Objective:
To show the magnetic resonance imaging characteristics of soft tissue masses, and to evaluate the aid of contrast-enhanced static and dynamic magnetic resonance imaging for the differentiation of benign and malignant lesions.

Methods:
A total of 35 soft tissue masses (16 benign and 19 malignant) were included in this prospective study. Diagnoses of 32 massses (all malignant and 13 benign masses) were histologically confirmed. Diagnoses of 3 benign masses (hematomas) were confirmed with clinical follow-up. Magnetic resonance (MR) images were performed with a 1.5 T MR system (Philips, Medical Systems, The Best, Netherlands). Body coil or surface coil was used depending on the location and size of the lesion. T1 weighted (W) turbo spin-echo (TSE), T2 -W TSE and short tau inversion recovery (STIR) sequences, dynamic contrast-enhanced (DCE) MR images were performed, followed by static contrast-enhanced MR images. The frequency distribution of the individual magnetic resonance imaging (MRI) parameters in the benign group was compared with that in the malignant group by using the Chi-square test.

Results:
On non-enhanced images; tumor size, peritumoral edema, bone and neurovascular involvement were statistically significant between benign and malignant lesions. Presence of necrosis was only seen in malignant lesions on static contrast-enhanced images. The sensitivity, spesificity and overall accuracy of DCE images for the differentiation of benign and malignant lesions was 94% 75% 86% respectively (p=0.0001).

Conclusion:
Our study shows that the use of DCE MRI can help for the differentiation of benign and malignant soft tissue tumors.