Diagnostic imaging may be improved by suppressing the contrast from fatty tissue, thus enhancing the contrast between bone marrow and possible intramedullary conditions such as oedema, infection or neoplastic disease. Fat suppression can be obtained by two methods. One such method, which is not completely specific for fat, but a robust sequence to be used on low to mid field scanners is STIR (Short Tau inversion recovery). The TI, depending on the scanner strength is set to nullify the signal from fat. As the resultant images have a low SNR, the image quality may be improved by using high NEX (Andrews, 2000).
Another method frequently used on high field magnets is Chemical saturation sequences. The fat suppression is based on the chemical shift, which selectively suppresses the fat with the selective presaturation of the protons immediately preceding the start of the actual sequence (Hayes & Balkissoon, 1996).
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