Vertebral bone mineral measurement using dual photon absorptiometry and computed tomography

The lumbar spine of 14 cadavers was studied both by 153Gd dual photon absorptiometry (DPA) and quantitative computed tomography (QCT) at 96 and 125 kVp. The intact spine and the individual vertebrae were analyzed. After these measurements the ash content of the vertebral body, the posterior elements, and the transverse processes was determined. The fat content of the vertebral body as well as its volume was also measured. With DPA, the bone mineral content (BMC) determined in situ as well as on excised spine specimens correlated highly with the amount of total vertebral ash (r greater than 0.92, SEE less than 3.2 g). The bone mineral density (BMD, area density) of 3 lumbar vertebrae correlated accurately with the mean ash density of the vertebral body (r greater than 0.81, SEE less than 0.015 g/cm3). The so-called corpus density and central density determinations were less accurate. No difference in accuracy was found between measurements when using 3 mm and 4.5 mm step intervals. Variations in the distribution of mineral between the vertebral body and the posterior elements contribute to the error in predicting vertebral body mineral with DPA. QCT gave a smaller error when a cylindric portion of the vertebral body with a 20 mm diameter was measured compared with one with a 9 mm diameter, when the dual energy technique was used (p less than 0.01). With dual energy QCT a correlation was found between a center segment of 3 vertebrae in the lumbar spine and the mean ash density of the vertebral body of r = 0.92 (SEE = 0.010 g/cm3).(ABSTRACT TRUNCATED AT 250 WORDS)     

Mineral content of the spongiosa of the lumbar spine determined by computer tomography. Normal values for healthy perimenopausal women and their relation to mechanical stress of the vertebral column

Healthy perimenopausal women (152) were examined by QCT to quantify the mineral content of the axial skeleton. The density was measured in the spongiosa of the L2-4, using single energy technique and the Cann-Genant calibration phantom. The women, aged 37 to 64, had no history of pathological fractures, ovariectomy, metabolic disease, or hormone therapy. The age-related mean values were 25 mg K2HP04/cm3 lower than the normal values reported by Genant et al. for 203 healthy American women. The 95% confidence interval was distinctly narrower (+/- 40 mg/cm3) than the American confidence interval (+/- 60 mg/cm3). To evaluate the relationship of the BMC to mechanical stress, the BMC was compared with body weight, body mass index (weight/height2), and the lumbar muscle mass estimated from cross sections of the paravertebral muscles in the CT images. The assumption that higher mechanical stress results in higher bone mineralization could not be confirmed.     

Effect of Paget's disease of bone on areal lumbar spine bone mineral density measured by DXA, and density of cortical and trabecular bone measured by quantitative CT

Although bone density may be increased in bone that is affected by Paget's disease, density changes in cortical and trabecular bone and the effect on bone that is apparently unaffected by Paget's disease are relatively unexplored. We have investigated 81 vertebrae (28 affected, 53 unaffected) in 27 patients with Paget's disease, by dual X-ray absorptiometry (DXA) and by quantitative CT (QCT) bone density measurements of trabecular and cortical bone. DXA bone density was high (mean z-score = 1.62, p < 0.001) in vertebrae affected by Paget's disease, but not significantly different from normal in unaffected vertebrae (mean z-score = 0.07, ns). Mean QCT z-score in Paget's vertebrae was 2.07 (p = 0.009) for cortical bone and 1.37 (p = 0.008) for trabecular bone. DXA correlated with QCT cortical values in affected and unaffected bone (r = 0.8 and 0.56, respectively), and with QCT trabecular values (r = 0.72 and 0.48, respectively). There was no significant difference in the slopes for the correlations in affected or unaffected bone. Cortical QCT values are underestimated in Paget's disease compared with physical measurements of density, owing to the computer algorithm used. High DXA values may alert to the possibility of Paget's disease, especially if the value deviates from the expected normal sequence in lumbar vertebrae. Osteoporotic vertebrae may be overlooked if the average value of bone mineral density is taken in the lumbar spine without reviewing each vertebra.     

