3．0TMRI上深筋膜完整性对于下肢软组织肿瘤良、恶性鉴别的价值

The diagnostic value of delineating deep fascia in distinguishing between benign and malignant soft-tissue tumors in lower limbs using 3. 0 T MRI

目的分析3．0TMRI上深筋膜形态改变对于鉴别下肢软组织肿瘤良、恶性的价值。方法回顾分析40例患者共41个经病理证实的下肢软组织肿瘤的3．0TMRI表现。将肿瘤按主体与深筋膜的关系分为位于皮下浅层深筋膜外侧、深筋膜内侧、筋膜鞘间隙内、肌肉内的4组肿瘤，分析肿瘤与深筋膜的关系及深筋膜的形态学改变。将深筋膜外侧及内侧组肿瘤归为浅在肿瘤，筋膜鞘间隙及肌肉内肿瘤归为深部肿瘤，分别对其筋膜完整及筋膜破坏肿瘤的最大径进行Mann—WhitneyU检验。结果深筋膜外侧肿瘤7个，深筋膜内侧肿瘤8个，筋膜鞘间隙内肿瘤10个，肌肉内肿瘤16个。良性肿瘤16个，MRI显示深筋膜均完整，筋膜鞘间脂肪间隙存在；恶性肿瘤25个，其中23个见深筋膜破坏征象，包括筋膜中断处被肿瘤取代，肿瘤穿透筋膜生长；筋膜鞘间结构破坏，肌肉层次模糊，2例恶性肿瘤深筋膜完整。浅在肿瘤中，深筋膜完整者及破坏者肿瘤最大径的中位数±四分位数区间分别为（5．0±3．8）cm和（5．74±6．9）cm，两者差异无统计学意义（T=47．5，P〉0．05）。深部肿瘤中，深筋膜完整者及破坏者最大径的中位数4-四分位数区间分别为（4．64±1．9）cm和（13．64±6．5）cm，两者差异有统计学意义（T=62．5，P〈0．01）。以深筋膜破坏指征诊断恶性软组织肿瘤，敏感度为92．0％（23／25），特异度为100％（16／16），准确度为95．1％（39／41）。结论在3．0TMRI上显示深筋膜的破坏征象有助于恶性软组织肿瘤的诊断。

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 were considered statistically significant. Results The deep fascial structures were intact in all of the 16 pathologically proven benign lesions. In 23 of the 25 malignant lesions, there was destruction of the deep fascia with the signs of displacement/disruption of the deep fascia and penetrating growth in （ 1 ） （ 2 ）, and displacement/distruption of intermuscular septum as well as involvement of interspaces of the deep fascial investment and loss of integrity of the faseial/museular planes in （3） （4）. Only 2 malignant lesions demonstrate intact deep fascia. In superficial lesions [ （ 1 ） （2） ], the maximum size were （ 5.0 ± 3.8 ） cm （Median ± Interquartile Range ） in those had intact deep fascia, and （5.7 ± 6. 90 ） cm in those had destruction signs （ T = 47.5, P 〉 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.