Computer-aided assessment of scoliosis on posteroanterior radiographs

In order to reduce the observer variability in radiographic scoliosis assessment, a computer-aided system was developed. The system semi-automatically measured the Cobb angle and vertebral rotation on posteroanterior radiographs based on Hough transform and snake model, respectively. Both algorithms were integrated with the shape priors to improve the performance. The system was tested twice by each of three observers. The intraobserver and interobserver reliability analyses resulted in the intraclass correlation coefficients higher than 0.9 and 0.8 for Cobb measurement on 70 radiographs and rotation measurement on 156 vertebrae, respectively. Both the Cobb and rotation measurements resulted in the average intraobserver and interobserver errors less than 2° and 3°, respectively. There were no significant differences in the measurement variability between groups of curve location, curve magnitude, observer experience, and vertebra location. Compared with the documented results, measurement variability is reduced by using the developed system. This system can help orthopedic surgeons assess scoliosis more reliably.     

Validity and Reliability of Active Shape Models for the Estimation of Cobb Angle in Patients with Adolescent Idiopathic Scoliosis

Choosing the most suitable treatment for scoliosis relies heavily on accurate and reproducible Cobb angle measurement from successive radiographs. The objective is to reduce variability of Cobb angle measurement by reducing user intervention and bias. Custom software to increase automation of the Cobb angle measurement from posteroanterior radiographs was developed using active shape models. Validity and reliability of the automated system against a manual and semiautomated measurement method was conducted by two examiners each performing measurements on three occasions from a test set (N = 22). A training set (N = 47) of radiographs representative of curves seen in a scoliosis clinic was used to train the software to recognize vertebrae from T4 to L4. Images with a maximum Cobb angle between 20 degrees and 50 degrees , excluding surgical cases, were selected for training and test sets. Automated Cobb angles were calculated using best-fit slopes of the detected vertebrae endplates. Intraclass correlation coefficient (ICC) and standard error of measurement (SEM) showed high intraexaminer (ICC > 0.90, SEM 2 degrees -3 degrees ) and interexaminer (ICC > 0.82, SEM 2 degrees -4 degrees ), but poor intermethod reliability (ICC = 0.30, SEM 8 degrees -9 degrees ). The automated method underestimated large curves. The reliability improved (ICC = 0.70, SEM 4 degrees -5 degrees ) with exclusion of the four largest curves (>40 degrees ) in the test set. The automated method was reliable for moderate-sized curves, and did detect vertebrae in larger curves with a modified training set of larger curves.     

Anterior instrumentation for correction of adolescent thoracic idiopathic scoliosis: historic prospective study

Aim

To compare the results of anterior instrumentation and standard posterior procedure for correction of adolescent thoracic idiopathic scoliosis.

Methods

The study included 50 patients with adolescent thoracic idiopathic scoliosis who underwent corrective spinal surgery. Anterior spinal fusion by use of modified Zielke ventral derotation system (anterior approach to spine through thorax) was performed in 25 patients, whereas posterior approach was used in 25 patients. The average preoperative thoracic curve in coronal plane was 66.7 ± 9.9° and 65.0 ± 11.7° in the anterior and posterior correction groups, respectively. The median age of patients before surgery was 14 years (range, 12-18) in the anterior and 16 years (range, 13-18) in the posterior correction group. Women-to-men ratio was 22 to 3 in each group. Coronal and sagittal correction, apical vertebral body rotation, rib hump, and rib depression correction were measured before surgery and at the first (30 days after surgery) and at the second follow-up visit (at least 2 years after surgery). Posteroanterior and laterolateral radiographs of the erect spine were used (according to the method of Cobb and Nash-Moe) to assess coronal, sagittal, and horizontal plane corrections. Rib hump and rib depression were measured with Thulbourne-Gillespie measuring device. The differences in scoliosis correction parameters in the two groups were tested with Student two-tailed t test.

