CT with IV contrast remains an important adjunct in the evaluation of a soft tissue mass. CT Area of Interest Without IV Contrast The literature does not support the use of single-phase CT without IV contrast as the next imaging study for the evaluation of a soft tissue mass. Although a multi-institutional study of 133 patients with primary soft tissue malignancies by Panicek et al [32] found no statistically significant difference between MRI and contrast-enhanced CT imaging in determining tumor involvement of muscle, bone, joint, or neurovascular structures, this study did not endorse the usefulness of single-phase CT without IV contrast. MRI Area of Interest Without and With IV Contrast MRI without and with IV contrast is the technique of choice as the next imaging study for the evaluation of soft tissue masses. Its improved soft tissue contrast and multiplanar capability have provided significant advantages for lesion conspicuity, intrinsic tumor characterization, and local staging [3,11]. Vascular structures and neurovascular involvement are more easily defined when compared with CT. Soft Tissue Masses The use of MR contrast agents improves the differentiation of benign from malignant soft tissue masses [33]. The contrast allows for better demarcation between viable tumor and muscle, edema-like reactive change, hemorrhage, and tumor necrosis, as well as providing information on tumor vascularity. In addition to static MR contrast imaging, there are several additional modern MR techniques that provide greater insight into the character and behavior of soft tissue masses and can assist with differentiation of benign from malignant tumors. These include diffusion-weighted imaging [34-37], dynamic contrast-enhanced perfusion imaging [38,39], and MR spectroscopy [38,39]. Of note, chemical-shift imaging has not shown utility in differentiating benign from malignant soft tissue masses [40].
Soft Tissue Masses. CT with IV contrast remains an important adjunct in the evaluation of a soft tissue mass. CT Area of Interest Without IV Contrast The literature does not support the use of single-phase CT without IV contrast as the next imaging study for the evaluation of a soft tissue mass. Although a multi-institutional study of 133 patients with primary soft tissue malignancies by Panicek et al [32] found no statistically significant difference between MRI and contrast-enhanced CT imaging in determining tumor involvement of muscle, bone, joint, or neurovascular structures, this study did not endorse the usefulness of single-phase CT without IV contrast. MRI Area of Interest Without and With IV Contrast MRI without and with IV contrast is the technique of choice as the next imaging study for the evaluation of soft tissue masses. Its improved soft tissue contrast and multiplanar capability have provided significant advantages for lesion conspicuity, intrinsic tumor characterization, and local staging [3,11]. Vascular structures and neurovascular involvement are more easily defined when compared with CT. Soft Tissue Masses The use of MR contrast agents improves the differentiation of benign from malignant soft tissue masses [33]. The contrast allows for better demarcation between viable tumor and muscle, edema-like reactive change, hemorrhage, and tumor necrosis, as well as providing information on tumor vascularity. In addition to static MR contrast imaging, there are several additional modern MR techniques that provide greater insight into the character and behavior of soft tissue masses and can assist with differentiation of benign from malignant tumors. These include diffusion-weighted imaging [34-37], dynamic contrast-enhanced perfusion imaging [38,39], and MR spectroscopy [38,39]. Of note, chemical-shift imaging has not shown utility in differentiating benign from malignant soft tissue masses [40].