The diagnostic value of delineating deep fascia in distinguishing between benign and malignant soft-tissue tumors in lower limbs using 3.0 T MRI

Objective To study the diagnostic value of the morphological changes to deep fascia in distinguishing between benign and malignant soft-tissue tumors in lower limbs using 3.0 T MRI. Methods MR images of 40 consecutive patients with 41 pathologically proven soft-tissue tumors of the lower limbs were retrospectively reviewed by two radiologists. Lesions were divided into four groups according to their predominant location with respect to the deep fascia: (1)Subcutaneous lesions superficial to the deep fascia (n=7). (2) Lesions located beneath the deep fascia (n=8). (3) Lesions in the interspaces of the deep fascia investment (n=10). (4) Intramuscular lesions (n=16). The relationship between tumors and the deep fascia and the morphology changes of deep fascia were analyzed. Lesions of groups (1) (2) were considered as superficial lesions, while lesions of group (3) (4) were considered as deeper lesions. The size differences between those had intact deep fascia and those had destructed deep fascia in superficial lesions and in deeper lesions were evaluated by using Mann-Whitney U test, respectively. P values 0.05). In deeper lesions [(3) (4)] the maximum size were (4.6±1.9) cm of those had intact deep fascia, and (13.6±6.5) cm of those had destruction signs (T= 62.5, P <0.01). Distinguish malignant from benign lesions on the signs of destructed deep fascia, the sensitivity, specificity and accuracy were 92.0% (23/25), 100% (16/16), and 95. 1% (39/,41), respectively. Conclusions Tumor involvements and disruption of the deep fascial structures visualized by 3.0 T MR imaging may be of utility in differentiating malignant from benign soft-tissue tumors. Key words: Soft tissue neoplasm; Fascia; Magnetic resonance imaging; Lower extremity