Results

In the coronal plane, the thoracic curve of 66.7 ± 9.9° before surgery in the anterior correction group was reduced to 14.8 ± 8.7° after surgery (78.1 ± 12.4% relative correction), and the curve of 65.0 ± 11.7° in the posterior correction group was corrected to 29.2 ± 7.8° after surgery (55.1 ± 8.6% relative correction) (P<0.001). Apical vertebral body rotation correction according to the Nash-Moe classification from 2.0 ± 0.4° to 0.8 ± 0.6° was achieved in the anterior correction group (62.0 ± 26.6% relative correction) and from 1.7 ± 0.5° to 1.4 ± 0.5° in the posterior correction group (12.0 ± 21.8% relative correction) (P<0.001). Rib hump correction from 22.4 ± 15.5 mm to 5.4 ± 5.2 mm was found in the anterior correction group (70.9 ± 26.0% relative correction) and from 25.3 ± 7.0 mm to 13.6 ± 6.8 mm (48.4 ± 16.5% relative correction) in the posterior correction group (P = 0.084).

Conclusion

Compared with the standard posterior approach, the anterior approach resulted in better three-dimensional correction of idiopathic thoracic scoliosis.In patients with adolescent idiopathic scoliosis, the spine is curved to the side and rotated around the long axis, producing unilateral prominence of the trunk. The prominence of the rib cage is visible on the convex side of the curve and depression is present on the concave side. It is often the rib hump rather than the lateral curve that is the major cosmetic deformity (1). The prevalence of idiopathic scoliosis varies significantly because of the lack of uniformity in defining target population and the use of different definitions of scoliosis (2,3).Traditionally, thoracic idiopathic scoliosis has been treated by posterior instrumentation and fusion, which is still the gold standard (4). Harrington instrumentation was the first accepted implant used for the correction of scoliosis (5). The next major step in scoliosis surgery was the use of Luque rods with sublaminar wires (6). Posterior spinal fusion with multisegmented hook-rod systems was widely used in the mid to late 1980s, with successful results (7). Suk et al (8) reported extensively on the posterior use of pedicle screw fixation for thoracic scoliosis, which also produced excellent results. Anterior spinal fusion with Dwyer instrumentation represented the first generation of anterior implants for correction of lumbar scoliosis (9). Subsequent to that, Zielke rigid rod anterior instrumentation has been adapted and used to save fusion levels in the distal lumbar spine (10). Because of the problems with a high rate of rod breakage reported during the follow-up study of Zielke instrumentation (11) used anteriorly for thoracic, thoracolumbar, and lumbar curves, a new rod-screw-nut system was developed. Slot added another rod to Zielke’s instrumentation to correct kyphosis (12). The Harms Study Group elaborated and refined the concepts of anterior instrumentation for thoracic idiopathic scoliosis (13).The posterior approach has a long history of success with different instrumentations, allowing a solution for any combination of thoracic deformities, whereas the anterior approach offers no possibility of correction for partial or complete structural left high thoracic curve (4). However, correction of the rotational component of thoracic spine deformity is not affected significantly with posterior approach (14,15). Kovač et al (16) showed better thoracic volume correction after the anterior than after the posterior approach. In some cases, a significant number of distal vertebral segments can be saved by use of anterior instrumentation, with an excellent spontaneous lumbar curve correction (17).Controversy still exists about the benefits of the anterior in comparison with the posterior approach (4). The aim of this study was to compare the scoliosis correction after the anterior instrumentation with that obtained by the standard posterior procedure in patients with adolescent thoracic idiopathic scoliosis.     

