Technology and Health Care - Volume 23, issue 5

Authors: Duif, Christian | Koutah, Mohamed Abou | Ackermann, Ole | Spyrou, Georgios | von Engelhardt, Lars Victor | Kaya, Daimi | Willburger, Roland E. | Lahner, Matthias

Article Type: Review Article

Abstract: OBJECTIVES: Modern orthopaedic surgery provides a variety of techniques for cartilage repair. Despite comprehensive scientific data about the single procedures, there is little experience with the combination of these methods. Inspired by a case from our clinic, we performed a PubMed based literature search about the combination of cartilage restoration principles. MATERIALS AND METHODS: The literature search was performed using the terms: ``mosaicplasty'' OR ``osteochondral transplantation'' OR ``OATS'' AND ``autologous chondrocyte implantation'' OR ``autologous chondrocyte transplantation'' OR ``ACI'' OR ``matrix-associated autologous chondrocyte implantation'' OR ``MACI'' AND ``combination''. Abstracts were revised for relevance to our case. Additionally, …we present a case report of the combinatory use of three established techniques. RESULTS: Two relevant publications, both reporting satisfying results concerning postoperative functional outcome, were found. Our results confirm this first encouraging assessment, although statistically valid data and prospective studies are still missing. CONCLUSIONS: The simultaneous use of different techniques for cartilage repair may provide alternative operative solutions for single complex cases, although further studies are required for a general recommendation. Show more

Keywords: Cartilage repair, OATS, mosaicplasty, ACI, osteochondral defect

DOI: 10.3233/THC-151003

Citation: Technology and Health Care, vol. 23, no. 5, pp. 531-537, 2015

Authors: Haga, Tomofumi | Javadzadegan, Ashkan | Kabir, Kaveh | Simmons, Anne | Barber, Tracie

Article Type: Research Article

Abstract: BACKGROUND: Haemodynamic parameters such as separated flow regions play a key role in the progression and development of atherosclerotic lesions in renal arteries, which typically originate at the renal ostium. OBJECTIVE: The aim of this study was to analyse the flow dynamics in a two-dimensional model of aorta-renal bifurcation, with a particular focus on the effect of aorta-to-renal flow ratio on flow separation regions. METHOD: A particle image velocimetry (PIV) experiment was conducted in an acrylic model of the aorta-renal ostium and the relationship between renal-to-aorta flow ratio and separated flow region …was investigated. RESULTS: For high flow ratios, a stagnation region was observed near the cranial side of the aorta. With a decrease in the flow ratio, however, this stagnation region disappeared. Furthermore, our results showed that an increase in the renal flow rate was associated with an increase in the length of the separated flow region, but a decrease in the width of the separation regions. CONCLUSIONS: As the renal-to-aorta flow ratio increased a longer separation region was observed on the cranial side of the renal channel. Show more

Keywords: Atherosclerosis, aorta-renal ostium, separated flow region, particle image velocimetry, renal-to-aorta flow ratio

DOI: 10.3233/THC-151005

Citation: Technology and Health Care, vol. 23, no. 5, pp. 539-545, 2015

Authors: Anzai, H. | Yoshida, Y. | Sugiyama, S. | Endo, H. | Matsumoto, Y. | Ohta, M.

Article Type: Research Article

Abstract: BACKGROUND: Optimal design of stents for a cerebral aneurysm is desired for efficient flow reduction in the aneurysm. OBJECTIVE: In this study, we aimed to optimize stent design at several porosities, estimate the influence of stent design on aneurysm flow, and evaluate the ability of stents to reduce flow. METHODS: Stent models were constructed as sets of squares or rectangles in the necks of a two-dimensional (2D) and realistic aneurysm. Then, automated optimization was performed using a combination of simulated annealing and lattice Boltzmann flow simulation. RESULTS: By simulated annealing, …stents were gradually modified to reduce the average velocity in an aneurysm. As a result of optimization, stents of all porosities demonstrated an inhomogeneous distribution with dense struts in the inflow area. Flow reduction was increased compared with the initial stent. Under the condition of high porosity, flow reduction by the stent drastically increased as porosity decreased. Under low porosity, the increase of velocity reduction was moderate even as porosity decreased. CONCLUSIONS: Optimization can enhance flow reduction by stents. However, the increase in reduction associated with decreasing porosity is moderate under lower-porosity conditions. This threshold may help in the choice of stent porosity for each specific aneurysm. Show more

