BackgroundOsteoporosis (OP) and osteomalacia (OM) are metabolic bone diseases characterized by mineral and matrix density changes. Quantitative bone matrix density differentiates OM from OP. MRI is a noninvasive and nonionizing imaging technique that can measure bone matrix density quantitatively in ex vivo and in vivo.PurposeTo demonstrate water + fat suppressed 1H MRI to compute bone matrix density in ex vivo rat femurs in the preclinical model.Study TypeProspective.Animal ModelFifteen skeletally mature female Sprague–Dawley rats, five per group (normal, ovariectomized (OVX), partially nephrectomized/vitamin D (Vit‐D) deficient), 250–275 g, ∼15 weeks old.Field Strength/Sequence7T, zero echo time sequence with water + fat (VAPOR) suppression capability, μCT imaging, and gravimetric measurements.AssessmentCortical and trabecular bone segments from normal and disease models were scanned in the same coil along with a dual calibration phantom for quantitative assessment of bone matrix density.Statistical TestsANOVA and linear regression were used for data analysis, with P‐values <0.05 statistically significant.ResultsThe MRI‐derived three‐density PEG pellet densities have a strong linear relationship with physical density measures (r2 = 0.99). The Vit‐D group had the lowest bone matrix density for cortical bone (0.47 ± 0.16 g cm−3), whereas the OVX had the lowest bone matrix density for trabecular bone (0.26 ± 0.04 g cm−3). Gravimetry results confirmed these MRI‐based observations for Vit‐D cortical (0.51 ± 0.07 g cm−3) and OVX trabecular (0.26 ± 0.03 g cm−3) bone groups.Data ConclusionRat femur images were obtained using a modified pulse sequence and a custom‐designed double‐tuned (1H/31P) transmit‐receive solenoid‐coil on a 7T preclinical MRI scanner. Phantom experiments confirmed a strong linear relation between MRI‐derived and physical density measures and quantitative bone matrix densities in rat femurs from normal, OVX, and Vit‐D deficient/partially nephrectomized animals were computed.Level of Evidence2Technical EfficacyStage 2

中文翻译：

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通过抑制水和脂肪的固态 1H ZTE 序列对正常和病理大鼠骨骼进行定量 1H 磁共振成像

背景骨质疏松症（OP）和骨软化症（OM）是代谢性骨病，其特征是矿物质和基质密度变化。定量骨基质密度可区分 OM 和 OP。 MRI是一种无创、非电离成像技术，可以定量测量离体和体内骨基质密度。目的证明水+脂肪受到抑制1H MRI 用于计算临床前模型中离体大鼠股骨的骨基质密度。研究类型前瞻性。动物模型 15 只骨骼成熟的雌性 Sprague-Dawley 大鼠，每组 5 只（正常、卵巢切除 (OVX)、部分肾切除/维生素 D (Vit-D) ），250–275 g，∼15 周龄。场强/序列7T，具有水+脂肪（VAPOR）抑制能力的零回波时间序列，μCT 成像和重量测量。评估正常和疾病模型的皮质骨和小梁骨片段在同一线圈中与双校准体模一起进行扫描，以定量评估骨基质密度。统计测试方差分析和线性回归用于数据分析，其中磷‐值 <0.05 具有统计显着性。结果 MRI 得出的三密度 PEG 颗粒密度与物理密度测量值具有很强的线性关系（r2= 0.99）。 Vit-D 组的皮质骨骨基质密度最低（0.47 ± 0.16 g cm−3），而 OVX 的骨小梁骨基质密度最低（0.26 ± 0.04 g cm−3）。重量分析结果证实了这些基于 MRI 的 Vit-D 皮质观察结果（0.51 ± 0.07 g cm−3) 和 OVX 小梁 (0.26 ± 0.03 g cm−3）骨组。数据结论使用修改的脉冲序列和定制设计的双调谐（1H/31P) 7T 临床前 MRI 扫描仪上的发射-接收螺线管线圈。体模实验证实，MRI 衍生的物理密度测量值与正常、OVX 和 Vit-D 缺乏/部分肾切除动物的大鼠股骨的定量骨基质密度之间存在很强的线性关系。证据级别 2 技术功效第 2 阶段