Limited flip angle MR imaging: Nonhemorrhagic applications

The authors used a 1.5-T MR imaging unit to obtain T1-weighted (repetition time [TR]/echo time [TE] = 300/12.3 msec, flip 600), intermediate (TR/TE = 500/10, flip 200), or T2-weighted (TR/TE = 500/40, flip 200) limited flip angle (LFA) images in 200 consecutive patients. The LFA images were characterized by (1) decreased signal intensity in the globus pallidus, red nucleus, and substantia nigra, consistent with ferritin; (2) artifact in brain adjacent to air interfaces; (3) increased signal intensity in arteries, veins, and aqueduct (cerebrospinal fluid pulsation) on the single-section T1-weighted sequence; (4) somewhat less sensitivity for the detection of nonhemorrhagic lesions than spin-echo studies; and (5) improved detection of calcification. Gradient echo imaging may thus have applications beyond the improved detection of hemorrhage