OpenUCT :: Browsing by Author "Douglas, Tania S"

Browsing by Author "Douglas, Tania S"

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Open Access
3D approximation of scapula bone shape from 2D X-ray images using landmark-constrained statistical shape model fitting
(2016) Wasswa, William; Mutsvangwa, Tinashe E M; Douglas, Tania S
Two-dimensional X-ray imaging is the dominant imaging modality in low-resource countries despite the existence of three-dimensional (3D) imaging modalities. This is because fewer hospitals in low-resource countries can afford the 3D imaging systems as their acquisition and operation costs are higher. However, 3D images are desirable in a range of clinical applications, for example surgical planning. The aim of this research was to develop a tool for 3D approximation of scapula bone from 2D X-ray images using landmark-constrained statistical shape model fitting. First, X-ray stereophotogrammetry was used to reconstruct the 3D coordinates of points located on 2D X-ray images of the scapula, acquired from two perspectives. A suitable calibration frame was used to map the image coordinates to their corresponding 3D realworld coordinates. The 3D point localization yielded average errors of (0.14, 0.07, 0.04) mm in the X, Y and Z coordinates respectively, and an absolute reconstruction error of 0.19 mm. The second phase assessed the reproducibility of the scapula landmarks reported by Ohl et al. (2010) and Borotikar et al. (2015). Only three (the inferior angle, acromion and the coracoid process) of the eight reproducible landmarks considered were selected as these were identifiable from the two different perspectives required for X-ray stereophotogrammetry in this project. For the last phase, an approximation of a scapula was produced with the aid of a statistical shape model (SSM) built from a training dataset of 84 CT scapulae. This involved constraining an SSM to the 3D reconstructed coordinates of the selected reproducible landmarks from 2D X-ray images. Comparison of the approximate model with a CT-derived ground truth 3D segmented volume resulted in surface-to-surface average distances of 4.28 mm and 3.20 mm, using three and sixteen landmarks respectively. Hence, increasing the number of landmarks produces a posterior model that makes better predictions of patientspecific reconstructions. An average Euclidean distance of 1.35 mm was obtained between the three selected landmarks on the approximation and the corresponding landmarks on the CT image. Conversely, a Euclidean distance of 5.99 mm was obtained between the three selected landmarks on the original SSM and corresponding landmarks on the CT image. The Euclidean distances confirm that a posterior model moves closer to the CT image, hence it reduces the search space for a more exact patient-specific 3D reconstruction by other fitting algorithms.
Open Access
Autofocusing and image segmentation in microscopy for automatic detection of tuberculosis in sputum smears
(2006) Russell, Megan J; Douglas, Tania S
The World Health Organisation (WHO) has declared that tuberculosis (TB) is a global emergency. With the common combination of TB and AIDS in sub-Saharan Africa, the number of people dying from TB has increased enormously (WHO, 1996). The smart microscope that is under development in the MRC/UCT Medical Imaging Research Unit would considerably aid the fast detection and tracking of TB. The microscope will automatically detect the presence of TB bacilli in Ziehl-Neelsen (ZN) stained sputum smears. The microscope consists of a digital camera, motorised stages, and will have an on-board processor containing the algorithms for autofocusing the microscope and for automatically identifying TB bacteria on the slides. This thesis deals with autofocusing the microscope and segmenting TB bacilli from focused sputum smear images.
