Evaluation of an Experimentally Designed Stereotactic Guidance System for Determining Needle Entry Point during Uniplanar Fluoroscopy-guided Intervention

BACKGROUND: In discography performed during percutaneous endoscopic lumbar discectomy (PELD) via the posterolateral approach, it is difficult to create a fluoroscopic tunnel view because a long needle is required for discography and the guide-wire used for consecutive PELD interrupts rotation of fluoroscope. A stereotactic system was designed to facilitate the determination of the needle entry point, and the feasibility of this system was evaluated during interventional spine procedures. METHODS: A newly designed stereotactic guidance system underwent a field test application for PELD. Sixty patients who underwent single-level PELD at L4-L5 were randomly divided into conventional or stereotactic groups. PELD was performed via the posterolateral approach using the entry point on the skin determined by premeasured distance from the midline and angles according to preoperative magnetic resonance imaging (MRI) findings. Needle entry accuracy provided by the two groups was determined by comparing the distance and angle measured by postoperative computed tomography with those measured by preoperative MRI. The duration and radiation exposure for determining the entry point were measured in the groups. RESULTS: The new stereotactic guidance system and the conventional method provided similarly accurate entry points for discography and consecutive PELD. However, the new stereotactic guidance system lowered the duration and radiation exposure for determining the entry point. CONCLUSIONS: The new stereotactic guidance system under fluoroscopy provided a reliable needle entry point for discography and consecutive PELD. Furthermore, it reduced the duration and radiation exposure associated with determining needle entry.

Development of Laser Ruler in Rigid Laryngoscope

OBJECTIVES: The objective of this study was to develop a new device that provides a simple, noninvasive method of measuring accurate lesion size while using an endoscope. METHODS: We developed a rigid laryngoscope with a built-in laser-ruler using a one-light emitting diode and an acrylic plate. The invention incorporates a built-in laser diode that projects an auto-parallel beam into the optical path of the rigid laryngoscope to form two spots in the field of view. RESULTS: While the interspot distance remains consistent despite changes in focal plane, magnification, or viewing angle of the laryngoscope, projection to an uneven surface introduces certain variations in the shape, and size of the spots, and the distance between the two spots. CONCLUSION: The device enables a laryngologist to easily measure the distance between landmarks, as well as the change in real size, and the progressive change of vocal fold lesions in an outpatient setting.

Development of a Wearable Pulse Transit Time Monitoring Device / 대한의료정보학회지

OBJECTIVES: We have developed a non.intrusive continuous PTT monitoring system, using a wearable device and wireless communication technology. METHODS: Pulse transit time (PTT) is a non.invasive measurement that shows promise in the continuous monitoring of blood pressure (BP) and the assessment of arterial stiffness. It has potential applications in wearable health monitoring devices. Generally, PTT is measured from the electrocardiogram (ECG) Rwave to a characteristic point on the peripheral pulse by photoplethysmography. However, for home healthcare applications, a system needs to be wearable and wireless. ECG and PPG were sampled at 1200 Hz and transmitted to a personal computer (PC) using Bluetooth communications. Heart rate (HR) and PTT were calculated by the PC from the signals received and waveforms of ECG, PPG, PTT and HR were displayed. RESULTS: In this study, we implemented a system that could be adapted to the wrist and measured ECG and a Photoplethysmogram (PPG). CONCLUSIONS: The wearable continuous PTT monitoring system developed in this study could be useful in home cardiovascular healthcare.

