Whole-tumor apparent diffusion coefficient histogram for identifying histological grade of alveolar soft part sarcoma
Objective To observe the value of whole-tumor apparent diffusion coefficient(ADC)histogram for identifying histopathological grade of alveolar soft part sarcoma(ASPS).Methods Forty-three ASPS patients,including 27 cases of high-grade ASPS(high-grade group)and 16 cases of low-grade ASPS(low-grade group)were retrospectively enrolled.Patients'survival data were collected,MRI manifestations of ASPS were recorded,and the whole-tumor ADC histogram parameters were obtained and compared between groups.The correlations of whole-tumor ADC histogram parameters being different between groups with tumors'histological grading were analyzed,and the efficacy of whole-tumor ADC histogram parameters for identifying high-grade and low-grade ASPS were assessed.Results The 5-year survival rate of ASPS patients in low-grade group was 82.05%,higher than that(51.28%)in high-grade group(P<0.05).The percentage of distant metastasis,tumor≥5 cm,as well as of tumors with features such as peritumoral edema and intra-tumoral septum in high-grade group were all higher than in low-grade group(all P<0.05).The 5th,10th,25th,50th,75th,90th and the mean values of ADC in high-grade group were all lower than those in low-grade group(all P<0.05)and negatively correlated with pathohistological grade of ASPS(from-0.547 to-0.385,all P<0.05).The aeras under the receiver operating characteristic curves of the above parameters ranged from 0.734 to 0.822,which were fairly good for identifying high-grade and low-grade ASPS.Conclusion Whole-tumor ADC histogram parameters could be used to effectively identify high-grade and low-grade ASPS.