Open Access
Characterization of the facial phenotype associated with fetal alcohol syndrome using stereo-photogrammetry and geometric morphometrics
(2009) Mutsvangwa, Tinashe E M; Douglas, Tania S; Meintjes, Ernesta
Fetal Alcohol Syndrome (FAS) is a clinical condition caused by excessive pre-natal alcohol exposure and is regarded as a leading identifiable and preventable cause of mental retardation in the Western world. The highest prevalence of FAS was reported in the wine-growing regions of South Africa but data for the rest of the country is not available. Required, therefore, are large-scale screening and surveillance programmes to be conducted in South Africa in order for the epidemiology of the disease to be understood. Efforts to this end have been stymied by the cost and labour-intensive nature of collecting the facial anthropometric data useful in FAS diagnosis. Stereo-photogrammetry provides a low cost, easy to use and non-invasive alternative to traditional facial anthropometry. The design and implementation of a landmark-based stereo-photogrammetry system to obtain 3D facial information for fetal alcohol syndrome diagnosis (FAS) is described. The system consists of three high resolution digital cameras resting on a purpose-built stand and a control frame which surrounds the subject's head during imaging. Reliability and assessments of accuracy for the stereo-photogrammetric tool are presented using 275 inter-landmark distance comparisons between the system and direct anthropometry using a doll. These showed the system to be highly reliable and precise.
Open Access
A comparison of methods for the registration of tractographic fibre images
(2011) Golding, Dan; Douglas, Tania S
Diffusion tensor imaging (DTI) and tractography have opened up new avenues in neuroscience and are allowing previously unexplored areas of neuroanatomy and function to be researched.
Open Access
Computer models for the design and optimization of a linear slot scanning mammography system
(2008) Hussein, Khalid Ibrahim; Douglas, Tania S
Includes abstract. Includes bibliographical references (p. 143-151).
Open Access
Computer-aided diagnosis of tuberculosis in paediatric chest X-rays using local textural analysis
(2009) Mouton, Andre; Douglas, Tania S
This report presents a computerised tool to analyse the appearance of the lung fields in paediatric chest X-rays to detect the presence of tuberculosis. The computer aided diagnosis (CAD) tool consists of 4 phases: 1) lung field segmentation; 2) lung field subdivision; 3) feature extraction and 4) classification. Lung field segmentation is performed using a semi-automatic implementation of the active shape model algorithm. Two approaches to subdividing the lung fields into regions of interest are compared. The first divides each lung field into 21 overlapping regions of varying sizes, resulting in a total of 42 regions per image; this approach is called the big region approach. The second approach divides the lung fields into a large number of overlapping circular regions of interest. The circular regions have a radius of 32 pixels and are placed on an 8 x 8 pixel grid. This approach is called the circular region approach. Textural features are extracted from each of the regions using the moments of responses to a multiscale bank of Gaussian filters. Additional positional features are added to the circular regions.
Open Access
Creating a virtual slide map from sputum smear images for region-of-interest localisation in automated microscopy
(2010) Patel, Bhavin; Douglas, Tania S
Automated microscopy for the detection of tuberculosis (TB) in sputum smears seeks to address the strain on technicians in busy TB laboratories and to achieve faster diagnosis in countries with a heavy TB burden. As a step in the development of an automated microscope, the project described here was concerned with microscope auto-positioning; this primarily involves generating a point of reference on a slide, which can be used to automatically bring desired fields on the slide to the field-of-view of the microscope for re-examination. The study was carried out using a conventional microscope and Ziehl- Neelsen (ZN) stained sputum smear slides. All images were captured at 40x magnification. A digital replication, the virtual slide map, of an actual slide was constructed by combining the manually acquired images of the different fields of the slide. The geometric hashing scheme was found to be suitable for auto-stitching a large number of images (over 300 images) to form a virtual slide map. An object recognition algorithm, which was also based on the geometric hashing technique, was used to localise a query image (the current field-of-view) on the virtual slide map. This localised field-of-view then served as the point of reference. The true positive (correct localisation of a query image on the virtual slide map) rate achieved by the algorithm was above 88% even for noisy query images captured at slide orientations up to 26°. The image registration error, computed as the average mean square error, was less than 14 pixel2 (corresponding to 1.02 μm2 and 0.001% error in an image measuring 1030 x 1300 pixels) corresponding to a root mean square registration error of 3.7 pixels. Superior image registration accuracy was obtained at the expense of time using the scale invariant feature transform (SIFT), with a image registration error of 1 pixel2 (0.07 μm2). The object recognition algorithm is inherently robust to changes in slide orientation and placement, which are likely to occur in practice as it is impossible to place the slide in exactly the same position on the microscope at different times. Moreover, the algorithm showed high tolerance to illumination changes and robustness to noise.
