Benign and malignant musculoskeletal masses: MR imaging differentiation with rim-to-center differential enhancement ratios.
OBJECTIVE
To assess the diagnostic potential of the rim-to-center differential enhancement ratio in the magnetic resonance (MR) imaging differentiation of benign from malignant musculoskeletal masses.


METHODS
Dynamic gadolinium-enhanced fast multiplanar spoiled gradient-recalled acquisition in the steady state imaging was performed to evaluate 17 one and soft-tissue masses (10 malignant, seven benign) in 14 patients. The rim-to-center differential enhancement ratio was determined from images at the maximal enhancement rate. The difference in differential enhancement ratios between benign and malignant masses was evaluated and compared with the maximum rate of enhancement for each mass.


RESULTS
Nine of 10 malignant masses showed rapid rim enhancement with delayed central fill-in. This enhancement pattern was absent in benign masses. The average rim-to-center differential enhancement ratio was 0.64 +/- 0.26 for malignant masses and -0.16 +/- 0.33 for benign masses (P < .001). This difference was statistically significant. The average maximum rate of enhancement was 3.41%/sec +/- 2.20 for malignant masses and 2.74%/sec +/- 2.46 for benign masses (P > .05).


CONCLUSIONS
Intratumoral enhancement patterns of malignant and benign masses differ because of differences in vascular architecture. These preliminary results suggest that the rim-to-center differential enhancement ratio has potential as an additional parameter for the MR imaging differentiation of indeterminate musculoskeletal masses.
Ma
L D
LD
Russell H. Morgan Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
Frassica
F J
FJ
McCarthy
E F
EF
Bluemke
D A
DA
Zerhouni
E A
EA
D000293:Adolescent; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000175:diagnosis*; D003287:Contrast Media; D003937:Diagnosis, Differential; D004338:Drug Combinations; D005260:Female; D005682:Gadolinium; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000175:diagnosis*; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives
D003287:Contrast Media; D004338:Drug Combinations; D009942:Organometallic Compounds; D008536:Meglumine; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA