Technology and Health Care - Volume 24, issue 3

Authors: Lin, Chia-Hung | Kan, Chung-Dann | Chen, Wei-Ling | Wu, Ming-Jui | Yu, Fan-Ming

Article Type: Research Article

Abstract: Narrowed vessel accesses produce blood flow changes, and induce flow instability and vessel wall vibration, resulting in blood pressure, flow velocity, and flow resistance increases. The vessel wall vibrates and propagates the low axial blood flow, as representing the resistance (R) to blood flow. The compliance is a blood pressure-blood volume relation, representing the systole and diastole capacity of the blood vessel. These dynamic behaviors increase blood flow resistances and reduce blood vessel compliances. Vibration phenomena result on the elastic vessel walls and induce simple harmonic motion due to transverse vibration pressure (TVP). The rise time, amplitude, and pulse duration …of transverse waves are determined by the flow resistances (R) and vessel compliances (C). Thus, a stenotic arteriovenous access has high resistance and low compliance, which can be expressed an astable multivibrator as an equivalent model consisting of a lumped resistor (R) and a lumped capacitor (C). TVP's oscillation frequency, rise time, and amplitude are determined by the flow resistances and vessel compliances. Hence, an astable multivibrator is used to model TVP parameters to estimate negative time constants, τ=(R× C), which are used to evaluate the flow instability and the dysfunction risk in in-vitro arteriovenous grafts (AVGs). Experimental results show the average negative time constants have the positive correlation as the degree of stenosis (DOS) increases (R2 = 0.8944), and their variations with the flow resistance and vessel compliance are also validated. Positive pole values, s=(-1/τ), are used to show that the force responses of the vessel walls grow in a finite time, 0.5415 ± 7.60 × 10-3 sec, and the equivalent model would be also unstable as DOS increases (R2 = 0.8802). By comparison with hemodynamic analysis, the finding of proposed model can be further carried out for screening AVG dysfunction risk during hemodialysis treatment. Show more

Keywords: Astable multivibrator, transverse vibration pressure (TVP), degree of stenosis (DOS), time constant, positive pole

DOI: 10.3233/THC-161130

Citation: Technology and Health Care, vol. 24, no. 3, pp. 295-308, 2016

Authors: Kratz, T. | Exner, M. | Campo dell'Orto, M. | Timmesfeld, N. | Schüttler, K.F. | Efe, T. | Zoremba, M. | Wulf, H. | Steinfeldt, T.

Article Type: Research Article

Abstract: BACKGROUND: The intraoperative application of focused transthoracic echocardiography (TTE) is often considered to be restricted. Echocardiography with pocket-sized hand held ultrasound systems has been shown to be feasible in various settings. OBJECTIVE: The aim of this study was to investigate the feasibility of the intraoperative application of pocket-sized echocardiography and the comparison of its imaging quality and diagnostic reliability and variability with a standard ultrasound system. METHODS: After written informed consent, TTE was performed on 40 anaesthetised general, vascular, visceral, thoracic surgical and orthopaedic patients according to the FATE protocol: first, with …a pocket-sized and second, with a high-end ultrasound system randomly by two anaesthetists. Imaging quality of four basic and three additional FATE views was rated on an established scale from 1 (impossible) to 5 (perfect). Successful TTE was defined, if one basic FATE views would be rated as grade 4 or 5 or alternatively two views as grade 3. Pathologic findings by both ultrasound devices were documented and imaging quality and pathologic findings were compared. RESULTS: All 40 patients presented acceptable imaging quality, resulting in a success rate of 1.0 (97.5%-CI 0.91-1, p= 0.015). The individual imaging ratings of each view were significantly lower with the pocket-sized system, but still showed acceptable imaging quality. With the high-end device more pathologic findings were detected (107 vs. 87), but none of the relevant or severe pathologies were overseen with the hand-held device. CONCLUSION: The application of a pocket-sized echocardiography device for focused intraoperative TTE is feasible and can appropriate be used for the initial evaluation of relevant pathologies in the operating theatre. Show more

Keywords: Focused TTE, intraoperative echocardiography, pocket-sized echocardiography device, hand held echocardiography

DOI: 10.3233/THC-161131

Citation: Technology and Health Care, vol. 24, no. 3, pp. 309-315, 2016

Authors: Frolov, S.V. | Sindeev, S.V. | Liepsch, D. | Balasso, A.

