Simultaneous Viability Assessment and Invasive Coronary Angiography Using a Therapeutic CT System in Chronic Myocardial Infarction Patients

Purpose@#In a preclinical study using a swine myocardial infarction (MI) model, a delayed enhancement (DE)-multi-detector computed tomography (MDCT) scan was performed using a hybrid system alongside diagnostic invasive coronary angiography (ICA) without the additional use of a contrast agent, and demonstrated an excellent correlation in the infarct area compared with histopathologic specimens. In the present investigation, we evaluated the feasibility and diagnostic accuracy of a myocardial viability assessment by DE-MDCT using a hybrid system comprising ICA and MDCT alongside diagnostic ICA without the additional use of a contrast agent. @*Materials and Methods@#We prospectively enrolled 13 patients (median age: 67 years) with a previous MI (>6 months) scheduled to undergo ICA. All patients underwent cardiac magnetic resonance (CMR) imaging before diagnostic ICA. MDCT viability scans were performed concurrently with diagnostic ICA without the use of additional contrast. The total myocardial scar volume per patient and average transmurality per myocardial segment measured by DE-MDCT were compared with those from DE-CMR. @*Results@#The DE volume measured by MDCT showed an excellent correlation with the volume measured by CMR (r=0.986, p<0.0001). The transmurality per segment by MDCT was well-correlated with CMR (r=0.900, p<0.0001); the diagnostic performance of MDCT in differentiating non-viable from viable myocardium using a 50% transmurality criterion was good with a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 87.5%, 99.5%, 87.5%, 99.5%, and 99.1%, respectively. @*Conclusion@#The feasibility of the DE-MDCT viability assessment acquired simultaneously with conventional ICA was proven in patients with chronic MI using DE-CMR as the reference standard.

Texture Analysis of Supraspinatus Ultrasound Image for Computer Aided Diagnostic System / 대한의료정보학회지

OBJECTIVES: In this paper, we proposed an algorithm for recognizing a rotator cuff supraspinatus tendon tear using a texture analysis based on a histogram, gray level co-occurrence matrix (GLCM), and gray level run length matrix (GLRLM). METHODS: First, we applied a total of 57 features (5 first order descriptors, 40 GLCM features, and 12 GLRLM features) to each rotator cuff region of interest. Our results show that first order statistics (mean, skewness, entropy, energy, smoothness), GLCM (correlation, contrast, energy, entropy, difference entropy, homogeneity, maximum probability, sum average, sum entropy), and GLRLM features are helpful to distinguish a normal supraspinatus tendon and an abnormal supraspinatus tendon. The statistical significance of these features is verified using a t-test. The support vector machine classification showed accuracy using feature combinations. Support Vector Machine offers good performance with a small amount of training data. Sensitivity, specificity, and accuracy are used to evaluate performance of a classification test. RESULTS: From the results, first order statics features and GLCM and GLRLM features afford 95%, 85%, and 100% accuracy, respectively. First order statistics and GLCM and GLRLM features in combination provided 100% accuracy. Combinations that include GLRLM features had high accuracy. GLRLM features were confirmed as highly accurate features for classified normal and abnormal. CONCLUSIONS: This algorithm will be helpful to diagnose supraspinatus tendon tear on ultrasound images.

Working Memory Deficits in Ultra-High Risk for Psychosis and Schizophrenia / 대한정신분열병학회지

OBJECTIVES: The aim of this study was to investigate whether verbal and spatial working memory functions were impaired not only in patients with schizophrenia but also in people at ultra-high risk for first-episode psychosis. METHODS: Twenty-five patients (M 13, F 12) with schizophrenia (SPR), 21 people at ultra-high risk for psychosis (UHR)(M 10, F 11) and 19 normal controls (NC)(M 10, F 9) were recruited. The working memory was assessed by using the verbal and spatial n-back test. The working memory load increased incrementally from the 0-back to the 3-back condition. RESULTS: SPR performed significantly lower than NC and UHR in terms of hit rates of verbal and spatial n-back test. UHR subjects conducted significantly lower than NC and higher in trend-level than SPR in terms of hit rates of verbal and spatial n-back test. These differences were derived from the high working memory load (2-back and 3-back), not from the low working memory load (0-back and 1-back). There was no significant difference between the verbal and spatial n-back test across the three groups. CONCLUSION: These findings suggest that verbal and spatial working memory dysfunction may be general rather than differential in terms of stimuli modality, and this working memory deficit may be an important trait factor in schizophrenia.

