FAT-SUPPRESSED MRI OF MUSCULOSKELETAL INFECTION - FAST T2-WEIGHTED TECHNIQUES VERSUS GADOLINIUM-ENHANCED T1-WEIGHTED IMAGES

Purpose. To investigate gadolinium's role in imaging musculoskeletal i nfection by comparing the conspicuity and extent of inflammatory chang es demonstrated on gadolinium-enhanced fat-suppressed T1-weighted imag es versus fat-suppressed fast T2-weighted sequences. Design. Eighteen patients with infection were imaged in a 1.5-T unit, using frequency-s elective and/or inversion recovery fat-suppressed fast T2-weighted ima ges (T2WI) and gadolinium-enhanced frequency-selective fat-suppressed T1-weighted images (T1WI). Thirty-four imaging planes with both a fat- suppressed gadolinium-enhanced TI-weighted sequence and a fat-suppress ed T2-weighted sequence were obtained, Comparison of the extent and co nspicuity of signal intensity changes was made for both bone and soft tissue in each plane. Results. In bane, inflammatory change was equal in extent and conspicuity on fat-suppressed T2WI and fat-suppressed T1 WI with gadolinium in 19 planes, more extensive or conspicuous on T2WI in three planes, and less so on T2WI in two planes. Marrow was normal on all three sequences in 10 cases. In soft tissue, inflammatory chan ge was seen equally well in 20 instances, more extensively or conspicu ously on the T2WI in ii instances, and less so on T2WI in 2 instances. One case had no soft tissue involvement on any of the sequences. Five abscesses and three joint effusions were present, all more conspicuou sly delineated from surrounding inflammatory change On the fat-saturat ed T1WI with gadolinium. The average imaging time for the fat-saturate d T1WI with gadolinium was 6.75 min, while that of the T2-weighted seq uences was 5.75 min. Conclusion. Routine use of gadolinium is not warr anted. Instead, gadolinium should be reserved for clinically suspected infection in or around a joint, and in cases refractory to medical or surgical treatment due to possible abscess formation.