Article Type: Research Article

Abstract: BACKGROUND: According to the clinical data, flow conditions play a major role in the genesis of intracranial aneurysms. The disorder of the flow structure is the cause of damage of the inner layer of the vessel wall, which leads to the development of cerebral aneurysms. Knowledge of the alteration of the flow field in the aneurysm region is important for treatment. OBJECTIVE: The aim is to study quantitatively the flow structure in an patient-specific aneurysm model of the internal carotid artery using both experimental and computational fluid dynamics (CFD) methods with Newtonian and non-Newtonian fluids. …METHODS: A patient-specific geometry of aneurysm of the internal carotid artery was used. Patient data was segmented and smoothed to obtain geometrical model. An elastic true-to-scale silicone model was created with stereolithography. For initial investigation of the blood flow, the flow was visualized by adding particles into the silicone model. The precise flow velocity measurements were done using 1D Laser Doppler Anemometer with a spatial resolution of 50 μ m and a temporal resolution of 1 ms. The local velocity measurements were done at a distance of 4 mm to each other. A fluid with non-Newtonian properties was used in the experiment. The CFD simulations for unsteady-state problem were done using constructed hexahedral mesh for Newtonian and non-Newtonian fluids. RESULTS: Using 1D laser Doppler Anemometer the minimum velocity magnitude at the end of systole -0.01 m/s was obtained in the aneurysm dome while the maximum velocity 1 m/s was at the center of the outlet segment. On central cross section of the aneurysm the maximum velocity value is only 20% of the average inlet velocity. The average velocity on the cross-section is only 11% of the inlet axial velocity. Using the CFD simulation the wall shear stresses for Newtonian and non-Newtonian fluid at the end of systolic phase (t= 0.25 s) were computed. The wall shear stress varies from 3.52 mPa (minimum value) to 10.21 Pa (maximum value) for the Newtonian fluid. For the non-Newtonian fluid the wall shear stress minimum is 2.94 mPa; the maximum is 9.14 Pa. The lowest value of the wall shear stress for both fluids was obtained at the dome of the aneurysm while the highest wall shear stress was at the beginning of the outlet segment. The vortex in the aneurysm region is unstable during the cardiac cycle. The clockwise rotation of the streamlines at the inlet segment for Newtonian and non-Newtonian fluid is shown. CONCLUSION: The results of the present study are in agreement with the hemodynamics theory of aneurysm genesis. Low value of wall shear stress is observed at the aneurysm dome which can cause a rupture of an aneurysm. Show more

Keywords: Hemodynamics, cerebral circulation, cardiovascular system, experimental set-up, laser doppler anemometer, flow visualization, mathematical model, aneurysm genesis

DOI: 10.3233/THC-161132

Citation: Technology and Health Care, vol. 24, no. 3, pp. 317-333, 2016

Authors: Shirazi, Syed H. | Umar, Arif Iqbal | Naz, Saeeda | Razzak, Muhammad I.

Article Type: Research Article

Abstract: BACKGROUND: Blood cell count, also known as differential count of various types of blood cells, provides valuable information in order to assess variety of diseases like AIDS, leukemia and blood cancer. Manual techniques are still used in diseases diagnosis that is very lingering and tedious process. However, machine based automatic analysis of leukocyte is a powerful tool that could reduce the human errors, improve the accuracy, and minimize the required time for blood cell analysis. However, leukocyte segmentation is a challenging process due to the complexity of the blood cell image; therefore, this task remains unresolved issue in the …blood cell segmentation. OBJECTIVE: The aim of this work is to develop an efficient leukocyte cell segmentation and classification system. METHODS: This paper presents an efficient strategy to segment cell images. This has been achieved by using Wiener filter along with Curvelet transform for image enhancement and noise elimination in order to elude false edges. We have also used combination of entropy filter, thresholding and mathematical morphology for obtaining image segmentation and boundary detection, whereas we have used back-propagation neural network for leukocyte classification into its sub classes. RESULTS: As a result, the generated segmentation results are fruitful in a sense that we have overcome the problem of overlapping cells. We have obtained 100%, 96.15%, 92.30%, 92.30% and 96.15% accuracy for basophil, eosinophil, monocyte, lymphocyte and neutrophil respectively. Show more

Keywords: Leukocyte, microscope image analysis, curvelet, leukocyte classification, blood cell segmentation

DOI: 10.3233/THC-161133

Citation: Technology and Health Care, vol. 24, no. 3, pp. 335-347, 2016

Authors: Xu, Lijian | Sugawara, Michiko | Tanaka, Gaku | Ohta, Makoto | Liu, Hao | Yamaguchi, Ryuhei