Integrated Solution for Physical Activity Monitoring Based on Mobile Phone and PC / 대한의료정보학회지

OBJECTIVES: This study is part of the ongoing development of treatment methods for metabolic syndrome (MS) project, which involves monitoring daily physical activity. In this study, we have focused on detecting walking activity from subjects which includes many other physical activities such as standing, sitting, lying, walking, running, and falling. Specially, we implemented an integrated solution for various physical activities monitoring using a mobile phone and PC. METHODS: We put the iPod touch has built in a tri-axial accelerometer on the waist of the subjects, and measured change in acceleration signal according to change in ambulatory movement and physical activities. First, we developed of programs that are aware of step counts, velocity of walking, energy consumptions, and metabolic equivalents based on iPod. Second, we have developed the activity recognition program based on PC. iPod synchronization with PC to transmit measured data using iPhoneBrowser program. Using the implemented system, we analyzed change in acceleration signal according to the change of six activity patterns. RESULTS: We compared results of the step counting algorithm with different positions. The mean accuracy across these tests was 99.6 +/- 0.61%, 99.1 +/- 0.87% (right waist location, right pants pocket). Moreover, six activities recognition was performed using Fuzzy c means classification algorithm recognized over 98% accuracy. In addition we developed of programs that synchronization of data between PC and iPod for long-term physical activity monitoring. CONCLUSIONS: This study will provide evidence on using mobile phone and PC for monitoring various activities in everyday life. The next step in our system will be addition of a standard value of various physical activities in everyday life such as household duties and a health guideline how to select and plan exercise considering one's physical characteristics and condition.

Non-linear Analysis of Single Electroencephalography (EEG) for Sleep-Related Healthcare Applications / 대한의료정보학회지

OBJECTIVES: Soft-computing techniques are commonly used to detect medical phenomena and to help with clinical diagnoses and treatment. The purpose of this paper is to analyze the single electroencephalography (EEG) signal with the chaotic methods in order to identify the sleep stages. METHODS: Data acquisition (polysomnography) was performed on four healthy young adults (all males with a mean age of 27.5 years). The evaluated algorithm was designed with a correlation dimension and Lyapunov's exponent using a single EEG signal that detects differences in chaotic characteristics. RESULTS: The change of the correlation dimension and the largest Lyapunov exponent over the whole night sleep EEG was performed. The results show that the correlation dimension and largest Lyapunov exponent decreased from light sleep to deep sleep and they increased during the rapid eye movement stage. CONCLUSIONS: These results suggest that chaotic analysis may be a useful adjunct to linear (spectral) analysis for identifying sleep stages. The single EEG based nonlinear analysis is suitable for u-healthcare applications for monitoring sleep.

Electro-Mechanical Safety Testing of Portable ECG Devices for Home Healthcare Usage / 대한의료정보학회지

OBJECTIVES: This paper suggests the experimental guidelines to evaluate the electro-mechanical safety of belt type equipment. The electro-mechanical safety was determined by using the International Electrotechnical Commission guidelines, which are widely used as important factors for assessing the electro-mechanical safety of belt type equipment. However, the local guidelines on wearable healthcare sensors are currently not well-established. Therefore, safety guidelines suited for the actual circumstances in Korea are required, and this paper attempts to try a new experimental safety test procedure of the wearable healthcare sensor. METHODS: This belt type device measures the electrocardiogram (ECG) and heart rates by attaching to the chest. Examination lists were selected by analyzing the common standards ofelectro-mechanical safety (IEC 60601-1) and environment tests (IEC 60068-1, IEC 60068-2) of home-healthcare equipment. RESULTS: The essential electrical safety, which was required for the RS300G3 as a medical device, was evaluated, and most of the examination lists were selected by considering the circumstances of the users. The device passed all the selected examinable lists that are applicable to the Korean environment. CONCLUSIONS: This study has limitations to estimate and to conduct electro-mechanical safety experiments because our study focused on the belt type of heart-rates equipment. We are not taking into account the overall electro-mechanical home-healthcare measurements. According to industrial and technological development, there are infinite possibilities for the advancement of home-healthcare equipment, so more examination lists for safety are being added in addition to what we have done.

