Value of dynamic magnetic resonance imaging in preoperative evaluation of pediatric osteosarcoma

Histologic response to neoadjuvant chemotherapy is an essential prognostic criterion in osteosarcoma. Non-invasive assessment of the effect of neoadjuvant chemotherapy influences the timing and method of definitive surgery. Aim This study evaluated the use of Dynamic Contrast Enhanced-MRI (DCE-MRI) in preoperative estimation of residual viable tumor present in Osteosarcoma following chemotherapy. Patients and methods We conducted a prospective study from July 2011 till April 2013 on 50 pediatric patients with a mean age of 12.8 years diagnosed as Highgrade osteosarcoma in long bones at the Children Cancer Hospital Egypt. Conventional and dynamic MRI performed before definitive surgery was compared with histopathology assessment of necrosis. For DCE-MRI, 3 regions of interest (ROIs) were chosen and the signal intensity was plotted against time. Signal intensity values and curve pattern were compared to percent of necrosis of the corresponding areas on the resected specimens. Results DCE-MRI showed sensitivity of 92.5% and specificity of 96% with positive predictive value of 92% and negative predictive value of 96%. Negative correlation was found between signal intensity values and percent of necrosis. Conclusions DCE-MRI can be used preoperatively as a sensitive, specific, and non-invasive method for detection of viability and necrosis within osteosarcoma.