Technology and Health Care - Volume 24, issue s2

Authors: Li, X. | Zhang, Y.Y. | Shi, Y.H. | Zhou, L.H. | Zhen, X.

Article Type: Research Article

Abstract: Deformable image registration (DIR) is a critical technic in adaptive radiotherapy (ART) to propagate contours between planning computerized tomography (CT) images and treatment CT/Cone-beam CT (CBCT) image to account for organ deformation for treatment re-planning. To validate the ability and accuracy of DIR algorithms in organ at risk (OAR) contours mapping, seven intensity-based DIR strategies are tested on the planning CT and weekly CBCT images from six Head & Neck cancer patients who underwent a 6 ∼ 7 weeks intensity-modulated radiation therapy (IMRT). Three similarity metrics, i.e. the Dice similarity coefficient (DSC), the percentage error (PE) and the Hausdorff distance …(HD), are employed to measure the agreement between the propagated contours and the physician delineated ground truths. It is found that the performance of all the evaluated DIR algorithms declines as the treatment proceeds. No statistically significant performance difference is observed between different DIR algorithms (p> 0.05), except for the double force demons (DFD) which yields the worst result in terms of DSC and PE. For the metric HD, all the DIR algorithms behaved unsatisfactorily with no statistically significant performance difference (p= 0.273). These findings suggested that special care should be taken when utilizing the intensity-based DIR algorithms involved in this study to deform OAR contours between CT and CBCT, especially for those organs with low contrast. Show more

Keywords: Adaptive radiotherapy, deformable image registration, CBCT, contour propagation, head & neck cancer

DOI: 10.3233/THC-161204

Citation: Technology and Health Care, vol. 24, no. s2, pp. S747-S755, 2016

Authors: Sun, Y.P. | Zhang, S. | Cui, Z. | Qu, L.L.

Article Type: Research Article

Abstract: Based on compressive sensing (CS) technology, a high resolution confocal microwave imaging algorithm is proposed for breast cancer detection. With the exploitation of the spatial sparsity of the target space, the proposed image reconstruction problem is cast within the framework of CS and solved by the sparse constraint optimization. The effectiveness and validity of the proposed CS imaging method is verified by the full wave synthetic data from numerical breast phantom using finite-difference time-domain (FDTD) method. The imaging results have shown that the proposed imaging scheme can improve the imaging quality while significantly reducing the amount of data measurements and …collection time when compared to the traditional delay-and-sum imaging algorithm. Show more

Keywords: Microwave imaging, breast cancer detection, compressive sensing (CS), FDTD method

DOI: 10.3233/THC-161205

Citation: Technology and Health Care, vol. 24, no. s2, pp. S757-S765, 2016

Authors: Ren, Fulong | Li, Wei | Yang, Jinzhu | Geng, Huan | Zhao, Dazhe

Article Type: Research Article

Abstract: BACKGROUND: Existing methods may fail to locate and segment the optic disc (OD) due to imprecise boundaries, inconsistent image contrast and deceptive edge features in retinal images. OBJECTIVE: To locate the OD and detect the OD boundary accurately. METHODS: The method exploits a multi-stage strategy in the detection procedure. Firstly, OD location candidate regions are identified based on high-intensity feature and vessels convergence property. Secondly, a line operator filter for circular brightness feature detection is designed to locate the OD accurately on candidates. Thirdly, an initialized contour is obtained by iterative thresholding and …ellipse fitting based on the detected OD position. Finally, a region-based active contour model in a variational level set formulation and ellipse fitting are employed to estimate the OD boundary. RESULTS: The proposed methodology achieves an accuracy of 98.67% for OD identification and a mean distance to the closest point of 2 pixels in detecting the OD boundary. CONCLUSION: The results illuminate that the proposed method is effective in the fast, automatic, and accurate localization and boundary detection of the OD. The present work contributes to the more effective evaluation of the OD and realizing automatic screening system for early eye diseases to a large extent. Show more

Keywords: Optic disc localization, optic disc segmentation, retinal images, level set method

DOI: 10.3233/THC-161206

Citation: Technology and Health Care, vol. 24, no. s2, pp. S767-S776, 2016

Authors: Lee, J.-S. | Lin, K.-W. | Syue, J.-L.