Article Type: Research Article

Abstract: BACKGROUND: Many numerical studies have been published with respect to about flow structures around cerebral aneurysm assuming to be rigid. Furthermore, there is little experimental research concerning aneurysm with elastic wall. Wall shear stress in elastic wall comparing with rigid wall should be clarified in experimental approach and verified in CFD. OBJECTIVE: We have experimentally realized elastic aneurysm model accompanying with wall deformation. Wall shear stress was examined for both rigid and elastic aneurysm models in pulsatile flow. METHODS: Effect of elasticity on wall shear stress inside aneurysm induced at the apex of …anterior cerebral artery was experimentally examined by particle image velocimetry in vitro . In order to adjust the wall deformation, the pressure adjustment chamber was specially equipped outside the aneurysm wall. RESULTS: Effect of elasticity on wall shear stress was noticed on the comparison with that of rigidity. Wall elasticity reduced the peak magnitude, the spatial and temporal averaged wall shear stress comparing with those of wall rigidity experimentally. These reductions were endorsed by fluid-structure interaction simulation. CONCLUSION: Elastic wall comparing with rigid wall would reduce the peak magnitude, the spatial and temporal averaged wall shear stress acting on vascular wall. Show more

Keywords: Cerebral aneurysm, elasticity, wall shear stress, PIV, CFD, hemodynamics

DOI: 10.3233/THC-161135

Citation: Technology and Health Care, vol. 24, no. 3, pp. 349-357, 2016

Authors: Ezechieli, Marco | De Meo, Federico | Bellotti, Vittorio | Cardenas, Carlomagno | Astarita, Emmanuele | Cavaliere, Pietro | Windhagen, Henning | Ribas, Manuel

Article Type: Research Article

Abstract: BACKGROUND: Surgical treatment of femoroacetabular impingement is becoming accepted worldwide, owing to improvements in clinical results and quality of life. In addition to treatment by surgical dislocation or arthroscopy, arthroscopic assisted mini-open approach was postulated to treat this pathology. OBJECTIVE: The aim of this study was to analyze early results of the first consecutive 72 cases of femoroacetabular impingement treated using the arthroscopic assisted mini-open approach in two different centers by two surgeons trained by a senior surgeon experienced in the technique. METHODS: Seventy-two consecutive cases of femoroacetabular impingement were operated …in arthroscopic assisted mini-open approach technique in two different centers. After a mean follow-up time of 15 months (range 6-24 months), the Western Ontario and McMaster Universities Arthritis Index, Hip disability and Osteoarthritis Outcome Score and University of California, Los Angeles activity score, alpha angle and Wiberg angle were obtained. RESULTS: In both centers, all three scores showed significantly better results at follow-up time than preoperatively. The Western Ontario and McMaster Universities Arthritis Index increased from 64.3 to 91.4 (A) and from 68.1 to 89 (B). The Hip disability and Osteoarthritis Outcome Score increased from 59.5 to 94.4 (A) and from 62.1 to 93.8 (B). The University of California, Los Angeles activity score increased from 5.2 to 8.1 (A) and from 5.3 to 8.4 (B). The alpha angle and the Wiberg angle were significantly reduced after osteoplasty. The overall complication rate was low. CONCLUSIONS: Early results of this study show a good clinical and radiological outcome; therefore, the arthroscopic assisted mini-open approach can be used as an alternative in treating femoroacetabular impingement. Show more

Keywords: Arthroscopic assisted mini-open approach, femoroacetabular impingement, learning curve

DOI: 10.3233/THC-151127

Citation: Technology and Health Care, vol. 24, no. 3, pp. 359-365, 2016

Authors: Daniilidis, Kiriakos | Yao, Daiwei | Gosheger, Georg | Berssen, Corinna | Budny, Tymoteusz | Dieckmann, Ralf | Höll, Steffen

Article Type: Research Article

Abstract: INTRODUCTION: Obesity is a common problem in the western European countries. Since the association between obesity and the emergence of gonarthrosis is approved, it is more important to gain reliable information about this patient group. The aim of the present retrospective study is to evaluate clinical outcomes of German obese patients after total knee arthroplasty (TKA). PATIENTS AND METHODS: Between 2001 and 2009 a total of 199 patients with 230 TKA were included in the present study. The collective was divided into four groups in relation to their Body-Mass-Index (BMI); group 1: BMI …< 25 kg/m2 , n = 24; group 2: BMI 25-30 kg/m2 , n = 80, group 3: BMI 30-40 kg/m2 , n = 109; group 4: BMI> 40 kg/m2 , n = 17. Clinical outcome measurement was scored postoperatively using the knee society score (KSS), hospital for special surgery score (HSS) and the visual analogue scale (VAS). Furthermore complications and subjective patient satisfaction were noted. RESULTS: We did not detect any significant differences in the clinical scores between the BMI-subgroups. However we measured statistically significant worse results in case of infection and instability in all BMI subgroups (p> 0.01). CONCLUSION: While infection and instability may have a negative influence for the clinical outcome, we did not detect any significant correlation between obesity and exiting complications. Obesity has no significant correlation to influence the outcome after TKA implantation negatively. Show more

Keywords: Obesity, total knee arthroplasty, outcome, infection

DOI: 10.3233/THC-151128

Citation: Technology and Health Care, vol. 24, no. 3, pp. 367-375, 2016

Authors: Moiduddin, Khaja | Al-Ahmari, Abdulrahman | Nasr, Emad S. Abouel | Mian, Syed Hammad | Al Kindi, Mohammed

