Menezes-Reis R, Salmon C E G, Carvalho C S, Bonugli G P, Chung C B, Nogueira-Barbosa M H
From the Division of Radiology (R.M.-R., G.P.B., C.S.C., M.H.N.-B.), Ribeirão Preto Medical School
Department of Physics (C.E.G.S.), Ribeirão Preto Philosophy and Sciences School, University of São Paulo, São Paulo, Brazil.
AJNR Am J Neuroradiol. 2015 Mar;36(3):606-11. doi: 10.3174/ajnr.A4125. Epub 2014 Oct 16.
Intervertebral disk biochemical composition could be accessed in vivo by T1ρ and T2 relaxometry. We found no studies in the literature comparing different segmentation methods for data extraction using these techniques. Our aim was to compare different manual segmentation methods used to extract T1ρ and T2 relaxation times of intervertebral disks from MR imaging. Seven different methods of partial-disk segmentation techniques were compared with whole-disk segmentation as the reference standard.
Sagittal T1ρ and T2 maps were generated by using a 1.5T MR imaging scanner in 57 asymptomatic volunteers 20-40 years of age. Two hundred eighty-five lumbar disks were separated into 2 groups: nondegenerated disk (Pfirrmann I and II) and degenerated disk (Pfirrmann III and IV). In whole-disk segmentation, the disk was segmented in its entirety on all sections. Partial-disk segmentation methods included segmentation of the disk into 6, 5, 4, 3, and 1 sagittal sections. Circular ROIs positioned in the nucleus pulposus and annulus fibrosus were also used to extract T1ρ and T2, and data were compared with whole-disk segmentation
In the nondegenerated group, segmentation of ≥5 sagittal sections showed no statistical difference with whole-disk segmentation. All the remaining partial-disk segmentation methods and circular ROIs showed different results from whole-disk segmentation (P < .001). In the degenerated disk group, all methods were statistically similar to whole-disk segmentation. All partial-segmentation methods, including circular ROIs, showed strong linear correlation with whole-disk segmentation in both the degenerated and nondegenerated disk groups.
Manual segmentation showed strong reproducibility for T1ρ and T2 and strong linear correlation between partial- and whole-disk segmentation. Absolute T1ρ and T2 values extracted from different segmentation techniques were statistically different in disks with Pfirrmann grades I and II.
通过T1ρ和T2弛豫测量法可在体内获取椎间盘的生化成分。我们在文献中未发现比较使用这些技术进行数据提取的不同分割方法的研究。我们的目的是比较用于从磁共振成像中提取椎间盘T1ρ和T2弛豫时间的不同手动分割方法。将七种不同的部分椎间盘分割技术方法与作为参考标准的全椎间盘分割进行比较。
使用1.5T磁共振成像扫描仪为57名20 - 40岁无症状志愿者生成矢状位T1ρ和T2图。285个腰椎间盘被分为两组：非退变椎间盘（Pfirrmann I级和II级）和退变椎间盘（Pfirrmann III级和IV级）。在全椎间盘分割中，在所有层面上对椎间盘进行整体分割。部分椎间盘分割方法包括将椎间盘分割为6、5、4、3和1个矢状层面。还使用位于髓核和纤维环中的圆形感兴趣区（ROI）来提取T1ρ和T2，并将数据与全椎间盘分割进行比较。
在非退变组中，≥5个矢状层面的分割与全椎间盘分割无统计学差异。所有其余的部分椎间盘分割方法和圆形ROI与全椎间盘分割结果不同（P <.001）。在退变椎间盘组中，所有方法与全椎间盘分割在统计学上相似。在退变和非退变椎间盘组中，所有部分分割方法（包括圆形ROI）与全椎间盘分割均显示出强线性相关性。
手动分割对T1ρ和T2显示出很强的可重复性，部分与全椎间盘分割之间具有强线性相关性。在Pfirrmann I级和II级椎间盘中，从不同分割技术提取的绝对T1ρ和T2值在统计学上存在差异。