Restricted
Development of an assessment framework for student engagement in design thinking projects for health innovation
(2020) Dikgomo, Kagiso; Douglas, Tania S; Mutsvangwa, Tinashe; Hendricks, Sharief
Student engagement is a dynamic and multifaceted concept – it encompasses physical, emotional, and cognitive components. Various instruments to assess student engagement exist, however these are not intended to assess how students engage with one another and with community stakeholders in participatory health projects. Although instruments do exist to assess participation/power-sharing in participatory health projects, none of the available instruments are suitable for the assessment of student engagement in such projects. The current study set out to develop an assessment framework for student engagement in design thinking projects for health innovation. Design thinking is a human-centred and participatory approach to problem-solving. The objectives of the project were: (1) the design and implementation of a questionnaire to assess student engagement in design thinking activities, and (2) assessment of the validity of the questionnaire. A preliminary questionnaire was developed with the aid of the literature and implemented for students taking a postgraduate course called Health Innovation & Design, which follows a design thinking approach for health innovation. Analysis of students’ written reflective reports and a focus group discussion were used to revise the questionnaire items. The revised questionnaire was validated by design thinking practitioners (the course lecturer and facilitators), and further modifications were made based on their views. The assessment framework developed in this study incorporates the design thinking phases according to the IDEO design thinking approach, an educational definition of student engagement, and recommendations by students of the Health Innovation & Design course and their course lecturer and facilitators. This questionnaire may be used to assess engagement in academic settings as well as non-academic settings when design thinking is applied for health innovation.
Open Access
Evaluating the usability of an X-ray imaging system in forensic pathology
(2018) Mutswangwa, Christopher T; Douglas, Tania S
Post mortem imaging (PMI) is increasingly being adopted as an alternative to invasive autopsies in forensic pathology. PMI can be used as a sole technique or adjunct to an autopsy. The Lodox Xmplar-dr is an X-ray imaging system that has been adopted for use in PMI. The purpose of this study was to evaluate the perceived usability of this imaging system by focusing on the satisfaction of forensic pathologists in use of the system. Assessment of satisfaction was guided by the subjective satisfaction characteristics of likability, pleasure, comfort and trust. Incorporation of user needs into updated system designs may lead to greater perceived ease of use, acceptance and adoption, resulting in increased device utilisation. The study location was the Lodox Xmplar-dr installation site at the Salt River Forensic Laboratory, Cape Town. Five forensic pathologists were observed using the Xmplar-dr system and four were interviewed on their experience using the system. A qualitative research design which used thematic analysis with the aid of NVIVO11 qualitative data analysis software was used to extract key usability and satisfaction themes emerging from the data, to show the extent of user satisfaction. Two key themes emerged. These were categorised as forensic pathologist-related, which focused on the hedonistic and subjective aspects of their satisfaction with the system, and systemrelated, which centred on the satisfaction users derived from the system’s ability to meet their pragmatic and objective expectations in their use of the system. In general, the forensic pathologists were satisfied with the Xmplar-dr system and it exceeded their expectations. Pleasure was derived from the ability of the system to increase work throughput by reducing the need to perform a dissectional post-mortem unless it was deemed absolutely necessary, i.e. when cause of death could not be determined from the X-ray images generated by the system. Participants felt that the system was an indispensable device when performing post mortems. Likability came from the ease of learning to use the basic functions of the system; the study participants stated that the system aided them in determining cause of death and saved time, in line with the definition of the likability characteristic that is centred on the extent to which a user is satisfied with perceived achievements of pragmatic goals. Trust was derived from participants’ views that the system worked as intended, although there could be improvements in terms of robustness, reliability and the imaging system`s support services. Image manipulation on the human-computer interface (HCI) and image representation were concerns highlighted. Most functions could be performed through the system’s HCI rather than by manipulation of the body being examined; this increased the physical comfort satisfaction characteristic. The need for manual placement of bodies on the system`s table by assistants and the associated health consequences were however raised as a concern that diminished the comfort-in-use characteristic of satisfaction. Understanding the user experience of the forensic pathologists who use the Lodox Xmplar-dr system to perform post mortems enabled the identification of areas for improvement. The improvements may increase user satisfaction resulting in better utilisation of the imaging system. The insights gained may be useful for the design of other imaging systems used in forensic pathology.
