Correlation Of Structural Geometric Properties Of The Proximal Femur With Hip Fracture And The Value Of MRS, R2~* Of The Proximal Femur Bone Marrow In Evaluating Osteoporosis

PART ONE:Correlation of structural geometric properties of the proximal femur with hip fracture in womenObjective:To evaluate the influence of age and bone mineral density on geometric structure of the proximal femur in women;to study the influence of hip geometry on hip strength and its value in predicting hip fracture.Material and methods:DXA measurements of the proximal femur were obtained from 698 women,73(age: 68.7±9.2) with prior hip fracture and 625(age:66.6±9.3) controls.In addition to the conventional densitometry measurements,structural variables were determined using the Hip Strength Analysis(HSA) program,including cross-sectional area(CSA), cross-sectional moment of inertia(CSMI),femoral neck width(FNW),hip axis length(HAL),neck shaft angle(NSA) and femur strength index(FSI).Results:CSA, CSMI and FSI were negatively correlated with age(r=-0.463,P＜0.01;r=-0.227, P＜0.01;r=-0.087,P＜0.05;respectively).CSA,CSMI,FSI were significantly lower and FNW significantly higher in osteoporotic group compared with healthy group. CSA,CSMI,FSI were significantly lower and FNW significantly higher in the fracture group compared with controls.HAL was significantly longer and NSA significantly narrower in hip fracture group compared with controls.The fracture discrimination ROC curve for the logistic regression probability model incorporating FSI and CSMI was significantly larger than that for T score alone(0.794 vs.0.682, P＜0.01),indicating that fracture discrimination improved when these femur structural variables were combined with BMD measurements.Conclusion:The reduction of the proximal femur strength in aging is not only influenced by bone loss,but also by the changed properties of its hip geometric structure.T score combining with CSMI and FSI may have a more effective capability of predicting hip fracture.PART TWO:Pilot study of correlation between MRS and osteoporosis in proximal femur in womenObjective:The purpose of this research is to investigate the correlation between MRS variables and BMD in proximal femur;to evaluate the diagnostic value of MRS variables for osteoporosis.Materials and methods:Proton MRS and BMD measurement of femoral neck,intertrochanteric and trochanter region of the right proximal femur were performed in 112 female subjects(age:62.14±10.4)。The single voxel PRESS(Point resolved spectroscopy) sequence was used at 3.0T MR imaging. All data were analyzed at SAGE 7.0 program and LWR(Lipid/water ratio),FF(Fat fraction),lipid line width(LW) and lipid unsaturation index(UI) were calculated. BMD measurements of the hip were obtained with DXA.Results:LWR and FF of the neck and intertrochanteric region had significant correlation with age(neck:LWR: r=0.293,FF:r=0.397,P＜0.01;intertrochanteric:LWR:r=0.358,FF:r=0.378,P＜0.01). The correlation of LWR and FF of the two measured regions in proximal femur with age remained significant after adjustment for BMD(neck:LWR:r=0.205,FF:r=0.233, P＜0.05;intertrochanteric:LWR:r=0.235,FF:r=0.253,P＜0.05).LWR and FF of the three measured regions were negatively correlated with BMD(LWR:r=-0.482,-0.401, -0.419,P＜0.01;FF:r=-0.462,-0.333,P＜0.01;r=-0.207,P＜0.05),and the significance remained after adjustment for age except for FF of trochanter region(LWR: r=-0.397,-0.341,-0.344,P＜0.01;FF:r=-0.415,P＜0.01;r=-0.313,P--0.01;r=-0.177, P=0.063).LWR and FF had significant difference between pre-and postmenopausal subgroups with these variables higher in premenopausal women.LWR and FF were significantly lower in healthy group compared with osteopenic and osteoporotic group for neck and intertrochanteric region.No significant difference was observed between osteopenic and osteoporotic groups in these two regions.LWR for trochanter was significantly higher in osteoporotic group compared with healthy and osteopenic groups while no significant disparity was obtained between healthy and osteopenic groups.FF for trochanter had no significant disparity in all three subgroups.Lipid LW of neck and intertrochanteric region was negatively correlated with age(r=-0.302, -0.255,p＜0.01),but the correlation became insignificant after adjustment for BMD(neck region:r=-0.033,p=0.730,intertrochanteric