Short tau inversion recovery

Last revised by Frank Gaillard on 16 Apr 2024

Short tau inversion recovery (STIR), also known as short TI inversion recovery, is a fat suppression technique with an inversion time TI = ln(2)·T1fat, where the signal of fat is zero. This equates to approximately 140 ms at 1.5 T.

To distinguish two tissue components with this technique, their T1 values must be different. FLAIR is a technique similar to suppressing water. 

Inversion recovery imaging allows homogeneous and global fat suppression and can be used with low-field-strength magnets. However, this technique is not specific for fat. Thus, the signal intensity of tissue with a long T1 and tissue with a short T1 may cause ambiguity.

Since STIR sequences use short inversion recovery time, they cannot be used with gadolinium injection because tissues that take up gadolinium will exhibit T1 shortening and may inadvertently be nulled.

History and etymology

STIR was first described in 1985 and was explicitly called short TI inversion recovery 4. For some time, this term remained more common, but gradually TI was replaced by tau, which has now become the dominant form.

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