Signal changes of MRI T1-weighted images of the medullary cavity before and after the neoadjuvant chemotherapy for extremity osteosarcoma
DENG Zhi-ping
DING Yi
SU Yong-bin
NIU Xiao-hui
Abstract：Objective To investigate the signal changes of MRI T1-weighted images of the medullary cavity before and after the neoadjuvant chemotherapy for extremity osteosarcoma.Methods The clinical data of 58 cases of extremity osteosarcoma were retrospectively studied. The MRI T1-weighted images of the medullary cavity before and after the neoadjuvant chemotherapy were compared. It was recorded whether the margin between the tumor and the normal medullary cavity was clear before and after the chemotherapy, the occurrence of blurring and the signal changes. The MRI examination of bilateral limbs was performed on some patients. The signal differences between the 2 sides were compared. After the tumor-bearing segment was resected, the specimen of abnormal signals after the chemotherapy was analyzed pathologically. The histological structures of such signals were studied.Results The signal aspects of MRI T1-weighted images of the medullary cavity could be classiifed into 4 kinds, which were clear, continuous diffuse, discontinuous island-like and discontinuous diffuse respectively. Before the chemotherapy, the clear margin could be observed in all 58 patients. After the chemotherapy, the clear margin could be observed in 22 patients ( 37.9% ). It occurred to 36 patients ( 62.1% ) that signals changed from clear to unclear after the chemotherapy. There were 20 continuous diffuse cases ( 34.5% ), 4 discontinuous island-like cases ( 6.9% ) and 12 discontinuous diffuse cases ( 20.7% ). The MRI showed bilateral femurs in 9 cases after the chemotherapy. The patchy and diffuse signals in the medullary cavity of the normal femur were similar to those of the affected femur. The specimen was taken based on the MRI T1-weighted images of 33 cases which showed abnormal signals. The histological studies showed no tumor cells but the proliferation of hematopoietic cells.Conclusions The range of abnormal signals in the medullary cavity with osteosarcoma may change based on the MRI T1-weighted images before and after the neoadjuvant chemotherapy. The abnormal signals beyond the tumor are noticed in some patients after the neoadjuvant chemotherapy, which are island-like, diffuse and patchy. For those signals that are lower than subcutaneous fat signals and higher than skeletal muscle signals, the marrow reconversion should be considered clinically, which is not the tumor progress but the normal marrow change. If misdiagnosed, the osteotomy length will be increased.
Keywords：OsteosarcomaChemoradiotherapyadjuvantMagnetic resonance imagingSignal
Publication Date：2014-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：4( 521-524 )