Quantification of the Magnetization-Transfer Contrast Effect: can it yieldadditional information in differentiation of musculoskeletal lesions particularly in separation of benign from malignant lesions.

Purpose: To investigate the potential information of the amount of magnetiz ation-transfer effect in musculoskeletal lesions and to compare Mi ratios f rom benign and malignant musculoskeletal lesions. Material and Method: 49 p atients with malignant tumors (3 osteosarcoma, 3 malignant fibrous histiocy toma, 4 chondrosarcoma, 2 Ewing sarcomas) and benign lesions (8 chondroma, 2 fibrous dysplasia, 3 osteoid-osteoma, 6 ganglion cyst,3 cyst, 3 osteomyel itis, 4 tendinitis, 3 rotator cuff tear, 5 scar tissue) were scanned using routine MRI protocols including T-1- and T-2-weighted spin echo as well as T-2*-weighted gradient echo (FFE) sequences at 1.5 Tesla (ACS ii, Philips M edical). Additionally MTC images were generated by combining the FFE sequen ce and the off-resonance Mf technique (- 1500 Hz off-resonance frequency, 1 770 degrees flip angle and 50 ms purse duration). MT ratios were calculated as SIo-SIm/SIo. Results: The MT ratio of benign lesions was 26 +/- 15 %, t hat of malignant lesions was 22 +/- 6 %. The difference was statistically n ot significant. As expected muscle showed a high MT ratio of 50 +/- 8 %. Sc ar tissue demonstrated an MT ratio of 39 +/- 16% which was significantly hi gher than the tumor MT ratios. Conclusion: MTC (MT ratios) failed to show s ignificant differences between benign and malignant lesions as was expected due to basic differences in cellularity, rate of mitosis and chromatin con tent. MTC might however gain more importance in separating scar tissue from recurrent tumor in the future.