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Study Design: Retrospective reliability study., Objectives: To investigate the intra- and interrater reliability of Cobb angle measurements on the plane of maximum curvature (PMC) using ultrasound (US) images on children with adolescent idiopathic scoliosis (AIS)., Summary of Background Data: Cobb angle measurement on posteroanterior (PA) radiographs is the gold standard to assess curve severity. However, the PA Cobb angle does not reflect the true three-dimensional deformity., Methods: One hundred one children with AIS (87 F; 14 M) (age: 13.7 ± 1.7 years) were recruited and 157 curves were recorded by clinicians on radiographs. Three raters, R1, R2, and R3 with 0, 4, and 20+ years of experience, respectively, measured the PA Cobb, vertebral axial rotation (VAR), PMC Cobb, and PMC orientations on US images. The true PMC orientations were determined using 3D reconstructions on the PA and lateral EOS radiographs. The reliability of R1 measurements on PMC orientations were validated using intermethod (US vs. EOS measurements) with the intraclass correlation coefficients (ICCs). Inter- and intrarater reliabilities, standard error measurements, and Bland-Altman's bias were used to report the PMC Cobb and VAR measurements., Results: Intermethod, inter-, and intrarater ICC(2,1) values for all reliability assessments were greater than 0.9. The mean absolute differences and the standard error measurements for both PMC Cobb and VAR were less than 4° and 0.5°, respectively. The PMC orientation was strongly correlated (r 2 = 0.88) between both measurement modalities. There appeared to be a positive association between the difference of PMC and PA Cobb when the PA Cobb and the maximum VAR were greater than 30° and 14°, respectively., Conclusion: The PMC Cobb and VAR can be measured reliably on US images. Future studies should validate the PMC Cobb angle and to include a wider Cobb angle range on participants., (Copyright © 2018 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Objective: This study aims to provide a clinical evaluation of the Advanced System for Implant Stability Testing (ASIST) for assessment of implant stability for bone-anchored hearing aid patients. We evaluate the longitudinal changes in implant interface stability during the first year following surgery., Methods: ASIST measurements were collected for 39 patients selected to receive a bone anchored hearing aid for hearing loss. Measurements were collected at the time of surgery and at 3 days, 2 weeks, 1 month, 3 months, 6 months, and 12 months following surgery. Longitudinal changes in ASIST Stability Coefficient (ASC) were determined for each patient. Correlations were investigated between initial implant stability as measured by the ASC and clinical parameters such as operating surgeon, patient age at surgery, and implant type., Results: ASC values ranged from 11.9 to 137.0 (31.9 ± 18.0). On average, there was a slight decrease in ASC up to 3 months after surgery followed by an increase up to 1 year. Preliminary results presented in this study suggest that there may be differences in the initial stability between operating surgeons (p = 0.0012; p = 0.0049) and there was a trend toward possible differences between different implant types., Conclusion: We have shown promising results using the ASIST in a clinical setting for longitudinal evaluation of bone-implant interface integrity. Isolating the interface properties from the implant-abutment system allows for objective comparisons across patients that are not possible with other stability measurement systems.

Intraoral ultrasonography uses high-frequency mechanical waves to study dento-periodontium. Besides the advantages of portability and cost-effectiveness, ultrasound technique has no ionizing radiation. Previous studies employed a single transducer or an array of transducer elements, and focused on enamel thickness and distance measurement. This study used a phased array system with a 128-element array transducer to image dento-periodontal tissues. We studied two porcine lower incisors from a 6-month-old piglet using 20-MHz ultrasound. The high-resolution ultrasonographs clearly showed the cross-sectional morphological images of the hard and soft tissues. The investigation used an integration of waveform analysis, travel-time calculation, and wavefield simulation to reveal the nature of the ultrasound data, which makes the study novel. With the assistance of time-distance radio-frequency records, we robustly justified the enamel-dentin interface, dentin-pulp interface, and the cemento-enamel junction. The alveolar crest level, the location of cemento-enamel junction, and the thickness of alveolar crest were measured from the images and compared favorably with those from the cone beam computed tomography with less than 10% difference. This preliminary and fundamental study has reinforced the conclusions from previous studies, that ultrasonography has great potential to become a non-invasive diagnostic imaging tool for quantitative assessment of periodontal structures and better delivery of oral care.

