Caracterización de los tumores de partes blandas mediante técnicas ecográficas avanzadaselastosonografía y ecografía con contraste

Abstract

Superficial soft tissue tumors (SSTT) are a large group of neoplasms that are difficult to diagnose by imaging, needing in most cases tumor biopsy for a certain diagnosis. After 10 years of development of elastosonography, there is not a reproducible and widespread qualitative nomenclature of tissues and lesions, using terms such as red-blue, soft-hard. Most studies that analyze muscle elasticity show their results using quantitative values (kPa or m/s), and there are no previous studies that compare muscle elasticity with fat tissue. Recent studies of SSTT have shown that there is no relationship between elasticity and tumor aggressiveness. The objectives of this study were to evaluate the elasticity of muscle and subcutaneous fat using ultrasound in 16 healthy volunteers, to describe a new qualitative nomenclature, useful for both qualitative (compression) and quantitative (SWE) elastography: hyperelastic, intermediate elasticity or hypoelastic, as well as evaluating the usefulness of elastography and contrast-enhancement ultrasound (CEUS) in 94 SSTT, 64 of them sarcomas. In addition, clinical, histological and radiological data were collected: characteristics in ultrasound (mode B and Doppler) and MRI. In the results, we found that the qualitative and quantitative elastograms were reproducible intra, inter-observer and inter-US machine, observing fatty tissue as hypoelastic in the qualitative and isoelastic to the muscle in the quantitative, but the quantitative values were not reproducible between equipments: Philips Vc values were 0.5-0.7 m/s above Siemens’. Elastosonography was useful in the differential diagnosis of SSTT, helping to determine the histological type, but it was not useful in evaluating tumor aggressiveness (benign or malignant). Hyperelastic lesions were associated with tumors of adipose strain, while hypoelastic with fibrous strain. The presence of intratumoral vascularization was highly suggestive of malignancy. CEUS helped us to detect the presence of microvascularization inside some sarcomas with negative Echo-Doppler. Qualitative nomenclature of tumors in 3 types: hyperelastic (<1.5 m/s), intermediate elasticity (1.5-3 m/s) or hypoelastic (>3m/s), is useful for greater reproducibility and expansion of the technique of elastography. With CEUS implementation in SSTT evaluation we decrease the possibility of false negatives.