老年男性腰椎的QCT骨密度测量

目的:探讨老年男性腰椎定量CT(QCT)骨密度(BMD)测量的价值及其应用中的注意事项。方法:对516例老年男性进行腰椎体松质骨的QCT骨密度测量。检查时通过L_(1～5)椎体中心和腰椎体模中心行轴位扫描。然后对各椎体及体模图像进行测量。所得数据由腰椎骨密度分析软件分析处理,得出个体腰椎的平均骨密度值及T-Score值、Z-Score值,再将其结果与正常人群的骨密度峰值进行比较,经分析得出诊断结论。诊断标准参照WHO的标准及国内推荐的标准执行。结果:516例中骨密度正常者24例,占4.7%;骨密度降低者109例,占21.1%;骨质疏松症者318例,占61.6%;严重骨质疏松症者65例,占12.6%。结论:腰椎体松质骨的QCT骨密度测量可较早地反映出老年男性体内骨矿含量的变化,对早期发现和确诊老年男性的骨质疏松症具有十分重要的价值。在QCT检查中,需高度重视测量质量的控制。     

Relationships of cervical, thoracic, and lumbar bone mineral density by quantitative CT

PURPOSE: The purpose of this work was to compare, using quantitative CT (QCT), vertebral bone mineral density (BMD) in the cervical, thoracic, and lumbar spine in healthy volunteers. METHOD: QCT of the vertebral bodies of C2, C5, T12, and L4 was performed on 50 healthy volunteers (25 women, 25 men; mean age 31.7 years). Trabecular BMD analysis was performed at each level. RESULTS: Mean BMDs (mg/cm3 calcium hydroxyapatite) for women and men were highest at C5 (BMD women/men 341.6/300.6 mg/cm3) and C2 (297.2/269.6 mg/cm3) and lowest at T12 (193.1/184.9 mg/cm3) and L4 (186.2/180.1 mg/cm3). The BMD of C2 was statistically significantly different from that of C5, T12, and L4 (p < 0.0001) for both genders. Also, the BMD of C5 differed significantly from that of T12 and L4 (p < 0.0001). The BMD of C5 showed significant gender differences (p = 0.002). Correlation coefficient showed a strong correlation between the BMD of T12 and L4 for both genders (women, r = 0.67; men, r = 0.90). CONCLUSION: Trabecular BMD of C2 and C5 measured by QCT is significantly higher than trabecular BMD of T12 and L4 in nonosteoporotic volunteers of both genders.     

Quantitative computed tomography

Quantitative computed tomography (QCT) is an established technique for measuring bone mineral density (BMD) in the axial spine and peripheral skeleton (forearm, tibia). QCT can determine in three dimensions the true volumetric density (mg/cm 3) of trabecular or cortical bone at any skeletal site. However, because of the high responsiveness of spinal trabecular bone and its importance for vertebral strength, QCT has been principally employed to determine trabecular BMD in the vertebral body. QCT has been used for assessment of vertebral fracture risk, measurement of age-related bone loss, and follow-up of osteoporosis and other metabolic bone diseases. This article reviews the current capabilities of QCT at different skeletal sites and the recent technical developments, including volumetric acquisition.     

Effect of bone distribution on vertebral strength: assessment with patient-specific nonlinear finite element analysis

Three-dimensional quantitative computed tomographic (QCT) studies of the lumbar spine were extended with finite element analysis (FEA) to include bone distribution in assessment of vertebral body strength. Fifty-nine FEA models were created from data from 43 patients, 28 with no evidence of osteoporosis and 15 with previous vertebral fractures. Simulated loads were applied to the vertebral models to estimate vertebral strength. Yield strength in the models from patients with osteoporosis was 0.22-1.05 MPa (average, 0.57 MPa +/- 0.26 [mean +/- standard deviation]), compared with 0.80-2.79 MPa (1.46 +/- 0.52, P less than .001) in patients with normal bone. Yield strength of vertebrae in patients with osteoporosis uniformly fell below approximately 1.0 MPa, with minimal overlap between patients with osteoporosis and those with normal bone compared with the overlap in bone mineral content and trabecular mineral density. Reproducibility of the FEA technique was 12.1% in a subgroup of patients with normal bone. A constant relationship between cortical and trabecular contributions was observed in patients with osteoporosis but not in control patients.     

