Abstract
Background
The aim of our study was to determine the value of single-voxel proton MR spectroscopy (1HMRS) in distinguishing benign from malignant focal bone lesions in the peripheral skeleton. MRI and 1HMRS was performed in 50 focal lesions (> 1 cm size) detected on radiographs of peripheral skeleton.1HMRS was performed at 1.5 T with TE of 144 ms with automatic shimming and water suppression. Qualitative analysis for a discrete choline peak at 3.2 ppm was done. Significance of the presence of choline peak on 1HMRS in distinguishing benign from malignant lesions was calculated using histopathology as a gold standard. Chi-square test was used and p value < 0.05 was considered significant.
Results
Forty-one benign and 9 malignant lesions were confirmed by histopathological results. Amongst malignant lesions, choline peak was positive in all but 1 case of low-grade lymphoma. MR spectra of 11 benign lesions showed the presence of choline peak. All 7 benign giant cell tumors (GCT) were positive for choline peak. The sensitivity, specificity, PPV, NPV of proton MR spectroscopy in differentiating benign from malignant lesions were 87.5%,71%,38.8%, and 96.4% respectively. p value was significant (< 0.05).
Conclusion
1HMRS in focal bone lesions can help in the differentiation of malignant from benign musculoskeletal tumors. Although some benign lesions may show false-positive result, absence of choline peak is a reliable reassurance against malignancy. GCT is an exception amongst benign bone tumors as it consistently shows the presence of choline peak on 1HMRS.
Proton MR spectroscopy in characterization of focal bone lesions of peripheral skeleton