Abstract:
Objective To investigate the correlation between the quantitative parameters of dynamic contrast-enhanced MRI (DCE-MRI) and microcirculation and hypoxia in osteosarcoma based on the comparison of MR and histopathological findings.
Methods Patients with osteosarcoma originating around the knee joint, who underwent MRI after neoadjuvant chemotherapy, were enrolled in Yunnan Cancer Hospital from January 2019 to June 2020. After surgery, a tissue slice was taken from the median sagittal plane of the gross specimen and divided into several 1 cm × 1 cm tissue blocks. The tumor necrosis rate (TNR), microvessel density (MVD), vascular endothelial growth factor (VEGF), and hypoxia inducible factor-1α (HIF-1α) of each tissue block were detected. According to the Huvos grading standard, specimens were classified into the good response group (TNR ≥ 90%) and poor response group (TNR<90%). On the sagittal DCE-MRI images, the regions of interest corresponding to the tissue blocks were located and quantitative parameters (Ktrans, Kep, Ve, and Vp) were measured. The relationship between the quantitative parameters and MVD, VEGF, and HIF-1 α was explored, and the receiver operating characteristic curve (ROC) was plotted.
Results A total of 460 histopathological specimens were obtained from10 patients with osteosarcoma, including 59 (12.8%) in the good response group and 401 (87.2%) in the poor response group; 311 (67.6%) were VEGF-positive and 149 (32.4%) were VEGF-negative; 68 (14.8%) were HIF-1α-positive and 392 (85.2%) were HIF-1α-negative. Ktrans, Kep, Ve, Vp, MVD, and the positive rate of VEGF in the good response group were higher than those in the poor response group, while the positive rate of HIF-1α was lower than that in the poor response group (P<0.05). Ktrans, Kep, and Ve were correlated with MVD, and the regression coefficients were -0.652, 0.525, and 0.418, respectively (P<0.01). The threshold, area under the curve, sensitivity, and specificity of Ve for VEGF and those of Kep for HIF-1α were respectively 0.634, 0.609, 63.7%, and 60.0% and 0.115/min, 0.614, 42.2%, and 83.3%.
Conclusions The quantitative parameters of DCE-MRI can be used to evaluate the microvessel status and hypoxia condition in the histopathological tissues of osteosarcoma, which could be a method of evaluating the efficacy of neoadjuvant chemotherapy.