Determination of bone mineral density in the third lumbar vertebral body using photon absorptiometry techniques

Dual-photon absorptiometry and triple-energy X-ray absorptiometry were used to investigate the total bone mineral content and density as well as the trabecular bone mineral density in the third lumbar vertebral body. Both anteroposterior (AP) and lateral (LAT) measurements were performed. By combining the two projections it was found that the mean trabecular bone mineral density for all 202 subjects included in the study was 52% (SD±20%) of the total bone mineral density in the third lumbar vertebral body. The mean trabecular bone mineral density as a fraction of the total vertebral body bone mineral density decreased as a function of age. The relative annual change in this fraction differed between males and females. It was also found that neither trabecular nor total bone mineral density differed significantly between male and female subjects aged 25–35 years, and bone mineral density (BMD), expressed in g/cm³, showed no correlation to subject height, body weight or body mass index (BMI). Male and female individuals showed different rates of change of trabecular bone mineral density with age.     

Assessment of the bone mineral density in the lumbar vertebrae of newborns by quantitative computed tomography

 Objective. To assess the true mineral density (BMD, in g/cm³) of the lumbar spine in newborns. Design and patients. A post-mortem analysis of five infants with gestational ages ranging from 35 to 40 weeks, and birth weights from 2765 to 3200 g, was conducted using dual-energy quantitative computed tomography (QCT; Siemens Somatom DR). A 2 or 4 mm thick slice was obtained for each lumbar vertebra from L1 to L4. The density measured in these vertebrae was corrected by reference to a solid phantom (Osteo-CT) measured simultaneously. A three-dimensional image of the spine (Elscint CT Twin), as well as a photomicrograph of histological preparation from L2 vertebra, were also obtained in another term baby for comparison with the CT results. Results and conclusions. In the range of values studied, the vertebral densities were not dependent on birth weight. BMD values measured in L2, L3 and L4 were not significantly different, but were 10% lower than in L1 in four of five infants. The spatial resolution of the QCT protocol used (0.4 mm) did not permit the differentiation of trabecular and cortical bone, and the vertebral bodies appeared very homogeneous and dense, with a mean density value of 210±30 mg Ca/cm³, which is 2.5 times higher than the mean maximum value found in young normal adults. These preliminary results highlight the potential of QCT in neonatology. Special protocols will, however, need to be developed for in vivo measurements in this particular paediatric field.     

Radiation osteoporosis — an assessment using single energy quantitative computed tomography

Radiation osteoporosis was assessed with single energy quantitative computed tomography (QCT) on 23 patients with cervical cancer. Eleven cases formed the radiation group, who received irradiation to the lumbar column. The other 12 cases formed the control group and were not irradiated. The absorbed dose to the lumbar column was 45 Gy over 5 weeks in nine cases and 22.5 Gy over 5 weeks in two cases. Bone mineral content (BMC) at the 3rd lumbar vertebra was scanned with QCT. BMC reduction was substantial in the radiation group and not evident in the control group. The mean reduction of the former was 52 mg/cm³ at the end of irradiation. The differences in changes of BMC between the two groups was statistically significant (p = 0.01). The two cases who received 22.5 Gy revealed similar BMC reduction to those who received 45 Gy. QCT performed at the end of irradiation demonstrated that more than 22.5 Gy over 5 weeks induced substantial osteoporotic changes.This paper was presented in part in ECT'91 Correspondence to: K. Nishiyama     

