Osteoid osteomas can be imaged with greater conspicuity by using dynamic gadolinium-enhanced instead of nonenhanced MR imaging and with conspicuity equal to or better than that obtained with thin-section CT.

Diagnostic image-guided needle biopsy plays a vital role in the work-up and treatment of patients with extremity bone tumors. The radiologist and the orthopedic oncologic surgeon should take a team approach to this procedure, especially when the bone lesion might be a primary sarcoma for which limb-sparing surgery (LSS) would be considered. A set of anatomically based guidelines were developed that can be used by the radiologist, in combination with case-by-case consultation with the surgeon, to plan image-guided core needle biopsies of extremity long bone lesions that may be treatable with LSS. By using these guidelines, along with the aforementioned consultation, the radiologist will be able to preserve the patient's chances of receiving optimal surgical treatment.

No abstract

The reverse shoulder prosthesis was approved for clinical use in the United States in March 2004. This new prosthesis reverses the normal ball-and-socket relationship of the shoulder joint. As a result of replacement of the glenoid component with a ball and of the humeral head with a socket, the center of rotation is moved distally and medially, allowing more control of shoulder motion by the deltoid muscle. This improved geometric configuration allows shoulder reconstruction in patients who have irreparable rotator cuff damage with secondary arthropathy, pain, and "pseudoparalysis" (ie, inability to lift the arm above the horizontal). Patients experience a significant improvement in range of motion and markedly decreased pain after undergoing reverse shoulder arthroplasty; however, the procedure is associated with a relatively high rate of complications, including dislocation, infection, loosening, malpositioning of the glenoid component or fixation screws, disassembly of the humeral component, periprosthetic fracture, and inferior glenoid impingement leading to scapular erosion. Therefore, it is important that the radiologist be familiar with the normal and abnormal imaging appearances of this new prosthesis.

Cryoablation appears to be an effective alternative treatment for the achievement of local control of small and moderately sized EAD tumors, but it is likely of limited use in patients with larger tumors that have untreatable regions due to involvement of vital structures. Continued research evaluating cryoablation for the treatment of EAD tumors is needed.

The experimental MAR reconstruction algorithm significantly improved CT image quality for patients with large metal implants. However, the MAR algorithm introduced blurring artifact that reduced image quality with small metal implants.

After arthrodesis of the ankle or subtalar joint, MDCT scans can be used to determine whether that joint is likely to be stable if > 33% of the joint has visible bone fusion on sagittal MDCT images.

Patients who present with slowly growing extremity masses are often imaged with MRI to be examined for possible tumors. In addition to cysts and neoplasms, chronic expanding hematomas should be considered in the differential diagnosis if the patient has a history of remote trauma. The presence or absence of internal contrast enhancement is often used to distinguish between hematomas and hemorrhagic neoplasms on MRI and CT. We present the unusual case of a patient who had a chronic expanding hematoma of the calf that demonstrated nodular internal enhancement on gadolinium-enhanced MRI, simulating a neoplasm.