The assessment of quantitative MR imaging contributing to diagnosis in postmenopausal women with osteoporosis and at risk of osteoporosis

The purpose of this study was to compare imaging findings of bonemineral densitometry and quantitative MR imaging (MRI) in postmenopausalwomen with osteoporosis and at risk of osteoporosis and to investigate theeffectiveness of quantitative MRI.87 postmenopausal women who are normal, osteopenic and osteoporoticbased on the results of DXA were included to the study. Their ages were between42-83 years (mean 59,7). 85 patients were studied by MRI of lumbar spine and 86were studied by MRI of hip. All of the cases were at postmenopausal period. Bonemineral density measurements were performed with DXA (GE Medical SystemsDPX Lunar) at lumbar spine (L1-L4), right femoral neck, ward?s, trochanter andintertrochanteric regions. All MR examinations were performed on 1,5 T imagingsystem (Signa Exite 1.5T, GE Medical Systems Wisconsin ,WI, USA). T2relaxation time measurements were obtained with using FSE-XL sequence in thesagittal plane for lumbar spine and using FSE-XL sequence in the coronal planefor hip. Pixels? avarege T2 relaxation time maps were obtained from the total of5-echo signals. T2* relaxation time measurements were obtained with using MFGREsequence in the sagittal plane for lumbar spine and using MF-GRE sequencein the coronal plane for hip. Pixels? avarege T2* relaxation time maps wereobtained from the total of 16-echo signals. T2 and T2* relaxation timemeasurements were performed at L1-L4 vertebral bodies, right femoral neck,ward?s, trochanter and intertrochanteric regions. T2 relaxation measurementsobtained from the L1-L4 vertebral bodies showed statistically significantdifferences and a significant negative corelation was seen between the T2relaxation measurements and BMD (g/cm²) values. Statistically significantdifference between groups in the measurement of T2* relaxation times andsignificant correlation values in comparision with BMD values were not detected.There were no statistically significant differences and correlations between groupsin T2 and T2* relaxation measurements obtained from the MRI of the hip.In our study it was concluded that T2 relaxation time measurements fromL1-L4 regions can be used to discriminate patients with postmenopausalosteoporotic from postmenopausal normal and osteopenic groups. T2 relaxationtime measurements from the right femur was not able to give the correct results todistinguish the postmenopausal osteoporotic patients. Because of T2*measurements from the lumbar spine and right femur can be affected byinhomogeneity of local magnetic field, T2* measurements does not help todetermine the level of bone mineralization.Key Words: Magnetic rezonans imaging; Osteoporosis; Dual-Energy X-RayAbsorptiometry