Ubiquitous-Severance Hospital Project: Implementation and Results / 대한의료정보학회지

OBJECTIVES: The purpose of this study was to review an implementation of u-Severance information system with focus on electronic hospital records (EHR) and to suggest future improvements. METHODS: Clinical Data Repository (CDR) of u-Severance involved implementing electronic medical records (EMR) as the basis of EHR and the management of individual health records. EHR were implemented with service enhancements extending to the clinical decision support system (CDSS) and expanding the knowledge base for research with a repository for clinical data and medical care information. RESULTS: The EMR system of Yonsei University Health Systems (YUHS) consists of HP integrity superdome servers using MS SQL as a database management system and MS Windows as its operating system. CONCLUSIONS: YUHS is a high-performing medical institution with regards to efficient management and customer satisfaction; however, after 5 years of implementation of u-Severance system, several limitations with regards to expandability and security have been identified.

Performance Test of Web Based 3D Medical Image System using Image Streaming Technique / 대한의료정보학회지

OBJECTIVE: It is still the important subject that 3D visualizing of medical images to help patient diagnose. There were many challenges for fast 3D visualization but it has some limitations that volume rendering without high price's hardware and software. Some techniques through the web were suggested to construct high quality's 3D visualization even though it was an only poor personal computer. This technique could share the volume rendering board and diagnose 3D images together. However there are some problems to construct web based 3D visualization. These are network delay, optimized visualization and security etc. The purpose of this paper was to visualize and control the 3D medical image having a high quality on the web. METHODS: To construct this system, we used mainly three tools which were VolumePro1000 board, WMV9(Windows Media Video 9 Codec) and socket functions based on TCP(Transmission Control Protocol). VolumePro1000 board could calculate quickly heavy matrixes of 3D images using phong's shading and shear-warp factorization. WMV9 was able to compress efficiently live images and to apply image streaming technique. Socket functions based on TCP transmitted messages to control the 3D images. RESULTS: We developed 3D visualization system and evaluated about image qualities and transmission conditions of different compression rates on unfixed network condition. CONCLUSION: It was big advantages that WMV9 encoder could decode automatically in many platforms(desk top, PDA, notebook, cellular phone, etc) without installing specific decoding programs if they only have Windows Media player. We expect 3D visualization system to be utilized various biomedical fields such as IIGS(Interactive Image Guided Surgery), CAD(Computer Aided Diagnosis) and Tele-medicine technologies.

A Size Change of Bone Defect Area after Autogenous Calvarial Bone Graft

Calvarial bone grafting in craniomaxillofacial trauma and facial reconstructive surgery is now widely recognized and accepted as a standard procedure. One of the commonly reported problems of calvarial bone graft is the contour defect caused by partial resorption of the graft. But, there are few reports that discuss the fate of the calvarial bone graft based on the quantitative data. In this article, the changes of grafted calvarial bone were evaluated using 3-dimensional computed tomography(CT). 9 patients were observed with the CT scans at 2mm thickness immediately after operation and at the time of last follow-up. The area of the bone defect was segmented on the 3-dimensional CT image and calculated by AnalyzeDirect 5.0 software. The immediate postoperative bone defect area of the recipient site and the donor site were 612.9mm2 and 441.5mm2, respectively, which became 1028.1mm2 and 268.8mm2, respectively at the last follow-up. In conclusion, the bone defect area was less increased on the donor site of calvarial bone graft than on the recipient site. And the CT scan is a valuable imaging method to assess and follow-up the clinical outcome of calvarial bone grafting.

The Design of Wavelet-based Biological Signal CODEC for Telemedicine Application / 대한의료정보학회지

In this paper, waveform preserving coding technique is proposed for the bio-signals based on wavelet transform local maxima representation. In order to efficiently encode the bio-signal, it utilize the inherent property of bio-signals that sharp waves corresponding to the local maxima in wavelet domain contain the most of the clinically significant information in general. The testing sets of ECG and EEG are experimented to select the appropriate wavelet basis and to demonstrate the usefulness regarding to coding efficiency. The spline basis is more suitable in designing the coder than the Harr basis since the spline basis produces less number of local maxima than the Harr basis. The proposed wavelet method based on spline basis outperforms the conventional subband coding technique in terms of wave form degradation and coding efficiency. The actual transmission experiment using external communication network and the general personal computer demonstrates the applicability to telemedicine system handling the bio-signals.

