Department of Radiology, Haukeland University Hospital, Jonas Liesvei 65, 5021, Bergen, Norway.
Department of Clinical Medicine, University of Bergen, P.O. Box 7804, 5020, Bergen, Norway.
BMC Musculoskelet Disord. 2022 Jul 22;23(1):695. doi: 10.1186/s12891-022-05610-4.
Modic Changes (MCs) in the vertebral bone marrow were related to back pain in some studies but have uncertain clinical relevance. Diffusion weighted MRI with apparent diffusion coefficient (ADC)-measurements can add information on bone marrow lesions. However, few have studied ADC measurements in MCs. Further studies require reproducible and valid measurements. We expect valid ADC values to be higher in MC type 1 (oedema type) vs type 3 (sclerotic type) vs type 2 (fatty type). Accordingly, the purpose of this study was to evaluate ADC values in MCs for interobserver reproducibility and relation to MC type.
We used ADC maps (b 50, 400, 800 s/mm) from 1.5 T lumbar spine MRI of 90 chronic low back pain patients with MCs in the AIM (Antibiotics In Modic changes)-study. Two radiologists independently measured ADC in fixed-sized regions of interests. Variables were MC-ADC (ADC in MC), MC-ADC% (0% = vertebral body, 100% = cerebrospinal fluid) and MC-ADC-ratio (MC-ADC divided by vertebral body ADC). We calculated mean difference between observers ± limits of agreement (LoA) at separate endplates. The relation between ADC variables and MC type was assessed using linear mixed-effects models and by calculating the area under the receiver operating characteristic curve (AUC).
The 90 patients (mean age 44 years; 54 women) had 224 MCs Th12-S1 comprising type 1 (n = 111), type 2 (n = 91) and type 3 MC groups (n = 22). All ADC variables had higher predicted mean for type 1 vs 3 vs 2 (p < 0.001 to 0.02): MC-ADC (10 mm/s) 1201/796/576, MC-ADC% 36/21/14, and MC-ADC-ratio 5.9/4.2/3.1. MC-ADC and MC-ADC% had moderate to high ability to discriminate between the MC type groups (AUC 0.73-0.91). MC-ADC-ratio had low to moderate ability (AUC 0.67-0.85). At L4-S1, widest/narrowest LoA were for MC-ADC 20 ± 407/12 ± 254, MC-ADC% 1.6 ± 18.8/1.4 ± 10.4, and MC-ADC-ratio 0.3 ± 4.3/0.2 ± 3.9. Difference between observers > 50% of their mean value was less frequent for MC-ADC (9% of MCs) vs MC-ADC% and MC-ADC-ratio (17-20%).
The MC-ADC variable (highest mean ADC in the MC) had best interobserver reproducibility, discriminated between MC type groups, and may be used in further research. ADC values differed between MC types as expected from previously reported MC histology.
椎体骨髓中的 Modic 改变（MCs）与某些研究中的背痛有关，但与临床相关性不确定。扩散加权 MRI 联合表观扩散系数（ADC）测量可提供骨髓病变的信息。然而，很少有研究对 MC 中的 ADC 测量进行研究。进一步的研究需要可重复和有效的测量。我们预计 MC 1 型（水肿型）的 ADC 值比 MC 3 型（硬化型）和 MC 2 型（脂肪型）更高。因此，本研究的目的是评估 MC 中 ADC 值的观察者间可重复性及其与 MC 类型的关系。
我们使用来自 AIM（抗生素诱导 Modic 改变研究）中 90 例慢性腰痛伴 MC 的 1.5T 腰椎 MRI 的 ADC 地图（b50、400、800 s/mm）。两名放射科医生独立测量固定大小 ROI 中的 ADC。变量为 MC-ADC（MC 中的 ADC）、MC-ADC%（0%=椎体，100%=脑脊液）和 MC-ADC-ratio（MC-ADC 除以椎体 ADC）。我们在单独的终板处计算了观察者之间的平均差异±限值协议（LoA）。使用线性混合效应模型和计算受试者工作特征曲线（ROC）下的面积（AUC）来评估 ADC 变量与 MC 类型之间的关系。
90 例患者（平均年龄 44 岁；54 名女性）共 224 例 MC，包括 T12-S1 段的 1 型（n=111）、2 型（n=91）和 3 型 MC 组（n=22）。所有 ADC 变量的预测均值均为 1 型>3 型>2 型（p<0.001 至 0.02）：MC-ADC（10mm/s）1201/796/576，MC-ADC%36/21/14，和 MC-ADC-ratio5.9/4.2/3.1。MC-ADC 和 MC-ADC% 具有区分 MC 类型组的中等至高能力（AUC 0.73-0.91）。MC-ADC-ratio 具有低至中等的能力（AUC 0.67-0.85）。在 L4-S1，最宽/最窄的 LoA 为 MC-ADC 20±407/12±254，MC-ADC%1.6±18.8/1.4±10.4，和 MC-ADC-ratio0.3±4.3/0.2±3.9。观察者之间的差异>其平均值的 50%的情况较少见，对于 MC-ADC（9%的 MC）而言，比 MC-ADC%和 MC-ADC-ratio（17-20%）少见。
MC-ADC 变量（MC 中最高的 ADC）具有最佳的观察者间可重复性，可区分 MC 类型组，可用于进一步的研究。ADC 值与 MC 类型一致，与之前报道的 MC 组织学一致。