Open Access
Hardware and software integration and testing for the automation of bright-field microscopy for tuberculosis detection
(2011) Sarala, Devi Krishna; Douglas, Tania S
Automated microscopy for the detection of tuberculosis (TB) in sputum smears would reduce the load on technicians, especially in countries with a high TB burden. This dissertation reports on the development and testing of an automated system built around a conventional microscope for the detection of TB in Ziehl-Neelsen (ZN) stained sputum smears. Microscope auto-focusing, image analysis and stage movement were integrated. Images were captured at 40x magnification.
Open Access
Image segmentation and object classification for automatic detection of tuberculosis in sputum smears
(2009) Khutlang, Rethabile; Douglas, Tania S
An automated microscope is being developed in the MRC/UCT Medical Imaging Research Unit at the University of Cape Town in an effort to ease the workload of laboratory technicians screening sputum smears for tuberculosis (TB), in order to improve screening in countries with a heavy burden of TB. As a step in the development of such a microscope, the project described here was concerned with the extraction and identification of TB bacilli in digital images of sputum smears obtained with a microscope. The investigations were carried out on Ziehl-Neelsen (ZN) stained sputum smears. Different image segmentation methods were compared and object classification was implemented using various two-class classifiers, for images obtained using a microscope with 100x objective lens magnification. The bacillus identification route established for the 100x images, was applied to images obtained using a microscope with 20x objective lens magnification. In addition, one-class classification was applied the 100x images. A combination of pixel classifiers performed best in image segmentation to extract objects of interest. For 100x images, the product of the Bayes’, quadratic and logistic linear classifiers resulted in a percentage of correctly classified bacillus pixels of 89.38%; 39.52% of pixels were incorrectly classified. The segmentation method did not miss any bacillus objects with their length in the focal plane of an image. The biggest source of error for the segmentation method was staining inconsistencies. The pixel segmentation method performed poorly on images with 20x magnification. Geometric change invariant features were extracted to describe segmented objects; Fourier coefficients, moment invariant features and colour features were used. All two-class object classifiers had balanced performance for 100x images, with sensitivity and specificity above 95% for the detection of an individual bacillus after Fisher mapping of the feature set. Object classification on images with 20x magnification performed similarly. One-class object classification using the mixture of Gaussians classifier, without Fisher mapping of features, produced sensitivity and specificity above 90% when applied to 100x images.
Open Access
The impact of mHealth interventions on health systems: a systematic review protocol
(BioMed Central, 2016-11-25) Fortuin, Jill; Salie, Faatiema; Abdullahi, Leila H; Douglas, Tania S
Background: Mobile health (mHealth) has been described as a health enabling tool that impacts positively on the health system in terms of improved access, quality and cost of health care. The proposed systematic review will examine the impact of mHealth on health systems by assessing access, quality and cost of health care as indicators. Methods: The systematic review will include literature from various sources including published and unpublished/grey literature. The databases to be searched include: PubMed, Cochrane Library, Google Scholar, NHS Health Technology Assessment Database and Web of Science. The reference lists of studies will be screened and conference proceedings searched for additional eligible reports. Literature to be included will have mHealth as the primary intervention. Two authors will independently screen the search output, select studies and extract data; discrepancies will be resolved by consensus and discussion with the assistance of the third author. Discussion: The systematic review will inform policy makers, investors, health professionals, technologists and engineers about the impact of mHealth in strengthening the health system. In particular, it will focus on three metrics to determine whether mHealth strengthens the health system, namely quality of, access to and cost of health care services. Systematic review registration: PROSPERO CRD42015026070.
