The fat suppression possible by STIR is generally uniform and relatively independent of magnetic field inhomogeneities. STIR may be superior to other fat saturation methods (such as spectral "fat-sat") especially near metallic foreign bodies, near tissue interfaces with high susceptibility differences (like the skull base/sinuses), and across large body parts (such as the abdomen and pelvis). It is even possible to perform whole-body STIR imaging as a screening technique for bone metastases. In lower field permanent magnet scanners with relatively poor homogeneity, STIR is one of the only fat suppression methods available.
- STIR cannot be used as a fat suppression technique post-gadolinium. STIR does not specifically suppress fat; it only suppresses tissues with T1 values in the range of fat (200-300 ms). Thus gadolinium-containing tissues with similar relaxation times will also be suppressed. Likewise, suppression proteinaceous materials and other short T1 tissues may occur.
- Although contrast-to-noise for certain lesions may be improved, overall signal-to-noise may be poor.
- The multiple 180°-pulses cause deposit extra energy and may result in tissue heating.
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Graeme Bydder and Ian Young, my two colleagues from our days on the Picker MR advisory board, invented, characterized, and named the STIR sequence in their 1985 JCAT paper referenced below. In their original description STIR stood for short TI inversion recovery. Subsequent papers by others using this technique replaced the "T" in STIR with the greek letter "tau", referring to the acronym as the Short-tau Inversion Recovery. This is incorrect and a corruption of the original term, so I continue to refer to STIR by its proper (older) name.
Bydder GM, Young IR. MR imaging: clinical use of the inversion recovery sequence. J Comput Assist Tomogr 1985; 9:659-675.
Krinsky G, Rofsky NM, Weinreb JC. Nonspecificity of short inversion time inversion recovery (STIR) as a technique of fat suppression: pitfalls in image interpretation. Am J Roentgenol 1996; 166:523-526.
Smith RC, Constable RT, Reinhold C, et al. Fast spin echo STIR imaging. J Comput Assist Tomogr 1994;18:209–213
Sugimoto H, Sakai O, Shinozaki T et al. Effect of water fraction in selection of optimal TI value for STIR sequences. J Comput Assist Tomogr 1994; 18:119-125.
Why use IR? What are the advantages?