Utility of Motor and Somatosensory Evoked Potentials for Neural Thermoprotection in Ablations of Musculoskeletal Tumors.

PURPOSE: To characterize the utility of monitoring transcranial electrical motor evoked potentials (TCeMEPs) and somatosensory evoked potentials (SSEPs) for neural thermoprotection during musculoskeletal tumor ablations. MATERIALS AND METHODS: Retrospective review of 29 patients (16 male; median age, 46 y; range, 7-77 y) who underwent musculoskeletal tumor radiofrequency ablation (n = 8) or cryoablation (n = 22) with intraprocedural TCeMEP and SSEP monitoring was performed. The most common tumor histologies were osteoid osteoma (n = 6), venous malformation (n = 5), sarcoma (n = 5), renal cell carcinoma (n = 4), and non-small-cell lung cancer (n = 3). The most common tumor sites were spine (n = 22) and lower extremities (n = 4). Abnormal TCeMEP change was defined by 100-V increase above baseline threshold activation for a given myotome; abnormal SSEP change was defined by 60% reduction in baseline amplitude and/or 10% increase in latency. RESULTS: Abnormal changes in TCeMEP (n = 9; 30%) and/or SSEP (n = 5; 17%) occurred in 12 procedures (40%) and did not recover in 5 patients. Patients with unchanged TCeMEP/SSEP activities throughout the procedure (n = 18) did not have motor or sensory symptoms after the procedure; 3 (60%) with unrecovered activity changes and 2 (29%) with transient activity changes had new motor (n = 1) or sensory (n = 4) symptoms. Relative risk for neurologic sequelae for patients with unrecovered TCeMEP/SSEP changes vs those with transient or no changes was 7.50 (95% confidence interval, 1.66-33.9; P = .009). CONCLUSIONS: Abnormal activity changes of TCeMEP or SSEP during percutaneous ablative procedures correlate with postprocedural neurologic sequelae.

Evaluation of Next-Generation Anti-CD20 Antibodies Labeled with 89Zr in Human Lymphoma Xenografts.

Radioimmunotherapies with monoclonal antibodies to the B-lymphocyte antigen 20 (CD20) are effective treatments for B-cell lymphomas, but U.S. Food and Drug Administration-approved radioimmunotherapies exclusively use radiolabeled murine antibodies, potentially limiting redosing. The Food and Drug Administration recently approved 2 unlabeled anti-CD20 monoclonal antibodies, obinutuzumab and ofatumumab, termed next generation as they are humanized (obinutuzumab) or fully human (ofatumumab), thus potentially allowing a greater potential for redosing than with previous-generation anti-CD20 antibodies, including rituximab (chimeric) and tositumomab (murine), which contain more murine peptide sequences. We prepared 89Zr-ofatumumab and 89Zr-obinituzumab and assessed their tumor targeting by PET/CT imaging and their biodistribution in a preclinical mouse model with CD20 xenografts to determine whether these antibodies have potential as theranostics or for radioimmunotherapy. Methods: Obinutuzumab, ofatumumab, rituximab, tositumomab, and human IgG (as control) were radiolabeled with 89Zr. Raji Burkitt lymphoma xenografts were established in severe combined immunodeficient mice. Mice with palpable tumors (n = 4-9) were injected with 89Zr-obinutuzumab, 89Zr-ofatumumab, 89Zr-rituximab, 89Zr-tositumomab, or 89Zr-IgG, with small-animal PET/CT images acquired at 1, 3, and 7 d after injection, and then sacrificed for biodistribution analyses. Results: At 1, 3, and 7 d after injection, all anti-CD20 antibodies showed clear tumor uptake on PET/CT, with minimal tumor uptake of IgG. Biodistribution data showed significantly (P < 0.005) higher tumor uptake for obinutuzumab (41.4 ± 7.6 percentage injected dose [%ID]/g), ofatumumab (32.6 ± 17.5 %ID/g), rituximab (28.6 ± 7.6 %ID/g), and tositumomab (28.0 ± 6.5 %ID/g) than IgG (7.2 ± 1.2 %ID/g). Tositumomab had much higher splenic uptake (186.4 ± 49.7 %ID/g, P < 0.001) than the other antibodies. Conclusion:89Zr-labeled obinutuzumab and ofatumumab localized to tumor as well as or better than labeled rituximab and tositumomab, 2 monoclonal antibodies that have been used previously in B-cell lymphoma radioimmunotherapy, and both obinutuzumab and ofatumumab have the potential for repeated dosing.

The Radiologist's Primer to Imaging the Noncuff, Nonlabral Postoperative Shoulder.

Many radiologists are familiar with the preoperative imaging assessment of patients with labral tears, rotator cuff abnormalities, and end-stage arthritis, as well as the subsequent primary reconstructions and repairs commonly encountered in routine clinical management. However, the second-line surgical procedures and augmentation procedures performed for refractory or recurrent shoulder instability and the extra-articular surgical procedures of the shoulder girdle may challenge even the most experienced musculoskeletal radiologist. Knowledge of the indications, surgical techniques, expected postoperative imaging appearance, and complications of these uncommon shoulder girdle reconstructions and repairs will aid the radiologist in both the pre- and postoperative assessment of the injured shoulder. This article is divided into two parts. In the first part, procedures performed for shoulder instability are addressed, including capsular shift, Bristow-Latarjet coracoid transfer, remplissage, and humeral head allografts. In the second part, the imaging findings of extra-articular procedures of the shoulder girdle are reviewed, including biceps tenodesis, os acromiale fixation, and coracoclavicular ligament reconstruction. ©RSNA, 2017.