Accuracy of lumbar spine bone mineral content by dual photon absorptiometry

The accuracy of measurement of the bone mineral content (BMC, g) and bone mineral density (BMD, g/cm2) of the lumbar spine by dual photon absorptiometry (DPA) was estimated by means of two different spine scanners (a Nuclear Data 2100 and a Lunar Radiation DP3). The lumbar spines of 13 cadavers were used. BMC and BMD were measured in situ and on the excised vertebrae in a solution of water/ethanol; and covered with ox muscle/porcine muscle/lard. The actual mineral weight and areal density were determined after chemical maceration, fat extraction, drying to a constant weight, ashing for 24 hr at 600 degrees C, and correction for the transverse processes. The true are was measured by parallax free X rays and planimetry. All measurements of BMC or BMD were highly interrelated (r = 0.94-0.99). The standard error of estimate (s.e.e.) of BMC in situ versus BMC in water/ethanol was 5.2%. The agreement between the BMD values of the two scanners was very good (s.e.e. = 2.9%). BMC in situ predicted the actual vertebral mineral mass with an s.e.e. of 8.1%. BMD in situ and BMD in water/ethanol predicted the actual area density with s.e.e.s of 10.3% and 5.0%, respectively. This study discloses the correlation and accuracy error of spinal DPA measurements in situ in whole cadavers versus the actual BMC and BMD. The error, which is underestimated in in vitro studies, amounts to 10%.     

Evaluation of bone mineral density with dual energy quantitative computed tomography (DEQCT)

Quantitative computed tomography (QCT) has been found useful in the evaluation of vertebral bone mineral density (BMD). It separates cortical from trabecular bone in the vertebral bodies. The accuracy of QCT, however, is limited because of the existence of unknown amounts of marrow fat in the trabecular bone. The purpose of this study is to investigate the precision and accuracy of QCT, with a particular emphasis on the advantage of dual energy technique over single energy technique, as well as to investigate age-related change of BMD in patients with no metabolic disorders. For evaluation of BMD, SOMATOM DR-H CT scanner was used, which provided dual energy scan with rapid kilovolt peak switching system. The lumbar vertebrae (L1-L3) were exposed at the middle portion together with the calibration phantom (Ca10(PO4)6(OH)2 200 mg/ml, 0 mg/ml). KV-separated images (KV-HI, KV-LO) and material-separated images (MAT-HI, MAT-LO) were calculated from dual-energy scan data. KV-separated data were considered as SEQCT data. In experiment, dipotassium hydrogen phosphate (K2HPO4) solution was used to simulate bone mineral, water to simulate lean soft tissue and ethanol (C2H5OH) to simulate fat. To investigate the variations originating from marrow fat, a series of phantoms (K2HPO4-C2H5OH-H2O mixtures) with a constant 10 gm% K2HPO4 concentration but with the various mixtures of C2H5OH ranging from 0-40% by volume was scanned with dual energy technique. The value of BMD obtained from KV-separated data was reduced about 12% per 10% fat by volume increase, while the value obtained by DEQCT technique was reduced 5.5% per 10% fat by volume increase. With the dual energy technique the error was greatly reduced. On the other hand, the higher precision of KV-separated images compared to MAT-HI images was obtained, as well as the relatively higher precision for determining high rather than low fraction of mineral. In conclusion, with the single energy technique, precision is high, and with the dual energy technique, accuracy is high. It was also noted that selection of the CT section was the most critical factor in clinical BMD analysis. Age-related change of BMD in vertebral trabecular and cortical bone was studied in 161 patients without bone metabolic disorders. There were two peaks of BMD in females in their 20s and 30s, and a single peak in males in their 20s.(ABSTRACT TRUNCATED AT 400 WORDS)     

