Accuracy of MRI in characterization of soft tissue tumors and tumor-like lesions. A prospective study in 548 patients

Abstract

The purpose of our study was to assess prospectively the value of MRI in characterization of soft tissue tumors (STT) and soft tissue tumor-like lesions in a multi-institutional setting by a group of experts. The material consisted of 548 untreated and proven STT or tumor-like lesions originating from a multi-institutional database of STT in which 930 consecutive patients with STT examined by MRI were registered between 1 January 2001 and 28 April 2003. Based on MRI findings, a suitably ordered differential diagnosis was made in consensus by two radiologists (J.L.M.A.G and A.M.D.S). MRI diagnoses were compared with histology results (455 cases, 83%) and/or 6-month follow-up (93 cases, 17%) as reference standards. The correlation between the MRI and histological diagnosis and between the radiological and histological phenotype were statistically determined. One hundred twenty-three patients presented with a malignant STT; 425 patients presented with a benign one. Concerning differentiation between malignant and benign lesions (dignity), a sensitivity of 93%, specificity of 82%, negative predictive value (NPV) of 98% and positive predictive value (PPV) of 60% with accuracy of 85% were obtained. Concerning phenotype characterization, if only the first MRI diagnosis was taken into account, a sensitivity of 67%, specificity of 98%, NPV of 98%, PPV of 70% and accuracy of 96% were obtained. For benign lesions, sensitivity of 75%, specificity of 98%, NPV of 98%, PPV of 76% and accuracy of 97% were obtained. The phenotype's definition of malignant STT had a sensitivity of 37%, a specificity of 96%, NPV of 96%, PPV of 40% and an accuracy of 92%. A correct diagnosis compared with histological assessment was proposed in 227(50%) of the 455 histologically confirmed cases. Despite non-quantified MR parameter evaluation, the results of our prospective study were better than those reported in previous studies and demonstrated the need for a centralized approach to such rare pathology.

Soft tissue chondroma of Hoffa's fat pad

“…MRI is an efficient imaging modality to characterize soft tissue tumors but will not always allow differentiating malignant from benign lesions with absolute certitude (9). Resection and histological analysis help to obtain the final diagnosis, showing signs of malignancy like increased cellularity and atypical cells.…”

Musculoskeletal Tumors: How to Use Anatomic, Functional, and Metabolic MR Techniques

“…For this purpose, conventional MR sequences are frequently entirely adequate in defining the full extent of a tumor, its relationship to the adjacent neurovascular bundle, and nearby joints (1). However, MR imaging may also be used for the roles of detection, characterization, and assessment of a tumor after treatment (both after neoadjuvant therapy before surgery for the assessment of treatment response and after surgery for assessment of postsurgical residual or recurrent disease) (2)(3)(4)(5)(6). The advent of chemical shift MR imaging (in-phase and opposed-phase imaging), diffusionweighted (DW) imaging, perfusion imaging, and MR spectroscopy has advanced the role of MR for characterizing lesions for malignancy and assessing lesions after treatment.…”

Diagnostic triage for sarcoma: an effective model for reducing referrals to the sarcoma multidisciplinary team

“…Ultrasound has been shown to be an effective triage tool and in conjunction with MRI, most STTs can be characterized with a high degree of sensitivity and specificity as benign, indeterminate or malignant. 4,5,15 However, imaging, particularly ultrasound, can also result in an increased referral rate if performed by inexperienced operators and in unclear clinical pathways, as is demonstrated in our article. For example, small lipomas were referred based on ultrasound scans performed by any qualified provider (AQP), despite clear NICE guidance ( Figure 5).…”

“…Imaging plays a vital role in characterizing lesions, and MR can provide a high degree of sensitivity and specificity in characterization. 4,5 NICE established criteria for a 2-week wait (2WW) referral for urgent specialist assessment (Table 1). Our institution is part of the regional East Midlands Sarcoma Service (EMSS).…”