Purpose

To evaluate the feasibility of histogram analysis of T2* value for the detection and grading of degenerative lumbar intervertebral discs (IVDs) and for the characterization of microstructural heterogeneity of discs.

Methods

Two hundred fourteen lumbar IVDs of 44 subjects with chronic low back pain were examined using sagittal T2WI and axial T2* mapping. All IVDs were classified according to the Pfirrmann grade on T2WI. The correlations between histogram-derived parameters based on T2* values (T2*-HPs) of IVDs and Pfirrmann grade as well as between “red zone ratio” (area of “red zone” on T2* color maps over cross-sectional area of corresponding IVDs) and Pfirrmann grade were calculated.

Results

The agreement for Pfirrmann grade of IVDs was excellent (κ = 0.808, P < 0.001). The consistency of the measured T2*-HPs was excellent, with ICCs ranging from 0.828–0.960. Each histogram-derived parameter had a statistically significant relationship with Pfirrmann grade (P < 0.001). The bright “red zone” on T2* color maps of IVDs displayed as a separated peak relative to the rest of voxels in histograms. The mean area ratio of “red zone” over the corresponding IVD was 9.234% ± 6.680 and ranged from 0.517% to 30.598%. The “red zone ratio” was highly related to Pfirrmann grade (r = − 0.732, P < 0.001).

Conclusion

Histogram analysis of T2* value is an effective tool for the detection and grading of degenerative IVDs. Identification of the “red zone” may provide new breakthroughs in the study of disc degeneration initiation and generate new hypotheses in anatomical and histological studies of IVDs.

中文翻译：

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使用T2 *值的直方图分析评估腰椎间盘退变的可行性研究。

目的

为了评估T2 *值的直方图分析在变性腰椎间盘（IVD）的检测和分级以及表征椎间盘的微结构异质性方面的可行性。

方法

使用矢状位T2WI和轴向T2 *标测检查了44位患有慢性下腰痛的受试者的124个腰椎IVD。所有IVD根据T2WI上的Pfirrmann等级进行分类。基于IVD的T2 *值（T2 * -HPs）和Pfirrmann等级的直方图衍生参数之间的相关性，以及“红色区域比率”（T2 *彩色图上“红色区域”的面积在横截面积上）之间的相关性。计算相应的IVDs和Pfirrmann等级。

结果

Pfirrmann级IVD的一致性非常好（κ  = 0.808，P  <0.001）。测得的T2 * -HP的一致性非常好，ICC在0.828-0.960之间。每个直方图派生的参数与Pfirrmann等级具有统计学意义（P <  0.001）。IVD的T2 *彩色图上的明亮“红色区域”显示为相对于直方图中其余体素的分离峰。相应IVD上“红色区域”的平均面积比为9.234％±6.680，范围为0.517％至30.598％。“红色区域比率”与Pfirrmann等级高度相关（r  = − 0.732，P <  0.001）。

结论

T2 *值的直方图分析是检测和分级变性IVD的有效工具。识别“红色区域”可能为椎间盘退变的起始研究提供新的突破，并在IVD的解剖学和组织学研究中产生新的假设。