Surface Topography Techniques Research Articles

Reliability and Validity of Scoliosis Measurements Obtained with Surface Topography Techniques: A Systematic Review.

Surface topography (ST) is one of the methods in scoliosis assessment. This study aimed to systematically review the reliability and validity of the ST measurements for assessing scoliosis. A literature search of four databases was performed and is reported following PRISMA guidelines. The methodological quality was evaluated using Brink and Louw appraisal tool and data extraction was performed. The results were analyzed and synthesized qualitatively using the level of evidence method. Eighteen studies were included and analyzed. Four were evaluated for reliability, six for validity, and eight for reliability and validity. The methodological quality of fourteen studies was high. Good to excellent intra-investigator reliability was shown on asymmetry, sagittal, horizontal, and most frontal ST measurements (evidence level: strong). Asymmetry and most frontal, sagittal, horizontal ST measurements showed good to excellent inter-investigator reliability (evidence level: moderate). When comparing corresponding ST and radiological measurements, good to strong validity was shown on most frontal, sagittal, and asymmetry measurements (evidence level: strong). Formetric measurements had good intra-investigator reliability and validity (evidence level: strong). Most asymmetry, sagittal, and frontal ST measurements showed satisfactory reliability and validity. Horizontal ST measurements showed good reliability and poor validity. The ST technique may have great potential in assessing scoliosis, especially in reducing radiation exposure and performing cosmetic assessments.

Investigation of the Relationship Between Hip and Knee Osteoarthritis and Disordered Spinal and Pelvic Morphology.

IntroductionA critical question is the causal relationship between hip or knee osteoarthritis (OA) and disordered spinal and pelvic morphology. The aim of this study is to examine this correlation. Therefore, we studied the effect of total hip or knee arthroplasty (THA/TKA) on truncal parameters to determine the causal relationship between these two situations.Materials and methodsThis is a prospective study of the effect of THA or TKA in patients with hip or knee OA on truncal morphological parameters. Patients with one-sided hip or knee OA who chose to undergo THA or TKA were enrolled and surveyed. A control group (CG) was also surveyed for comparison with the patients. The patients were preoperatively examined for truncal parameters using the Diers Formetric four-D analysis system (surface topography technique) to calculate several truncal parameters in all planes at four months and 12 months postoperatively. Measurable examinations were performed using the Statistical Package for the Social Sciences (SPSS) version 17.00 (SPSS Inc., Chicago), and statistical significance was set at a p-value of <0.05.ResultsThe study examined 34 patients who underwent THA, including 19 women and 15 men with a mean age of 67.62 ± 8.28 years. The study also examined 45 patients who underwent TKA, including 34 women and 11 men, with a mean age of 72.42 ± 7.0 years. These patients were also compared with a CG that consisted of 25 normal individuals, including 12 women and 13 men, with a mean age of 69.28 ± 10.11 years.The results of this study from four months after THA revealed that the lordotic angle, trunk torsion, pelvic inclination, pelvic obliquity, and pelvis rotation were improved to normal levels. At 12 months after THA, only the pelvic obliquity was improved to normal levels. At four months after TKA the lordotic angle, pelvic inclination, and pelvic obliquity were improved to normal levels. However, the fleche cervicale and vertebral rotation were worse. At 12 months after TKA, only the pelvic obliquity was improved to normal levels.ConclusionsTHA and TKA to correct hip and knee OA do not correct the disordered morphology of the trunk in the long term. Thus, hip or knee OA does not seem to be responsible for disordered trunk morphology. However, it cannot be ruled out whether the disturbed morphology is responsible for the appearance of the hip and knee OA.

