Department of Oral and Maxillofacial Surgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
Department of Oral and Maxillofacial Surgery, Translational Implantology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Dentomaxillofac Radiol. 2021 Feb 1;50(2):20200068. doi: 10.1259/dmfr.20200068. Epub 2020 Nov 17.
Autologous bone grafts are the gold standard to augment deficient alveolar bone. Dimensional graft alterations during healing are not known as they are not accessible to radiography. Therefore, MRI was used to display autologous onlay bone grafts in vivo during early healing.
Ten patients with alveolar bone atrophy and autologous onlay grafts were included. MRI was performed with a clinical MR system and an intraoral coil preoperatively (t0), 1 week (t1), 6 weeks (t2) and 12 weeks (t3) postoperatively, respectively. The graft volumes were assessed in MRI by manual segmentation by three examiners. Graft volumes for each time point were calculated and dimensional alteration was documented. Cortical and cancellous proportions of bone grafts were assessed. The intraobserver and interobserver variability were calculated. Statistical analysis was performed using a mixed linear regression model.
Autologous onlay bone grafts with cortical and cancellous properties were displayed in eight patients over 12 weeks. The fixation screws were visible as signal voids with a thin hyperintense fringe. The calculated volumes were between 0.12-0.74 cm (t1), 0.15-0.73 cm (t2), and 0.17-0.64 cm (t3). Median changes of bone graft volumes of -15% were observed. There was no significant difference between the examiners ( = 0.3).
MRI is eligible for the display and longitudinal observation of autologous onlay bone grafts. Image artifacts caused measurements deviations in some cases and minimized the precise assessment of graft volume. To the knowledge of the authors, this is the first study that used MRI for the longitudinal observation of autologous onlay bone grafts.
自体骨移植物是增加牙槽骨缺损的金标准。由于在愈合过程中无法进行放射线检查，因此不知道移植物的尺寸变化。因此，本研究使用 MRI 活体显示早期愈合过程中的自体骨块移植。
纳入 10 例牙槽骨萎缩伴自体骨块移植的患者。分别在术前（t0）、术后 1 周（t1）、6 周（t2）和 12 周（t3）进行临床 MRI 系统和口腔内线圈 MRI 检查。由三位观察者手动分割 MRI 评估移植体体积。计算每个时间点的移植体体积，并记录尺寸变化。评估移植骨皮质和松质的比例。计算观察者内和观察者间的可变性。使用混合线性回归模型进行统计分析。
8 例患者在 12 周内显示出具有皮质和松质特性的自体骨块移植。固定螺钉表现为信号缺失的线状低信号影，伴有薄的高亮边缘。计算的体积分别为 0.12-0.74cm³（t1）、0.15-0.73cm³（t2）和 0.17-0.64cm³（t3）。骨移植体积的中位数变化为-15%。观察者之间无显著差异（ = 0.3）。
MRI 适用于显示和纵向观察自体骨块移植。在某些情况下，图像伪影会导致测量偏差，从而无法精确评估移植物体积。据作者所知，这是首例使用 MRI 对自体骨块移植进行纵向观察的研究。
