Department of Radiology, Stanford University, Stanford, CA, USA.
Department of Radiology, Stanford University, Stanford, CA, USA.
Osteoarthritis Cartilage. 2018 Jun;26(6):790-796. doi: 10.1016/j.joca.2018.04.001. Epub 2018 Apr 12.
To investigate changes in bone metabolism by positron emission tomography (PET), as well as spatial relationships between bone metabolism and magnetic resonance imaging (MRI) quantitative markers of early cartilage degradation, in anterior cruciate ligament (ACL)-reconstructed knees.
Both knees of 15 participants with unilateral reconstructed ACL tears and unaffected contralateral knees were scanned using a simultaneous 3.0T PET-MRI system following injection of F-sodium fluoride (F-NaF). The maximum pixel standardized uptake value (SUV) in the subchondral bone and the average T relaxation time in cartilage were measured in each knee in eight knee compartments. We tested differences in SUV and cartilage T relaxation times between the ACL-injured knee and the contralateral control knee as well as spatial relationships between these bone and cartilage changes.
Significantly increased subchondral bone F-NaF SUV and cartilage T times were observed in the ACL-reconstructed knees (median [inter-quartile-range (IQR)]: 5.0 [5.8], 36.8 [3.6] ms) compared to the contralateral knees (median [IQR]: 1.9 [1.4], 34.4 [3.8] ms). A spatial relationship between the two markers was also seen. Using the contralateral knee as a control, we observed a significant correlation of r = 0.59 between the difference in subchondral bone SUV (between injured and contralateral knees) and the adjacent cartilage T (between the two knees) [P < 0.001], with a slope of 0.49 ms/a.u. This correlation and slope were higher in deep layers (r = 0.73, slope = 0.60 ms/a.u.) of cartilage compared to superficial layers (r = 0.40, slope = 0.43 ms/a.u.).
F-NaF PET-MR imaging enables detection of increased subchondral bone metabolism in ACL-reconstructed knees and may serve as an important marker of early osteoarthritis (OA) progression. Spatial relationships observed between early OA changes across bone and cartilage support the need to study whole-joint disease mechanisms in OA.
通过正电子发射断层扫描（PET）研究骨代谢的变化，以及骨代谢与磁共振成像（MRI）定量评估早期软骨退变的标志物之间的空间关系，在重建前交叉韧带（ACL）的膝关节中。
使用同时 3.0T 的 PET-MRI 系统对 15 名单侧 ACL 撕裂患者的双侧膝关节和未受伤的对侧膝关节进行扫描，注射 F-氟化钠（F-NaF）后。在每个膝关节的 8 个膝关节间隙中测量软骨下骨的最大像素标准化摄取值（SUV）和软骨的平均 T 弛豫时间。我们测试了 ACL 损伤侧膝关节与对侧对照膝关节之间 SUV 和软骨 T 弛豫时间的差异以及这些骨和软骨变化之间的空间关系。
与对侧膝关节相比，重建 ACL 的膝关节中软骨下骨 F-NaF SUV 和软骨 T 时间显著增加（中位数[四分位数范围（IQR）]：5.0[5.8]，36.8[3.6]ms）（中位数[IQR]：1.9[1.4]，34.4[3.8]ms）。还观察到这两个标志物之间的空间关系。以对侧膝关节为对照，我们观察到损伤侧与对侧膝关节之间软骨下骨 SUV 差异（r=0.59）与两个膝关节之间相邻软骨 T 之间的显著相关性[P<0.001]，斜率为 0.49ms/a.u。与浅层（r=0.40，斜率=0.43ms/a.u.）相比，这种相关性和斜率在软骨的深层（r=0.73，斜率=0.60ms/a.u.）更高。
F-NaF PET-MR 成像能够检测到重建 ACL 的膝关节中软骨下骨代谢增加，可能是早期骨关节炎（OA）进展的重要标志物。在骨和软骨之间观察到的早期 OA 变化的空间关系支持需要研究 OA 中的整个关节疾病机制。
