| Objective:To evaluate the difference between the ADC value in the whole body diffusion weighted imaging(WB-DWI)and the T1 weighted water-fat separation Dixon imaging,and assessed the correlation between these quantitative parameters and the ratio of bone marrow plasma cells in multiple myeloma,it is helpful to evaluate the proliferation of intramedullary plasmacytoma using whole-body MRI.To observe the distribution of focal lesions of multiple myeloma in whole body bone,to explore the difference between the ADC value in whole-body diffusion weighted imaging(WB-DWI)and the water signal value and the fat signal value in the T1 weighted water-fat separation Dixon imaging of the difference between thoracolumbar and posterior superior iliac spine focal lesions,and assessed the correlation between these quantitative parameters and the ratio of bone marrow plasma cells in multiple myeloma,it is helpful to use whole-body MRI to find the bone marrow puncture site of multiple myeloma.To evaluate the correlation between baseline ADC values of thoracolumbar and posterior superior iliac spine focal lesions in patients with primary multiple myeloma,T1 weighted water-fat separation Dixon imaging signal values,fat signal values and imaging parameters of MRI images with different treatment responses after chemotherapy in patients with primary multiple myeloma,to find the MRI parameters or imaging characteristics that are helpful to predict the early therapeutic response.Materials and Methods:Part Ⅰ:35 patients with newly diagnosed multiple myeloma in Tianjin first Central Hospital from February 2015 to July 2017 were analyzed retrospectively,including 20males,aged 54.4 years(36-67 years)and 15 females,aged 49.9(32-69 years).Whole body diffusion weighted imaging(WB-DWI)and T1weighted water-fat separation Dixon imaging were performed in all patients before treatment,measured ADC,fat signal value(Mfat)and water signal value(Mwater)in focal lesions(FLs)of the thoracolumbar spine and adjacent normal bone marrow(NABM).The fat fraction(FF)was also calculated by dividing the fat signal value of the focal lesion in the fat image by the sum of the fat signal value(Mfat)and the water signal value(Mwater)of the corresponding site.The standardized fat signal value(nMfat),the standardized water molecule signal value(nMwater)and the standardized fat fraction(nFF)were obtained by standardizing the MRI parameters.The difference of MRI parameters between focal lesions(FLs)and adjacent normal bone marrow(NABM)was compared by Mann-Whitney U test,Spearman correlation test was used to estimate the correlation between the ADC value and the signal value of each parameter of T1 weighted water-fat separation Dixon imaging.In addition,we also explored the correlation between these MRI parameter values and the ratio of bone marrow plasma cells.As a result,it is helpful to evaluate the proliferation of intramedullary plasmacytoma using whole-body MRI.Part Ⅱ:A retrospective analysis of 39 patients with newly diagnosed multiple myeloma in Tianjin first Central Hospital from February 2015 to June 2019 was made.There were 24 males,aged 55.6 years(46-72 years)and 15 females,aged 50.7(42-69 years).All patients underwent whole body diffusion weighted imaging(WB-DWI)and T1 weighted water fat separation Dixon imaging before treatment.Bone marrow puncture were used to detect the ratio of bone marrow plasma cells,the focal lesions of posterior superior iliac spine,thoracolumbar vertebrae,ribs,sternum,scapula,clavicle,femur,sacral vertebra,ischium,humerus,pubis,tibia and skull were counted on whole body MRI images.The whole body diffusion weighted imaging(WB-DWI)and T1 weighted water-fat separation Dixon images with a sufficient number of lesions were confirmed.Finally,the focal lesions in the posterior superior iliac spine and thoracolumbar vertebrae were selected,and the ADC value,fat signal value(Mfat)and water molecule signal value(Mwater)were measured.The fat fraction(FF)is also calculated by dividing the fat signal value of the focal lesion in the fat image by the sum of the fat signal value(Mfat)and the water signal value(Mwater).The standardized fat signal value(nMfat),the standardized water