Keywords: Computational fluid dynamics, design optimization, cerebral aneurysm, flow diverter stent, lattice boltzmann method

DOI: 10.3233/THC-151007

Citation: Technology and Health Care, vol. 23, no. 5, pp. 547-556, 2015

Authors: Panetta, Daniele | Pelosi, Gualtiero | Viglione, Federica | Kusmic, Claudia | Terreni, Marianna | Belcari, Nicola | Guerra, Alberto Del | Athanasiou, Lambros | Exarchos, Themistoklis | Fotiadis, Dimitrios I. | Filipovic, Nenad | Trivella, Maria Giovanna | Salvadori, Piero A. | Parodi, Oberdan

Article Type: Research Article

Abstract: BACKGROUND: Micro-CT is an established imaging technique for high-resolution non-destructive assessment of vascular samples, which is gaining growing interest for investigations of atherosclerotic arteries both in humans and in animal models. However, there is still a lack in the definition of micro-CT image metrics suitable for comprehensive evaluation and quantification of features of interest in the field of experimental atherosclerosis (ATS). OBJECTIVE: A novel approach to micro-CT image processing for profiling of coronary ATS is described, providing comprehensive visualization and quantification of contrast agent-free 3D high-resolution reconstruction of full-length artery walls. METHODS: Accelerated …coronary ATS has been induced by high fat cholesterol-enriched diet in swine and left coronary artery (LCA) harvested en bloc for micro-CT scanning and histologic processing. A cylindrical coordinate system has been defined on the image space after curved multiplanar reformation of the coronary vessel for the comprehensive visualization of the main vessel features such as wall thickening and calcium content. A novel semi-automatic segmentation procedure based on 2D histograms has been implemented and the quantitative results validated by histology. RESULTS: The potentiality of attenuation-based micro-CT at low kV to reliably separate arterial wall layers from adjacent tissue as well as identify wall and plaque contours and major tissue components has been validated by histology. Morphometric indexes from histological data corresponding to several micro-CT slices have been derived (double observer evaluation at different coronary ATS stages) and highly significant correlations (R2 > 0.90) evidenced. Semi-automatic morphometry has been validated by double observer manual morphometry of micro-CT slices and highly significant correlations were found (R2 > 0.92). CONCLUSION: The micro-CT methodology described represents a handy and reliable tool for quantitative high resolution and contrast agent free full length coronary wall profiling, able to assist atherosclerotic vessels morphometry in a preclinical experimental model of coronary ATS and providing a link between in vivo imaging and histology. Show more

Keywords: Micro-CT, experimental atherosclerosis, artery segmentation, histomorphometry, cylindrical coordinates

DOI: 10.3233/THC-151010

Citation: Technology and Health Care, vol. 23, no. 5, pp. 557-570, 2015

Authors: Sucharitha, M. | Geetha, K. Parimala

Article Type: Research Article

Abstract: BACKGROUND: Medical image segmentation is an essential step for most consequent image analysis tasks. Medical images can be segmented manually, but the accuracy of image segmentation using the automated segmentation algorithms is more when compared with the manual calculations. In this paper, an automated segmentation and classification of tissues are proposed for MR brain images. OBJECTIVE: To classify MR brain image into three segments such as Grey Matter (GM), White Matter (WM) and Cerebro-Spinal Fluid (CSF). Classification of brain into tissues helps to diagnose several diseases such as tumors, Alzheimer's disease, stroke, multiple sclerosis. …METHODS: An unsupervised clustering technique such as Fuzzy C-Means (FCM) algorithm has been widely used in segmenting the images. The spatial information is not fully utilized by the conventional clustering algorithm and hence it is not applicable for clustering a noisy image. We incorporate a method for image clustering called out as Reformulated Fuzzy Local information C-Means Clustering algorithm [RFLICM] which is a variant of traditional Clustering algorithm by considering both spatial and gray level information. In RFLICM, spatial distance is replaced by local coefficient of variation in a fuzzy manner. RESULTS: Experiments are conducted on brain images to validate the performance of the proposed technique in segmenting the medical images and the efficiency achieved in the presence of salt and pepper noise is 99.86%. CONCLUSION: Standard FCM, Fuzzy Local information C-means clustering algorithm [FLICM], Reformulated Fuzzy Local information C-means clustering algorithm [RFLICM] are compared to explore the accuracy of our proposed approach. Clustering results show that RFLICM segmentation method is appropriate for classifying tissues in brain MR image. Show more

