The fast spin echo sequence combines data from many echo signals in a Carr-Purcell-Meiboom-Gill echo train to form a single image. Much of the signal in the second and later echoes results from the coherent addition of stimulated echo signal components back to the spin echo signal. Because stimulated echoes experience no dephasing effects during the time that they are stored as Mz magnetization, they experience a different gradient first moment than does the spin echo. This leads to flow-related phase differences between different echo components and results in flow voids and ghosting, even when the first moment is nulled for the spin echo signal. A method of gradient moment nulling that correctly compensates both spin echo and stimulated echo components has been developed. The simplest solution involves nulling the first gradient moment at least at the RF pulses and preferably at both the RF pulses and the echoes. Phantom and volunteer studies demonstrate good suppression of flow-related artifacts.
when selecting another value in the spinner in the first tab -items not changed. (but data is changing in adapter class.Ie. First, it is not null then null during selection. But the first not nulled data is not appearing, its replacing with null. Found it using breakpoints).
On the whole this build is a little weaker than my aether Templar and a bit stronger than my aether Shieldbreaker. The best of the spinners I have posted is by far the aether Oppressor. The lightning spinner is on par with this one.
These problems can be mitigated using phase-sensitive inversion-recovery (PSIR). PSIR is commonly used for LGE image acquisition as it avoids the need for precise selection of the TI to null viable myocardium . Compared to a conventional IR sequence, the PSIR sequence only applies a 180° inversion pulse once every two heartbeats and a small-flip-angle reference acquisition is performed during the second heartbeat. This reference acquisition is used to accurately determine the phase of the measured signal, acquired during the first heartbeat. The PSIR sequence is therefore able to distinguish between positive and negative longitudinal magnetization and will represent the recovered longitudinal magnetization (Mz) differently in the (corrected real) image produced for clinical assessment: negative Mz appears darkest, nulled tissue appears mid-gray, and positive Mz appears bright; whereas in a traditional magnitude image nulled tissue appears darkest and both negative and positive Mz appear bright (Fig. 1). PSIR is routinely used in combination with nulling of the viable myocardium magnetization, and the clinical observer may adjust window levels to further darken viable myocardial tissue, mimicking a magnitude image representation while maintaining the benefits of PSIR. 2b1af7f3a8