Open Access
Implementation and evaluation of a bony structure suppression software tool for chest X-ray imaging
(2012) Dixon, Toinette-Lee; Douglas, Tania S
This project proposed to implement a bony structure suppression tool and analyse its effects on a texture-based classification algorithm in order to assist in the analysis of chest X-ray images. The diagnosis of pulmonary tuberculosis (TB) often includes the evaluation of chest X-ray images, and the reliability of image interpretation depends upon the experience of the radiologist. Computer-aided diagnosis (CAD) may be used to increase the accuracy of diagnosis. Overlapping structures in chest X-ray images hinder the ability of lung texture analysis for CAD to detect abnormalities. This dissertation examines whether the performance of texturebased CAD tools may be improved by the suppression of bony structures, particularly of the ribs, in the chest region.
Open Access
Interlandmark measurements from lodox statscan images with application to femoral neck anteversion assessment
(2013) Chimhundu, Chipo; Douglas, Tania S
Clinicians often take measurements between anatomical landmarks on X-ray radiographs for diagnosis and treatment planning, for example in orthopaedics and orthodontics. X-ray images, however, overlap three-dimensional internal structures onto a two-dimensional plane during image formation. Depth information is therefore lost and measurements do not truly reflect spatial relationships. The main aim of this study was to develop an inter-landmark measurement tool for the Lodox Statscan digital radiography system. X-ray stereophotogrammetry was applied to Statscan images to enable three-dimensional point localization for inter-landmark measurement using two-dimensional radiographs. This technique requires images of the anatomical region of interest to be acquired from different perspectives as well as a suitable calibration tool to map image coordinates to real world coordinates. The Statscan is suited to the technique because it is capable of axial rotations for multiview imaging. Three-dimensional coordinate reconstruction and inter-landmark measurements were taken using a planar object and a dry pelvis specimen in order to assess the intra-observer measurement accuracy, reliability and precision. The system yielded average (X, Y, Z) coordinate reconstruction accuracy of (0.08 0.12 0.34) mm and resultant coordinate reconstruction accuracy within 0.4mm (range 0.3mm – 0.6mm). Inter-landmark measurements within 2mm for lengths and 1.80 for angles were obtained, with average accuracies of 0.4mm (range 0.0mm – 2.0 mm) and 0.30 (range 0.0 – 1.8)0 respectively. The results also showed excellent overall precision of (0.5mm, 0.10) and were highly reliable when all landmarks were completely visible in both images. Femoral neck anteversion measurement on Statscan images was also explored using 30 dry right adult femurs. This was done in order to assess the feasibility of the algorithm for a clinical application. For this investigation, four methods were tested to determine the optimal landmarks for measurement and the measurement process involved calculation of virtual landmarks. The method that yielded the best results produced all measurements within 10 of reference values and the measurements were highly reliable with very good precision within 0.10. The average accuracy was within 0.40 (range 0.10 –0.80).In conclusion, X-ray stereophotogrammetry enables accurate, reliable and precise inter-landmark measurements for the Lodox Statscan X-ray imaging system. The machine may therefore be used as an inter-landmark measurement tool for routine clinical applications.
