse magnetization with the readout gradient. A slice is selected in the z-direction and v- and y-dimension are frequency and phase encoded, respectively.

FIf. 18. Pulse sequence methods for controlling radiation damping. (A) Gradient recalled echoes in the evolution period. The bipolar gradient pulse uses only very weak -gradients ( 0.2 G cm" ). (B) Bipolar gradient pulses between the acquisition of data points in the... 

Leach, J.L.,W.M. Strub, andM.F. Gaskhl-Shipley, Cerebral venous thrombus signal intensity and susceptibility effects on gradient recalled-echo MR imaging. AJNR Am J Neuroradiol, 2007. 28(5) p. 940-5. 

Wang SF, Cheng HC et al. (1999) Fat-suppressed three-dimensional fast spoiled gradient-recalled echo imaging a modified FS 3D SPGR technique for assessment of patellofemoral joint chondromalacia. Clin Imaging 23 177-180... 

Fig. 10.11. a Three dimensional fat suppressed spoiled gradient recalled echo image showing the normal appearances of the growth plate in a 13-year-old boy. b 3D reconstruction of the distal tibial growth plate of the same child... 

AIP average intensity projection GRE gradient recalled echo... 

While morphologic MRI with regard to mass assessment, detailed soft tissue differentiation, and cardiac morphology, is mainly carried out on T1-weighted or T2-weighted fast spin-echo (FSE) techniques, the majority of todays applications is covered with the use of gradient-recalled-echo (CRE) techniques. 

The qualitative evaluation of laser-induced effects was based on an analysis of lesions and surrounding liver parenchyma before and after the evaluation periods, and included documentation of the morphology of lesions as seen in T2- and Tl-weighted spin-echo (SE) and gradient recalled echo (GRE) sequences. Quantitative data were obtained by volumetric calculation of tumor and necrosis volumes before and after intervention with the formula (axbxc)x0.5y where a was the maximum anterior-posterior diameter, fiwas the maximum lateral-medial diameter and c was maximum cranial-caudal diameter. 

Figure 6 Magnetization transfer technique. (A) Two-pool model used for the evaluation. This is certainly a simplification of reality, although imaging data quality does not justify further elaboration. (B) MTC imaging sequence. A gradient-recalled echo data acquisition is used once more. The spoiler shown is used to dephase residual transverse magnetization after the end of the off-resonance irradiation period (of length t). Practical sequences of all types use pulses like this to eliminate the unwanted signals from spins pursuing complex patterns of excitation and recovery.

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