Article Type: Research Article

Abstract: Currently, cardiovascular disease affects a relatively high proportion of the world's population. Thus, developing simple and effective methods for monitoring patients with cardiovascular disease is critical for research. Monitoring the heart rate of patients is a relatively simple and effective method for managing patients with this condition. For patients, the desired heart rate monitoring equipment should be portable, instantaneous, and accurate. Because smartphones have become the most prevalent mobile device, we utilized this technology as a platform for developing a novel heart-rate measurement system. Catering to the phenomenon of people using the front camera of their smartphones as a mirror, …the proposed system was designed to analyze facial-image sequences captured using the front camera. A spatiotemporal alpha-trimmed mean filter was developed to estimate a user's heart rate quickly and accurately. The experimental results show that in addition to achieving these objectives, the developed system outperforms a similar personal computer-based system. In addition, the system performs effectively even when users are wearing glasses. Hence, the proposed system demonstrates practical value for people who must monitor their heart rate daily. Show more

Keywords: Smartphone, photoplethysmography (PPG), heart rate

DOI: 10.3233/THC-161207

Citation: Technology and Health Care, vol. 24, no. s2, pp. S777-S783, 2016

Authors: Feng, Yuan | Guo, Hao | Zhang, Hongmiao | Li, Chungang | Sun, Lining | Mutic, Sasa | Ji, Songbai | Hu, Yanle

Article Type: Research Article

Abstract: BACKGROUND: In recent years, MR images have been increasingly used in therapeutic applications such as image-guided radiotherapy (IGRT). However, images with low contrast values and noises present challenges for image segmentation. OBJECTIVE: The objective of this study is to develop a robust method based on fuzzy C-means (FCM) method which can segment MR images polluted with Gaussian noise. METHODS: A modified FCM algorithm accommodating non-local pixel information via Hausdorff distance was developed for segmenting MR images. The membership and objective functions were modified accordingly. Segmentations with different weights of the Hausdorff distance …were compared. RESULTS: Segmentation tests using synthetic and MR images showed that the proposed algorithm was better at resolving boundaries and more robust to Gaussian noise. By segmenting a sample MR image of a tumor, we further showed the capability of the method in capturing the centroid of the target region. CONCLUSIONS: The modified FCM algorithm with neighboring information can be used to segment blurry images with potential applications in segmenting motion MR images in image-guided radiotherapy (IGRT). Show more

Keywords: Segmentation, Hausdorff distance, fuzzy C-means, motion images, MR images

DOI: 10.3233/THC-161208

Citation: Technology and Health Care, vol. 24, no. s2, pp. S785-S793, 2016

Authors: Liang, Shuang | Choi, Kup-Sze | Qin, Jing | Wang, Qiong | Pang, Wai-Man | Heng, Pheng-Ann

Article Type: Research Article

Abstract: BACKGROUND: The effective connectivity refers explicitly to the influence that one neural system exerts over another in frequency domain. To investigate the propagation of neuronal activity in certain frequency can help us reveal the mechanisms of information processing by brain. OBJECTIVE: This study investigates the detection of effective connectivity and analyzes the complex brain network connection mode associated with motor imagery (MI) tasks. METHODS: The effective connectivity among the primary motor area is firstly explored using partial directed coherence (PDC) combined with multivariate empirical mode decomposition (MEMD) based on electroencephalography (EEG) …data. Then a new approach is proposed to analyze the connection mode of the complex brain network via the information flow pattern. RESULTS: Our results demonstrate that significant effective connectivity exists in the bilateral hemisphere during the tasks, regardless of the left-/right-hand MI tasks. Furthermore, the out-in rate results of the information flow reveal the existence of the contralateral lateralization. The classification performance of left-/right-hand MI tasks can be improved by careful selection of intrinsic mode functions (IMFs). CONCLUSION: The proposed method can provide efficient features for the detection of MI tasks and has great potential to be applied in brain computer interface (BCI). Show more

Keywords: Electroencephalogram (EEG), information flow pattern, multivariate empirical mode decomposition (MEMD), effective connectivity, motor imagery (MI)

DOI: 10.3233/THC-161212

Citation: Technology and Health Care, vol. 24, no. s2, pp. S795-S801, 2016

Authors: Stepanov, Rodion | Podtaev, Sergey | Dumler, Andrey | Chugainov, Sergey

Article Type: Research Article

Abstract: BACKGROUND: Impedance cardiography (ICG) is an inexpensive, noninvasive technique for estimating hemodynamic parameters. ICG can be used to obtain the ejection fraction of the left atrium and to monitor systolic time intervals. Traditional ICG technique does not enable unambiguous detection of the left ventricle ejection time (LVET) and the time relationships between specific marker points. OBJECTIVE: This work aims to approbate a new approach for ICG signal processing using wavelet transform (WT) and to investigate the possibilities of this approach for determination of the parameters which are related to the stroke volume (SV), in particular …LVET. METHODS: Thoracic tetrapolar polyrheocardiography method for simultaneous registration of ECG, ICG and phonocardiograms has been used. A control group consisted of eight healthy men aged 20-25 years. In addition, four patients with essential hypertension participated in the study. Wavelet representation of the ICG data produced local maxima in a two dimensional distribution of the wavelet coefficient. Each extremum point was characterized by the amplitude, scale and time, which determine SV. RESULTS: LVET was defined as the scale corresponding to the E-wave maximum related to the systolic phase of the cardiac cycle. Also, we defined the initial systolic time interval (ISTI) as the time interval between R peak in the ECG and E-wave maximum on the wavelet plane. During functional test LVET and ISTI values defined by WT demonstrated a proper hemodynamic response to loading for the control group and patients with essential hypertension. CONCLUSION: The proposed approach demonstrates the ability of ICG-WT technique for adequate assessment of SV parameters, including cardiac time intervals. Show more

