[The quantification of the magnetization transfer contrast (MTC) effect by calculating MT quotients: does it yield additional information for the differentiation of benign and malignant diseases of the locomotor apparatus?].
OBJECTIVE
To investigate the potential information of the amount of magnetization-transfer effect in musculoskeletal lesions and to compare MT ratios from benign and malignant musculoskeletal lesions.


METHODS
49 patients with malignant tumors (3 osteosarcoma, 3 malignant fibrous histiocytoma, 4 chondrosarcoma, 2 Ewing sarcomas) and benign lesions (8 chondroma, 2 fibrous dysplasia, 3 osteoid-osteoma, 6 ganglion cyst, 3 cyst, 3 osteomyelitis, 4 tendinitis, 3 rotator cuff tear, 5 scar tissue) were scanned using routine MRI protocols including T1- and T2-weighted spin echo as well as T2*-weighted gradient echo (FFE) sequences at 1.5 Tesla (ACS II, Philips Medical). Additionally MTC images were generated by combining the FFE sequence and the off-resonance MT technique (-1500 Hz off-resonance frequency, 1770 degrees flip angle and 50 ms pulse duration). MT ratios were calculated as Slo-Slm/Slo.


RESULTS
The MT ratio of benign lesions was 26 +/- 15%, that of malignant lesions was 22 +/- 6%. The difference was statistically not significant. As expected muscle showed a high MT ratio of 50 +/- 8%. Scar tissue demonstrated an MT ratio of 39 +/- 16% which was significantly higher than the tumor MT ratios.


CONCLUSIONS
MTC (MT ratios) failed to show significant differences between benign and malignant lesions as was expected due to basic differences in cellularity, rate of mitosis and chromatin content. MTC might however gain more importance in separating scar tissue from recurrent tumor in the future.
Vahlensieck
M
M
Radiologische Universitätsklinik Bonn. m.vahlensieck@uni-bonn.de
Gieseke
J
J
Träber
F
F
Schild
H
H
D000293:Adolescent; D000328:Adult; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000175:diagnosis*; D009141:Musculoskeletal System / Q000473:pathology; D009369:Neoplasms / Q000175:diagnosis; D018709:Statistics, Nonparametric