目的 探讨MR弛豫技术及参数与双能X线吸收法(DXA)对诊断大鼠骨质疏松模型的优劣.方法 雌性3月龄大鼠30只,按完全随机化方法分为对照组和去势骨质疏松造模组(每组15只).30只大鼠造模前及造模12周后分别行DXA测量,测量参数包括全身骨量(BMC)、全身骨密度(BMD)、左侧股骨骨密度(Hbmdl);造模成型后,在MR 1.5 T成像系统下完成:(1)多回波快速梯度脉冲序列,分别以不同回波间隔测量T_2~*;(2)多回波快速SE序列测量T_2图(T_2map);(3)SE序列测量T_1map;(4)用两样本t检验分析对照组和实验组间各指标参数的差别,用Fisher检验筛选对骨质疏松作用有统计学意义的指标.最后分别提取2组大鼠的股骨做病理组织学检查.结果 (1)病理组织学证实骨质疏松组造模成型;(2)成模后对照组、骨质疏松组间DXA的参数(BMC、BMD、Hbmdl)经Fisher检验,筛选出BMD为判别指标,其判别正确率为86.7%;(3)对照组和骨质疏松组之间所测得的2组MR弛豫数据值[T_2~* 1000、横向弛豫率(R_2~*)1000、T_2~* 500、R_2~* 500、T_2~* 400、R_2~* 400、T_2 ~* 300、R_2~* 300、T_2~* 200、R_2~* 200、T_2~* 100、R_2~* 100、T_2map、R_2map、T_1map]作两样本t检验,t值分别为6.20、4.79、5.18、5.22、5.59、4.37、6.14、5.12、5.09、4.99、5.57、4.84、4.07、2.98、6.75,除R_2map P=0.07以外,其余P值均<0.01,差异有统计学意义;(4)对A、B 2组MR弛豫和双能DXA的17个参数(T_2~* 1000,T_2~* 500,T_2 ~* 400,T_2~* 300,T_2~* 200,T_2~* 100,T_2map,R_2~* 1000,R_2~* 500,R_2~* 400,R_2~* 300,R_2~* 200,R_2~* 100,T_1map,BMC,BMD,Hbmdl)经Fisher检验,17个参数中T_2map和T_1map 2个指标对骨质疏松的表达较佳,其判别正确率为100%.结论 MR的T_2map是骨质疏松的较佳判别指标,在MR弛豫技术的运用中,磁场的稳定性是重要的;而MR弛豫技术与DXA结合可更精确地诊断骨质疏松的程度.
目的 探討MR弛豫技術及參數與雙能X線吸收法(DXA)對診斷大鼠骨質疏鬆模型的優劣.方法 雌性3月齡大鼠30隻,按完全隨機化方法分為對照組和去勢骨質疏鬆造模組(每組15隻).30隻大鼠造模前及造模12週後分彆行DXA測量,測量參數包括全身骨量(BMC)、全身骨密度(BMD)、左側股骨骨密度(Hbmdl);造模成型後,在MR 1.5 T成像繫統下完成:(1)多迴波快速梯度脈遲序列,分彆以不同迴波間隔測量T_2~*;(2)多迴波快速SE序列測量T_2圖(T_2map);(3)SE序列測量T_1map;(4)用兩樣本t檢驗分析對照組和實驗組間各指標參數的差彆,用Fisher檢驗篩選對骨質疏鬆作用有統計學意義的指標.最後分彆提取2組大鼠的股骨做病理組織學檢查.結果 (1)病理組織學證實骨質疏鬆組造模成型;(2)成模後對照組、骨質疏鬆組間DXA的參數(BMC、BMD、Hbmdl)經Fisher檢驗,篩選齣BMD為判彆指標,其判彆正確率為86.7%;(3)對照組和骨質疏鬆組之間所測得的2組MR弛豫數據值[T_2~* 1000、橫嚮弛豫率(R_2~*)1000、T_2~* 500、R_2~* 500、T_2~* 400、R_2~* 400、T_2 ~* 300、R_2~* 300、T_2~* 200、R_2~* 200、T_2~* 100、R_2~* 100、T_2map、R_2map、T_1map]作兩樣本t檢驗,t值分彆為6.20、4.79、5.18、5.22、5.59、4.37、6.14、5.12、5.09、4.99、5.57、4.84、4.07、2.98、6.75,除R_2map P=0.07以外,其餘P值均<0.01,差異有統計學意義;(4)對A、B 2組MR弛豫和雙能DXA的17箇參數(T_2~* 1000,T_2~* 500,T_2 ~* 400,T_2~* 300,T_2~* 200,T_2~* 100,T_2map,R_2~* 1000,R_2~* 500,R_2~* 400,R_2~* 300,R_2~* 200,R_2~* 100,T_1map,BMC,BMD,Hbmdl)經Fisher檢驗,17箇參數中T_2map和T_1map 2箇指標對骨質疏鬆的錶達較佳,其判彆正確率為100%.結論 MR的T_2map是骨質疏鬆的較佳判彆指標,在MR弛豫技術的運用中,磁場的穩定性是重要的;而MR弛豫技術與DXA結閤可更精確地診斷骨質疏鬆的程度.
