量化后路脊柱内固定对相邻椎间盘MRI信号的影响。

Quantifying the effect of posterior spinal instrumentation on the MRI signal of adjacent intervertebral discs.

作者信息

Foltz Mary H, O'Leary Robert M, Reader Diana, Rudolph Nicholas L, Schlitter Krista A, Ellermann Jutta, Johnson Casey P, Polly David W, Ellingson Arin M

机构信息

Division of Rehabilitation Science, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, MN, USA.

Division of Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, MN, USA.

出版信息

Spine Deform. 2020 Oct;8(5):845-851. doi: 10.1007/s43390-020-00139-9. Epub 2020 May 24.

DOI:10.1007/s43390-020-00139-9

PMID:32449035

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7541587/

Abstract

STUDY DESIGN

Ex vivo porcine imaging study.

OBJECTIVES

Quantitatively evaluate change in MRI signal at the discs caudal to spinal fusion instrumentation. Individuals who receive posterior spinal instrumentation are at risk of developing accelerated disc degeneration at adjacent levels. Degeneration is associated with a loss of biochemical composition and mechanical integrity of the disc, which can be noninvasively assessed through quantitative T2* (qT2*) MRI techniques. However, qT2* is sensitive to magnetic susceptibility introduced by metal.

METHODS

Nine ex vivo porcine lumbar specimens were imaged with 3 T MRI. Fast spin-echo T2-weighted (T2w) images and gradient-echo qT2* maps were acquired, both without and with posterior spinal fusion instrumentation. Average T2* relaxation times of the nuclei pulposi (NP) were measured at the adjacent and sub-adjacent discs and measurements were compared using t tests before and after instrumentation. The size of the signal void and metal artifact were determined (modified ASTM F2119-07) within the vertebral body and spinal cord for both MRI sequences. The relationship between T2* signal loss and distance from the instrumentation was evaluated using Pearson's correlation.

RESULTS

There was no significant difference between adjacent and sub-adjacent NP T2* relaxation time prior to instrumentation (p = 0.86). Following instrumentation, there was a significant decrease in the T2* relaxation time at the adjacent NP (average = 20%, p = 0.02), and no significant difference at the sub-adjacent NP (average = - 3%, p = 0.30). Furthermore, there was a significant negative correlation between signal loss and distance to disc (r = - 0.61, p < 0.01).

CONCLUSIONS

Spinal fusion instrumentation interferes with T2* relaxation time measurements at the adjacent disc but not at the sub-adjacent discs. However, there is sufficient signal at the adjacent disc to quantify changes in the T2* relaxation time following spinal fusion. Hence, baseline MRI scan following spinal fusion surgery are required to interpret and track changes in disc health at the caudal discs.

LEVEL OF EVIDENCE

N/A.

摘要

研究设计

猪离体成像研究。

目的

定量评估脊柱融合内固定器械尾侧椎间盘的MRI信号变化。接受后路脊柱内固定的个体有相邻节段椎间盘退变加速的风险。椎间盘退变与椎间盘生化成分和力学完整性的丧失有关，可通过定量T2*（qT2*）MRI技术进行无创评估。然而，qT2*对金属引入的磁化率敏感。

方法

对9个猪离体腰椎标本进行3T MRI成像。在有无后路脊柱融合内固定的情况下，均采集快速自旋回波T2加权（T2w）图像和梯度回波qT2图。测量相邻和次相邻椎间盘髓核的平均T2弛豫时间，并在置入内固定前后使用t检验进行测量比较。对于两种MRI序列，确定椎体和脊髓内信号空洞和金属伪影的大小（修改后的ASTM F2119-07）。使用Pearson相关性评估T2*信号损失与距内固定器械距离之间的关系。

结果

置入内固定前，相邻和次相邻髓核T2弛豫时间无显著差异（p = 0.86）。置入内固定后，相邻髓核的T2弛豫时间显著缩短（平均 = 20%，p = 0.02），次相邻髓核无显著差异（平均 = -3%，p = 0.30）。此外，信号损失与椎间盘距离之间存在显著负相关（r = -0.61，p < 0.01）。