Background: The purpose of this study is to compare turbo spin echo diffusion-weighted images in radial trajectory (BLADE DWI) with multi-shot echoplanar imaging (RESOLVE DWI) for imaging the metastatic lesion in the pelvic bone to find a correlation between ADC values and standardized uptake values (SUVs) of FDG uptake in PET/CT. The study also seeks to compare the values of metastatic lesions with those of benign bone lesions, specifically red marrow hyperplasia. Methods: The retrospective IRB-approved study included patients with bone metastasis and red marrow hyperplasia in the pelvic bone who underwent 3.0 T MRI with BLADE/RESOLVE DWI sequences and F-18 FDG PET/CT within one month. BVC (best value comparator) was used in determining the nature of bone lesions. Apparent diffusion coefficient (ADC) and standardized uptake value (SUV) were measured by a radiologist and a nuclear medicine physician. MRI image quality was graded with a Likert scale regarding the visualization of the sacroiliac joint, sacral neural foramen, hamstring tendon at ischial tuberosity, and tumor border. Signal-to-noise ratio (SNR) and imaging time were compared between the two DWIs. Mean, peak, and maximum SUVs between metastatic and benign red marrow lesions were compared. SUVs and ADC values were compared. AUROC analyses and cut-off values were obtained for each parameter. Mann–Whitney U, Spearman’s rho, and Kolmogorov–Smirnov tests were applied using SPSS. Results: The final study group included 58 bone lesions (19 patients (male: female = 6:13, age 52.5 ± 9.6, forty-four (75.9%) bone metastasis, fourteen (24.1%) benign red marrow hyperplasia). ADCs from BLADE and RESOLVE were significantly higher in bone metastasis than red marrow hyperplasia. BLADE showed higher ADC values, higher anatomical scores, and higher SNR than RESOLVE DWI (p< 0.05). Imaging times were longer for BLADE than RESOLVE (6 min 3 s vs. 3 min 47 s,p< 0.05). There was a poor correlation between ADC values and SUVs (correlation coefficient from 0.04 to 0.31). The AUROC values of BLADE and RESOLVE MRI ranged from 0.892~0.995. Those of PET ranged from 0.877~0.895. The cut-off ADC values between the bone metastasis and red marrow hyperplasia were 355.0, 686.5, 531.0 for BLADE min, max, and average, respectively, and 112.5, 737.0, 273.0 for RESOLVE min, max, and average, respectively. The cut-off SUV values were 1.84, 5.01, and 3.81 for mean, peak, and max values, respectively (p< 0.05). Conclusions: Compared with RESOLVE DWI, BLADE DWI showed improved image quality of pelvic bone MRI in the aspect of anatomical depiction and SNR, higher ADC values, albeit longer imaging time. BLADE and RESOLVE could differentiate bone metastasis and red marrow hyperplasia with quantifiable cut-off values. Further study is necessary to evaluate the discrepancy between the quantifiers between PET and MRI.
背景：本研究旨在比较径向轨迹涡轮自旋回波扩散加权成像（BLADE DWI）与多激发平面回波成像（RESOLVE DWI）在骨盆骨转移灶显像中的应用，探讨表观扩散系数（ADC）值与PET/CT中氟代脱氧葡萄糖（FDG）摄取的标准化摄取值（SUV）之间的相关性。同时，研究还比较了转移性病灶与良性骨病变（特别是红骨髓增生）的数值差异。 方法：这项经机构审查委员会批准的回顾性研究纳入了骨盆骨转移及红骨髓增生患者，所有患者在1个月内接受了3.0T磁共振成像（包含BLADE/RESOLVE DWI序列）和F-18 FDG PET/CT检查。采用最佳值比较法（BVC）判定骨病变性质。由放射科医师和核医学医师分别测量ADC值与SUV值。采用李克特量表对MRI图像质量进行分级评估，评估内容包括骶髂关节、骶神经孔、坐骨结节处腘绳肌腱及肿瘤边界的显示情况。比较两种DWI序列的信噪比（SNR）和成像时间。分析转移性与良性红骨髓病变的平均SUV、峰值SUV和最大SUV差异，并对SUV与ADC值进行相关性分析。通过受试者工作特征曲线（AUROC）分析获取各参数的诊断阈值及截断值。采用SPSS软件进行曼-惠特尼U检验、斯皮尔曼秩相关检验及柯尔莫哥洛夫-斯米尔诺夫检验。 结果：最终研究纳入58处骨病变（19例患者，男女比例6:13，年龄52.5±9.6岁），其中骨转移44处（75.9%），良性红骨髓增生14处（24.1%）。骨转移灶的BLADE与RESOLVE ADC值均显著高于红骨髓增生。BLADE序列较RESOLVE DWI显示出更高的ADC值、解剖结构评分及信噪比（p<0.05），但成像时间更长（6分3秒 vs. 3分47秒，p<0.05）。ADC值与SUV值相关性较弱（相关系数0.04-0.31）。BLADE与RESOLVE MRI的AUROC值范围为0.892~0.995，PET的AUROC值范围为0.877~0.895。骨转移与红骨髓增生的ADC截断值分别为：BLADE序列最小值355.0、最大值686.5、平均值531.0；RESOLVE序列最小值112.5、最大值737.0、平均值273.0。SUV截断值分别为：平均值1.84、峰值5.01、最大值3.81（p<0.05）。 结论：与RESOLVE DWI相比，BLADE DWI在骨盆MRI成像中具有更优的解剖显示能力和信噪比，ADC值更高，但成像时间较长。两种序列均可通过量化截断值区分骨转移与红骨髓增生。未来需进一步研究PET与MRI量化参数间的差异。
Evaluation of Three Imaging Methods to Quantify Key Events in Pelvic Bone Metastasis
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