Modified Classification of MRI Findings to Predict Histologic Grading of Liposarcomas

Purpose: To predict the histopathologic grading of liposarcomas with the modified classification of MRI findings. Materials and Methods: The 47 MRI studies of pathologically confirmed liposarcomas were retrospectively analyzed, and found to have well-differentiated (n=17) and myxoid (n=16) types, representing the 'low grade' sarcomas, as well as the round cell (n=9) and pleomorphic (n=5) types, which represent the 'high grade' sarcomas. The MRI findings of liposarcomas were classified into four groups as the one with fat signal above 80%, 20-80%, below 20%, and no fat signal on T1-weighted images (WIs), into three groups as the one with high signals with reticular or irregular lines, homogeneous above 50% of the area, and heterogeneous above 50% on the T2WIs, and into three groups as the one enhanced with reticular or irregular lines and enhancement areas above 50% and below 50% on the Gd-DTPA T1WIs. Results: The sarcomas with a lower amount of fat signals on T1WIs had a significantly higher histologic grade (p = 0.026) and also showed heterogeneous high signals above 50% on the T2WIs was statistically significant difference (p = 0.010) but not on the contrast enhanced T1WIs (p = 0.070). Conclusion: The modified classification of the MR findings could help predict the histologic grading of liposarcomas.