Computer-Generated Index for Evaluation of Idiopathic Scoliosis in Digital Chest Images: A Comparison with Digital Measurement

An intelligence system was used to generate index for scoliosis. Tests were designed to evaluate the consistency of the automatic computer-generated index and to quantify the correlation between Cobb angle and computer generated scoliosis classification index (SCI). A fully automatic computer-generated index can be used to assess the extent of spinal curvature rather than manual measurement on radiographs. This study aims to evaluate the relation of an automatic computer-generated index in assessing the spinal curvature of scoliosis quantitatively on digital chest images. Sixty chest radiographs were obtained in this study. Cobb angle measurement and the index generated were compared by parametric statistical tests. The SCI method was demonstrated to be reproducible. There was also statically significant positive correlation between Cobb angle and SCI (Pearson’s correlation: r = 0.9229). The Computer-generated index method is valid and reliable in quantifying measurement of spinal curvature of scoliosis as the correlation between Cobb’s angle and SCI in nearly perfect positive for Cobb angle more than 10 degree. It is noted that with widely use of this computer method, this quantitative method proposed is a promising method in improving the reliability of scoliosis assessment and reducing the workload of clinical staff.     

Convolutional Neural Network to Segment Laminae on 3D Ultrasound Spinal Images to Assist Cobb Angle Measurement

A recent innovation in scoliosis monitoring is the use of ultrasonography, which provides true 3D information in one scan and does not emit ionizing radiation. Measuring the severity of scoliosis on ultrasonographs requires identifying lamina pairs on the most tilted vertebrae, which is difficult and time-consuming. To expedite and automate measurement steps, this paper detailed an automatic convolutional neural network-based algorithm for identifying the laminae on 3D ultrasonographs. The predicted laminae were manually paired to measure the lateral spinal curvature on the coronal view, called the Cobb angle. In total, 130 spinal ultrasonographs of adolescents with idiopathic scoliosis recruited from a scoliosis clinic were selected, with 70 for training and 60 for testing. Data augmentation increased the effective training set size to 140 ultrasonographs. Semi-automatic Cobb measurements were compared to manual measurements on the same ultrasonographs. The semi-automatic measurements demonstrated good inter-method reliability (ICC_3,1 = 0.87) and performed better on thoracic (ICC_3,1 = 0.91) than lumbar curves (ICC_3,1 = 0.81). The mean absolute difference and standard deviation between semi-automatic and manual was 3.6° ± 3.0°. In conclusion, the semi-automatic method to measure the Cobb angle on ultrasonographs is feasible and accurate. This is the first algorithm that automates steps of Cobb angle measurement on ultrasonographs.

     

Support Vector Machine Model for Diagnosing Pneumoconiosis Based on Wavelet Texture Features of Digital Chest Radiographs

This study aims to explore the classification ability of decision trees (DTs) and support vector machines (SVMs) to discriminate between the digital chest radiographs (DRs) of pneumoconiosis patients and control subjects. Twenty-eight wavelet-based energy texture features were calculated at the lung fields on DRs of 85 healthy controls and 40 patients with stage I and stage II pneumoconiosis. DTs with algorithm C5.0 and SVMs with four different kernels were trained by samples with two combinations of the texture features to classify a DR as of a healthy subject or of a patient with pneumoconiosis. All of the models were developed with fivefold cross-validation, and the final performances of each model were compared by the area under receiver operating characteristic (ROC) curve. For both SVM (with a radial basis function kernel) and DT (with algorithm C5.0), areas under ROC curves (AUCs) were 0.94 ± 0.02 and 0.86 ± 0.04 (P = 0.02) when using the full feature set and 0.95 ± 0.02 and 0.88 ± 0.04 (P = 0.05) when using the selected feature set, respectively. When built on the selected texture features, the SVM with a polynomial kernel showed a higher diagnostic performance with an AUC value of 0.97 ± 0.02 than SVMs with a linear kernel, a radial basis function kernel and a sigmoid kernel with AUC values of 0.96 ± 0.02 (P = 0.37), 0.95 ± 0.02 (P = 0.24), and 0.90 ± 0.03 (P = 0.01), respectively. The SVM model with a polynomial kernel built on the selected feature set showed the highest diagnostic performance among all tested models when using either all the wavelet texture features or the selected ones. The model has a good potential in diagnosing pneumoconiosis based on digital chest radiographs.     

