T2 fat suppressed sequencing is used for sensitive detection of abnormal fluid of the distal Supraspinatus tendon. In contrast to an inversion recovery sequence, potential magic angle artifact is eliminated due to the long TE of theT2 sequence.
Magic angle artifact can occur on short TE sequences and can result in tendons/ligaments having erroneous areas of high T2 signal. Normally, transverse magnetization decay is enhanced (and therefore T2 is shortened) in non-random structures such as the parallel fibers of tendons and ligaments. But when tendons/ligaments are oriented at 55 degrees to the magnetic field, magnetization decay is hindered, increasing T2 signal intensity. Longer TE sequences are required to allow for full decay of transverse magnetization/T2 signal.
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