MR扩散加权成像评估椎体骨量状况的初步研究

目的 探讨椎体MR扩散加权成像(DWI)测量值与双能X线(DXA)、定量GT(QCT)所测骨密度的相关性.方法 152例女性志愿者分别进行以下检查:胸腰椎侧位(T4～L4)X线平片,并采用Genant半定量法对其进行评阅;腰椎(L2～L4)DXA和QCT骨密度测量;腰椎常规行MR矢状面T2 WI、T1 WI和横断面T2 WI扫描;MR常规扫描结束后采用单次激发自旋回波平面回波扩散加权序列(SS-SE-EPI DWI)[扩散敏感因子(b)=500 s/mm2]进行L2～L4椎体横断面DWI扫描,并使用GE-Functool分析软件测量相应椎体表观扩散系数(ADC值).计量资料间的相关性采用Pearson相关分析.结果 随年龄增加,椎体ADC值呈逐步降低趋势.L2～L4椎体平均ADC值(0.241×10-3 mm2/s)与相应椎体平均骨密度DXA(I.038 s/cm2)、QCT(104.2 mg/cm3)具有相关性(r值分别为0.461、0.731,P值均＜0.01).结论 DWI可在常规2腰椎MRI基础上无创性评估椎体骨髓变化状况,进而来评估骨髓的变化对于骨量状况所带来的影响.     

SAPHO syndrome: MR appearance of vertebral involvement

PURPOSE: To retrospectively evaluate the magnetic resonance (MR) imaging findings of vertebral involvement in patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. MATERIALS AND METHODS: Ethics committee approval and informed patient consent were not required for this retrospective study. MR images obtained in 12 patients (seven female, five male; mean age, 42 years; range, 16-65 years) with SAPHO syndrome involving the spine were reviewed. One vertebral lesion separated by one or more normal vertebrae was analyzed as a distinct lesion. For each lesion, the number of associated vertebrae with abnormal signal intensity (SI) (ie, single vertebra, two adjacent vertebrae, or more than two adjacent vertebrae) was noted. The following MR imaging findings were evaluated: cortical bone erosion, abnormal vertebral body SI compared with normal vertebral body SI, increased anteroposterior diameter of the vertebral body, soft-tissue involvement, vertebral body height loss of more than 30%, and abnormal SI of the adjacent intervertebral disk compared with the SI of the other disks. RESULTS: Of 24 vertebral lesions found, 17 involved a single vertebra, four involved two adjacent vertebrae, and three involved three or four adjacent vertebrae. Vertebral corner cortical erosion was present in all lesions, and 23 (96%) lesions had anterior vertebral corner involvement. The erosion was confined to a vertebral corner in five (21%) lesions and included the adjacent endplate and/or the anterior cortex of the vertebral body in the remaining 19 (79%) lesions. In four (17%) lesions, involvement of two adjacent vertebral corners on either side of an intervertebral disk mimicked to some extent early disk space infection. An adjacent disk space was narrowed in six (25%) lesions and exhibited abnormal SI in two (8%). Prevertebral tissue thickening was observed in eight (33%) lesions. CONCLUSION: Erosion of a vertebral body corner is consistently seen on MR images of SAPHO vertebral lesions and may support the diagnosis of SAPHO syndrome in the appropriate clinical context.     

Measurement of bone mineral content and bone density in healthy twelve-year-old white females.

Bone mineral content (BMC) and bone mineral density (BMD) measurements were made by dual-energy x-ray absorptiometry (DEXA) in 112 healthy 12-yr-old white girls for the purposes of: (1) establishing reference data on total-body mineral content of 12-yr-old girls and (2) comparing the lumbar spinal bone density values from a dedicated scan with the lumbar region of interest bone density values from a whole-body scan. Total BMC ranged from 799 g to 2083 g with mean and median values of 1276 g and 1218 g. Total-body bone density ranged from 0.75 to 1.03 g/cm2 with mean and median values of 0.88 and 0.87 g/cm2. The mean and median lumbar bone density values from the lumbar scan mode were 0.74 and 0.73 g/cm2 and were not significantly different from the mean and median lumbar bone density values of 0.71 and 0.70 g/cm2 obtained from the region of interest data from the total-body scan. These results establish baseline bone mass and bone density values for our longitudinal study of bone accretion in young women and validate the use of lumbar vertebral bone density values obtained from whole-body scans.     