Segmental patterns of sagittal spinal curvatures in children screened for scoliosis: Kyphotic angulation at the thoracolumbar region and the mortice joint

This paper reports a segmental analysis of the lateral spinal radiographs of 37 children referred to hospital in a school screening study of 4,890 school children aged 12–13 years. On each lateral radiograph a line was drawn along the posterior surface of each vertebral body from T5-L5 and the angle of this line from the vertical was recorded. After measuring the scoliosis curve (Cobb) angle and using conventional criteria for diagnosis, three groups of patients are defined, namely, 1) a control group (average scoliosis curve angle (Cobb) of 5°, n = 14), 2) a group with lumbar curves (average Cobb angle 21°, n = 7), and 3) a group with thoracic curves (average Cobb angle 19 degrees, n = 10). Individual lateral spinal profiles are also analyzed. The findings show: (1) In the control group, there are different degrees of vertical backward tilt (declivity) from T7–L3, with a maximum tilt at T12 (mean 26°). The most vertical vertebrae are T6 and L4, with forward tilting (proclivity) at each of (T5 and L5.2) In the lumbar curve group, the segmental sagittal tilt is not significantly different from that in the control group. The mean declivity at T12 is 25°. (3) In the thoracic curve group, the segmental sagittal tilt is significantly less than that in the control group at each of T10–L1. The mean declivity at T12 is 17°. A more vertical T12 is associated with a larger Cobb angle. (4) The individual sagittal spinal profiles of the thoracic curve group (but no other group) show lordosis in the region of the lateral spinal curve (scoliosis) and a kyphotic angulation at an average of three vertebrae below the apical vertebrae of the scoliosis curve. (5) It is suggested that as a thoracic lordoscoliosis develops, the appearance of a kyphotic angulation in the thoracolumbar and upper lumbar spine is determined by the compressibility of each disc in relation to the length of the articular processes at the corresponding level. Where the combination of disc weakness to facet length is most adverse, forward flexion occurs, as in a spinal fracture, to produce the kyphotic angulation. © 1992 Wiley-Liss, Inc.     

骨质疏松椎体压缩性骨折患者脊柱矢状面的失平衡

背景：国内外总结脊柱失平衡的原因包括脊柱畸形、脊柱退变性疾病、骨质疏松椎体压缩性骨折等,作者通过临床研究认为动力性因素(腰背肌)在脊柱矢状面失平衡中起关键作用。 目的：通过观察骨质疏松椎体压缩性骨折患者的临床表现和治疗效果,分析脊柱矢状面失平衡的原因。 方法：回顾性分析2012年1月至2013年5月收治的骨质疏松压缩性骨折伴脊柱矢状面失平衡患者41例,均在局麻下行经皮穿刺球囊扩张椎体成形治疗。治疗前患者均行骨密度、站立位全脊柱正侧位X射线、以伤椎为中心的CT及MR检查。于患者站立位全脊柱正侧位片中测量伤椎前缘高度、脊柱后凸Cobb角及改善角度、伤椎楔形变角度及改善角度;要求患者行负重试验及行走试验,对比治疗前后数据。 结果与结论：治疗前患者出现脊柱矢状面失平衡症状所需行走的距离显著短于治疗后(P < 0.05);治疗前出现脊柱矢状面失平衡负重试验时间亦显著短于治疗后(P < 0.05)。在治疗前后站立位全脊柱正侧位片中,Cobb角的平均差值为(10.01±0.76)°,椎体楔形变改善的平均差值为(4.84±0.40)°,差异有显著性意义(P < 0.05)。所有患者均获随访,患者腰背部疼痛及矢状面失平衡症状明显缓解。所有患者行经皮球囊扩张椎体成形治疗后无严重并发症发生。提示骨质疏松压缩性骨折部分患者会出现脊柱矢状面失平衡症状,原因并非伤椎楔形变单一因素所致。且患者通过经皮球囊扩张后凸成形治疗后,失平衡症状往往会明显改善,提示脊柱骨折后腰痛限制腰背肌力量是导致脊柱矢状面失平衡的一个重要原因。中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程全文链接：     

