Purpose: To evaluate the need for additional MR sequences including administration of Gd-DTPA after inconspicuous Short-Tau Inversion-Recovery (STIR) sequence to exclude the diagnosis of osteomyelitis.
Material and methods: 112 MR examinations of 79 patients acquired for the detection of possible osteomyelitis were analyzed retrospectively. All examinations were performed at 0.5 T including STIR, T1-weighted spin echo sequences (T1 SE) before and after application of Gd-DTPA. Additionally, 93 T2-weighted spin echo sequences were available. The examinations were analyzed by two experienced radiologists. First, the STIR sequences were studied, followed by the T1 SE images before and after administration of contrast material. Finally, the T2-weighted images were evaluated. Diagnoses were confirmed by operation (22), biopsy (10), and follow-up (80).
Results: In 53 cases osteomyelitis was diagnosed, while the remaining 59 cases suffered from another disease. The sensitivity of the STIR sequence was 100% while the specificity for osteomyelitis was 49.2%. The specificity increased to 79.7% by including T1 SE images into the analysis and reached 83.1% after considering the contrast enhanced images. T2-weighted images yielded no additional information.
Conclusion: The combination of STIR and T1SE images shows a high sensitivity and specificity for osteomyelitis, thus obviating the need for any additional examinations.