Purpose: To evaluate whether proton MR spectroscopy (MRS) at 3 T with metabolite quantification is helpful for characterizing musculoskeletal lesions and to reveal whether the concentration of choline is correlated with the pathologic degree of malignancy.
Material and methods: Three-tesla MR images and proton MRS data from 27 consecutive patients with surgically proven musculoskeletal lesions were retrospectively analyzed. We analyzed the presence of choline peaks of malignant tumors according to the degree of malignancies, and we compared them with those of benign lesions. The concentrations of choline calculated by means of the linear combination of model spectra were also compared with respect to the degree of malignancy in each group.
Results: The proton MRS had an overall sensitivity of 68.4%, specificity of 87.5%, positive predictive value of 92.3%, and negative predictive value of 53.8% for the detection of choline compounds. The positive detection rate for choline compounds in the primary malignancy group (53.8%) was lower than that of the metastasis group (100%). All false-negative results were shown in the Grade 1 primary malignancy group. There was no difference in the concentration of choline compounds with respect to the pathologic degree of differentiation.
Conclusion: MR spectroscopy at 3 T with metabolite quantification is a helpful method that shows high specificity (87.5%) in characterizing musculoskeletal lesions, even though its sensitivity (68.4%) is relatively low. Grade 1 primary malignancies of bone and soft tissue tumor have a high potential for producing false-negative results.
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