Keywords: Impedance cardiography, wavelet transform, hemodynamic parameters

DOI: 10.3233/THC-161213

Citation: Technology and Health Care, vol. 24, no. s2, pp. S803-S809, 2016

Authors: Wang, Hao | Li, Xin-Yuan | An, Yan-Ming | Guo, Ya-Min

Article Type: Research Article

Abstract: BACKGROUND: Surgical site infection is one of the most common complications of conventional laparoscopic surgery. Preventing infection of the incision is particularly important. OBJECTIVE: To discuss how to prevent the occurrence of surgical site infection after contaminated abdominal surgery. METHODS: Five hundred and fifty-one surgery patients with ``contaminated abdominal incisions'' from January 2011 to May 2013 were analyzed in terms of the preventative treatment, and summarized for surgical site infection. Subcutaneous tissue flushed with normal saline + hydrogen peroxide before suturing in the intervention 1 group; subcutaneous tissue flushed with normal saline + …0.5% povidone-iodine before suturing in the intervention 2 group. RESULTS: When subcutaneous fat was contaminated to a depth of ≤ 2.5 cm, the rates of surgical site infection in the control group and the intervention groups showed no significant difference (P > 0.05). When subcutaneous fat was contaminated to a depth of ≥ 3.0 cm, the rate of surgical site infection in the control group compared with the intervention one group was not statistically different (P > 0.05). The rate of surgical site infection in the control group compared with the intervention two group was statistical significant (P < 0.05). The rate of surgical site infection in the intervention one group compared with the intervention two group was statistical significant (P < 0.05). CONCLUSIONS: Preoperative control of the blood sugar; correction of anemia and the hypoalbuminemia; use of intraoperative the high-frequency electrotome; irrigation of the incision with plenty of physiological saline +$ iodophor before suturing the subcutaneous fat layer were key to effectively preventing infection in contaminated abdominal incisions. Show more

Keywords: Surgical site infection, preventive treatment

DOI: 10.3233/THC-161209

Citation: Technology and Health Care, vol. 24, no. s2, pp. S811-S815, 2016

Authors: Zou, Ling | Guo, Qian | Xu, Yi | Yang, Biao | Jiao, Zhuqing | Xiang, Jianbo

Article Type: Research Article

Abstract: Functional magnetic resonance imaging (fMRI) is an important tool in neuroscience for assessing connectivity and interactions between distant areas of the brain. To find and characterize the coherent patterns of brain activity as a means of identifying brain systems for the cognitive reappraisal of the emotion task, both density-based k-means clustering and independent component analysis (ICA) methods can be applied to characterize the interactions between brain regions involved in cognitive reappraisal of emotion. Our results reveal that compared with the ICA method, the density-based k-means clustering method provides a higher sensitivity of polymerization. In addition, it is more sensitive to …those relatively weak functional connection regions. Thus, the study concludes that in the process of receiving emotional stimuli, the relatively obvious activation areas are mainly distributed in the frontal lobe, cingulum and near the hypothalamus. Furthermore, density-based k-means clustering method creates a more reliable method for follow-up studies of brain functional connectivity. Show more

Keywords: Functional connectivity, cognitive reappraisal, density-based k-means clustering method, ICA

DOI: 10.3233/THC-161210

Citation: Technology and Health Care, vol. 24, no. s2, pp. S817-S825, 2016

Authors: Wang, Heng | Wu, Jianan | Zhuo, Zihan | Tang, Jintian

Article Type: Research Article

Abstract: In order to ensure the safety and effectiveness of magnetic induction hyperthermia in clinical applications, numerical simulations on the temperature distributions and extent of thermal damage to the targeted regions must be conducted in the preoperative treatment planning system. In this paper, three models, including a thermoseed thermogenesis model, tissue heat transfer model, and tissue thermal damage model, were established based on the four-dimensional energy field, temperature field, and thermal damage field distributions exhibited during hyperthermia. In addition, a numerical simulation study was conducted using the Finite Volume Method (FVM), and the accuracy and reliability of the magnetic induction hyperthermia …model and its numerical calculations were verified using computer simulations and experimental results. Thus, this study promoted the application of computing methods to magnetic induction therapy and conformal hyperthermia, and improved the accuracy of the temperature field and tissue thermal damage distribution predictions. Show more

Keywords: Magnetic induction hyperthermia, numerical simulation, tissue thermal damage, FVM

DOI: 10.3233/THC-161211

Citation: Technology and Health Care, vol. 24, no. s2, pp. S827-S839, 2016