| Research background and purpose:Accurate preoperative assessment of vertebral bone mineral density(BMD)is a prerequisite for optimizing spinal surgery and reducing surgical complications.Studies have shown that the reduction of BMD is highly related to the failure of internal fixation,adjacent segmental fractures and cage subsidence after spinal surgery.Therefore,spinal surgeons will pay attention to the BMD of patients when making preoperative plans.At present,the gold standard for clinical evaluation of BMD is dual-energy X-ray absorptiometry(DEXA).However,it is reported in the literature that due to the lack of understanding of the preoperative BMD assessment by some surgeons,and the additional medical costs and X-ray radiation caused by patients undergoing DEXA examination,the loss rate of DEXA test before spinal surgery is as high as 60%.Moreover,the results of DEXA are easily affected by peri-vertebral bone calcification,obesity,previous spinal surgery history and other factors,and may also have a large error because of the size of the vertebral body,so the current bone quality evaluation methods still need to be further improved.In order to make better preoperative planning and evaluate the treatment effect,it is particularly important to find new supplementary methods for BMD screening and evaluation.In recent years,Vertebral Bone Quality score(VBQ)based on lumbar magnetic resonance imaging(MRI)T1 imaging and imaging methods based on vertebral body computed tomography(CT)Hounsfield units(HU)have shown good research prospects in the diagnosis of osteoporosis(OP).However,there are few studies on the use of VBQ score in the evaluation of BMD in Chinese population,and the effect of the combination of the two on the evaluation of BMD is not clear.The purpose of this study is to analyze the predictive value of VBQ score and HU value to BMD by measuring the VBQ score and Hu value of patients undergoing spinal surgery,and to establish a predictive model for BMD evaluation.Finally,to evaluate the value of the combination of VBQ score and HU value in the evaluation of BMD in patients undergoing spinal surgery,so as to provide a theoretical basis for the discovery of new auxiliary diagnostic tools for OP.Research object and methods:This study retrospectively analyzed the data of patients who underwent lumbar internal fixation in our hospital from January 2016 to January 2022.According to the inclusion criteria and exclusion criteria,complete case data and imaging data were collected.According to the value of bone mineral density T measured by DEXA,the patients were divided into two groups: abnormal bone mineral density group and normal bone mineral density group.Then the VBQ score of lumbar MRI and the cross-sectional HU value of lumbar 1 vertebrae were recorded according to the prescribed method.The following observation indexes of the two groups were statistically analyzed by statistical software R(Version4.1.1;RCore Team,2021).1.Comparison of the general conditions of the two groups: the independent sample t test was used when the quantitative data(such as age,body mass index(BMI),BMDT value,VBQ score,HU value)were normal,and nonparametric test was used if they did not.Chi-square 2 test was used for classified data(such as sex,long-term history of hormone use,history of hyperlipidemia,history of hypertension and diabetes),and intra-observer and intra-observer consistency of VBQ and HU measurements were evaluated by intra-group correlation coefficient(ICC)(ICC ≥ 0.8 was considered to be reliable).2.To evaluate the relationship between VBQ score and BMFT value: Pearson correlation coefficient was used to describe the correlation between VBQ score and BMFT value in the two groups,as well as the correlation degree between gender and age.It is stipulated that the threshold value of correlation intensity is: < 0.4 indicates weak correlation,0.4-0.7 indicates moderate correlation,and > 0.7 indicates strong correlation.3.To evaluate the relationship between HU value and BMDT value: Pearson correlation coefficient was used to describe the correlation between HU value and BMD T value in two groups and the correlation degree between them in different genders and ages.4.Analysis of the value of VBQ score in the diagnosis of abnormal bone mass: the area under the curve(AUC),sensitivity,specificity and most approximate index of the subject working characteristic curve(ROC)were used to determine the predictive value of VBQ score for abnormal bone mass.5.Analysis of the value of HU value in the diagnosis of abnormal bone mass: AUC and most approximate index of ROC were used to determine the best threshold,sensitivity and specificity for the diagnosis of abnormal bone mass.6.The analysis of the value of VBQ score and HU value in the diagnosis of abnormal bone mass: the HU value and VBQ score were regarded as independent variables,and whether the bone mass was normal or not as dependent variable.Logistic regression was used to construct a model for the diagnosis of abnormal bone mass.Then the AUC and other indexes of ROC were used to determine the accuracy,the best sensitivity and specificity of the two methods in the diagnosis of abnormal bone mass.Finally,Delong test was used to compare the predictive performance between joint evaluation and single use(P < 0.05).Research result:Finally,a total of 269 patients with lumbar internal fixation were enrolled.The BMFT values of femoral neck and hip were measured by DEXA.According to the lowest BMD value,according to the OP diagnostic criteria of WHO,there were 43 patients with normal bone mass(T value ≥-1.0)and 226 patients with abnormal bone mass(osteopenia / osteoporosis group,T value <-1.0).1.Comparison of general conditions between the two groups: there was no significant difference in age,sex,BMI,long-term history of hormone use,history of hyperlipidemia,history of hypertension and history of diabetes between the two groups,but there were significant differences in BMD Tvalue,VBQ score and HU value between the two