Potassium channel blocker crafted by α-hairpinin scaffold engineering

The α-Hairpinins are a family of plant defense peptides with a common fold presenting two short α-helices stabilized by two invariant S–S-bridges. We have shown previously that substitution of just two amino acid residues in a wheat α-hairpinin Tk-AMP-X2 leads to Tk-hefu-2 that features specific affinity to voltage-gated potassium channels KV1.3. Here, we utilize a combined molecular modeling approach based on molecular dynamics simulations and protein surface topography technique to improve the affinity of Tk-hefu-2 to KV1.3 while preserving its specificity. An important advance of this work compared with our previous studies is transition from the analysis of various physicochemical properties of an isolated toxin molecule to its consideration in complex with its target, a membrane-bound ion channel. As a result, a panel of computationally designed Tk-hefu-2 derivatives was synthesized and tested against KV1.3. The most active mutant Tk-hefu-10 showed a half-maximal inhibitory concentration of ∼150 nM being >10 times more active than Tk-hefu-2 and >200 times more active than the original Tk-hefu. We conclude that α-hairpinins provide an attractive disulfide-stabilized scaffold for the rational design of ion channel inhibitors. Furthermore, the success rate can be considerably increased by the proposed “target-based” iterative strategy of molecular design.

3D characterisation using plasma FIB-SEM: A large-area tomography technique for complex surfaces like black silicon

This paper demonstrates an improved method to accurately extract the surface morphology of black silicon (BSi). The method is based on an automated Xe+ plasma focused ion beam (PFIB) and scanning electron microscope (SEM) tomography technique. A comprehensive new sample preparation method is described and shown to minimize the PFIB artifacts induced by both the top surface sample-PFIB interaction and the non-uniform material density. An optimized post-image processing procedure is also described that ensures the accuracy of the reconstructed 3D surface model. The application of these new methods is demonstrated by applying them to extract the surface topography of BSi formed by reactive ion etching (RIE) consisting of 2 µm tall needles. An area of 320 µm2 is investigated with a controlled slice thickness of 10 nm. The reconstructed 3D model allows the extraction of critical roughness characteristics, such as height distribution, correlation length, and surface enhancement ratio. Furthermore, it is demonstrated that the particular surface studied contains regions in which under-etching has resulted in overhanging structures, which would not have been identified with other surface topography techniques. Such overhanging structures can be present in a broad range of BSi surfaces, including BSi surfaces formed by RIE and metal catalyst chemical etching (MCCE). Without proper measurement, the un-detected overhangs would result in the underestimation of many critical surface characteristics, such as absolute surface area, electrochemical reactivity and light-trapping.

Measurement of spine parameters and possible scoliosis cases with surface topography Techniques: A case study with young Indian males

Abstract In India, the measurement of Idiopathic Scoliosis (IS) is assessed by multiple radiographs. The long-term exposure of x-ray radiation ill effects. The Statico 3D system based on surface topography is compared the first time with radiography for the assessment of twenty-two subjects identified with IS. In the case of surface topography, a standard deviation of ±3.4 degrees and the reliability coefficient were found 0.996. At 95% confidence interval, a strong correlation (Pearson coefficient > 0.75) was observed in thoracic kyphosis, lumbar lordosis angle and left vertebral rotation while a moderate correlation (Pearson coefficient > 0.65) was measured in right vertebral rotation using radiograph and the Statico 3D system. ANOVA indicated a significant relation (p-value

Surface Topography Classification Trees for Assessing Severity and Monitoring Progression in Adolescent Idiopathic Scoliosis.