Web-Based Asthma Care System / 대한의료정보학회지

Asthma is a chronic disease, which requires a successive and long-term management. In this paper, we implemented a web-based caring system for a more effective management of the asthmatics. The service of this asthmatic-caring system targeted on both the doctor and the patient. The patient connects to the asthma management server through the Internet everyday and inputs his or her daily condition and dosage. Then the doctor will give a proper comment or order to the patient according to the data that patient has filled in. By merely connecting to this web-site, doctors can manage asthmatics everyday and the patient can be under the doctor's management without frequently visiting the hospital. The test verifying the user's satisfaction of the implemented system has been taken by both the doctor- and the patient-groups. The doctor-group pointed out the successive management, an easy inspection of the patient condition, and the accumulation of clinical data for future researches as advantages. The patientgroup pointed out being under the daily management without visiting hospital and the active attitude they can have toward their diseases as advantages.

Multiagent System using Data Mining Technique for the Management of Asthma in Mobile Computing Environments / 대한의료정보학회지

OBJECTIVE: In the mobile computing environments, doctors or patients with mobile devices can access services at any time, any place. It makes chronic diseases, such as asthma care successively and in long-term. This paper presents a new multiagent system using data mining technique for the management of asthma in mobile computing environments. METHODS: In mobile computing environments, mobile communication is prone to disconnection. To use the services when disconnected, we locally store the recommendation information in mobile devices. Then, when user reconnects network, the new information is delivered in mobile devices. Because mobile devices have a limitation of resource, we store only patterns and recent data. We adopted data mining technique from the large pool of accumulated patients data can be utilized to summarize observed correlations and trends. RESULTS: We propose multiagent system composed of a Pattern Agent, a Selection Agent and a Recommendation Agent. They make asthmatic-caring system access effectively in mobile computing environments. We describe the underlying architecture and the process. Then we make a prototype with asthmatic patients data in the Severance Hospital in Korea. CONCLUSION: The results of our study can be contributed to aid management of asthma in mobile computing environments.

The Development and Application of Emergency Teleradiology(Medical Image Transmission) System with Personal Computer

In the clinical practice of neurosurgery, there are frequent needs which require urgent communication between housestaff and attending physician due to the emergency situation. But, the traditional methods such as telephone communication were not sufficient and sometimes, result in misjudgement of patient's status. So, our research team develop the computer software which can be used for emergency surgical and medical decision making. This software can transmitted the high quality images of CT, MRI and other X-ray with the conventional telephone line and personal computer system.

3-Dimensional Reconstruction of CT Image

According to the rapid development of computer technology, 3-dimensional reconstruction of CT scan data is becoming one of most up-to-dated diagnostic imaging techniques. This technique is helpful for determining the morphology of complex human structures, surgical plannings and for training aids. The authors developed the 3-dimensional reconstruction software which can be running at the personal computer. The various phases in the generation of 3-D reconstruction are described and clinical application is demonstrated by examples.

Application of Simulated Three Dimensional CT Image in Orthognathic Surgery / 대한구강악안면방사선학회지

In orthodontics and orthognathic surgery, cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery, too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipments and because of its expenses and amount of exposure to radiation, limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram, pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms, and for validation of new method, in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery, computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of dry skull that position of mandible was displaced, range of displacement between computer-simulated three dimensional images and actual postoperative three dimensional images in co-ordinates values was from -1.8 mm to 1.8 mm and 94% in displacement of all co-ordinates values was from -1.0 mm to 1.0 mm and no significant difference between computer-simulated three dimensional images and actual postoperative three dimensional images was noticed(p>0.05). 2. In four cases of orthognathic surgery patients, range of displacement between computer-simulated three dimensional images and actual postoperative three dimensional images in co-ordinates values was from -6.7 mm to 7.7 mm and 90% in displacement of all co-ordinates values was from -4.0 to 4.0 mm and no significant difference between computer-simulated three dimensional images and actual postoperative three dimensional images was noticed(p>0.05). Conclusively, computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms. Therefore, potentiality that can construct postoperative three dimensional image without three dimensional computed tomography after surgery was presented.

Anesthetic Management for Carotid Endarterectomy: case report / 대한마취과학회지

We have experienced an anesthetic management of 56-year-old male patient with carotid stenosis. Carotid endarterectomy was performed with processed electroencephalography (compressed spectral array, CSA) monitoring. Carotid endarterectomy has significant risk of perioperative stroke and myocardial infarction. For brain protection during carotid cross clamp, body temperature of patient was maintained at 33.5oC and thiopental was infused continuously to induce burst suppression. To maintain blood pressure during cross clamp, dopamine was infused continuously and phenylephrine was injected intermittently. CSA was performed to monitor thiopental-induced burst suppression and ischemic brain insult. After releasing carotid cross clamp, body temperature was raised to 35oC.