Open Access
An investigation into the use of stereophotogrammetry for the analysis of craniofacial dysmorphology in schizophrenia
(2015) Cousins, Michael; Douglas, Tania S
Studies of craniofacial dysmorphology in schizophrenia, carried out since the 1960s, have reported minor physical anomalies in those with schizophrenia, prominently in the craniofacial region. Indirect methods, most notably 3D laser imaging, have been used previously for investigating craniofacial dysmorphology in schizophrenia. This project aimed to investigate the ability of a stereophotogrammetry system to detect craniofacial dysmorphology in individuals diagnosed with schizophrenia. Furthermore, observed dysmorphology was characterised and compared with that found in previous studies. Three-dimensional craniofacial landmark coordinates were obtained from images collected using a bespoke design stereophotogrammetry system. The system includes a camera rig and a calibration rig. On the camera rig is mounted three digital single-lens reflex cameras hardwired to a trigger for simultaneous image capture. The calibration rig consists of a frame with strategically positioned retro-reflective calibration markers of known 3D orientation. The precision and reliability of the stereophotogrammetry system was tested using a human subject. Measurements were taken using the system and directly using callipers by two operators on two separate occasions. Intra- and inter-operator precision and inter-modality reliability were calculated and scored. All intra- and inter-operator precision scores were at least below a 7% error, and considered "good". Inter -modality reliability scores had at least a "good" score in 72% of all measurements. Excluding one soft landmark and one landmark with small measurement value, all inter-modality reliability scores were at least "good". The study cohort consisted of 17 African (8 control, 9 schizophrenia) and 13 Caucasian ( 8 control, 5 schizophrenia) males. A set of 18 landmarks focused about the eyes, nose, mouth and chin was identified for each subject and collated in 3D coordinate space. Geometric morphometric analysis - particularly generalised Procrustes analysis and principal component analysis - was carried out on these landmark sets. Discriminant Function Analysis was applied to identify discriminating features in the data set, and classification techniques, aided by feature selection, were applied to separate affected and control subjects. In the African cohort, the results showed wider inward slanting (cat-like) eyes, a wider upturned nose and narrower downturned mouth. In the Caucasian cohort, narrower and wide set eyes, a narrower downturned nose with anteriorly displaced alare, a wider downturned mouth and posteriorly set chin were shown. The Caucasian cohort demonstrates similar dysmorphology as described in the literature. Published data for the African cohort is lacking. The nearest mean and k- nearest neighbour classifiers had the highest accuracy in the African and Caucasian groups respectively, with 71% and 77% correct classification. The efficacy of the stereophotogrammetry system introduced in this study has been shown, with craniofacial dysmorphology in schizophrenia successfully detected. Further studies with larger cohorts are recommended to attempt improved classification accuracy, but a platform now exists to pursue dysmorphology studies in other psychoses, such as bipolar disorder.
Open Access
Investigation of differences in cortical activation during wrist flexion and extension performed under real, passive and motor imagined paradigms
(2016) Stoeckigt, Stefan; John, Lester; Franz, Thomas; Douglas, Tania S
The neuromuscular control comparison between flexion and extension of the upper extremities has been conducted in a number of studies. It has been speculated that differences in the corticospinal pathway between flexion and extension may play a role in the cortical difference detected between flexion and extension, resulting in higher cortical activation for extension. However, it is still unclear as to what roles these pathways play, and to what degree other factors (muscle force activation, sensory feedback, frequency of movement, structural and/or functional differences) might influence the cortical activation in the brain. It has been speculated that the difference in cortical muscular pathways is due to flexion movements being used more often in day to day activities, therefore requiring less cortical activation for that movement. Through the investigation of the cortical differences present during different movement types, a deeper understanding into the differences between flexion and extension may be obtained. No previous study has compared the cortical differences between flexion and extension of the upper extremities during different movement types. In this study, an offline investigation is conducted between wrist flexion and extension, during real, passive and motor imaginary movement with the help of a servo controlled hand device. Simultaneous recording of EEG, EMG and wrist dynamics (velocity, angle, strain) were made on fifteen healthy right handed subjects performing 60 randomized repartitions of right wrist flexion and extension, for kinaesthetic motor imaginary, passively moved, and voluntary real active movements. Real movements were conducted at 10% relative subject maximum voluntary contraction (MVC). A servo controlled hand device was used to regulate dynamic force applied for real movements, and provide motion during passive movements. The use of different movement types with the aid of a servo controlled hand device, may give a deeper understanding into the effects of muscle force activation, rate of movement and corticospinal pathway on flexion and extension. In order to investigate the cortical differences between flexion and extension, subjects perceived difficulty, movement dynamics, movement related cortical potential (MRCP), event related desynchronization and synchronization (ERD/ERS), and phase locking value (PLV) were measured. Each measurement examines a different aspect of the cortical activation present in the brain, during the different movement types. Although relative muscle force activation between wrist real flexion and extension was similar, the motor cortex activation during extension was higher than during flexion, by MRCP and mu-band ERD, with subjects also perceiving real wrist extension to be more difficult to perform. Passive movements found higher motor cortex activation for flexion (MRCP, beta-band ERD), however higher somatosensory cortical activation was present during extension, by mu-band ERS and PLV. Motor imagined wrist flexion showed higher cortical activation during wrist flexion, by MRCP and beta-band ERD. Although numerous variables were tested (each in difference frequency bands), with some being significant and others being non-significant, overall it can be suggested that there was higher cortical activation for extension. The higher cortical activation during wrist extension movements may be due to corticospinal and somatosensory motor control pathways to motor neuron and from sensory neuron pools for extensor/flexor muscle and muscle spindle of the upper extremities. This investigation contributes to the current literature relating to cortical differences between flexion and extension of the upper extremities, by including the real, passive and motor imaginary differences between flexion and extension.
