Effect of Low Refocusing Angle in T1-Weighted Spin Echo and Fast Spin Echo MRI on Low-Contrast Detectability: A Comparative Phantom Study at 1.5 and 3 Tesla
Figure 2
Spin echo (SE) and fast spin echo (FSE) images at 1.5 T (a)–(d) and at 3 T (e)–(h). (a) SE (CNR 3.8 for 180° refocusing), (b) SE (CNR 1.8 for 120° refocusing), (c) FSE (CNR 3.2 for 180° refocusing), (d) FSE (CNR 1.7 for 120° refocusing), (e) SE (CNR 3.8 for 180° refocusing), (f) SE (CNR 1.0 for 120° refocusing), (g) FSE (CNR 3.8 for 180° refocusing), and (h) FSE (CNR 1.1 for 120° refocusing); Note that 180° refocusing pulses produce 2–4 times the CNR present at 120° depending on the main magnetic field. Also, overall signal at 3 T is higher than that at 1.5 T.
