Diffusion weighted imaging and magnetic resonance spectroscopy in evaluation of malignant degree of primary osteosarcoma / 中国医学影像技术

ABSTRACT

Objective To explore the value of DWI and 1 H-MRS in evaluation of malignant degree of primary osteosarcoma.Methods A retrospective analysis was performed in 41 patients with osteosarcoma confirmed pathologically and examined with DWI and 1 H-MRS.The b values were 0,400,800,1 000 and 1 500 s/ mm2 in DWI,respectively.ADC map was obtained,and ROIs were selected to measure ADC values.Eighteen cases which had stable spectral lines in MRS were selected and analyzed.The spectral lines,Choline (Cho),Creatine (Cr) and Cho/Cr ratio were obtained.Analysis of ADC values of high and low grade osteosarcoma were performed with Kruskal-Wallis H test,and Cho/Cr values were analyzed with Mann-Whitney U test.Results When b values were 400,800,1 000 s/mm2,ADC values of high and low grade osteosarcoma were significantly different (x2=6.26,4.37,4.87,P=0.01,0.04,0.03).When b value was 1 500 s/mm2,ADC value of high and low grade osteosarcoma had no statistical difference (x2 =2.39,P=0.12).Moreover,when 400 s/mm2 was taken as the optimal b value,the specificity and sensitivity of ADC value for identifying high grade osteosarcoma was 73.30 ％ and 72.70 ％,respectively.Cho/Cr values between high and low grade osteosarcoma were significantly different (Z=-2.45,P＜0.05).As a diagnostic parameter,the best threshold value of Cho/Cr was 2.21.And the specificity and sensitivity for diagnosing high grade osteosarcoma was 75.00 ％ and 92.90 ％,respectively.Conclusion ADC (b=400 s/mm2) and Cho/Cr values may be helpful to identifying malignant degree in osteosarcoma.