Article Type: Research Article

Abstract: BACKGROUND: The customized mandible reconstruction has been a challenging task in maxillofacial surgery. Designing an implant taking into considering the surrounding bone contours is really critical. Various computer aided design techniques have been used in the designing the customized reconstruction implants, but nevertheless study on the comparison between these techniques is rarely used. OBJECTIVE: The objective of this study is to compare the mirroring and anatomical reconstruction design techniques used in the maxillofacial surgery and select the best design technique. METHODS: The three mandible bone defects-small (< 20 mm), medium (20 to 40 …mm) and large (41 to 53 mm) tumors are reconstructed using the two reconstruction design techniques and compared to their accuracy, using a 3 dimensional (3D) implant design evaluation and part to Computer aided design (CAD) comparison using a Co-ordinate measuring machine (CMM). RESULTS: The analysis results indicate that the mirroring technique provides higher accuracy for the implant design as compared to the anatomical technique for the medium and large tumors at maxillofacial regions. In case of implant design in small tumors, the anatomical design provides perfect implant fitting. CONCLUSIONS: Based on the results, it is recommended to select the anatomy design technique only for small tumor regions and mirroring technique for medium and large tumors. Show more

Keywords: CT scan, medical modelling, maxillofacial surgery, customized design implants, mirroring technique, anatomy reconstruction, co-ordinate measuring machine

DOI: 10.3233/THC-161136

Citation: Technology and Health Care, vol. 24, no. 3, pp. 377-389, 2016

Authors: Hagen, Marco | Asholt, Johannes | Lemke, Martin | Lahner, Matthias

Article Type: Research Article

Abstract: BACKGROUND: It is currently unclear how participation in different sports affects the angle-specific subtalar pronator and supinator muscle strength and pronator-to-supinator strength ratio (PSR). OBJECTIVE: Based on the hypothesis that both differences sport-related patterns of play and foot-ground interaction may lead to sport-specific muscle adaptations, this study compared the angle specific pronator and supinator strength capacity of handball and soccer players. METHODS: Eighteen healthy male handball and 19 soccer players performed maximum isometric voluntary isometric contractions using a custom-made testing apparatus. Peak pronator (PPT) and supinator torques (PST), pronator and supinator strength …curves (normalised to the peak torque across all joint angles) and PSR were measured in five anatomical joint angles across the active subtalar range of motion (ROM). RESULTS: All analysed parameters were dependent on the subtalar joint angle. The ANOVA revealed significant `joint angle' × `group' interactions on PPT, pronator strength curves and PSR. No group differences were found for active subtalar ROM. CONCLUSION: In previously uninjured handball and soccer athletes, there were intrinsic differences in angle-specific subtalar pronator muscle strength. The lower PSR, which was found in the most supinated angle, can be seen as a risk factor for sustaining an ankle sprain. Show more

Keywords: Ankle, subtalar joint angle, muscle strength, pronation, supination, strength ratio

DOI: 10.3233/THC-161138

Citation: Technology and Health Care, vol. 24, no. 3, pp. 391-399, 2016

Authors: Chou, C.-H. | Hwang, Y.-S. | Chen, C.-C. | Chen, S.-C. | Chou, S.-W. | Chen, Y.-L.

Article Type: Research Article

Abstract: BACKGROUND: A patient whose spinal cord was damaged due to accident may result in Tetraplegia or lose the ability to control his/her daily living environment. Currently, patients must use an invasive tool tongue movement, to help the patient communicate with the external environment. OBJECTIVE: This study designed a non-invasive tongue movement computer mouse system that allows the patient to use tongue movement to control a computer to communicate with the external environment. METHODS: Via a pressure sensor and assistive holder designed in this study, the pressure sensor can be moved using the assistive …holder close to the mylohyoid muscle of the patient's lower jaw. The changes in pressure from the mylohyoid muscle are converted into computer mouse control signals to control a computer to communicate with the external environment. RESULTS: This study is based on ISO9241-Part 9 to design four kinds of training modes with varying difficulties. The data were collected from five able persons participating in the test over 7 days. The data includes throughput, path efficiency, test completion time and reaction time. The data verifies that the proposed system is stable and practical for persons with disabilities. CONCLUSION: The non-invasive computer mouse system for sensing tongue movement can completely breakthrough the limitations of the invasive tongue movement sensing system. This study uses non-invasive, simple tongue movements that correspond to the stretching and shrinking of the lower jaw mylohyoid muscle to control the computer mouse. Show more

Keywords: Tongue drive system, assistive technology, human computer interface, non-invasive

DOI: 10.3233/THC-161137

Citation: Technology and Health Care, vol. 24, no. 3, pp. 401-408, 2016