molecule signal value(nMwater)and the standardized fat fraction(nFF)were obtained by standardizing the MRI parameters.Mann-Whitney U test was used to compare the differences of MRI parameters of bone marrow between focal lesions of posterior superior iliac spine and normal bone marrow of contralateral posterior superior iliac spine,and also used to compare the differences of MRI parameters of bone marrow between focal lesions of posterior superior iliac spine and thoracolumbar vertebrae.Spearman correlation analysis was used to evaluate the correlation between ADC value,normalized fat signal intensity(nMfat),normalized water molecular signal intensity(nMwater),normalized fat fraction(nFF)and bone marrow plasma cell ratio in focal lesions of posterior superior iliac spine and thoracolumbar vertebrae,which is helpful to find the bone marrow puncture site of multiple myeloma with MRI.Part Ⅲ:A retrospective analysis of 39 patients with newly diagnosed multiple myeloma in Tianjin first Central Hospital from July 2017 to May 2020,including22males,56.4 years(46-74 years),and 17females,52.1years(46-71years).All patients underwent whole body diffusion weighted imaging(WB-DWI)and T1 weighted water-fat separation Dixon imaging before treatment.39 focal lesions in posterior superior iliac spine and 39 focal lesions in thoracolumbar vertebrae were identified,and their ADC value,fat signal value(Mfat)and water molecule signal value(Mwater)were measured.The fat fraction(FF)is also calculated by dividing the fat signal value of the focal lesion in the fat image by the sum of the fat signal value(Mfat)and the water signal value(Mwater).The standardized fat signal value(nMfat),the standardized water molecule signal value(nMwater)and the standardized fat fraction(nFF)were obtained by standardizing the MRI parameters.At the same time,the imaging features of focal lesions of posterior superior iliac spine and thoracolumbar spine were extracted.Bone marrow smears were used to detect the proportion of bone marrow plasma cells(BMPC).At the same time,the basic clinical data of these newly diagnosed patients(includingβ-2-microglobulin,albumin,Hb,Cr,etc.)were recorded,and the treatment responses of all patients after 4 cycles of chemotherapy were evaluated.According to strict complete remission(SCR),complete remission(CR),Very good partial response(VGPR),partial remission(PR),minor remission(MR)and stable disease(SD),they were divided into deep remission group(SCR,CR,VGPR)and non-deep remission group(PR,MR,SD).The subjects’working characteristic(ROC)curves of baseline ADC value,normalized fat signal intensity(nMfat),normalized water molecular signal intensity(nMwater)and normalized fat fraction(nFF)of focal lesions in posterior superior iliac spine and thoracolumbar vertebrae were drawn.The sensitivity and specificity of area under curve(AUC)were obtained.In addition,the imaging characteristics of MRI parameters were screened by single-factor/multi-factor logistic regression model,and the ROC curve of subjects’working characteristics was drawn according to different therapeutic efficacy,and the area under curve(AUC)was obtained.The area under curve of ROC curve of MRI parameters and imaging characteristics of subjects were compared to find the MRI parameters or imaging characteristics which are helpful to predict the early treatment response of patients with newly diagnosed multiple myeloma.Results:Part Ⅰ:Statistical difference between focal lesions of the thoracolumbar spine and ADC values of adjacent normal bone marrow(0.72 vs 0.33mm~2,p<0.001).Significant increases in nMwater values and decreases in nMfat and nFF values were observed in focal lesions.However,this correlation was not found in adjacent normal bone marrow(p>0.050).The ADC values of focal lesions were highly negatively correlated with nMfat and nFF values(r=-0.899,-0.834),moderately positive correlation with nMwater values(r=0.642),The p values<0.001.In focal lesions,ADC values was highly correlated with the ratio of bone marrow plasma cells(r=0.984),nMfat and nFF values were highly negatively correlated with the ratio of bone marrow plasma cells(r=-0.938 and-0.905),nMwater values was moderately positive