Hamouda Abdelrahman M, Pennington Zach, Astudillo Potes Maria, Shafi Mahnoor, Mikula Anthony L, Lakomkin Nikita, Martini Michael L, Bydon Mohamad, Kennel Kurt A, Drake Matthew T, Freedman Brett A, Sebastian Arjun S, Nassr Ahmad, Fogelson Jeremy L, Elder Benjamin D
Departments of1Neurosurgery.
2Endocrinology, and.
J Neurosurg Spine. 2024 Dec 13;42(3):331-339. doi: 10.3171/2024.8.SPINE24732. Print 2025 Mar 1.
Hounsfield units (HUs) may better predict biomechanical complications of instrumented fusion than conventional bone quality measures. Typically, noncontrast axial slices are used. This study aims to address the influence of reconstruction plane and contrast administration on measured HUs in patients undergoing lumbar spine imaging.
Patients without prior spine surgery, infection, or tumor were identified for 3 groups: 1) 150 patients with high-resolution noncontrast lumbar CT, 2) 109 patients with noncontrast and contrast-enhanced lumbar CT, and 3) 100 patients with noncontrast lumbar CT and lumbar CT myelograms. Noncontrast HU measures in group 1 were compared between axial, sagittal, and coronal reconstructions. HU measures for groups 2 and 3 were compared on axial slice averages. HU measures between groups were compared using the Wilcoxon signed-rank test to investigate the presence of a statistically significant difference between groups (α = 0.05). Linear regression was also used to determine the degree of correlation between HU measures on noncontrast axial CT slices and HU measures on other sequences.
The mean patient age was 58.8 ± 15.9 years for group 1 (54.0% male), 65.5 ± 15.9 years for group 2 (61.5% male), and 65.2 ± 14.2 years (53.5% male) for group 3. Comparison of HU measures in group 1 showed significant differences across measurement modalities with the exception of axial average versus coronal average measures (p = 0.257) and sagittal average versus midsagittal measures (p = 0.726). There were significant differences in average axial HUs for each vertebral body between contrast and noncontrast lumbar CT and between CT myelography and noncontrast CT. Linear regression analysis demonstrated an extremely high correlation between measures for all methodologies (r2 = 0.950-0.986, all p < 0.001), and between contrast-enhanced and noncontrast studies (r2 = 0.870, p < 0.001). Measurements on CT myelography were significantly correlated with those in noncontrast studies, although to a lesser degree (r2 = 0.745, p < 0.001).
HU measures on noncontrast CT appear similar across multiple different planes, suggesting that a simpler methodology such as single-slice measurement on midsagittal reconstruction may allow for more rapid assessment of underlying bone quality. Consistent with prior work, contrast-enhanced CT sequences appear to reliably mirror underlying bone quality, although CT myelogram measures may vary in a more unpredictable way that precludes their use to interpret underlying bone quality. HU measures on contrast-enhanced studies are on average greater, suggesting the need for higher cutoff values.
亨氏单位（HU）可能比传统的骨质量测量方法能更好地预测器械融合的生物力学并发症。通常，使用非增强轴向切片。本研究旨在探讨重建平面和造影剂注入对接受腰椎成像患者测量的HU的影响。
确定未接受过脊柱手术、感染或肿瘤的患者分为3组：1）150例接受高分辨率非增强腰椎CT检查的患者，2）109例接受非增强和增强腰椎CT检查的患者，3）100例接受非增强腰椎CT和腰椎CT脊髓造影检查的患者。比较第1组轴向、矢状和冠状重建之间的非增强HU测量值。比较第2组和第3组轴向切片平均值的HU测量值。使用Wilcoxon符号秩检验比较组间的HU测量值，以研究组间是否存在统计学显著差异（α = 0.05）。还使用线性回归来确定非增强轴向CT切片上的HU测量值与其他序列上的HU测量值之间的相关程度。
第1组患者的平均年龄为58.8±15.9岁（男性占54.0%），第2组为65.5±15.9岁（男性占61.5%），第3组为65.2±14.2岁（男性占53.5%）。第1组HU测量值的比较显示，除轴向平均值与冠状平均值测量值（p = 0.257）和矢状平均值与正中矢状面测量值（p = 0.726）外，各测量方式之间存在显著差异。对比剂增强腰椎CT与非增强腰椎CT之间以及CT脊髓造影与非增强CT之间，每个椎体的平均轴向HU存在显著差异。线性回归分析表明，所有方法的测量值之间具有极高的相关性（r2 = 0.950 - 0.986，均p < 0.001），增强与非增强研究之间也具有相关性（r2 = 0.870，p < 0.001）。CT脊髓造影的测量值与非增强研究的测量值显著相关，尽管程度较小（r2 = 0.745，p < 0.001）。
非增强CT上的HU测量值在多个不同平面上看起来相似，这表明一种更简单的方法，如在正中矢状面重建上进行单切片测量，可能允许更快速地评估潜在的骨质量。与先前的研究一致，增强CT序列似乎能可靠地反映潜在的骨质量，尽管CT脊髓造影测量值可能以更不可预测的方式变化，这使得它们无法用于解释潜在的骨质量。增强研究中的HU测量值平均更高，这表明需要更高的临界值。
