Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, and Diakonhjemmet Hospital and University of Oslo, Oslo, Norway.
University of Arizona College of Medicine, Tucson.
Arthritis Care Res (Hoboken). 2022 Dec;74(12):2013-2023. doi: 10.1002/acr.24745. Epub 2022 Sep 6.
Local-area cartilage segmentation (LACS) software was developed to segment medial femur (MF) cartilage on magnetic resonance imaging (MRI). Our objectives were 1) to extend LACS to the lateral femur (LF), medial tibia (MT), and lateral tibia (LT), 2) to compare LACS to an established manual segmentation method, and 3) to visualize cartilage responsiveness over each cartilage plate.
Osteoarthritis Initiative participants with symptomatic knee osteoarthritis (OA) were selected, including knees selected at random (n = 40) and knees identified with loss of cartilage based on manual segmentation (Chondrometrics GmbH), an enriched sample of 126 knees. LACS was used to segment cartilage in the MF, LF, MT, and LT on sagittal 3D double-echo steady-state MRI scans at baseline and at 2-year follow-up. We compared LACS and Chondrometrics average thickness measures by estimating the correlation in each cartilage plate and estimating the standardized response mean (SRM) for 2-year cartilage change. We illustrated cartilage loss topographically with SRM heatmaps.
The estimated correlation between LACS and Chondrometrics measures was r = 0.91 (95% confidence interval [95% CI] 0.86, 0.94) for LF, r = 0.93 (95% CI 0.89, 0.95) for MF, r = 0.97 (95% CI 0.96, 0.98) for LT, and r = 0.87 (95% CI 0.81, 0.91) for MT. Estimated SRMs for LACS and Chondrometrics measures were similar in the random sample, and SRM heatmaps identified subregions of LACS-measured cartilage loss.
LACS cartilage thickness measurement in the MF and LF and tibia correlated well with established manual segmentation-based measurement, with similar responsiveness to change, among knees with symptomatic knee OA. LACS measurement of cartilage plate topography enables spatiotemporal analysis of cartilage loss in future knee OA studies.
局部软骨分割（LACS）软件用于对磁共振成像（MRI）上的内侧股骨（MF）软骨进行分割。我们的目标是 1）将 LACS 扩展到外侧股骨（LF）、内侧胫骨（MT）和外侧胫骨（LT），2）将 LACS 与已建立的手动分割方法进行比较，3）可视化每个软骨板上的软骨反应性。
选择患有症状性膝骨关节炎（OA）的骨关节炎倡议参与者，包括随机选择的膝关节（n=40）和根据手动分割（Chondrometrics GmbH）识别的软骨丢失的膝关节，这是一个 126 个膝关节的富集样本。在基线和 2 年随访时，使用 LACS 对矢状位 3D 双回波稳态 MRI 扫描中的 MF、LF、MT 和 LT 进行软骨分割。我们通过估计每个软骨板中的相关性和估计 2 年软骨变化的标准化反应均值（SRM）来比较 LACS 和 Chondrometrics 的平均厚度测量值。我们使用 SRM 热图对软骨损失进行地形学描绘。
LACS 和 Chondrometrics 测量值之间的估计相关性在 LF 为 r=0.91（95%置信区间[95%CI]0.86，0.94），在 MF 为 r=0.93（95%CI 0.89，0.95），在 LT 为 r=0.97（95%CI 0.96，0.98），在 MT 为 r=0.87（95%CI 0.81，0.91）。在随机样本中，LACS 和 Chondrometrics 测量值的估计 SRM 相似，并且 SRM 热图确定了 LACS 测量的软骨损失的亚区。
在有症状的膝骨关节炎膝关节中，MF 和 LF 以及胫骨的 LACS 软骨厚度测量与基于已建立的手动分割的测量值相关性良好，与变化的反应性相似。LACS 对软骨板地形的测量可实现未来膝骨关节炎研究中软骨损失的时空分析。