correlation with the ratio of bone marrow plasma cells(r=0.716),p values<0.050.Part Ⅱ:Distribution of whole body lesions in 39 patients:posterior superior iliac spine:39/39,thoracolumbar spine:39/39,rib:39/39,sternum:27/39,scapula:23/39,clavicle:23/39,femur:23/39,sacral vertebrae:18/39,ischium:15/39,umeral:12/39,pubic:10/39,tibia:6/39,Skull:4/39.Among them,sternum,scapula,clavicle,femur,sacral vertebrae,ischium,umeral,pubic,tibia,skull lesion less than 39.The posterior superior iliac spine,thoracolumbar spine and rib were all 39 lesions,and the intergroup consistency of rib lesions was poor,so only focal lesions of posterior superior iliac spine and thoracolumbar vertebrae were evaluated.The ADC value,nMfat value,nMwater value and nFF value of the bone marrow involved in the superior iliac spine of the normal lateral iliac spine and the affected superior iliac spine were 0.32 mm~2/s vs 0.74mm~2/s,0.401vs 0.064,2.564vs 3.586,0.145vs 0.013,were statistically different(all p values<0.001);the ADC,nMfat and nFF values were0.74 between posterior superior iliac spine and thoracolumbar lesions,0.74 mm~2/s vs0.73 mm~2/s,0.06 vs 0.06,0.01 vs 0.01,(p values were 0.990,0.350,0.773),nMwater between posterior superior iliac spine and thoracolumbar lesions were 3.59 vs 4.79,respectively There was significant difference(p<0.001);In focal lesions of the posterior superior iliac spine and the thoracolumbar spine,The ratio of bone marrow plasma cells(BMPC)was highly correlated with ADCvalues(r=0.989,0.989),highly negatively correlated with nMfat and nFF values(r=-0.978,-0.930,-0.888,-0.917),The p values<0.001.However,There was no significant correlation between the ratio of BMPC bone marrow plasma cells and the nMwater of focal lesions of superior iliac spine(r=0.144,p=0.382)had a moderate correlation with nMwater of thoracolumbar focal lesions(r=0.645,p<0.001).Part Ⅲ:Among the 39 patients,there were 26 cases in deep remission group and 13cases in non-deep remission group.Baseline ADC values,standardized fat signal values(nMfat),standardized water molecular signal values(nMwater),and standardized fat fraction values(nFF)in predicting early treatment responses in patients with primary multiple myeloma,The area under the working characteristics(ROC)curve of each single parameter is between 0.654～0.74,Among them,The area under the ROC curve of predicting depth reaction with nMwater-tlv value is the highest,The area under the ROC curve combined with two parameters is the highest in the ROC curve ADC-psis+nMwater-psis predicting depth reaction,In the joint parameter,All the parameters of the two parts are combined under the ROC curve,0.769,Imaging features of nuclear magnetic parameters in predicting early treatment responses in patients with primary multiple myeloma,The area under the curve of the working characteristics(ROC)curve is between 0.84～0.983,With ADC-tlv wavelet-HLL＿glszm＿Small Area High Gray Level Emphasis+wavelet-LLL＿glszm＿Smal l Area Emphasis+wavelet-The LLL＿glszm＿Gray Level Non Uniformity is the highest and the area under the ROC curve is 0.983.Conclusion:The quantitative parameters of whole-body diffusion-weighted imaging combined with T1 weighted-fat separation Dixon imaging parameters can be used to assess the relationship between thoracolumbar spine and bone marrow plasma cell(BMPC)ratio of multiple myeloma,among which ADC value is the most sensitive,which is helpful to evaluate the proliferation of multiple myeloma intramedullary plasmacytoma.The whole body MRI can evaluate the distribution of focal lesions in the whole body bone of patients with multiple myeloma.Compared with the parameters of thoracolumbar spine,the correlation betweenMRI parameters and plasma cell ratio of focal lesions of posterior superior iliac spine is higher.Among the MRI parameters,ADC value is the most sensitive,which can help determine the bone marrow puncture site of multiple myeloma.The combination of MRI features based on posterior superior iliac spine and thoracolumbar focal lesions may be used as a non-invasive imaging biomarker to predict the early treatment response of newly diagnosed multiple myeloma. |
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