Click on any image below to see an enlargement of that image.

Case 1: 44-year-old patient with history of recently resected pelvic sarcoma
(A) Pre-contrast axial images demonstrate a complex pelvic mass	(B) Dynamic enhanced axial image shows some remaining viable tumor within the mass
Case 2: 36 year old patient with recently diagnosed soft tissue sarcoma of the calf	Case 3: 42 year old with history of recently resected pericardial liposarcoma
Dynamic contrast technique showing fragmentation of soft tissue sarcoma in response to radiation therapy	Single shot ECG gated coronal image of the chest demonstrates recurrent tumor
Case 4: 29 year old with mediastinal tumor
(A) Dynamic scan using volume interpolated technique showing an avidly enhancing pericardial tumor	(B) Reconstructed surface rendering image Pathologic diagnosis: sclerosing hemangioma
Case 5: 22 year old with history of recently resected soft tissue sarcoma of the thigh
(A) Pre-contrast axial image shows normal post-surgical changes	(B) Dynamic enhanced axial image obtained 30 seconds after injection demonstrates recurrent tumor
(C) Delayed coronal scan demonstrates a large area of enhancement. Recurrent tumor now cannot be differentiated from post-surgical scar tissue

Above images are all original MR scans performed at Parkside MR Center.

Discussion

MRI has been used extensively for many years to evaluate, diagnose and stage suspected primary soft tissue tumors. Many recent studies have shown the added value of dynamic gadolinium enhanced MR imaging in the differentiation of benign from malignant soft tissue masses and in the subsequent differentiation of post surgical scar from recurrent tumor. This technique has been made possible by the development of faster scan techniques that allow for the acquisition of multiple images in a few seconds.

In the evaluation of primary soft tissue tumors, dynamic gadolinium enhanced imaging can often differentiate between benign and malignant lesions. In general, benign tumors are characterized by enhancement that is delayed, slow and diffuse. Malignant lesions, on the other hand, manifest early, rapid and peripheral enhancement.¹ Peak enhancement of malignant lesions usually occurs at about one minute. After resection, the benign changes in the post-surgical bed, consisting of edema, inflammation and fibrosis can be differentiated from recurrent or residual tumor. Post-operative changes demonstrate delayed peak enhancement at three to four minutes.²

Dynamic techniques may also be used to assess tumor response to chemotherapy and radiation therapy. In general, a thin rim of enhancement characterizes a good response to therapy while small enhancing soft tissue nodules are frequently seen in poor responders.¹ Knowledge of the tumor characteristics prior to surgery or therapy is also often helpful for comparison as well.³

At Parkside MR Center, we routinely use dynamic gadolinium enhanced techniques to evaluate primary soft tissue tumors and to follow possible recurrence after resection. In the chest, we have modified this technique by dynamically scanning with a single shot high resolution ECG gated sequence. This allows more accurate visualization of mediastinal and cardiac tumors. MR findings of recurrent tumor have also been used to direct biopsy or surgery of remaining viable tumor.

References:
1. Murphey, M.D. Fundamental concepts of CT and MRI in evaluation of musculoskeletal neoplasm. Armed Forces Institute of Pathology: Course Syllabus 2001.

2. Vanel, D., Shapeero L.G., Baere, T.D., Gilles, R., Tardivon, A., Genin J., Guinebretiere, JM. MR imaging in the follow-up of malignant and aggressive soft tissue tumors: results of 511 examinations. Radiology 1994; 190: 263-268.

3. Davies, A.M. Vanel, D. Follow-up of musculoskeletal tumors. I. Local recurrence. Eur J Radiol 1998; 8:791-799.

Back to Case Studies