退行性腰椎侧凸程度与骨质疏松症程度无关

背景：骨质疏松是以全身骨组织显微结构损坏及全身骨量减少为特征,有学者认为骨质疏松患者腰椎椎体前高不会减少,反而会有增加的趋势。 目的：分析退行性腰椎侧凸与骨质疏松症的相关性。 方法：选取退行性腰椎侧凸患者37例,另选取同期在住院治疗的腰椎非侧凸组患者37例。测量时采用改良Cobb法,沿患者的T12-L5各椎体上终板平行划线,2条线的最大夹角为侧凸角,两线所在椎体即为上、下端椎。运用双能X射线吸收法对患者L₂-L₄、股骨颈、Ward’s三角区以及股骨转子的骨密度进行测定。采用Linear regression对骨质疏松和退行性腰椎侧凸症的相关性进行分析 结果与结论：腰椎侧凸组患者L₂-L₄、股骨颈、Ward’s三角区以及股骨转子部位的骨密度T值与腰椎非侧凸组比较差异有显著性意义(P < 0.05),其中股骨各部位骨密度较腰椎(L₂-L₄)较低。腰椎侧凸组患者骨质疏松症发病率明显高于腰椎非侧凸组患者(P < 0.05)。Linear regression回归分析结果显示骨质疏松症是退行性腰椎侧凸发病的危险因素;退行性腰椎侧凸患者的腰椎及股骨近端各个部位的T值与侧凸Cobb’s角无明显相关性。结果提示,骨质疏松症是退行性腰椎侧凸发病的危险因素,同时骨质疏松程度与侧凸程度无关。     

青少年特发性脊柱侧凸的脊柱后路矫形及其影响因素

背景：后路矫形是治疗青少年特发性脊柱侧凸较为有效的方法,但目前关于青少年特发性脊柱侧凸患者后路矫形后脊柱高度的矫正程度及其影响因素鲜见报道。 目的：分析后路矫形对青少年特发性脊柱侧凸患者的脊柱矫形效果及其影响因素。 方法：回顾性分析青少年特发性脊柱侧凸患者346例的病历资料,其中单弯组203例,双弯组143例。测量患者矫形前后脊柱侧弯Cobb角和脊柱高度,采用逐步筛选回归法分析探讨性别、年龄、体质量、治疗前脊柱高度、治疗后脊柱高度、治疗前Cobb角、Cobb角矫正值、Cobb角矫正率、融合节段数、脊柱单弯或双弯、Lenke分型与矫形后脊柱高度增加值的关系。 结果与结论：单弯组和双弯组患者矫形后的Cobb角均显著小于矫形前(P < 0.05),脊柱高度显著高于矫形前(P < 0.05),随着矫形前Cobb角的增加Cobb角减少值(?Cobb)和脊柱高度增加值(?SH)均显著增加(P < 0.05)。多元线性回归分析结果显示Cobb角矫正值、治疗前Cobb角、治疗后脊柱高度、Lenke分型、脊柱单弯或双弯、年龄对治疗后脊柱高度增加值(?SH)有显著性影响(P < 0.01),其中Cobb角矫正值是最大的影响因素。提示后路矫形对青少年特发性脊柱侧凸有显著的脊柱矫形效果,影响治疗后脊柱高度增加值的影响因素包括Cobb角矫正值、治疗前Cobb角、治疗后脊柱高度、Lenke分型、脊柱单弯或双弯、年龄。 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程      

