Osteosarcoma: chemotherapy-induced changes at MR imaging.

Abstract

Fifty-seven patients undergoing chemotherapy for osteosarcoma underwent evaluation with magnetic resonance (MR) imaging to identify changes related to a good or poor response. Spin-echo MR images obtained after preoperative chemotherapy were compared with images obtained before treatment. Histopathologic examination of each resected specimen was used to quantify the response. An increase in tumor volume and increased or unchanged edema were predictive of a poor histopathologic response (predictive values, 85%-92%). Decreased or unchanged tumor volume and a decrease in edema were poor predictors of a good response (predictive values, 56%-62%). Improved tumor demarcation, an increase in the size of areas of low signal intensity, and a decrease in joint effusion occurred independently of histopathologic response in almost half of the patients. With a subjective interpretation of MR images, poor respondents can be identified if an increase in tumor volume or no decrease in the amount of edema is seen. Subjective criteria do not contribute to the identification of good respondents.

Osteosarcoma after Preoperative Chemotherapy: Tissue Characterization with Specimen MR and the Role of Enhanced MR Imaging

“…Pan et al (6) found that peritumoral edema decreased following chemotherapy, but they did not perform statistical analysis. Holscher et al (8) reported that increased or stable peritumoral edema was a good predictor of poor responders (predictive value, 85 89%) and this is in accordance with our results. Three years later, however, they obtained contradictory results after one cycle of chemotherapy (9), and believed this outcome was related to changes in the degree of edema occurring later in the course of chemotherapy.…”

“…Correlation between changes of tumor volume and histopathologic response has been reported (8,9) and in our study, increased tumor volume was a good predictor of poor response (predictive value 83%). This result is in accordance with that of Holscher et al (8,9), noted that decreased or unchanged tumor volume in both good and poor responders. There were only two good responders with increased tumor volume, and one of these showed massive postchemotherapy tumor bleeding.…”

Prostaglandin levels of primary bone tumor tissues correlate with peritumoral edema demonstrated by magnetic resonance imaging

“…Keller et al investigated the effect of local PGE 2 on the periosteum in rabbits, and vestigated as an indicator of chemotherapeutic responses. [22][23][24] The reaction has recently been observed showed a primitive periosteal-woven bone with thin trabeculae in a richly vascularized connective tissue more dramatically in some benign bone tumors rather than malignant tumors. 5 -7,9 However, the mechanism after local PGE 2 infusion.…”

MRI: an update and review on bio-effects and safety considerations

“…Missile-effect accidents, where ferromagnetic objects are attracted to the center of the magnet, have resulted in injury and death. 12 In order to help reduce the risks of projectile accidents, ferrous objects and devices are typically prohibited in proximity to the MRI scanner, with non-ferromagnetic versions of many tools and devices typically retained by the scanning facility. Patients undergoing MRI examinations are required to remove all metallic objects, often by changing into a gown or scrubs.…”