Bone mineral content in early-postmenopausal and postmenopausal osteoporotic women: comparison of measurement methods

To investigate associations among methods for noninvasive measurement of skeletal bone mass, we studied 40 healthy early postmenopausal women and 68 older postmenopausal women with osteoporosis. Methods included single- and dual-energy quantitative computed tomography (QCT) and dual-photon absorptiometry (DPA) of the lumbar spine, single-photon absorptiometry (SPA) of the distal third of the radius, and combined cortical thickness (CCT) of the second metacarpal shaft. Lateral thoracolumbar radiography was performed, and a spinal fracture index was calculated. There was good correlation between QCT and DPA methods in early postmenopausal women and modest correlation in postmenopausal osteoporotic women. Correlations between spinal measurements (QCT or DPA) and appendicular cortical measurements (SPA or CCT) were modest in healthy women and poor in osteoporotic women. Measurements resulting from one method are not predictive of those by another method for the individual patient. The strongest correlation with severity of vertebral fracture is provided by QCT; the weakest, by SPA. There was a high correlation between single- and dual-energy QCT results, indicating that errors due to vertebral fat are not substantial in these postmenopausal women. Single-energy QCT may be adequate and perhaps preferable for assessing postmenopausal women. The measurement of spinal trabecular bone density by QCT discriminates between osteoporotic women and younger healthy women with more sensitivity than measurements of spinal integral bone by DPA or of appendicular cortical bone by SPA or CCT.     

绝经期女性胸腰椎后凸与椎体压缩骨折相关性分析

目的探讨绝经期女性骨质疏松骨折的临床特点,以及胸腰段脊柱力线对骨折发生的风险分析。方法本研究为病例对照研究,收集自2013年1月至2015年6月因骨质疏松性压缩骨折在北京积水潭医院住院,并行椎体成形术的绝经期女性患者396例(研究组),平均年龄64岁(55~72岁);对照组选取因下腰椎退行性疾病住院手术的患者271例,平均年龄62岁(55~84岁)。记录所有患者入院时的年龄、体质量指数(BMI)、骨密度定量CT(QCT)、骨折椎体。利用站立位X线影像测量胸腰段(T11~L2)矢状位和冠状位的Cobb角。利用患者胸腰段椎体的平均Cobb角,修订并推算骨折前患者T11~L2的矢状位和冠状位Cobb角。分析胸腰段骨质疏松性骨折的临床点和危险因素。结果研究组患者中,T11椎体骨折患者69例(19.6%),T12椎体骨折153例(43.5%),L1椎体骨折174例(49.4%),L2椎体骨折70例(19.9%)。研究组和对照组患者的年龄和BMI差异无统计学意义(P>0.05)。研究组患者修订后的胸腰段矢状位Cobb角为(13.6°±7.6°),对照组为(5.9°±6.0°),两组间差异有统计学意义(P<0.01)。研究组患者修订后胸腰段冠状位Cobb角为(0.4°±4.0°),对照组为(0.1°±4.1°),两组间差异无统计学意义(P>0.05)。使用ROC曲线和尤登指数计算胸腰段矢状位Cobb角,对于胸腰椎骨质疏松性骨折的最佳分界值为7.5°,OR值为7.6(95%可信区间为2.5~22.8)。结论胸腰段矢状位后凸会增加骨质疏松性骨折的风险,后凸Cobb角度>7.5°时,骨折风险增加7倍,但冠状位的侧弯不增加骨折的风险。     

Quantitative computed tomography: comparative study using different scanners with two calibration phantoms.

