VERTEBRAL MINERAL DETERMINATION BY QUANTITATIVE COMPUTED-TOMOGRAPHY (QCT) - ACCURACY OF SINGLE AND DUAL ENERGY MEASUREMENTS
VERTEBRAL MINERAL DETERMINATION BY QUANTITATIVE COMPUTED-TOMOGRAPHY (QCT) - ACCURACY OF SINGLE AND DUAL ENERGY MEASUREMENTS
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DOI：
10.1097/00004728-198803000-00013
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发表时间：
1988-03-01
影响因子：
1.3
通讯作者：
GENANT, HK
中科院分区：
文献类型：
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作者：
GLUER, CC;REISER, UJ;GENANT, HK
在GE CC/T 9800型扫描仪上对体外培养的松质骨组织进行了定量CT（QCT）研究。将单能（SE）80 kVp和双能（DE）80/140 kVp QCT数据的结果与化学矿物分析进行比较，以确定准确性。我们检查了28具尸体（19名男性和9名女性，年龄范围为19-93岁，平均= 60.4）的62个椎体标本。将同一个人所有椎体的结果平均为SEQ CT与灰分重量，我们发现相关系数（r）为0.94（p < 0.0001），估计值的标准误差（SEE）为12.2 mg/cm 3（校准为K2 HPO 4），变异系数（CV）为13.2%，骨矿物质含量平均低估为18.7 mg/cm 3。相应的DEQCT结果为r=0.98（p < 0.0001），SEE = 7.4 mg/cm 3，CV= 7.0%，平均低估4.9 mg/cm 3。SE和DE结果相关性r=0.98（p < 0.0001），SEE=8.0 mg/cm 3，CV= 8.7%。根据我们的SEQID CT数据以及骨矿物质和脂肪含量的化学分析结果，我们计算出扫描仪的脂肪灵敏度为7.7 mg/cm 3 K2 HPO 4/100 mg/cm 3脂肪变化。使用87.5 mg/cm 3的平均脂肪变异性，这导致6.7 mg/cm 3的标准性SEQID CT数据的脂肪相关不确定性，其远低于29.4 mg/cm 3的正常生物变异。使用来自五个合作中心的188个椎骨标本的脂肪含量与年龄和矿物质含量的表格标准化数据，我们推导出了QCT测量的校正算法，将我们的平均低估降低到0.88 mg/cm 3，SEE为12.1 mg/cm 3。因此，该校正程序可用于估计脂肪校正的绝对矿物质密度，以用于研究目的或用于具有高脂肪灵敏度的扫描仪。对于GE CT/T 9800扫描仪，在80 kVp时脂肪对矿物质的灵敏度相对较低，通常不建议将校正程序用于临床研究，因为它最大限度地减少了平均脂肪引起的误差，但没有减少剩余的、部分脂肪相关的不确定性。最后，由于脂肪相关的不确定性与生物学变异相比较小，因此SEQID CT和DEQCT之间的相关性较高，并且SEQID CT的辐射剂量较低，精度较高，因此我们建议大多数使用GE CT/T 9800扫描仪进行骨矿物质测定的临床诊断研究采用80 kVp的SEQID CT。
Quantitative CT (QCT) studies of trabecular vertebral bone tissue have been carried out in vitro on a GE CC/T 9800 scanner. Results of both single energy (SE) 80 kVp and dual energy (DE) 80/140 kVp QCT data are compared with chemical mineral analysis to determine accuracy. We examined 62 vertebral specimens, from 28 cadavers (19 male and 9 female with an age range of 19-93 years, mean = 60.4). Averaging the results of all vertebral bodies of the same individual for SEQCT versus ashweight, we found a correlation coefficient (r) of 0.94 (p < 0.0001), a standard error of the estimate (SEE) of 12.2 mg/cm3 (calibrated to K2HPO4), with a coefficient of variation (CV) of 13.2% and an average underestimation of bone mineral content of 18.7 mg/cm3. The corresponding DEQCT results were r=0.98 (p < 0.0001), SEE = 7.4 mg/cm3, CV=7.0%, and an average underestimation of 4.9 mg/cm3. The SE and DE results are correlated with r=0.98 (p < 0.0001), SEE=8.0 mg/cm3, and CV=8.7%. From our SEQCT data and the results of the chemical analysis of bone mineral and fat content we calculated a fat sensitivity of 7.7 mg/cm3 K2HPO4 per 100 mg/cm3 fat change for our scanner. Using an average fat variability of 87.5 mg/cm3, this leads to a fat-related uncertainty for the normative SEQCT data of 6.7 mg/cm3, which is far lower than the normal biological variation of 29.4 mg/cm3. Using tabulated normative data on fat content versus age and versus mineral content of 188 vertebral specimens from five collaborating centers, we derived a correction algorithm for QCT measurement that reduces our average underestimation to 0.88 mg/cm3 with an SEE of 12.1 mg/cm3. Hence, this correction procedure can be used to estimate the fat corrected absolute mineral density for research purposes or for scanners with high fat sensitivity. For the GE CT/T 9800 scanner, with a relatively low fat to mineral sensitivity at 80 kVp, the correction procedure is generally not recommended for clinical studies since it minimizes the average fat induced error but does not reduce the residual, partially fat related uncertainty. Finally, since the fat related uncertainty is small compared to biological variation, the correlation is high between SEQCT and DEQCT, and the radiation dose is lower and the precision higher for SEQCT, we suggest that most clinical diagnostic studies using the GE CT/T 9800 scanner for bone mineral determination employ SEQCT at 80 kVp.