Cobb法测量先天性脊柱侧凸角度的可信度研究

目的评价Cobb法测量先天性脊柱侧凸角度的可靠性和可重复性。方法选取第四军医大学西京医院脊柱外科2010年1月—2013年12月收治的78例先天性脊柱侧凸患者的标准前后位全脊柱X线片。由5名医生利用Digimizer软件对全脊柱X线片测量Cobb角度,每人测量2次,2次测量间隔3周。记录测量的Cobb角度以及两次测量的差值。应用组内相关系数（ICC）判定可靠性和可重复性。结果Cobb法测量先天性脊柱侧凸角度的可信度范围为0．84—0．98,5名测量者两次测量间最大差值的范围为20°-57°,其中差值〉10°的例数范围为13～46例,同一测量者两次测量间的误差约8．5°;测量者之间的可信度为0．947,5名测量者在81°～110°组和〉110°组之间的ICC为0．623和0．822。结论Cobb法测量先天性脊柱侧凸可以获得较好的可靠性和可重复性,但是测量者内部以及测量者之间仍然出现较多且较大的误差,尤其在侧凸角度较大时,Cobb法测量先天性脊柱侧凸的准确性缺乏稳定性。     

Design and Validation of Automated Femoral Bone Morphology Measurements in Cerebral Palsy

Accurate quantification of bone morphology is important for monitoring the progress of bony deformation in patients with cerebral palsy. The purpose of the study was to develop an automatic bone morphology measurement method using one or two radiographs. The study focused on four morphologic measurements—neck-shaft angle, femoral anteversion, shaft bowing angle, and neck length. Fifty-four three-dimensional (3D) geometrical femur models were generated from the computed tomography (CT) of cerebral palsy patients. Principal component analysis was performed on the combined data of geometrical femur models and manual measurements of the four morphologic measurements to generate a statistical femur model. The 3D–2D registration of the statistical femur model for radiography computes four morphological measurements of the femur in the radiographs automatically. The prediction performance was tested here by means of leave-one-out cross-validation and was quantified by the intraclass correlation coefficient (ICC) and by measuring the absolute differences between automatic prediction from two radiographs and manual measurements using original CT images. For the neck-shaft angle, femoral anteversion, shaft bowing angle, and neck length, the ICCs were 0.812, 0.960, 0.834, and 0.750, respectively, and the mean absolute differences were 2.52°, 2.85°, 0.92°, and 1.88 mm, respectively. Four important dimensions of the femur could be predicted from two views with very good agreement with manual measurements from CT and hip radiographs. The proposed method can help young patients avoid instances of large radiation exposure from CT, and their femoral deformities can be quantified robustly and effectively from one or two radiograph(s).     

Prediction of scoliosis progression with serial three-dimensional spinal curves and the artificial progression surface technique

Adolescent idiopathic scoliosis (AIS) progression is clinically monitored by a series of full spinal X-rays. To decrease radiation exposure, an artificial progression surface (APS) is proposed to predict progression. Fifty-six acquisitions (posteroanterior radiographs, 0° and 20°) were obtained from 11 AIS patients (29.8 ± 9.6° Cobb angle). Three-dimensional curves were constructed through vertebral pedicle centers. Three previous serial spinal curves (6-month intervals) were used to construct an APS with a Non-uniform Rational B-Spline surfacing technique. Future progression was achieved by aligning the curves on the APS using the generalized cross-validation extrapolation technique. With three and four previous serial spinal curves, the prediction accuracies of future progression at the next 6-month interval were 4.1 ± 3.3° for Cobb angles and 3.6 ± 3.5 mm for apex lateral deviations. Apex locations and Cobb regions varied within one vertebral level. The proposed technique shows potential as an accurate three-dimensional prediction method for AIS progression and could help pediatricians make decisions about treatment. However, it could only be applied once before more radiographic data would be needed.     

