To assess the diagnostic performance of individual and combined morphological MRI features to distinguish low from high grade soft tissue sarcoma.

We retrospectively evaluated 64 patients (figure 1) with histologically confirmed diagnosis of soft tissue sarcoma (STS) and pre-treatment MRI with T1, fluid sensitive sequencesand contrast enhanced images. Two musculoskeletal (MSK) radiologists (16 years and 7years of experience) analyzed severaltumoral features such as size, location, intra-tumoral enhancement, heterogeneity and internal low signal intensity components on T2, peritumoral enhancement and the presence of a fascia tail. The radiologists were blinded to the definitive diagnosis. According to the French Federation of Cancer Centers grading system (figure 2), tumors...

A total of 14 features were assessed. Among these 14 features, the degree of intra-tumoral enhancement (>51%), internal low signal intensity components on T2, intra-tumoral hemorrhage and peri-tumoral enhancement were significantly different between low and high grade tumors for both readers (p≤0.05), whereas signal heterogeneity onfluid sensitive sequence (>2/3 of the tumor), tumor margin (poorly or partially defined), and the presence of a fascia tail sign were significantly different between low and high grade tumors only for reader 1 (p≤0.04)(figure 4). For those features, which...

Only some morphological MRI features may help to differentiate low from high grade sarcoma, however, a learning curve is required for their interpretation. Nevertheless, the “and” combination of features yields similar specificity and the “or” combination results in similar sensitivity independently of expertise.

1. Can MR imaging be used to predict tumor grade in soft-tissue sarcoma?Fang Zhao, Shivani Ahlawat, Sahar J. Farahani, Kristy L. Weber, Elizabeth A. Montgomery, John A. Carrino, Laura M. FayadRadiology.2014 Jul;272(1): 192–201.Published online 2014 Mar 8.doi:10.1148/radiol.14131871 2. Conventional MR and diffusion weighted imaging of muskuloskeletal soft tissue malignancy: correlation with histologic grading ChhabraA, Ashikyan O, Slepicka C, Dettori N, Hwang H, Callan A, Sharma RR, Xi Y.Eur Radiol. 2018 Dec 3. doi: 10.1007/s00330-018-5845-9. [Epub ahead of print] PMID:30511176