Department of Imaging and Interventional Radiology, Faculty of Medicine, The Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
Department of Orthopaedics and Traumatology, Faculty of Medicine, The Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
BMC Musculoskelet Disord. 2020 Aug 18;21(1):558. doi: 10.1186/s12891-020-03561-2.
Although computed tomography (CT) is commonly used to diagnose the scoliotic spine in patients with adolescent idiopathic scoliosis (AIS) preoperatively, it is limited by the high radiation and prone scanning position. Recently, a new biplanar stereoradiography (EOS) was used to image the scoliotic spine in an upright posture with significantly less radiation in non-severe AIS subjects. However, its reliability to assess preoperative AIS patients remains unreported. Hence, the purpose of this study is to compare the scoliotic curvature between prone (CT) and upright positions (EOS) in preoperative AIS patients.
Thirty-three pre-operative AIS patients (mean age:18.4 ± 4.2) were recruited. EOS was used to scan the whole thoracic spine at upright position. Whereas on the same day, a conventional CT scan was used to evaluate the spine in prone position. The three-dimensional reconstruction of EOS and CT of the spine were then generated. Using previous validated techniques, multiple scoliotic parameters in both modalities were determined. The agreement between the two modalities was compared using the Bland-Altman test, whereas the correlation was assessed by the intraclass correlation coefficient (ICC).
The mean ICC (prone and upright) of intra-rater/inter-rater reliabilities for the measured parameters were 0.985,0.961/0.969,0.903, respectively. Thoracic Cobb angles, intervertebral wedging and lumbar lordosis correlated significantly between upright EOS imaging radiographs (62.9 ± 9.3°,6.4 ± 2.9° and 48.8 ± 12.4°) and prone CT (47.3 ± 10.0°,5.8 ± 2.7° and 27.9 ± 11.4°; P < 0.001). The apical vertebral wedging and apical intervertebral disc wedging showed a good correlation among the two modalities (upright, 6.5 ± 3.5° and 6.4 ± 2.9°; prone, 6.5 ± 3.6° and 5.8 ± 2.7°; R ≥ 0.94; P < 0.01). Similarly, there was significant correlation in apical intervertebral rotation (R = 0.834; P < 0.01) between the prone CT (3.4 ± 3.0°) and upright EOS (3.8 ± 3.2°). In addition, the Cobb angle was significantly larger in upright EOS (62.9 ± 9.3°) than in prone CT (47.3 ± 10.0°, P < 0.01) position. There was significant underestimation on scoliotic severity in the prone position when compared with upright position.
Importantly, the image acquisition and reconstruction from EOS can better provide accurate three-dimensional spinal representations of the scoliotic curvature in preoperative AIS patients. Moreover, our findings suggested that scoliotic curvatures in preoperative AIS patients can be largely represented by both imaging modalities despite the difference in body positioning.
尽管计算机断层扫描（CT）常用于术前诊断青少年特发性脊柱侧凸（AIS）患者的脊柱侧弯，但它受到高辐射和易位扫描位置的限制。最近，一种新的双平面立体放射摄影术（EOS）用于在非重度 AIS 患者的直立姿势下对脊柱侧弯进行成像，辐射显著减少。然而，其评估术前 AIS 患者的可靠性仍未报道。因此，本研究的目的是比较术前 AIS 患者的俯卧位（CT）和直立位（EOS）的脊柱侧弯程度。
招募了 33 例术前 AIS 患者（平均年龄：18.4±4.2）。EOS 用于在直立位置扫描整个胸椎。而在同一天，使用常规 CT 扫描评估俯卧位的脊柱。然后对 EOS 和 CT 的脊柱进行三维重建。使用先前验证的技术，在两种模式下确定多个脊柱侧弯参数。使用 Bland-Altman 检验比较两种模式之间的一致性，使用组内相关系数（ICC）评估相关性。
两种模式下的测量参数的组内/组间可靠性的平均 ICC（俯卧和直立）分别为 0.985、0.961/0.969、0.903。直立 EOS 成像片（62.9±9.3°、6.4±2.9°和 48.8±12.4°）和俯卧 CT（47.3±10.0°、5.8±2.7°和 27.9±11.4°）之间的胸椎 Cobb 角、椎间隙楔形和腰椎前凸相关性显著（P<0.001）。顶椎椎体楔形和顶椎椎间盘楔形在两种模式之间具有良好的相关性（直立，6.5±3.5°和 6.4±2.9°；俯卧，6.5±3.6°和 5.8±2.7°；R≥0.94；P<0.01）。同样，顶椎椎间旋转在俯卧 CT（3.4±3.0°）和直立 EOS（3.8±3.2°）之间具有显著相关性（R=0.834；P<0.01）。此外，直立 EOS 中的 Cobb 角（62.9±9.3°）显著大于俯卧 CT（47.3±10.0°，P<0.01）位置。与直立位置相比，俯卧位对脊柱侧弯严重程度的估计明显低估。
重要的是，EOS 的图像采集和重建可以更好地提供术前 AIS 患者脊柱侧弯的准确三维脊柱表示。此外，尽管体位不同，但我们的发现表明，两种成像方式都可以很好地代表术前 AIS 患者的脊柱侧弯程度。