体位设定复位联合椎体骨水泥注入成形治疗重度椎体骨质疏松压缩性骨折

背景：在压缩程度超过原有椎体高度2/3的重度压缩骨折病例中,椎体成形是禁忌的。 目的：验证可通过椎体成形联合患者体位设定治疗重度椎体骨质疏松压缩性骨折。 方法：共75例骨质疏松单一椎体压缩骨折患者行椎体成形及体位设定复位,根据发病时间不同分为<4周组、4~8周组、>8周组,其中30例患者椎体高度压缩程度超过原有椎体2/3,分别测量椎体压缩比(椎体前方高度/后方高度)和节段Cobb角,分析复位程度与发病持续时间的关系。 结果与结论：最初检查时患者骨折椎体前后方平均压缩比为0.60±0.15,椎体成形后增加到0.75±0.17。最初检查时Cobb角为(16.14±11.29)°,椎体成形后矫正到(10.71±12.08)°。压缩比差、矢状面骨折节段Cobb角差均随发病持续时间延长而减小。30例中的28例(占其中的93%)重度压缩骨折患者通过体位复位后,可行椎体成形。患者椎体成形后疼痛均缓解。提示椎体骨折发病时间越短,复位程度越好,Cobb角纠正越多,脊柱矢状面后凸畸形改善越明显,椎体成形后疼痛程度越明显改善。     

伤椎椎弓根植骨加短节段椎弓根螺钉置入内固定治疗老年人胸腰椎骨折

背景：传统椎弓根内固定系统加后外侧植骨融合治疗老年胸腰椎爆裂性骨折易发生复位角度、高度丢失,迟发性神经损伤,内固定松动。 目的：观察经骨折椎椎弓根植骨联合椎弓根内固定治疗老年胸腰椎爆裂性骨折的方法和效果。 方法：采用经骨折椎椎弓根植骨结合短节段椎弓根螺钉内固定治疗60岁以上老年胸腰椎爆裂性骨折患者32例。评价患者内固定置入前、后及随访时椎体高度、后凸角、椎管内占位,神经功能改变及腰背疼痛等变化。 结果与结论：32例病例均随访6个月以上。无断钉及内固定物松动,椎体高度、后凸角、椎管内占位、神经功能及腰背疼痛明显改善,且椎体高度、后凸角、椎管内占位无明显再丢失。提示经骨折椎椎弓根植骨联合椎弓根内固定,能同时恢复椎体高度及强度,能即时增加椎体的骨容量和脊柱的稳定性,减少内固定因应力过大造成的断钉、断棒、椎体高度丢失等并发症。     

Improvement in Detection of Wrong-Patient Errors When Radiologists Include Patient Photographs in Their Interpretation of Portable Chest Radiographs

This study was conducted to determine whether facial photographs obtained simultaneously with radiographs improve radiologists’ detection rate of wrong-patient errors, when they are explicitly asked to include the photographs in their evaluation. Radiograph-photograph combinations were obtained from 28 patients at the time of portable chest radiography imaging. From these, pairs of radiographs were generated. Each unique pair consisted of one new and one old (comparison) radiograph. Twelve pairs of mismatched radiographs (i.e., pairs containing radiographs of different patients) were also generated. In phase 1 of the study, 5 blinded radiologist observers were asked to interpret 20 pairs of radiographs without the photographs. In phase 2, each radiologist interpreted another 20 pairs of radiographs with the photographs. Radiologist observers were not instructed about the purpose of the photographs but were asked to include the photographs in their review. The detection rate of mismatched errors was recorded along with the interpretation time for each session for each observer. The two-tailed Fisher exact test was used to evaluate differences in mismatch detection rates between the two phases. A p value of <0.05 was considered significant. The error detection rates without (0/20 = 0 %) and with (17/18 = 94.4 %) photographs were different (p = 0.0001). The average interpretation times for the set of 20 radiographs were 26.45 (SD 8.69) and 20.55 (SD 3.40) min, for phase 1 and phase 2, respectively (two-tailed Student t test, p = 0.1911). When radiologists include simultaneously obtained photographs in their review of portable chest radiographs, there is a significant improvement in the detection of labeling errors. No statistically significant difference in interpretation time was observed. This may lead to improved patient safety without affecting radiologists’ throughput.     