Purpose: To determine the reliability of a prognostic curve progression model and the role of the quantity and quality of brace wear for adolescent idiopathic scoliosis (AIS) brace treatment., Methods: To develop a curve progression model for full-time AIS brace treatment, 20 AIS subjects (Group 1) prescribed full-time thoracolumbar sacral orthosis (TLSO) were monitored and followed for 2 years beyond maturity. The developed curve progression model was: curve progression (in degrees) = 33 + 0.11 × Peterson risk (%) - 0.07 in-brace correction (%) - 0.45 × quality (%) - 0.48 × quantity (%) + 0.0062 × quantity × quality. To validate the model, 40 new (test) subjects (Group 2) who met the same inclusion criteria and used the same type of monitors, were monitored and followed for 2 years after bracing., Results: For the 40 test subjects (Group 2), the average in-brace correction was 40 ± 22 %. The average quantity and quality of the brace wear were 56 ± 19 and 55 ± 17 %, respectively. Twelve subjects (30 %) progressed of which 10 subjects (25 %) required surgery and 28 subjects (70 %) showed no progression. The accuracy of the model to determine which patients would progress was 88 % (35/40) which was better than the Peterson's risk model (68 %; 26/40) alone. Patients who had the combined quantity times the quality over a threshold 43 % had a success treatment rate of 95 %., Conclusions: This study showed the prognostic model of brace treatment outcome on AIS patients treated with full-time TLSO was reliable. Both the quantity and quality of the brace wear were important factors in achieving successful brace treatment.

Spinal deformity is a three-dimensional (3D) spinal disorder with a lateral deviation and coupled with axial vertebral rotation (AVR). The current clinical practice only measures its severity on postero-anterior (PA) radiographs, which may underestimate the deformity. The actual severity should be obtained on the plane of maximal curvature (PMC), which requires a 3D spinal image. There are many approaches to reconstruct 3D spinal images; however, ultrasound is one of the promising techniques with its non-ionizing characteristic. This study proposed an image processing method using the voxel-based bilinear interpolation to reconstruct a 3D spinal image from ultrasound data, from which the AVR was measured and the spinal curvature on the PMC was determined. In-vitro and in-vivo experiments were performed to determine the accuracy of the measurements from the ultrasound method. The results showed that the 3D ultrasound spinal image could be reconstructed. The curvature angle on the PA and the PMC planes could also be determined. The tilt angle of each individual vertebra in in-vitro study showed high accuracy and correlation (MAD <; 0.9° ± 0.2° and r(2) > 0.87) when comparing the measurements from CT with ultrasound. In in-vivo study, the curvature angles measured on the PA radiographs and ultrasound images yielded a small difference (MAD 3.4° ± 1.0°) and a strong correlation (r(2) = 0.63) within a clinical accepted error of 5°.

Scoliosis is a type of spinal deformity that commonly develops in adolescents. Cobb angle, using the most tilted vertebrae, is the gold standard to assess scoliosis on radiographs. However, regularly taking radiographs introduces harmful ionizing radiation to patients, thus non-ionizing radiation methods have been explored for many years. Ultrasound has been proposed as one of the non-ionizing radiation methods to measure the deformity. This research was divided into two studies: 1) to investigate the reliability and repeatability of a new proposed method to measure Cobb angle; 2) to determine if landmarks can be identified from ultrasound images to measure curvature of spine. Based on the two studies, the feasibility of using ultrasound images to assess spinal deformity will be determined. Thirty-nine radiographs were used in the first study. The new method agreed well with the traditional Cobb method with intraclass correlation coefficient (ICC) value greater than 0.7 in different severity groups, and the average angle difference was 1.6° ± 3.1°. The second study showed laminae and transverse processes could be recognized from ultrasound images. The difference of the width of the laminae between the phantom and the ultrasound image was 0.3 mm. Therefore, it is feasible to use the proposed method and the laminae from the ultrasound images to assess the severity of scoliosis.

Scoliosis surgery involves the insertion of screws and/or hooks into selected vertebrae to secure a pre-bent rod placed along the concave side of the spine. Usually conventional x-rays will be taken before the surgery to plan the alignment and positioning of the pedicle screws. However, reports state that perforation rate range from 6% to 54%. A misalignment of a pedicle screw can potentially cause permanent neurological spinal cord injury or even a life-threatening vascular injury. Because of the importance of positioning and aligning of pedicle screws, we are working on an ultrasound method to guide the insertion of pedicle screws in real time. A pulse-echo immersion experiment was set up to study how well the edges of cortical bone could be detected using a bovine spinous process in-vitro. Two ultrasound frequencies (3.5 MHz and 5.0 MHz) were considered in this study. This preliminary study shows that ultrasound is able to penetrate cortical bone and reflect back from the outer boundary. All interfaces are clearly identified for both frequencies. Strong reflection signals are obtained when the beam is normal to the interface. Derived thickness values from the reflections are comparable with those from micro-CT image. The 5.0 MHz ultrasound frequency provided better resolution than the 3.0 MHz frequency.

