Correlation between apparent diffusion coefficient and histopathology subtypes of osteosarcoma after neoadjuvant chemotherapy.

BackgroundNeoadjuvant chemotherapy has made limb-salvage surgery possible for the patients with osteosarcoma. Diffusion-weighted magnetic resonance imaging (DWI) has been used to monitor chemotherapy response.PurposeTo correlate the apparent diffusion coefficient (ADC) values with histopathology subtypes of osteosarcoma after neoadjuvant chemotherapy.Material and MethodsTwelve patients with osteoblastic (n = 7), chondroblastic (n = 4), and fibroblastic (n = 1) osteosarcomas underwent post-chemotherapy DWI before limb-salvage surgery. ADCs corresponding to 127 histological tissue samples from the 12 resected specimens were compared to histological features.ResultsThe mean ADC value of non-cartilaginous viable tumor (38/91, ADC = 1.22 ± 0.03 × 10−3 mm2/s) was significantly (P < 0.001) lower than that of non-cartilaginous tumor cell necrosis without stroma disintegration (25/91, ADC =1.77 ± 0.03 × 10−3 mm2/s), cartilaginous viable tumor (14/91, ADC = 2.19 ± 0.04 × 10−3 mm2/s), and cystic areas including liqu...