groups.The BMD T and HU values of the abnormal bone mass group were significantly lower than those of the normal bone mass group,and the VBQ score of the abnormal bone mass group was significantly higher than that of the normal bone mass group.The intra-observer and inter-observer correlation coefficients of HU values were 0.913 and 0.934 respectively,and the correlation coefficients were 0.924 and 0.953 respectively,indicating that the HU value and VBQ score were consistent and repeatable.2.The relationship between VBQ score and BMD T value: there was a moderate negative correlation between VBQ score and the lowest T value,a moderate negative correlation between VBQ score and femoral neck T value,and a moderate negative correlation between VBQ score and total hip T value.Among them,the correlation between VBQ score and the lowest T value was higher than that of the other two.There was a moderate negative correlation between the VBQ score and the lowest T value in male patients and a moderate negative correlation between VBQ score and the lowest T value in female patients and female patients.In different age stages,there was a moderate negative correlation between VBQ score and the lowest T value,among which50-59 years old: r=-0.404,P < 0.001,60-69 years old: r=-0.434,P < 0.001,70-79 years,r=-0.453,P < 0.001,80-89 years,r=-0.476,P < 0.001.The correlation coefficient was the highest between the ages of 80 and 89.3.The relationship between HU value and BMD T value: there was a moderate positive correlation between HU value and the lowest T value(r = 0.639,P < 0.05),a moderate positive correlation between HU value and femoral neck T value(r = 0.631,P< 0.05),and a moderate negative correlation with total hip T value(r = 0.611,P < 0.05).Among them,the correlation between HU value and the lowest T value is higher than the other two.In terms of sex,there was a moderate positive correlation between HU value and the lowest T value in male patients,and in female patients,there was a moderate positive correlation between HU value and the lowest T value in all age groups,and there was no significant difference among different groups,and the correlation coefficient was the highest in 50-59 years old group(r = 0.648,P < 0.001).4.The value of VBQ score in the diagnosis of abnormal bone mass: the accuracy of VBQ score in the diagnosis of abnormal bone mass is 70.5%.When the maximum value of Jordan index is 0.334,the threshold is 2.71,the sensitivity is 84.5% and the specificity is 48.8%.In male patients,the threshold for diagnosing abnormal bone mass was 2.68,the accuracy was 64.2%,the sensitivity was 85.4%,and the specificity was46.2%.In female patients,the threshold was 3.11,the accuracy was 73.1%,the sensitivity was 62.7%,and the specificity was 73.3%.In different age stages,the threshold of VBQ score for the diagnosis of abnormal bone mass increased with the increase of age,and the accuracy and sensitivity were the highest in the stage of 70-79 years old.5.The value of HU value in diagnosing abnormal bone mass: the accuracy of HU value in diagnosing abnormal bone mass is 84.1%.When the maximum value of Jordan index is 0.504,the threshold is 86.0,the sensitivity is 85.5%,and the specificity is59.7%.In male patients,the threshold of HU value in diagnosing abnormal bone mass was 124.0,the sensitivity was 61.5%,the specificity was 92.7%,and the accuracy was85.6%.In female patients,the threshold,sensitivity and specificity were 86.0,90.0%,59.5% and 83.4%,respectively.In terms of age,the threshold of HU value for diagnosing abnormal bone mass decreased with the increase of age.in the age group of80-89 years old,HU value had the highest accuracy and sensitivity in the diagnosis of abnormal bone mass.When the threshold is 90.0,the accuracy is 96.1%,the sensitivity is 100%,and the specificity is 92.1%.6.The value of VBQ score combined with HU value in the diagnosis of abnormal bone mass: the accuracy,sensitivity and specificity of VBQ score and HU value in the diagnosis of abnormal bone mass were 85.2%,90.7% and 48.8%,respectively.In male patients,the diagnostic accuracy of bone mass abnormality was 87.2% in males and84.6% in females.There was no significant difference in diagnostic value among different age stages,among which the accuracy was the highest in the 80-89 age group.Generally speaking,the diagnostic performance of the combination of the two in the diagnosis of abnormal bone mass was better than that of VBQ score or HU value alone,which was statistically significant(Delong test P < 0.05),and the sensitivity was higher than that of single use.Research conclusion:1.VBQ score can effectively distinguish normal bone mass from abnormal bone mass in patients of different genders and ages,and can be used as a new effective supplementary method for BMD evaluation.Attention should be paid to the difference of gender and age in the application.The diagnostic threshold for males is lower,while the threshold for diagnosing abnormal bone mass increases with the increase of age.The higher the age,the higher the threshold.2.The correlation between HU value and BMD T value has no difference between different ages and genders,which can effectively distinguish patients with normal bone mass and abnormal bone mass,and can be used as an effective supplementary method for BMD evaluation.However,in the process of use,attention should be paid to the difference between sex and age,the diagnostic threshold of males is significantly higher than that of female patients,and the threshold for the diagnosis of abnormal bone mass will decrease with the increase of age,that is,the higher the age,the lower the threshold.3.The combination of the two methods is more effective in the diagnosis of abnormal bone mass,which is statistically significant(Delong test P < 0.05),and the sensitivity is higher than that of single use.The combination of the two is helpful to reduce the number of false negative patients and prevent missed diagnosis. |
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