To reduce variability of Cobb angle measurement for scoliosis assessment, a computerized method was developed. This method automatically measured the Cobb angle on spinal posteroanterior radiographs after the brightness and the contrast of the image were adjusted, and the top and bottom of the vertebrae were selected. The automated process started with the edge detection of the vertebra by Canny edge detector. After that, the fuzzy Hough transform was used to find line structures in the vertebral edge images. The lines that fitted to the endplates of vertebrae were identified by selecting peaks in Hough space under the vertebral shape constraints. The Cobb angle was then calculated according to the directions of these lines. A total of 76 radiographs were respectively analyzed by an experienced surgeon using the manual measurement method and by two examiners using the proposed method twice. Intraclass correlation coefficients (ICC) showed high agreement between automatic and manual measurements (ICCs > 0.95). The mean absolute differences between automatic and manual measurements were less than 5 degrees . In the interobserver analyses, ICCs were higher than 0.95, and mean absolute differences were less than 5 degrees . In the intraobserver analyses, ICCs were 0.985 and 0.978, respectively, for each examiner, and mean absolute differences were less than 3 degrees . These results demonstrated the validity and reliability of the proposed method.

Adolescent idiopathic scoliosis (AIS) presents as an abnormal curvature of spine with vertebral rotation. It may impact the patient for their entire life. Approximately 0.25% of adolescents will require treatment. Brace treatment is the most commonly used non-surgical treatment for AIS. Its goal is stop the progression and maintain the curve at an acceptable level through the high risk growth phase of adolescence. However, its effectiveness is controversial and the actual biomechanical action of the brace is not fully understood. Recently, the Scoliosis Research society (SRS) created a standard criterion for AIS brace studies. However, to evaluate the effectiveness of the brace treatment, the spine flexibility, in brace correction and patient's compliance should also be included in a study. Although bracing has been used for more than 50 years, there are still many unknowns. How much wear time per day is needed for an optimum treatment outcome? How much brace tightness is optimal? What is the best weaning protocol? What is the best method to determine the curve flexibility? How much in-brace correction is needed to obtain good results? Without accurate and precise methods to objectively measure or answer the above questions, it is misleading to state whether or not brace treatment is effective. Therefore, a lot of research is still required before one can answer the effectiveness of the brace treatment.

Broadband ultrasound attenuation (BUA) is commonly measured by the spectral ratio method. Conventionally BUA is measured in transverse transmission mode where ultrasound signal is recorded with and without the sample. The spectral ratio method was extended to estimate nBUA (BUA normalized by thickness) in axial transmission mode using spectral amplitudes of the primary reflection and multiple reflection, which echoes more than once between the material interfaces within a layer. We performed three experiments. First, reflections were numerically simulated to verify the accuracy of the method. We then applied the method to estimate attenuation of silicon rubber and the cortex of a bovine femur. The center frequency of the transducers is 2.25 MHz. We obtained 93% accuracy for a simulated data set with 10% random noise after bandpass filtering. For the silicon rubber, 15 measurements were collected and the mean attenuation was 6.33 +/- 0.19 dB MHz(-1) cm(-1). For the bovine bone, eight measurements were performed in the middle portion of the femur. The mean attenuation was 4.91 +/- 0.65 dB MHz(-1) cm(-1) and compared well with those reported in the literature. The results demonstrate that the proposed method has the potential to provide a quick, reliable and robust cortical attenuation assessment in vivo.

In order to study a physiotherapeutic approach to idiopathic scoliosis treatment a posture monitoring system is being built. The system is a small, lightweight, fully portable system capable of monitoring and providing feedback to a patient regarding their posture. Using the combination of accelerometer and electromagnetic technology, distance and angle measurements can be obtained for receivers placed strategically on the patient's back. This data is recorded for further analysis of the patient's progress and to provide immediate feedback to the patient on the status of their posture. Preliminary testing has shown that angular changes of one degree can be detected by the system and that the speed of the electromagnetic field detection has been increased ten times greater than the previous architecture.