Preliminary study of 3T 1H MR spectroscopy in bone and soft tissue tumors.

BACKGROUND

Magnetic resonance spectroscopy (MRS) is one method that can examine noninvasively the alive specimen of the organ, metabolism of the organ and cell, and the biochemistry change. MRS provides the biochemistry information that may be used to diagnose tumors or differentiate the malignant tumor from benign. The objective of this study is to investigate the benign and malignant bone and soft tissue tumors by 1H-MR spectroscopy ((1)H-MRS) on a 3 Tesla MR scanner, then to assess the usefulness of (1)H-MRS in diagnosing bone and soft tissue tumors and distinguishing benign from malignant tumors.

METHODS

Fifty-six patients with bone and soft tissue tumors proved clinically and pathologically were examined with (1)H-MRS. (1)H-MRS was performed to study malignant musculoskeletal tumors, benign tumors and normal muscle adjacent to lesions to analyze the characteristics, and single-voxel point-resolved spectroscopy sequence was used. Proton brain exam-single voxel of (1)H-MRS which directly appeared in the spectrum, was observed to find the peak height of choline compounds (Cho) opposite to the creatine (Cr), and whether there was a Cho peak. Metabolite values were calculated automatically from the area under each metabolite peak by the Functool 3.1 software. Metabolite ratios of Cho/Cr were manually calculated. Then according to the results, it was judged whether there existed benign or malignant tumors. The Kappa statistical test was used to analyze the MRS results, the histopathology data and the surgical situation. Statistics processing was performed using the software package SPSS11.5 for Windows.

RESULTS

(1)H-MRS spectra style of bone and soft tissue tumors was different from that of normal muscle, and differences also existed between benign and malignant tumors. Choline level in malignant tumor was markedly higher than that in benign tumors. Cho/Cr in malignant tumor was higher than in benign tumor significantly (P < 0.05). The true positive rate of bone and soft tissue between benign and malignant tumors was 34/36, the true negative rate was 15/18, the false positive rate was 3/18 and the false negative rate was 2/36. Therefore in the group, sensitivity of the (1)H-MRS was 94% (34/36), specificity was 83% (15/18), positive predictive value was 92% (34/37), negative predictive value was 88% (15/17) and the accuracy rate was 91% (49/54). The MRS results and the histopathology inspection conclusions had very good uniformity. The kappa value was 0.76 +/- 0.10 (P < 0.01).

CONCLUSIONS

The increase of Cho level measured by (1)H-MRS is related to the bone and soft tissue malignant tumor. Cho/Cr in malignant tumor was higher than in benign tumor, so they will play a vital role in the diagnosis and differential diagnosis of bone and soft tissue tumors.