Rosario Salvador

Infrared Thermal Imaging in the Diagnosis of Musculoskeletal Injuries: A Systematic Review and Meta-Analysis

OBJECTIVE Musculoskeletal injuries occur frequently. Diagnostic tests using ionizing radiation can lead to problems for patients, and infrared thermal imaging could be useful when diagnosing these injuries. CONCLUSION A systematic review was performed to determine the diagnostic accuracy of infrared thermal imaging in patients with musculoskeletal injuries. A meta-analysis of three studies evaluating stress fractures was performed and found a lack of support for the usefulness of infrared thermal imaging in musculoskeletal injuries diagnosis.

Determination of the object surface function by structured light: application to the study of spinal deformities

The projection of structured light is a technique frequently used to determine the surface shape of an object. In this paper, a new procedure is described that efficiently resolves the correspondence between the knots of the projected grid and those obtained on the object when the projection is made. The method is based on the use of three images of the projected grid. In two of them the grid is projected over a flat surface placed, respectively, before and behind the object; both images are used for calibration. In the third image the grid is projected over the object. It is not reliant on accurate determination of the camera and projector pair relative to the grid and object. Once the method is calibrated, we can obtain the surface function by just analysing the projected grid on the object. The procedure is especially suitable for the study of objects without discontinuities or large depth gradients. It can be employed for determining, in a non-invasive way, the patients back surface function. Symmetry differences permit a quantitative diagnosis of spinal deformities such as scoliosis.

AUTOMATIC ANALYSIS OF SPECKLE PHOTOGRAPHY FRINGES

Speckle interferometry is a technique adequate to metrological problems such as the measurement of object deformation. An automatic system of analysis of such measurements is given; it consists of a motorized x-y plate positioner controlled by computer, a CCD video camera, and software for image analysis. A fringe-recognition algorithm determines the spacing and orientation of the fringes and permits the calculation of the magnitude and direction of the displacement of the analyzed object point in images with variable degrees of illumination. For a 256 x 256 pixel image resolution, the procedure allows one to analyze from three fringes to a number of fringes that corresponds to 3 pixels/fringe.

Speckle correlation technique to determine roughness in the dermatologic interval

A non-invasive method is proposed to determine human skin roughness. The technique is based on measurement of the correlation between two field distributions scattered by a metallised triafol (cellulose acetate foil) replica of the epidermal area to be analysed. The two speckle patterns are produced from the same rough surface illuminated by two coherent plane waves (He-Ne laser) under two slightly different angles. The accuracy of the method is highlighted by measurements made on a set of standard samples with roughnesses previously determined by mechanical profilometry. Analysis of the results indicates a precision of around 10%, and an applicability within the interest range of very rough surfaces in excess of 4-5 microns.

Sensitivity and optimization in the determination of deformations by holographic interferometry

Abstract The use of a fringe-counting holographic interferometric technique for measuring small superficial displacements can present difficulties in determining the measurement inaccuracy. A useful general method is given here for the analysis of errors in displacement measurements. The optimum number and type of observation directions are determined and correspond to counting in the four semi-diagonals of the holographic plate. The technique, as applied to skull experiments, makes it possible to measure directly displacements of up to 20 μm, in the object plane parallel to the holographic plate. The associated errors range from 0.1–0.3 μm, for a counting inaccuracy of 1 8 – 1 4 of a fringe and increments of traction of 100 g to 1 kg of force.

A semi-automatic method for measuring interferometry fringes: prototype design and first results

Abstract A device for automatically obtaining the information contained in holographic interferometry fringes is proposed. The method may be applied to any kind of interferometric fringes. Accuracy has been demonstrated by contrasting the results obtained with our prototype system and those with the single-beam speckle interferometry technique for the measurement of displacements in a plane. The results show good correlation between the two series of measurements.

A New Equation for Predicting Evolution of Oral Pain in Orthodontic Treatment: A Longitudinal, Prospective Cohort Study

AIMS To develop an equation capable of relating the evolution of oral pain to the time elapsed, measured from the moment of dental archwire fitting and identifying when pain begins, peaks, and ends; and secondly, to compare pain during orthodontic treatment in relation to archwire material (steel or nickel-titanium [Ni-Ti]) and position (maxillary or mandibular) and patient age (child, teenager, or adult) and gender (male or female). METHODS A longitudinal prospective cohort study was conducted of 112 patients who filled in a scale to evaluate pain, noting the times when the pain occurred. The total sample consisted of 60 males and 52 females with a mean (± standard deviation [SD]) age of 19.8 ± 6.2 years. The sample was divided into five groups depending on archwire material and position, and patient age and gender. A univariate four-way ANOVA model was performed to compare mean pain levels between groups. Bonferroni test was used for multiple comparisons. A univariate nonlinear regression model was carried out for pain level, 95% confidence intervals (95% CI) were calculated, and the statistic R² was used. RESULTS An equation was developed based on pain levels in relation to time elapsed, measured from the moment when the archwire had been fitted in the mouth. The equation had three coefficients related to mean pain values: overall pain, peak pain, and how pain decreased. It fitted all study groups with a correlation coefficient > 0.9. The model showed that pain levels were influenced by archwire material and patient gender and age, but not archwire position. CONCLUSION The equation reproduced the data registered and can be applied to studies of pain derived from archwires, and this methodology could be used for other external agents fitted in the mouth. Patients receiving dental treatment involving external agents can be made aware of the pain they can expect to experience. This will enable them to distinguish expected pain from other pain, which will help them identify other pathologies requiring medical attention and to approach treatment with better motivation since the pattern of pain evolution is known in advance.

Infrared Thermography Protocol for the Diagnosis and Monitoring of the Diabetic Foot: Preliminary Results

The diabetic foot, according to the International Consensus on the Diabetic Foot, is an infection, ulceration or destruction of the deep tissues related to neurological alterations and peripheral vascular disease in the lower limbs [1]. This pathology represents an important problem of public health because the affected patients can suffer amputations and even the death [2].

Measurements of deformations in osseous structures and implants by digital speckle interferometry (DSPI)

Knowledge of how osseous structures and implants behave under deforming stress is an interesting point when evaluating the response of an implanted prosthesis. The failure of an implant is not always due to the great stress a structure may be subjected to at a particular moment, but rather to the effects of deterioration associated with lesser stress but which is continuously applied. Therefore it is helpful to know how bones and implants respond to this lesser stress. Digital speckle interferometry (DSPI) is suitable for this type of determination, as it is a highly sensitive, non-invasive optical technique. In this study we present the results we obtained when determining the elasticity of a sample of a macerated human radius, a titanium implant and a titanium screw used to treat the fractures of this bone. The correlation ratios we obtained in determining Youngs modulus were in the order of r=0.994. Models were made of these structures using the finite elements method (FEM) with the aid of the ANSYS 10.0 program, applying Youngs modulus values determined by DSPI. With a view to monitoring the accuracy of the FEM models of the bone and the implant elements we designed a flexion experiment to obtain the DSPI values in and out of plane. The high degree of concordance between the results of both methods makes it possible to continue studying osseous samples with a fixed implant, and also other implants made of different alloys.