The Value Of ADC In Differential Diagnosis Of Vertebral Compression Fracture Caused By Osteoporosis And Metastatic Tumor

Objective To explore the value of ADC in differential diagnosis of vertebral compression fracture caused by osteoporosis and metastatic tumor.Materials and methods(1)The imaging data of 82 cases of vertebral compression fracture with abnormal signal were collected from the first hospital of Zibo from December 2015 to December 2017 and analyzed retrospectively.These included 50patients with osteoporotic compression fractures(involving 64 vertebrae)and 32 patients with bone metastases(involving 40 vertebrae).(2)The image post-processing method transfers all collected data to the PACS system,and the workstation of the post-processing platform automatically generates ADC diagrams.In DWI images,the region of interest(ROI)is located at the most homogeneous signal of the lesion,and the area of ROI is between 20 and 30 mm~2.The ADC diagram automatically copies the ROI selected from the DWI image.(3)To observe the difference of signal types between osteoporotic compression fracture and metastasis compression fracture in different routine MRI sequences and DWI sequences.The selected b values was 0 s/mm~2,300 s/mm~2 and 500s/mm~2,respectively,the ADC values of osteoporotic compression fracture,metastatic compression fracture and adjacent normal vertebrae were measured.The selected b values were 0 s/mm~2,300 s/mm~2 and 500 s/mm~2,respectively,the signal intensity of osteoporotic compression fracture,metastatic compression fracture and adjacent normal vertebrae were measured,and the signal attenuation rate SAR value was calculated according to the formula.(4)All data and material were analyzed by SPSS 21.0 software.Under different b values,the ADC values obtained in ROI delineated by osteoporotic compression fracture and metastasis fracture and adjacent normal vertebrae were compared by t-test.When the different b values were taken,the correlation between ADC value and SAR value was analyzed.Under different b values,the SAR values obtained in the ROI delineated by osteoporotic compression fracture and metastasis fracture vertebrae and adjacent normal vertebrae were compared by t-test.The ROC curves of vertebral ADC and SAR values of osteoporotic compression fracture and metastasis fracture obtained at different b values were established,and the differential diagnostic value of ADC and SAR values for osteoporotic compression fracture and metastasis fracture was analyzed and evaluated.Results(1)Routine MRI sequence and DWI sequence in the detection of lesions,T1WI,T2WI/FS and DWI were significantly better than FSE T2WI,the difference was statistically significant;there was no significant difference between T1WI,T2WI/FS and DWI.But,there was no significant difference in signal types between osteoporotic compression fracture and metastatic compression fracture,whether in conventional MRI sequence or DWI sequence;neither of them could make a definite differential diagnosis.(2)When the b value was 300 s/mm~2,the ADC value of the osteoporotic compression fracture group was(1.852±0.235)x10~-33 mm~2/s,the ADC value of the group of metastatic tumor compression fracture was(1.427±0.139)x10~-33 mm~2/s,the ADC value of the normal control group was(0.515±0.065)x10~-33 mm~2/s and performed t test,and t value was 9.24,37.74,49.51,p value were less than 0.01.The difference was statistically significant.When the b value was 500 s/mm~2,the ADC value of the osteoporotic compression fracture group was(1.460±0.193)x10~-33 mm~2/s,the ADC value of the metastatic tumor group was(1.010±0.135)x10~-33 mm~2/s,the ADC value of the normal control group was(0.408±0.047)x10~-33 mm~2/s,and performed t test,t value was 11.53,35.41,47.17,p value was less than 0.01,and the difference was statistically significant.(3)When the b value was 300 s/mm~2,the SAR value of the osteoporotic compression fracture group was 42.46±5.31%,the SAR value of the metastatic tumor group was 35.27±5.42%,the SAR value of the normal control group was 14.81±2.87%,and the t test was performed respectively.The t value was 6.08,26.12,38.49,and p value was less than 0.01,and the difference had significant meaning.When the b value was 500 s/mm~2,the SAR value of the osteoporotic compression fracture group was 50.59±6.46%,the SAR value of the metastatic tumor group was 40.10±5.81%,the SAR value of the normal control group was 18.80±2.93%,and the t test was performed respectively.The t value was 7.44,26.35,38.59,and p value was less than 0.01,and the difference was significant.(4)The correlation coefficients of ADC and SAR were 0.982,0.980 and 0.998 for osteoporotic compression fracture,metastatic compression fracture and control group when b value was 300 s/mm~2,respectively.The correlation coefficients of ADC and SAR in osteoporotic compression fracture,metastatic compression fracture and control group were 0.988,0.984 and 0.998 respectively when the b value was 500 s/mm~2.Therefore,the ADC value of the same tissue was positively correlated with the SAR value under the same imaging condition.(5)From the ROC curve of osteoporotic compression fracture and metastatic compression fracture,it can be concluded that when b value was 300s/mm~2 and ADC value was 1.596x10~-33 mm~2/s as boundary value,the sensitivity was 90%,the specificity was 90.6%,AUC was 93.7%;when SAR value was 39.88%,the sensitivity was 80%,specificity was 84.4%,AUC was 83.6%.When the b value is 500 s/mm~2 and the ADC value is 1.199x10~-33 mm~2/s as the boundary value,the sensitivity of the two is94%,the specificity is 96.9%,the AUC is 98.3%;the sensitivity is 76%,the specificity is93.7%,and the AUC is 89.8%when SAR value is the boundary value.Conclusion(1)Both ADC values and SAR values can be used for differential diagnosis of osteoporotic compression fractures and metastatic tumor compression fractures.(2)When DWI sequence is used to differentiate osteoporotic compression fracture from metastatic compression fracture,ADC value is better than SAR value,and ADC value is more valuable when b value is higher.