A validation study. The aim of this study was to independently validate the diagnostic accuracy of surface topography (ST) classification trees to identify curve severity and progression using a new sample of data in participants with adolescent idiopathic scoliosis (AIS). Radiographs for diagnosing and monitoring AIS involve harmful radiation exposure repeated at successive clinical visits. Classification trees using a novel ST technique have been proposed to determine curve severity and progression noninvasively that could be used to monitor scoliosis. Forty-five adolescents with AIS treated nonoperatively, with ST scans and radiographs at baseline and follow-up (1 year later), were recruited from a scoliosis clinic. The Cobb angle (CA) from radiographs determined curve severity as mild (10° < CA < 25°) or moderate/severe (CA ≥ 25°) and progression as an increase >5°.ST scans were analyzed to calculate the best plane of symmetry and associated deviation color map. Root mean squares and maximum deviation were calculated for each area of asymmetry. ST measurements were analyzed using two published decision trees developed to maximize sensitivity and negative predictive value. Curves were classified as mild or moderate/severe and curve progression was predicted. Accuracy statistics were calculated to evaluate performance. For curve severity, sensitivity and specificity were 95% and 35%, respectively. Negative and positive predictive values were 90% and 53%, respectively, with an accuracy of 61%. For curve progression, sensitivity and specificity were 73% and 44%, respectively. Negative and positive predictive values were 83% and 30%, respectively, with an accuracy of 51%. Assuming that mild and nonprogressive curves would not require an x-ray, the use of ST decision trees could eliminate 31% of x-rays. Decision trees showed strong negative predictive values and sensitivity suggesting it may be possible to safely use ST asymmetry analysis with validated decision trees to reduce x-rays in patients with mild and nonprogressive curves. 2.

Asymmetry Assessment Using Surface Topography in Healthy Adolescents

The ability to assess geometric asymmetry in the torsos of individuals is important for detecting Adolescent Idiopathic Scoliosis (AIS). A markerless technique using Surface Topography (ST) has been introduced as a non-invasive alternative to standard diagnostic radiographs. The technique has been used to identify asymmetry patterns associated with AIS. However, the presence and nature of asymmetries in the healthy population has not been properly studied. The purpose of this study is therefore to identify asymmetries and potential relationships to development factors such as age, gender, hand dominance and unilateral physical activity in healthy adolescents. Full torso scans of 83 participants were analyzed. Using Geomagic, deviation contour maps (DCMs) were created by reflecting the torso along the best plane of sagittal symmetry with each spectrum normalized. Two classes of asymmetry were observed: twist and thickness each with subgroupings. Averaged interobserver and intraobserver Kappas for twist subgroupings were 0.84 and 0.84, respectively, and for thickness subgroupings were 0.53 and 0.63 respectively. Further significant relationships were observed between specific types of asymmetry and gender such as females displaying predominately twist asymmetry, and males with thickness asymmetry. However, no relationships were found between type of asymmetry and age, hand dominance or unilateral physical activity. Understanding asymmetries in healthy subjects will continue to enhance assessment ability of the markerless ST technique.

Examination of the breast asymmetry associated with adolescent idiopathic scoliosis using surface topography methods

Surface topography (ST) is a tool used to assess adolescent idiopathic scoliosis (AIS), which affects females more severely than males. However, current ST techniques fail to measure breast asymmetry related to torso deformity. Cosmetic deformity is important to patients because poor body appearance can cause psychological distress. Breast asymmetry is especially important to adolescent females. This study develops a method for assessing breast asymmetry using ST in patients with AIS, and proposes a reliable breast asymmetry classification for such patients. To achieve this, ST torso scans of 25 females (age: 15.4 ± 1.3 years; range: 13.5-17.5 years) with AIS were obtained. Scans were analyzed using a method that finds a rotoinversion matrix to minimize the distance between the torso scan and its reflected image about the sagittal plane. The mirrored torso was then fitted to the original torso using an iterative leastsquares method, such that the average deviation between the observed and reflected torsos was minimized. The relative deviation between the two torsos was measured and displayed as a deviation colour map (DCM). Each patient's DCM was visually appraised by two of the authors and a breast asymmetry classification system was created based on this appraisal. Good intra- and inter-rater reliability was found for the classification decisions by five observers. All of the patients presented breast asymmetry that could be reliably categorized into the proposed five-group classification with all patients exhibiting deviations exceeding the threshold of 3 mm between sides routinely observed in healthy teenagers without scoliosis.

