MR IMAGING OF MUSCULOSKELETAL TUMORS IN THE ELBOW REGION

Pitfalls in MR Image Interpretation Prompting Referrals to an Orthopedic Oncology Clinic

Patients referred to the authors' hospital for evaluation on suspicion of a bone or soft-tissue malignancy frequently present to the Orthopaedic Oncology Clinic with magnetic resonance (MR) images that show typical features of nonmalignant or nonneoplastic entities. The purpose of this article is to review the benign entities that may be mistaken by the radiologist for a malignancy and thus lead to needless referral to an orthopedic oncologist. Normal hematopoietic marrow and marrow edema due to a stress reaction may mimic a neoplasm at MR imaging, but knowledge of the typical patterns and locations of these features allows an accurate radiologic interpretation. The MR imaging appearance of osteonecrosis, Paget disease, benign bone lesions, and rheumatologic conditions may be confusing; in such circumstances, radiographic findings may help formulate a correct diagnosis. Knowledge of the common locations and appearances of bursae and ganglia is necessary so that radiologists do not misinterpret these benign entities as soft-tissue sarcomas. Soft-tissue trauma and inflammation also may mimic tumors at MR imaging, but a familiarity with the imaging patterns of nonneoplastic change in muscle allows the avoidance of misinterpretation. The clinical history, as always, is an important component of proper diagnosis. The radiologist can be especially useful to both the clinician and the patient by recognizing entities that are highly unlikely to represent malignancy and by confidently reporting those entities as benign, thereby sparing the patient an unnecessary trip to the orthopedic oncologist.

The use of MRI scanning for investigating soft-tissue abnormalities in the elbow

It is well known that the elbow is one of the most difficult joints to be examined in MR, because of its position in relation to the body during the examination. Moreover, there is relatively little information about the elbow, even less in its soft tissues abnormalities, in the literature in comparison to other joints. This article describes the spectrum of MR findings soft tissues abnormalities of the elbow, giving an analysis of injuries to the elbow ranging from inflammation to rupture to masses, and the role of MR in post-surgical follow-up. It is demonstrated that MR provides an excellent alternative to other imaging techniques that would be of interest to orthopedic surgeons. The value of MRI to accurately determine the nature and extent of the pathologic changes in ligaments, tendons and muscles structures of the elbow joint is presented in the following discussion.