Correlation of radiographic and MRI parameters to morphological and biochemical assessment of intervertebral disc degeneration
Correlation of radiographic and MRI parameters to morphological and biochemical assessment of intervertebral disc degeneration
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DOI：
10.1007/s00586-004-0759-4
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发表时间：
2005-02-01
影响因子：
2.8
通讯作者：
Ito, K
中科院分区：
文献类型：
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作者：
Benneker, LM;Heini, PF;Ito, K
退行性间盘疾病(DDD)是MRI扫描和X光检查的常见表现。然而，它们与形态和生化变化的相关性还没有得到很好的证实。在这项研究中，评估了DDD的放射学和MRI参数，并与椎间盘退变的形态和生化结果进行了比较。取8具人腰椎间盘标本39个，年龄19~86岁。在死后48小时内，获得了各种自旋回波序列的磁共振成像和完整脊柱的双向X线片。然后在正中矢状面对有终板的单个椎间盘进行切片，并根据形态进行分级。从每个圆盘的核中采集样本进行生化分析，包括水和蛋白多糖含量。在MRI上，对T2信号强度、MODIC改变、椎间盘向间隙外延伸(借方)、髓核形态、环状撕裂、骨赘和终板完整性进行分级。在X线片上，一位独立的观察者将参数分类为椎间盘高度、终板硬化、骨赘、Schmorl‘s结节、椎间盘内钙化和终板形状。统计分析采用一般线性回归模型。采用10%显著界值的后向剔除法来确定最显著的参数，然后将这些参数相加，以产生X线片、MRI以及两种方法的组合的综合评分。评分由三个观察者进行，并使用Cronbach的α模型进行信度分析以控制观察者间的一致性。高度丢失、骨赘和椎间盘内钙化三个X线参数与退变程度显著相关(p<；0.001，R-2=642)。除1级与2级和4级与5级之间的极端值外，即使只有一个形态级别的综合评分也有显著差异(p<；0.05)。所有MRI参数都与形态级别显著相关(p<；0.05)；然而，Modic改变、T2信号和骨赘可以解释数据中83%的变化。T2信号强度与H2O和蛋白多糖含量显著相关(p<；0.001)，最适合检测高度退变的椎间盘。回归分析显示，综合评分与肿瘤的形态分级(p<；0.001，R2=775)的相关性优于单纯X线平片(p<；0.001，r2=642)和磁共振成像(p<；0.001，r2=696)。在综合评分的基础上，进行了向后剔除回归，其中MODIC参数变化，T2信号强度损失(MRI)和钙化(X线)占变异性的87%。观察者间验证显示，所有三个分数(Cronbach‘s Alpha值从0.95到0.97)都有很高的相关性。结论：选择性成像参数和新制定的评分方案与形态学方法所确定的椎间盘退变相关。令人惊讶的是，放射学参数能够区分不同阶段的退变，而MRI只能发现晚期的椎间盘退变。我们的结论是，X射线可能仍然是一种经济有效的、非侵入性的体内分级方法来检测早期的椎间盘退变，并且结合MRI，与椎间盘退变的形态和生化评估最相关。
Degenerative disc disease (DDD) is a common finding in MRI scans and X-rays. However, their correlation to morphological and biochemical changes is not well established. In this study, radiological and MRI parameters of DDD were assessed and compared with morphological and biochemical findings of disc degeneration. Thirty-nine human lumbar discs (L1 - S1), age 19 - 86 years, were harvested from eight cadavers. Within 48 h postmortem, MRIs in various spin-echo sequences and biplanar radiographs of intact spines were obtained. Individual discs with endplates were then sectioned in the mid-sagittal plane and graded according to the morphological appearance. Samples from the nucleus of each disc were harvested for biochemical analysis including water and proteoglycan contents. On MRIs, T2-signal intensity, Modic changes, disc extension beyond the interspace ( DEBIT), nucleus pulposus shape, annular tears, osteophytes and endplate integrity were graded. On radiographs, an independent observer classified the parameters disc height, endplate sclerosis, osteophytes, Schmorl's nodes, intradiscal calcifications and endplate shape. General linear-regression models were used for statistical analysis. Backward elimination with a 10% significance cut-off level was used to identify the most significant parameters, which then were summed to create composite scores for radiography, MRI and the combination of both methods. The grading was performed by three observers, and a reliability analysis using Cronbach's alpha model was used to control interobserver agreement. The three radiographic parameters height-loss, osteophytes and intradiscal calcifications correlated significantly with the morphological degree of degeneration (p< 0.001, R-2 = 642). Significant differences of even one morphological grade could also be differentiated in the composite radiological score ( p< 0.05), except at the extremes between grades 1 and 2 and grades 4 and 5. All MRI parameters correlated significantly with the morphological grade ( p< 0.05); however Modic changes, T2-intensity and osteophytes accounted for 83% of the variation in the data. T2-signal intensity correlated significantly with H2O and proteoglycan content ( p< 0.001), and was best for detecting highly degenerated discs. Regression showed that the combined score was better correlated with the morphological grade ( p< 0.001, R-2 = 775) than either the composite radiographic ( p< 0.001, R2= 642) or composite MRI ( p< 0.001, R2= 696) alone. Based on the combined score, a backwards elimination of the regression was performed, in which the parameters Modic changes, and T2-intensity loss ( MRI) as well as calcifications (X-ray) accounted for 87% of the variability. The interobserver validation showed a high correlation for all three scores ( Cronbach's alpha values ranging from 0.95 to 0.97). Conclusion: selective imaging parameters and a newly created scoring scheme were found to correlate with disc degeneration as determined in a morphological manner. Surprisingly, radiographic parameters were able to distinguish different stages of degeneration, whereas MRI could only detect advanced stages of disc degeneration. We conclude that X-rays may remain a cost-effective, non-invasive in vivo-grading method to detect early disc degeneration, and, combined with MRI, correlate best with morphological and biochemical assessment of disc degeneration.