목적 탐토MR이예기술급삼수여쌍능X선흡수법(DXA)대진단대서골질소송모형적우렬.방법 자성3월령대서30지,안완전수궤화방법분위대조조화거세골질소송조모조(매조15지).30지대서조모전급조모12주후분별행DXA측량,측량삼수포괄전신골량(BMC)、전신골밀도(BMD)、좌측고골골밀도(Hbmdl);조모성형후,재MR 1.5 T성상계통하완성:(1)다회파쾌속제도맥충서렬,분별이불동회파간격측량T_2~*;(2)다회파쾌속SE서렬측량T_2도(T_2map);(3)SE서렬측량T_1map;(4)용량양본t검험분석대조조화실험조간각지표삼수적차별,용Fisher검험사선대골질소송작용유통계학의의적지표.최후분별제취2조대서적고골주병리조직학검사.결과 (1)병리조직학증실골질소송조조모성형;(2)성모후대조조、골질소송조간DXA적삼수(BMC、BMD、Hbmdl)경Fisher검험,사선출BMD위판별지표,기판별정학솔위86.7%;(3)대조조화골질소송조지간소측득적2조MR이예수거치[T_2~* 1000、횡향이예솔(R_2~*)1000、T_2~* 500、R_2~* 500、T_2~* 400、R_2~* 400、T_2 ~* 300、R_2~* 300、T_2~* 200、R_2~* 200、T_2~* 100、R_2~* 100、T_2map、R_2map、T_1map]작량양본t검험,t치분별위6.20、4.79、5.18、5.22、5.59、4.37、6.14、5.12、5.09、4.99、5.57、4.84、4.07、2.98、6.75,제R_2map P=0.07이외,기여P치균<0.01,차이유통계학의의;(4)대A、B 2조MR이예화쌍능DXA적17개삼수(T_2~* 1000,T_2~* 500,T_2 ~* 400,T_2~* 300,T_2~* 200,T_2~* 100,T_2map,R_2~* 1000,R_2~* 500,R_2~* 400,R_2~* 300,R_2~* 200,R_2~* 100,T_1map,BMC,BMD,Hbmdl)경Fisher검험,17개삼수중T_2map화T_1map 2개지표대골질소송적표체교가,기판별정학솔위100%.결론 MR적T_2map시골질소송적교가판별지표,재MR이예기술적운용중,자장적은정성시중요적;이MR이예기술여DXA결합가경정학지진단골질소송적정도.
Objective To evaluate MR relaxometry techniques and dual-energy X-ray absorptiometry (DXA) for the diagnosis of osteoporotic diseases in rats. Methods Thirty 3-month-old female rats were randomly divided (using completely randomized grouping method) into two groups (each contained 15 rats). Animals in group A without osteoporotic castration were included as normal controls, whereas osteoporotic castration was created in each animal in group B. Three parameters (BMC, BMD, Hbmdl)was measured for both groups by DXA at two time points, one immediately before the castration and another at the 12 th week after the castration. Then animals from the control group and the osteoporotic group went through the following three diagnostic procedures using a 1.5 T MR system: (1) A fast multi echo gradient echo (MEGRE) pulse train sequence with different inter-echo intervals (1000, 500, 400, 300, 200, 100) to obtain the T_2~* value. (2) A multi-echo fast spin echo sequence to obtain the T_2map. (3) A conventional spin-echo (CSE) sequence to obtain the T_1map. The statistical difference between group A and group B was tested by t-test to analyze parameters. And, the most significant parameter for diagnosis ofosteoporotic diseases was picked out from all parameters by Fisher Sequential diseriminant analysis. At the end of experiments, animals were killed and histopathological examination was performed on the femurs of animals from both control and osteoporotic groups. Results (1) Histopathological examination confirmed the presence of osteoperosis in all animals in group B. (2) BMD was picked out from 3 DXA parameters (BMC,BMD,Hbmdl) by fisher stepwise discriminant analysis, and its discriminant rates was 87.6%. (3) All 2-sample t-test results(t=6.20, 4.79, 5.18, 5.22, 5.59, 4.37, 6.14, 5.12, 5.09, 4.99, 5.57, 4.84, 4.07, 2.98, 6.75 individually) for MR relaxometry parameters(T_2~* 1000,R_2~* 1000,T_2~* 500,R-2~* 500,T_2~* 400,R_2~* 400,T_2~* 300,R_2~* 300,T_2~* 200, R_2~* 200, T_2~* 100, R_2~* 100, T_2map, R_2map, T_1map) showed statistically significant differences between groups A and B (P=0.01 for T_2~* map, P=0.00 for all other parameters) except the R_2map(P=0.07). (4) Using fisher stepwise discriminafion method in the analysis of 14 parameters of MR relaxometry techniques and 3 parameters of dual X-ray absorptiometry(T_2~* 1000,T_2~* 500,T_2~* 400,T_2~* 300,T_2~* 200,T_2~* 100,T_2map, R_2~* 1000, R_2~* 500, R_2~* 400, R_2~* 300, R_2~* 2OO, R_2~* 100,T_1map,BMC,BMD,Hbmdl), we found that the most significant difference was from the T_2map and T_1map. Conclusions The MR relaxometry parameter-T_2map in the present study is shown to be appropriate parameter for the diagnosis of osteoperotie diseases, and stability of magnetic field plays an important role in this process. It would be the optimal method to make a diagnosis of osteoporotic diseases with both MR relaxometry and DXA technological means.