region:r=-0.031,p=0.748). Lipid LW in premenopausal group was significantly higher compared with postmenopausal group.Lipid LW of three measured regions were positively significant with BMD(neck region:r=0.550,P＜0.01;intertrochanteric region:r=0.417, P＜0.01;trochanter region:r=0.409,P＜0.01),and the correlation still remained significant after adjustment for age(neck region:r=0.448,P＜0.01;intertrochanteric region:r=0.350,P＜0.01;trochanter region:r=0.396,P＜0.01).UI of neck and intertrochanteric region were negatively significant with age factor(r=-0.374,-0.334, p＜0.01;respectively) and the correlation remained significant after adjusted for BMD factor(neck region:r=-0.258,P=0.005;intertrochanteric region:r=-0.215,P=0.025).It showed positive correlation between UI of neck and intertrochanteric region and BMD factors(r=0.281,0.308,p＜0.05;respectively) and the correlation remained significant after the age factor was controlled as one partial variable(neck region: r=0.203,P=0.021;intertrochanteric region;r=0.211;P=0.014).It showed no significant correlation between UI of trochater region and age as well as BMD.UI of neck and intertrocanteric region were significantly lower in postmenopausal group compared with premenopausal group.UI of neck and intertrochanteric region were significantly lower in osteoporotic group compared with healthy group.There were no significant disparity between healthy and osteopenic group as well as osteopenic and osteoporotic group for UI of neck and intertrochanteric region.No significant difference was observed for UI of trochanteric region among all three groups.ROC curve area of LWR,FF,lipid LW of the three measured regions for osteoporosis discrimination ranged from 0.728～0.859.ROC curve area of LWR,FF and lipid LW for neck region were larger compared with those of introchanteric and trochanter region.Conclusion:The marrow fat content of proximal femur is positively correlated with age and negatively correlated with BMD.Lipid LW was positively correlated with BMD and has no significant correlation with age.UI of proximal femur has negative correlation with age and positive correlation with BMD.LWR,FF and lipid LW can be used as noninvasive MR variables in evaluation of BMD as well as in determination of osteoporosis.PART THREE:Assessment for osteoporosis with R2~* characteristics in proximal femur in womenObjective:To investigate the correlation of R2* measurement with BMD obtained from DXA in proximal femur,to evaluate the diagnostic value of R2~* for osteoporosis. Material and methods:T2~* map of the proximal femur were obtained at 3.0T MR in 112 women(age:62.1±10.4).A multi-echo gradient echo sequence called MEGRE was used in this study.R2~* values were measured in three regions of interest:femoral neck,intertrochanteric region and trochanter.BMD measurements of the hip were obtained with DXA.Results:The R2~* values of all three regions were negatively correlated to age(femoral neck region:r=-0.521,P＜0.01;intertrochantetic region: r=-0.285,P＜0.01;trochanter region:r=-0.399,P＜0.01).After adjusted for BMD, insignificant correlation was obtained on femoral neck region and intertrochanteric region,while trochanter region still showed significant correlation to age,only to have a lower correlation coefficient(r=-0.199,P＜0.030).The R2~* value of all three measurement regions were significantly correlated to BMD(neck region:r=0.701, P＜0.01;intertrochantetic region:r=0.492,P＜0.01;trochanter region:r=0.550,P＜0.01), even so after adjustment for age(neck region:r=0.572;p＜0.01,intertrochantetic region:r=0.424,p＜0.01;trochanter:r=0.453,p＜0.01).Mean R2~* values were significantly higher in premenopausal group compared with postmenopausal group. Significant difference of R2~* values between all three groups as regard to healthy women,osteopenic women and osteoporotic women were obtained in three proximal femur measurement regions.The ROC curve area for osteoporosis determination was 0.859 for neck region,0.767 for intertrochanteric region and 0.851 for trochanteric.Conclusion:The R2~* values of proximal femur were significantly correlated with BMD,but not to age,indicating that it is a MR variable for noninvasive detection of changes in BMD.The R2~* value of neck region has the largest ROC curve area for discrimination value for osteoporosis compared with intertrochanteric region and trochanter.