Examination of the breast asymmetry associated with adolescent idiopathic scoliosis using surface topography methods

Surface topography (ST) is a tool used to assess adolescent idiopathic scoliosis (AIS), which affects females more severely than males. However, current ST techniques fail to measure breast asymmetry related to torso deformity. Cosmetic deformity is important to patients because poor body appearance can cause psychological distress. Breast asymmetry is especially important to adolescent females. This study develops a method for assessing breast asymmetry using ST in patients with AIS, and proposes a reliable breast asymmetry classification for such patients. To achieve this, ST torso scans of 25 females (age: 15.4 ± 1.3 years; range: 13.5-17.5 years) with AIS were obtained. Scans were analyzed using a method that finds a rotoinversion matrix to minimize the distance between the torso scan and its reflected image about the sagittal plane. The mirrored torso was then fitted to the original torso using an iterative leastsquares method, such that the average deviation between the observed and reflected torsos was minimized. The relative deviation between the two torsos was measured and displayed as a deviation colour map (DCM). Each patient's DCM was visually appraised by two of the authors and a breast asymmetry classification system was created based on this appraisal. Good intra- and inter-rater reliability was found for the classification decisions by five observers. All of the patients presented breast asymmetry that could be reliably categorized into the proposed five-group classification with all patients exhibiting deviations exceeding the threshold of 3 mm between sides routinely observed in healthy teenagers without scoliosis.

Three-dimensional measuring technique for surface topography using a light-sectioning microscope

Three-dimensional (3D) surface topographic analysis, measurement, and assessment techniques have raised great interest not only among researchers but also among industrial users. Many industrial processes and applications are directly influenced by the small-scale roughness of surface finishes. This paper describes the development and implementation of a noncontact, three-dimensional, microtopography measuring system. The instrument is formed by combining a modified light-sectioning microscope subsystem with a computer subsystem. In particular, optical system characteristics of the light-sectioning microscope are investigated, and a textured steel sheet is measured to demonstrate good practical outcomes. Details of measuring processes and image processing algorithms are provided, such as procedures for measurement, image edge extraction, and 3D topography reconstruction. After the 3D topography of the measured surface has been reconstructed, the topography field description parameters are calculated. A standard roughness block was used for calibration of the surface microtopography measuring system. Results obtained showed the measurement method output has good agreement with the actual asperity (unevenness or roughness) of the surface. The computer subsystem is used to process and control asperity measurements and image generation, and for image acquisition and presentation.

Immediate correction required to expect a long-term effectiveness of a brace treatment: a biomechanical insight

Methods The three-dimensional geometry of 30 patients was acquired using multi-view radiographic reconstruction and surface topography techniques. A finite element model of the trunk and a parametric brace model were created. For each case, two spinal stiffnesses (flexible, stiff) were tested. Installation of the brace was simulated. Using an experimental design framework including thirteen design factors, 768 braces were tested for each patient (total of 69120 tested braces). Immediate inbrace correction of the coronal Cobb angles and loads acting on the growth plates of the apical vertebrae were computed and analyzed.

Correlation Between Immediate In-Brace Correction and Biomechanical Effectiveness of Brace Treatment in Adolescent Idiopathic Scoliosis

Multiple brace designs were simulated using a finite element model and their biomechanical effect was evaluated. To study correlations between immediate in-brace correction of coronal curves and bending moments acting on the apical vertebrae. Immediate in-brace correction has often been deemed as fundamental to long-term brace effect but the biomechanical explanation is unclear. Three-dimensional geometry of 3 patients was acquired using multiview radiographs and surface topography techniques. A finite element model of the patients' trunk including gravitational forces and a parametric brace model were created. Two sets of mechanical properties of the spine (stiff and flexible) were tested. Installation of the brace on the patients was simulated. Using an experimental design framework including fourteen design factors, 1024 different virtual braces were tested for each patient. For each brace, immediate in-brace correction of the coronal Cobb angles and the bending moment acting on the apical vertebrae were computed and their correlation was studied. Immediate correction of coronal curves and corresponding impact on the apical vertebrae bending moments were linearly correlated (mean R = 0.88). The amount of immediate correction necessary to nullify the bending moment ranged between 19% and 61% with average 48% (flexible spine model) and 27% (stiff spine model). The braces corrected the apical vertebrae bending moment more in the flexible spine model. In the framework of the Hueter-Volkmann principle, the correlation between coronal immediate in-brace correction and corresponding apical bending moment can be interpreted as a correlation between immediate in-brace correction and long-term treatment outcome. The amount of immediate correction necessary to invert the bending moments, and in theory counteract the progression of the scoliotic deformity, depends on spine stiffness and spine segment. This study confirms the importance of immediate in-brace correction to predict long-term outcome of the treatment and provides insights in the understanding of brace biomechanics.