Keywords: Image segmentation, fuzzy clustering, spatial information, grey level information, classification, brain MRI

DOI: 10.3233/THC-151012

Citation: Technology and Health Care, vol. 23, no. 5, pp. 571-580, 2015

Authors: Morina, Nexhmedin | Brinkman, Willem-Paul | Hartanto, Dwi | Kampmann, Isabel L. | Emmelkamp, Paul M.G.

Article Type: Research Article

Abstract: BACKGROUND AND OBJECTIVES: Research on virtual reality exposure therapy (VRET) has demonstrated good treatment efficacy with regards to several anxiety disorders. Yet, there is lack of knowledge about the value of integrating interaction between clients and virtual humans in VRET. Such interaction might prove effective in treating psychological complaints that involve social interactions, such as social anxiety. METHODS: A VRET system specifically designed to expose clients with social anxiety disorder to anxiety provoking social situations was applied to 16 and 18 individuals with high and low levels of social anxiety, respectively. Participants engaged in …two exposure sessions in several free speech dialogues with virtual humans while being monitored by a therapist. RESULTS: Participants with high levels of social anxiety reported significantly lower levels of social anxiety three months after exposure to two virtual reality interaction sessions than before treatment (p < 0.01). In the group with low levels of social anxiety, no significant change of social anxiety was reported between pre-treatment and follow-up. Additionally, participants in both groups reported higher self-efficacy three months after treatment than before treatment (ps ≤ 0.001). CONCLUSION: These findings indicate that virtual reality technology that incorporates social interactions may be successfully applied for therapeutic purposes. Show more

Keywords: Virtual reality, exposure, social phobia, social anxiety

DOI: 10.3233/THC-151014

Citation: Technology and Health Care, vol. 23, no. 5, pp. 581-589, 2015

Authors: Mendez-Zorrilla, A. | Garcia-Zapirain, B.

Article Type: Research Article

Abstract: BACKGROUND: Given the importance of the voice in our daily lives, any study focused on its pathologies and the way of caring and promoting the health of them is of common interest. OBJECTIVE: This paper describes a method to automatically aid indetecting vocal folds benign pathologies based on glottal space segmentation vocal fold video sequences captured by a laryngoscope. METHODS: The proposed algorithm is based on automatic segmentation supported by Gabor filters, and features classification with Principal Component Analysis (PCA) to achieve the expected results. RESULTS: The authors wish …to emphasize that the proposed algorithm is independent from the images' resolution and zoom, but their quality depends on specialist experience with the instrumentation. Segmentation block provides good results for 95% of images and classification block distinguishes successfully between pathological and healthy images in 92.1% of cases. The proposed system's findings have been compared with the diagnosis made by doctors and it obtains the same results in all the 45 sequences. CONCLUSIONS: One of the proposed study's key elements has been which objective measurements are of significance for the specialist. In this case, it is those that enable the specialist to calculate the size of the pathology (previously classified automatically) that he/she is observing, thus enabling them to provide the patient with more information or to prescribe treatment and even measure its development. Show more

Keywords: Gabor filters, principal component analysis, vocal folds, stroboscope, glottal space

DOI: 10.3233/THC-151016

Citation: Technology and Health Care, vol. 23, no. 5, pp. 591-604, 2015

Authors: Xiang, Wei | Li, Chong

Article Type: Research Article

Abstract: BACKGROUND: Operating Room (OR) is the core sector in hospital expenditure, the operation management of which involves a complete three-stage surgery flow, multiple resources, prioritization of the various surgeries, and several real-life OR constraints. As such reasonable surgery scheduling is crucial to OR management. OBJECTIVE: To optimize OR management and reduce operation cost, a short-term surgery scheduling problem is proposed and defined based on the survey of the OR operation in a typical hospital in China. METHOD: The comprehensive operation cost is clearly defined considering both under-utilization and overutilization. A nested Ant …Colony Optimization (nested-ACO) incorporated with several real-life OR constraints is proposed to solve such a combinatorial optimization problem. RESULTS: The 10-day manual surgery schedules from a hospital in China are compared with the optimized schedules solved by the nested-ACO. Comparison results show the advantage using the nested-ACO in several measurements: OR-related time, nurse-related time, variation in resources' working time, and the end time. CONCLUSIONS: The nested-ACO considering real-life operation constraints such as the difference between first and following case, surgeries priority, and fixed nurses in pre/post-operative stage is proposed to solve the surgery scheduling optimization problem. The results clearly show the benefit of using the nested-ACO in enhancing the OR management efficiency and minimizing the comprehensive overall operation cost. Show more

