Department of Radiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Ismaningerstr. 22, 81675, Munich, Germany.
Department of Neuroradiology, Klinikum Rechts Der Isar, School of Medicine, Technical University of Munich, Munich, Germany.
Osteoporos Int. 2022 Feb;33(2):487-496. doi: 10.1007/s00198-021-06147-3. Epub 2021 Sep 18.
The bone marrow proton density fat fraction (PDFF) assessed with MRI enables the differentiation between osteoporotic/osteopenic patients with and without vertebral fractures. Therefore, PDFF may be a potentially useful biomarker for bone fragility assessment.
To evaluate whether magnetic resonance imaging (MRI)-based proton density fat fraction (PDFF) of vertebral bone marrow can differentiate between osteoporotic/osteopenic patients with and without vertebral fractures.
Of the 52 study patients, 32 presented with vertebral fractures of the lumbar spine (66.4 ± 14.4 years, 62.5% women; acute low-energy osteoporotic/osteopenic vertebral fractures, N = 25; acute high-energy traumatic vertebral fractures, N = 7). These patients were frequency matched for age and sex to patients without vertebral fractures (N = 20, 69.3 ± 10.1 years, 70.0% women). Trabecular bone mineral density (BMD) values were derived from quantitative computed tomography. Chemical shift encoding-based water-fat MRI of the lumbar spine was performed, and PDFF maps were calculated. Associations between fracture status and PDFF were assessed using multivariable linear regression models.
Over all patients, mean PDFF and trabecular BMD correlated significantly (r = - 0.51, P < 0.001). In the osteoporotic/osteopenic group, those patients with osteoporotic/osteopenic fractures had a significantly higher PDFF than those without osteoporotic fractures after adjusting for age, sex, weight, height, and trabecular BMD (adjusted mean difference [95% confidence interval], 20.8% [10.4%, 30.7%]; P < 0.001), although trabecular BMD values showed no significant difference between the subgroups (P = 0.63). For the differentiation of patients with and without vertebral fractures in the osteoporotic/osteopenic subgroup using mean PDFF, an area under the receiver operating characteristic (ROC) curve (AUC) of 0.88 (P = 0.006) was assessed. When evaluating all patients with vertebral fractures, those with high-energy traumatic fractures had a significantly lower PDFF than those with low-energy osteoporotic/osteopenic vertebral fractures (P < 0.001).
MR-based PDFF enables the differentiation between osteoporotic/osteopenic patients with and without vertebral fractures, suggesting the use of PDFF as a potential biomarker for bone fragility.
评估磁共振成像（MRI）基于椎体骨髓质子密度脂肪分数（PDFF）是否可以区分骨质疏松/低骨密度患者是否伴有椎体骨折。
52 名研究患者中，32 名患者有腰椎骨折（66.4±14.4 岁，62.5%为女性；急性低能量骨质疏松/低骨密度性椎体骨折 25 例；急性高能量创伤性椎体骨折 7 例）。这些患者按照年龄和性别与无椎体骨折的患者进行频数匹配（20 例，69.3±10.1 岁，70.0%为女性）。采用定量 CT 测定松质骨骨密度（BMD）值。对腰椎进行基于化学位移编码的水脂 MRI，计算 PDFF 图。采用多元线性回归模型评估骨折状态与 PDFF 之间的相关性。
所有患者的平均 PDFF 和松质骨 BMD 呈显著负相关（r=-0.51，P<0.001）。在骨质疏松/低骨密度组中，调整年龄、性别、体重、身高和松质骨 BMD 后，有骨质疏松/低骨密度性骨折的患者的 PDFF 明显高于无骨质疏松性骨折的患者（调整后的平均差异[95%置信区间]，20.8%[10.4%，30.7%]；P<0.001），尽管两组的松质骨 BMD 值无显著差异（P=0.63）。在骨质疏松/低骨密度亚组中，使用平均 PDFF 区分有和无椎体骨折的患者，其受试者工作特征（ROC）曲线下面积（AUC）为 0.88（P=0.006）。当评估所有有椎体骨折的患者时，高能创伤性骨折患者的 PDFF 明显低于低能骨质疏松/低骨密度性椎体骨折患者（P<0.001）。
基于 MRI 的 PDFF 能够区分骨质疏松/低骨密度患者是否伴有椎体骨折，提示 PDFF 可作为骨脆弱性的潜在生物标志物。