Automated bullet-identification system based on surface topography techniques

Every firearm has individual characteristics that are as unique to it as fingerprints are to human beings. When a firearm is fired, it transfers these characteristics – in the form of microscopic scratches and dents – to the fired bullets and cartridge casings. The rifling of the barrel of the firearm marks the bullets travelling through it, and the firearm's breech mechanism marks the ammunition's cartridge casing. Characterising these marks is the critical element in identifying firearms. Traditionally the comparison of ballistic evidence has been a tedious and time-consuming process requiring highly skilled examiners. In the past decade, engineers have created automated ballistics identification systems that meld traditional comparison microscopes with digital cameras, computers, huge databases, and image analysis techniques. This kind of system can help investigators to link crimes by automatically finding similarities among images of bullet but suffering significant drawbacks and minimal matching. More recently, approaches based on 3D digital representations of evidence surface topography have started to appear, both in research and industrial products. Potentially the introduction of 3D surface topography measurement can overcome the limitations of digital imaging systems by making the bullet surface measurement reproducible and reliable. A 3D quantitative approach for bullet identification is proposed in this paper. In this system the surface topography of the whole bullet can be acquired for analysis and identification. Primary researches have been done by applying advanced surface topography techniques for bullet marks’ characteristics extraction. A variety of 2D and 3D visualization graphics have also been provided to help firearm examiners to make final decisions.

Correlation of topography measurements of NIST SRM 2460 standard bullets by four techniques

Three optical instruments including an interferometric microscope, a Nipkow disc confocal microscope and a laser scanning confocal microscope and a stylus instrument are used for the measurements of bullet profile signatures of a National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 2460 standard bullet. The two-dimensional profile signatures are compared with the virtual bullet standard signature established by the same stylus instrument. The bullet signature differences are quantified by the maximum cross-correlation function CCFmax. If the compared signatures were exactly the same, CCFmax would be 100%. Comparison results show close agreement among the four techniques for bullet profile signature measurements. The average CCFmax values are higher than 90%. This supports the possibility of using surface topography techniques for ballistic identifications as an alternative to the current technology based on image comparisons.

Influence of stress intensity and crack speed on fracture surface topography: mirror to mist transition

The transition from very smooth “mirror” crack growth to the early stages of roughening associated with “mist” has been investigated using a range of surface topography techniques. The fracture mechanics properties of the brittle, glassy and isotropic epoxy resin used in this work were characterized using compact tension (CT) and double torsion (DT) tests (K Ic=0.65 MN m−3/2). In the DT test, the mist to mirror transition occurred over a large section of the test sample and this facilitated examination by optical microscopy, scanning electron microscopy, atomic force microscopy and non-contact laser profilometry. Measurements on Wallner lines and river lines were used to map the crack velocities and directions over the fracture surface. The transition from mist to mirror, for a decelerating crack, occurred at a crack velocity, v c=0.1 v t, where v t is the shear wave velocity. There was a sharp change in roughness at the transition but no discontinuity in the crack deceleration behaviour. Two main topographical features were observed at the transition: firstly, undulations in the mirror region which decreased in amplitude away from the transition for a decelerating crack and, by implication, vice versa; secondly, a progressive decrease in river line density (for a decelerating crack). Detailed atomic force microscope profilometry was used to determine the surface topography associated with these features. The results provide an insight into the development of crack instabilities under dynamic conditions and a basis for interpreting the progressive development of roughness up to macroscopic bifurcation.