To assess computed tomography (CT) scanners in vertebral quantitative computed tomography (QCT) measurement, five cadaveric vertebrae fixed in a water phantom were measured using 16 CT scanners of 10 different models using two types (CaCO3 and K2HPO4) of reference phantom. Although the same reference phantoms were used, the QCT values varied markedly depending on the CT scanner employed. The differences in QCT values were greater in the equivalent amount of CaCO3 than in that of K2HPO4. The largest difference between CT scanners was 40 mg/cm3 in the equivalent amount of CaCO3 and 28 mg/cm3 in that of K2HPO4. These differences were reflected among CT scanners by different slopes and intercepts of the reference lines of CaCO3, K2HPO4 and ash density depending on the CT scanner used. However, good correlations (r greater than 0.97) were observed for the QCT values obtained by various CT scanners. These results show that QCT values on one machine can be compared more closely with those of another machine if conversion formulae, determined by using materials equivalent to human vertebral bone, are employed.     

Comparative bone density measurements in healthy women and women with osteoporosis

To compare methods of noninvasive measurement of bone mineral content, 40 healthy early postmenopausal women and 68 postmenopausal women with osteoporosis were studied. The methods included mono- and dual-energy quantitative computed tomography (QCT) and dual-photon absorptiometry (DPA) of the lumbar spine, single-photon absorptiometry (SPA) of the distal third of the radius, and combined cortical thickness (CCT) of the second metacarpal shaft. Lateral thoracolumbar radiographic studies were performed and the spinal fracture index calculated. There was good correlation between QCT and DPA methods in early postmenopausal women and moderate correlation in postmenopausal osteoporotic women. Correlations between spinal measurements (QCT or DPA) and appendicular cortical measurements (SPA or CCT) were moderate in healthy women and poor in osteoporotic women. Measurements resulting from one method were not predictive of measurements obtained by another method for individual patients. The strongest correlation with severity of vertebral fracture was provided by QCT and the weakest by SPA. There was good correlation between single- and dual-energy QCT results. Osteoporotic women and younger healthy women can be distinguished by the measurement of spinal trabecular bone density using QCT, and this method is more sensitive than the measurement of spinal integral bone by DPA or of appendicular cortical bone by SPA or CCT.     

Comparison of vertebral morphometry in the lumbar vertebrae by T1-weighted sagittal MRI and radiograph

PURPOSE: In this study, we investigated the usefulness of T1-weighted sagittal MR images at the lumbar vertebrae in the vertebral morphometry, in comparison with lateral radiographs. SUBJECTS AND METHODS: The subjects were 42 men (mean age: 53.0 years) and 41 women (mean age: 57.9 years). Both MRI and radiography of the lumbar spine were performed within 1 month. The vertebral body heights and their ratios were measured by the semi-automatic measuring system. The frequency of a vertebral fracture and the absolute value of vertebral body height in both morphometry were compared. RESULTS: Based on the criteria for prevalent vertebral fracture using vertebral height ratios, the vertebrae were classified into four groups. Group 1 was defined as the vertebrae without fracture (n=347 vertebrae). Groups 2-4 were defined as the vertebrae with fracture; Group 2 by both MRI and X-ray morphometry (n=17), Group 3 by MRI morphometry alone (n=17), and Group 4 by X-ray morphometry alone (n=4). The rate of prevalent vertebral fracture diagnosed by MRI morphometry (8.8%) was higher than that by X-ray morphometry (5.5%). In Group 1, the values of anterior and posterior vertebral height obtained by MRI morphometry were greater than those obtained by X-ray morphometry. On the other hand, the values of central vertebral height obtained by MRI morphometry were smaller than those obtained by X-ray morphometry. CONCLUSION: Severe biconcave deformity of vertebra can be detected by both MRI and X-ray morphometry, although mild biconcave deformity can be detected only by MRI morphometry.