Role of MAGNETIC RESONANCE IMAGING in Characterization of Superficial Soft Tissue Masses

In the clinical practice, there is a large number & variety of superficial soft tissue masses. The differentiation of such masses represents a major obstacle for the surgeons. Benign &malignant neoplasms as well as non-neoplastic swellings may have similar clinical presentation. The differentiation between malignant & benign superficial soft tissue neoplasms is required for appropriate therapeutic planning and decisions. Masses can be characterized in terms of their size, number, component &vascularity using US and Doppler US. However, US is operator dependent & may display a number of artifacts that can result in misinterpretation. So MRI is superior in the assessment of such soft tissue masses due its brilliant soft tissue discrimination. Some features that will help distinguish malignant from benign lesions are evident on MRI examination such as signal characteristics,enhancement pattern,margin,lobulation,necrosis, haemorrhage,internal septation,peritumoral edema and extension through the deep fascia .However very forcful tumors may show benign behavior & appear similar to benign masses , Thus further histopathology is required for accurate diagnosis. Diffusion weighted MRI visualizes the random microscopic motion of molecules. Diffusion-weighted imaging (DWI) is the technique which allows measurement of the Brownian motion of water in the tissue microenvironment depending on the organization of the tissue, integrity of cell membranes, and tortuosity of extracellular space. Apparent Diffusion Coefficient (ADC) is a numerical parameter which is calculated from DWI. Previously, DWI technique was used with great success in the central nervous system (CNS), in the differentiation between benign and malignant tumors in addition to its great value in early diagnosis of recent strokes. Nowadays, DWI was used in the differentiation between malignant and benign soft tissue masses. Malignant tumors have abundant cellularity than benign tumors hence they have more restricted diffusion. The addition of quantitative ADC values plays a fundamental role in more accurate diagnosis of malignant superficial soft tissue neoplasms.