Ahn Ga Young, Koo Bon San, Joo Kyung Bin, Kim Tae-Hwan, Lee Seunghun
Division of Rheumatology, Department of Internal Medicine, Korea University Guro Hospital, Seoul, Korea.
Division of Rheumatology, Department of Internal Medicine, Inje University College of Medicine, Seoul, Korea.
Korean J Radiol. 2021 Oct;22(10):1671-1679. doi: 10.3348/kjr.2020.0953. Epub 2021 Jul 26.
We quantitatively measured the fat fraction (FF) in the vertebrae of patients with ankylosing spondylitis (AS) using magnetic resonance imaging (MRI) and investigated the role of FF as an indicator of both active inflammation and chronicity.
A total of 52 patients with AS who underwent spinal MRI were retrospectively evaluated. The FF values of the anterosuperior and anteroinferior corners of the bone marrow in the L1-S1 spine were assessed using the modified Dixon technique. AS activity was measured using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), AS Disease Activity Score (ASDAS), and serum inflammatory marker levels. AS disease chronicity was assessed by AS disease duration and the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). Univariable and multivariable regression analyses were conducted to investigate the correlation between FF and other clinical characteristics.
The mean FF ± standard deviation of the total lumbar spine was 43.0% ± 11.3%. At univariable analysis, spinal FF showed significant negative correlation with BASDAI (β = -0.474, = 0.002) and ASDAS with C-reactive protein (ASDAS-CRP; β = -0.478, = 0.002) and a significant positive correlation with AS disease duration (β = 0.440, = 0.001). After adjusting for patient age, sex, and total mSASSS score, spinal FF remained significantly negatively correlated with BASDAI (β = -0.543, < 0.001), ASDAS-CRP (β = -0.568, < 0.001), and ASDAS with erythrocyte sedimentation rate (β = -0.533, = 0.001). Spinal FF was significantly lower in patients with very high disease activity (ASDAS-CRP > 3.5) than in those with only high disease activity (2.1 ≤ ASDAS-CRP ≤ 3.5) ( = 0.010).
Spinal FF may help assess both AS disease activity and chronicity.
我们使用磁共振成像（MRI）定量测量强直性脊柱炎（AS）患者椎体中的脂肪分数（FF），并研究FF作为活动性炎症和慢性炎症指标的作用。
对52例接受脊柱MRI检查的AS患者进行回顾性评估。采用改良的狄克逊技术评估L1-S1脊柱骨髓前上角和前下角的FF值。使用巴斯强直性脊柱炎疾病活动指数（BASDAI）、巴斯强直性脊柱炎功能指数（BASFI）、AS疾病活动评分（ASDAS）和血清炎症标志物水平来测量AS活动度。通过AS病程和改良的斯托克强直性脊柱炎脊柱评分（mSASSS）评估AS疾病的慢性程度。进行单变量和多变量回归分析以研究FF与其他临床特征之间的相关性。
整个腰椎的平均FF±标准差为43.0%±11.3%。在单变量分析中，脊柱FF与BASDAI（β = -0.474，P = 0.002）以及ASDAS与C反应蛋白（ASDAS-CRP；β = -0.478，P = 0.002）呈显著负相关，与AS病程呈显著正相关（β = 0.440，P = 0.001）。在调整患者年龄、性别和总mSASSS评分后，脊柱FF与BASDAI（β = -0.543，P < 0.001）、ASDAS-CRP（β = -0.568，P < 0.001）以及ASDAS与红细胞沉降率（β = -0.533，P = 0.001）仍呈显著负相关。疾病活动度非常高（ASDAS-CRP > 3.5）的患者脊柱FF显著低于疾病活动度仅为高（2.1≤ASDAS-CRP≤3.5）的患者（P = 0.010）。
脊柱FF可能有助于评估AS疾病的活动度和慢性程度。