Design of an emergency teleradiology system based on progressive transmission

In clinical surgery, there are frequent needs for communication between the house staff and the attending physician in an emergency situation. To overcome the limitation of voice communication through the telephone line, we have designed an 'emergency teleradiology system' which can be used for emergency surgical and medical decision making. This system can transmit the high quality images of CT, MRI, and other X-ray data using a PC attached to a modem through the conventional telephone line. It is based on the progressive transmission system which enables the successive update of a received image. The iterative residual coding/decoding algorithm efficiently compresses the image to maximally utilize the low bandwidth PSTN channels. This system also satisfies design requirements such as low-cost, ease of operation, fast transmission, and interactive image communication including voice. Test results using several CT, MR, and X-ray images evaluate the compression performance, image quality, transmission time and computational time of the coding and decoding processes, thus demonstrate the usefulness of this system in an emergency situation.

Evaluation of Web-Based Real-Time Telemedicine Application Using ActiveX ontrols for Medical Moving Picture Analysis / 대한의료정보학회지

Telemedicine is described as combination of topics from the fields of telecommunication, medicine, and information and literally telemedicine means medicine at a distance. In this study, we present a web based real-time telemedicine application(WEBRETA) that was designed for patients who needs diagnosis on the Internet. The WEBRETA system is supporting transmitting of MPEG-4 video format(640*480)that was appropriate for Internet and designed with ActiveX controls technology that is also suitable for telecommunication link such as ADSL, VDSL and Cable modem which are very popular communication link in Korea. To improve the reliability and the usefulness of this prototype we involved the PSNR method and subjective score measuring from doctors. Futhermore, we will evaluate the WEBRETA with various communication network environment to improve how this system can contribute the diagnosis of patients and to analysis.

Clinical Validity of the Domestic EEG and Mapping System(Neuronics) / 수면정신생리

The clinical validity of a korean EEG and EP mapping system(Neuronics) was evaluated with schizophrenic patients(n=20), normal controls(n=19), and 10 patients with central nervous system disease(8 patients with cerebrovascular accident, 1 patient with brain mass, and 1 patient with periodic paralysis). In the normal control group, the pattern of resting computerzied EEG with eyes closed showed normal parieto-occipital dominance of alpha wave. Compared with normal controls, schizophrenic patients had more delta activity in the frontal region, and less alpha activity especially in the parieto-occipital region. In most cases patients with cortical organic lesions(n=5) revealed increased delta and theta activity and decreased alpha activity on the lesion areas. These findings were compatible with their MRI and clinical findings. However in the cases of subcortical lesions(n=5) EEG showed various findings which suggest diverse influences of subcortical abnormalities on cortical activities. The P300 of schizophrenic group was smaller and more delayed than those of normal controls. These results are generally compatible with the previous studies using other EEG and EP mapping systems consequenty and suggest that the this EEG and EP mapping system(Neuronics) has clinical validity.

Design of Mobile Emergency Telemedicine System Based on CDMA2000 1X-EVDO / 대한의료정보학회지

Using a high bandwidth cellular communication network is appropriate to implement a high-quality mobile emergency telemedicine system. In Korea, the commercial service of CDMA2000 1X-EVDO has been providing since 2002. In this paper, we designed the system that transfers the biological signal and the video information of a patient simultaneously based on this CDMA2000 1X-EVDO network environment. In CDMA2000 1X-EVDO, the maximum speed of its reverse link can be observed within 153.6Kbps. Before the system design, several field tests had been performed using commercial CDMA2000 1X-EVDO reverse link with the UDP data segments. The test had been taken under several velocity and tunnel areas of Seoul. With the test result we implemented an efficient emergency telemedicine system fitted to the features of CDMA2000 1X-EVDO reverse link using UDP packets. Additional header information is added to the UDP packet data. With the header information the emergency system can transmits the ECG signal prior to the video data and controls the transmission error. The designed system has the ability to transmit both the biological signals and MPEG4 video of 640x480 spatial resolution at the same time. We set up the ambulance with this system and test it on the road.