Are Portable Imaging Intraoperative Radiographs Helpful for Assessing Adequate Acetabular Cup Positioning in Total Hip Arthroplasty?

Despite advances in surgical techniques and instrumentation, current intra-operative estimations of acetabular version in total hip arthroplasty are of limited accuracy. In the present study, two experienced orthopedic surgeons compared intra-operatively measured (using portable imaging) anteversions and vertical inclinations of acetabular components with those measured using standardized radiographs post-operatively in 40 patients. Of the all vertical inclinations measured from intra-operative radiographs, 72.5% (n=29) were within ±2°, and 97.5% (n=39) were within ±5° of those determined using post-operative radiographs, and for anteversion, 52.5% (n=21) were within ±2°, and 97.5% (n=39) were within ±5°. Post-operative radiographs demonstrated that 90.0% (n=36) of vertical inclinations and anteversions were within the adequate zone. Obviously, our method has its limitations, but the authors conclude that the method described in this article better allows surgeons to verify acetabular version intra-operatively. In particular, the described method is suitable in cases with a deformed acetabular anatomy and difficult revision surgery.     

An Investigation into the Consistency in Mammographic Density Identification by Radiologists: Effect of Radiologist Expertise and Mammographic Appearance

The aim of this work is to investigate how radiologist expertise and image appearance may have an impact on inter-reader variability of mammographic density (MD) identification. Seventeen radiologists, divided into three expertise groups, were asked to manually segment the areas they consider to be MD in 40 clinical images. The variation in identification of MD for each image was quantified by finding the range of segmentation areas. The impact of radiologist expertise and image appearance on this variation was explored. The range of areas chosen by participating radiologists varied from 7 to 73 % across the 40 images, with a mean range of 35 ± 13 %. Participants with high expertise were more likely to choose similar areas to one another, compared to participants with medium and low expertise levels (mean range were 19 ± 10 %, 29 ± 13 % and 25 ± 14 %, respectively, p < 0.0001). There was a significantly higher average grey level for the area segmented by all radiologists as MD compared to the area of variation, with mean grey level value for 8-bit images being 146 ± 19 vs. 99 ± 14, respectively. MD segmentation borders were consistent in areas where there was a sharp intensity change within a short distance. In conclusion, radiologists with high expertise tend to have a higher agreement when identifying MD. Tissues which have a lower contrast and a less visually sharp gradient change at the interface between high density tissue and adipose background lead to inter-reader variation in choosing mammographic density.     

Fast 3D reconstruction of the spine from biplanar radiographs using a deformable articulated model

This paper proposes a novel method for fast 3D reconstructions of the scoliotic spine from two planar radiographs. The method uses a statistical model of the shape of the spine for computing the 3D reconstruction that best matches the user input (about 7 control points per radiograph). In addition, the spine was modelled as an articulated structure to take advantage of the dependencies between adjacent vertebrae in terms of location, orientation and shape. The accuracy of the method was assessed for a total of 30 patients with mild to severe scoliosis (Cobb angle [22°, 70°]) by comparison with a previous validated method. Reconstruction time was 90 s for mild patients, and 110 s for severe. Results show an accuracy of ～0.5mm locating vertebrae, while orientation accuracy was up to 1.5° for all except axial rotation (3.3° on moderate and 4.4° on severe cases). Clinical indices presented no significant differences to the reference method (Wilcoxon test, p ≤ 0.05) on patients with moderate scoliosis. Significant differences were found for two of the five indices (p=0.03) on the severe cases, while errors remain within the inter-observer variability of the reference method. Comparison with state-of-the-art methods shows that the method proposed here generally achieves superior accuracy while requiring less reconstruction time, making it especially appealing for clinical routine use.