Open Access
Issues in the processing and analysis of functional NIRS imaging and a contrast with fMRI findings in a study of sensorimotor deactivation and connectivity
(2012) Robertson, Frances; Meintjies, Ernesta; Douglas, Tania S
The first part of this thesis examines issues in the processing and analysis of continuous wave functional linear infrared spectroscopy (fNIRS) of the brain usung the DYNOT system. In the second part, the same sensorimotor experiment is carried out using functional magnetic resonance imaging (fMRI) and near infrared spectroscopy in eleven of the same subjects, to establish whether similar results can be obtained at the group level with each modality. Various techniques for motion artefact removal in fNIRS are compared. Imaging channels with negligible distance between source and detector are used to detect subject motion, and in data sets containing deliberate motion artefacts, independent component analysis and multiple-channel regression are found to improve the signal-to-noise ratio.
Open Access
Localising discrete points in 3D space using stereo pairs of digital slot-scanning X-rays
(2006) Wynne, Susan M; Vaughan, Christopher Leonard (Kit); Douglas, Tania S
Includes bibliographical references (p. 104-111).
Open Access
Locating regions of interest prior to X-ray imaging using stereo-photogrammetry
(2011) Kulkarni, Radhika; Douglas, Tania S
The research project aims at locating regions of interest (ROIs) on human subjects prior to X-ray imaging on the Lodox Statscan whole body imaging system.
Open Access
Mobile phone applications to screen for hearing loss in low-and middle-income countries: a state-of-the-art review
(2022) Abbey, Humphrey Kwaku; Douglas, Tania S; Saidi, Trust
Hearing impairment is a chronic condition for which limited screening and diagnostic services are available in low-and-middle income countries (LMICs). In addition to the conventional medical devices existing to screen for the condition, several smartphone- and tablet-based applications have been introduced as mobile health (mHealth) solutions. This study was aimed at reviewing the set of mobile health tools available for screening for hearing loss in both developed countries and LMICs. Furthermore, to consider the suitability of the screening tools identified in the first objective for use in developing countries. The research approach adopted for this study was that of a state-of-the-art review. Relevant literature on mobile technology solutions to assess hearing loss were identified in electronic databases and reviewed. The mHealth solutions were reviewed with a focus on: countries of origin and evaluation; devices, software platforms and hardware considerations; hearing loss characteristics of recruited populations; features of the tests conducted and of the testing environment; reference methods to which the mobile application was compared; application performance; feedback from users; and cost. Eighteen available smartphone- and tablet-based applications for hearing loss screening were reviewed. Studies on these applications included participants from a variety of ages and, with and without hearing loss. A variety of testing environments were used. Studies on the applications found 11 of them to have acceptable functionality for use in screening for hearing loss. These 11 applications are also potentially suitable for use in LMICs, although they have some limitations. While these applications are not able to replace the conventional audiometer, they have potential as a first point of access for referral to conventional audiometry, and to help increase access to hearing loss tests in resource-constrained health systems.