Keywords: Surgery scheduling, operation cost, operating room management, ant colony optimization

DOI: 10.3233/THC-151017

Citation: Technology and Health Care, vol. 23, no. 5, pp. 605-617, 2015

Authors: Chen, Chih-Wen | Lin, Wei-Chao | Ke, Shih-Wen | Tsai, Chih-Fong | Hu, Ya-Han

Article Type: Research Article

Abstract: BACKGROUND: To collect medical datasets, it is usually the case that a number of data samples contain some missing values. Performing the data mining task over the incomplete datasets is a difficult problem. In general, missing value imputation can be approached, which aims at providing estimations for missing values by reasoning from the observed data. Consequently, the effectiveness of missing value imputation is heavily dependent on the observed data (or complete data) in the incomplete datasets. OBJECTIVE: In this paper, the research objective is to perform instance selection to filter out some noisy data (or …outliers) from a given (complete) dataset to see its effect on the final imputation result. Specifically, four different processes of combining instance selection and missing value imputation are proposed and compared in terms of data classification. METHODS: Experiments are conducted based on 11 medical related datasets containing categorical, numerical, and mixed attribute types of data. In addition, missing values for each dataset are introduced into all attributes (the missing data rates are 10%, 20%, 30%, 40%, and 50%). For instance selection and missing value imputation, the DROP3 and k-nearest neighbor imputation methods are employed. On the other hand, the support vector machine (SVM) classifier is used to assess the final classification accuracy of the four different processes. RESULTS: The experimental results show that the second process by performing instance selection first and imputation second allows the SVM classifiers to outperform the other processes. CONCLUSIONS: For incomplete medical datasets containing some missing values, it is necessary to perform missing value imputation. In this paper, we demonstrate that instance selection can be used to filter out some noisy data or outliers before the imputation process. In other words, the observed data for missing value imputation may contain some noisy information, which can degrade the quality of the imputation result as well as the classification performance. Show more

Keywords: Instance selection, missing value imputation, incomplete data, medical data mining

DOI: 10.3233/THC-151018

Citation: Technology and Health Care, vol. 23, no. 5, pp. 619-625, 2015

Authors: Hagen, Marco | Lemke, Martin | Kutsch, Heinrich-Peter | Lahner, Matthias

Article Type: Research Article

Abstract: BACKGROUND: The strength training industry has failed in designing a machine for exercising the pronators and supinators, despite their substantial medio-lateral bracing function. OBJECTIVE: The present study documents the muscle strength generation capabilities of the pronators and supinators within their functional anatomic movement plane, using an innovative strength training machine with an oblique axis. METHODS: By using two force transducers, the angle-torque relationship of the pronators and supinators of 18 healthy male subjects was identified during maximum voluntary isometric contractions at five anatomical joint angles. Surface EMG was recorded from anterior tibial …(TA), peroneus longus (PL) and soleus (SOL) muscles. RESULTS: The pronator strength curve showed an inverted U-shaped characteristic, whereas the supinator curve descends from pronated to supinated position. Compared to the muscle activities for one-leg heel raise and toe raise, PL (108-131%) and TA (59-83%), respectively, showed highest activity during pronations. The most activated supinator is SOL (67% of a one-leg heel raise). CONCLUSIONS: Differences in the shape of the pronator and supinator strength curves revealed that two different variable cams have to be implemented for matching the human torque capability. We anticipate our study to be a starting point for preventive machine-based training interventions. Show more

Keywords: Machine-based strength training, subtalar joint, ankle stability, strength curves, muscle activity

DOI: 10.3233/THC-151004

Citation: Technology and Health Care, vol. 23, no. 5, pp. 627-635, 2015