Standardized volumetric 3D-analysis of SPECT/CT imaging in orthopaedics: overcoming the limitations of qualitative 2D analysis

<p>Abstract</p> <p>Background</p> <p>SPECT/CT combines high resolution anatomical 3D computerized tomography (CT) and single photon emission computerized tomography (SPECT) as functional imaging, which provides 3D information about biological processes into a single imaging modality. The clinical utility of SPECT/CT imaging has been recognized in a variety of medical fields and most recently in orthopaedics; however, clinical adoption has been limited due to shortcomings of analytical tools available. Specifically, SPECT analyses are mainly qualitative due to variation in overall metabolic uptake among patients. Furthermore, most analyses are done in 2D, although rich 3D data are available. Consequently, it is difficult to quantitatively compare the position, size, and intensity of SPECT uptake regions among patients, and therefore difficult to draw meaningful clinical conclusions.</p> <p>Methods</p> <p>We propose a method for normalizing orthopaedic SPECT/CT data that enables standardised 3D volumetric quantitative measurements and comparison among patients. Our method is based on 3D localisation using clinically relevant anatomical landmarks and frames of reference, along with intensity value normalisation using clinically relevant reference regions. Using the normalised data, we describe a thresholding technique to distinguish clinically relevant hot spots from background activity.</p> <p>Results</p> <p>Using an exemplar comparison of two patients, we demonstrate how the normalised, 3D-rendered data can provide a richer source of clinical information and allow quantitative comparison of SPECT/CT measurements across patients. Specifically, we demonstrate how non-normalized SPECT/CT analysis can lead to different clinical conclusions than the normalized SPECT/CT analysis, and that normalized quantitative analysis can be a more accurate indicator of pathology.</p> <p>Conclusions</p> <p>Conventional orthopaedic frames of reference, 3D volumetric data analysis and thresholding are used to distinguish clinically relevant hot spots from background activity. Our goal is to facilitate a standardised approach to quantitative data collection and comparison of clinical studies using SPECT/CT, enabling more widespread clinical use of this powerful imaging tool.</p

Diagnosing mucopolysaccharidosis IVA

Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is an autosomal recessive lysosomal storage disorder resulting from a deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS) activity. Diagnosis can be challenging and requires agreement of clinical, radiographic, and laboratory findings. A group of biochemical genetics laboratory directors and clinicians involved in the diagnosis of MPS IVA, convened by BioMarin Pharmaceutical Inc., met to develop recommendations for diagnosis. The following conclusions were reached. Due to the wide variation and subtleties of radiographic findings, imaging of multiple body regions is recommended. Urinary glycosaminoglycan analysis is particularly problematic for MPS IVA and it is strongly recommended to proceed to enzyme activity testing even if urine appears normal when there is clinical suspicion of MPS IVA. Enzyme activity testing of GALNS is essential in diagnosing MPS IVA. Additional analyses to confirm sample integrity and rule out MPS IVB, multiple sulfatase deficiency, and mucolipidoses types II/III are critical as part of enzyme activity testing. Leukocytes or cultured dermal fibroblasts are strongly recommended for enzyme activity testing to confirm screening results. Molecular testing may also be used to confirm the diagnosis in many patients. However, two known or probable causative mutations may not be identified in all cases of MPS IVA. A diagnostic testing algorithm is presented which attempts to streamline this complex testing process

Numerical synthesis of Stephenson six-bar mechanism using a CAD geometric approach

Geometric construction and analytical calculation are recognised as two basic approaches for planar mechanism design. However the geometric construction is only available for relatively simple cases while the analytical calculation is quite complicated and far from being visualised too. Both of them are complicated to be used for the Stephenson six-bar mechanism design due to complexity. Therefore the Computer-aided Design (CAD) geometric approach is developed to fulfil research needs. In this study, an approximate position and posture synthesis for the Stephenson six-bar mechanism is investigated via using the CAD geometric approach. Firstly using the geometric constraint and dimension driving techniques, a primary simulated mechanism is generated. Then based on different tasks of path and motion generations for the dimensional synthesis, the simulated mechanisms of the Stephenson six-bar mechanism are developed from primary simulation. The computer simulation results on approximation dimensional synthesis of the mechanism prove that the CAD geometric approach not only visualises the mechanism accurately and reliably but also increases the number of prescribed positions of synthesis for mechanism

Position analysis of a class of n-RRR planar parallel robots

Trabajo presentado en el International Conference of IFToMM ITALY, celebrada en Nápoles (Italia) del 9 al 11 de septiembre de 2020Parallel robots with a configurable platform are a class of parallel robots in which the end-effector is a closed-loop kinematic chain. In n-RRR planar robots the end-effector is a n-bar chain controlled by n actuated RRR chains connected to the base. We solve the direct kinematic problem for 4, 5 and 6-RRR mechanisms by using bilateration, a method that easily lends itself to generalization. Finally, we present the results from experimental tests that have been performed on a 5-RRR prototype.F. Thomas and J. M. Porta were partially supported by the Spanish Ministry of Economy and Competitiveness through projects DPI2017-88282-P and MDM-2016-0656. The support of Dr. Patrick Grosch in building the prototype is gratefully acknowledged

A Real Time Anatomical Converter For Human Motion Capture

There are many possible ways of identifying the posture of a human character from a set of known positions. These methods differ in subtle but important ways. We propose an alternative method to the jacobian-based Inverse Kinematics, one which allows for simple calibration, allows for sensors slippage, and can take advantage of knowledge of the type of motion being performed. This approach gives real-time conversion of magnetic sensors measurements into human anatomical rotations. Our converter is used in a wide range of applications from real time applications to animation design. It provides a useful complement to the traditional keyframe editing software