Integrating-Types Biomedical Signal Communication System Combined Power Line and Radio Frequency Communication / 대한의료정보학회지

OBJECTIVES: In order to devise the combination module transmitting bio signal and signal data remotely, as defect of wirewireless combination module was complemented by designing a single combination of wireless module and power supply module, a single system was implemented. METHODS: Currently in case of wireless transmission, it had various problems causing by some factors such as buildings, obstruction, and entanglement of wires and so on. In order to overcome problems of wireless transmission, a single combination module design was researched, which transmits vital signal and sign data using basic electric line installed in the inner building or between others. Even though it was also possible of wireless communication and the internet, in case of a power supply without them, it could be possible to transfer data to underground or top ground in the inner building without any special communication line. RESULTS: Bio signal data was transmitted through a power supply line, a noise problem occurred would be solved by the designed noise filter. The filter showed that noise was cut off about more than 90%. It was also confirmed that the used ECG signals was stably received on transmission experiment. An internal PCB antenna could make the system be wireless communication without the disclosure of an antenna. CONCLUSIONS: In this study, in order to implement a useful system transmitting bio signal and data through wire and wireless management for combination design of wireless module and electrical line module, bio signal transmission system was implemented by design of noise break filter circuit to reduce power noise and PCB internal antenna design.

Simulation of the Cardiovascular System Using PID Control Model / 대한의료정보학회지

OBJECTIVE: The electric analog circuit model can be used to analyse the various function of the cardio vascular system and the dynamic characteristics on each part of human body. According to the previous studies, viscous resistance, flow inertia, and vascular compliance in the cardiovascular system are analogous to resistance, inductance, and capacitance in electric circuit, so the cardiovascular system models have been represented by the electric circuit models. These approaches were to propose suitable models for the interested part of body and to simulate the various characteristics on the cardiovascular system. METHODS: This paper tried to put the characteristics of morphologic structure into the suggested electric circuit model. After setting parameter values of the model the dynamic characteristics of the cardio vascular system is simulated using VisSim, which is one of the simulation tools. RESULTS: The derived simulation results have represented major cardiovascular functions of normal adults. Also simulation results reflect the variation due to the pathophysiological state. CONCLUSION: The controller by baroreceptor, which is one of controllers to control the cardiovascular system, is appended in the model. The dynamic response characteristics and the procedure to restore blood pressure to normal state was observed by simulation lasted a certain period of bleeding.

A Study of the Use of EEG Analysis to Evaluate the Depth of Anesthesia Using Bispectrum Analysis Method / 대한마취과학회지

BACKGROUND:In this study, a distribute characteristics on the bispectral coupling of EEG were examined according to the depth of anesthesia by using bispectum analysis a type of nonlinear signal processing. METHODS: 25 patients during the general anesthesia were studied. In the preprocess, base line correction and linear detrend was used. During the awakening state, preoperatively and postoperatively, appearance rate of bispectral coupling was observed that a strong appearance rate was represented in major frequency zone such as (15, 15) Hz but weak appearance rate investigated in the other minor frequency zone. Whilst anesthetized, a strong appearance rate revealed the low frequency range below (10, 10) Hz and a weak appearance rate viewed in the other frequency range. As such was compared with the delta ratio and spectrum edge frequency (SEF). RESULTS: The delta ratio showed significantly lower values at induction (3.60 +/- 0.98) and during the maintenance (5.0+/-1.74) of anaesthesia than preoperatively (10.30 +/- 2.44) and postoperatively (13.03 +/- 2.29)(P < 0.05). These results were consistent with the trend of delta ratio, namely that the index of evaluation for the depth of anesthesia, known as the reflex of the conscious level of patient's during anesthesia. While these results were not consistent with SEF analysis results that the index of evaluation for suppression level of patient's during recovery stage of anesthesia. SEF shows lower values at maintenance (17.00 +/- 1.22) and postoperatively (12.20 +/- 1.53) than preoperatively (22.50 +/- 1.75) and at the induction (22.40 +/- 1.18) of anesthesia(P < 0.05). CONCLUSIONS: The bispectrum analysis method provided useful information about the index of evaluation according to the level of unconsciousness and suppression among other evaluation factor on depth of anesthesia.

A Quantitative Analysis for Pre-processing Algorithm of Aberration Chromosome Observation / 대한의료정보학회지

The task of chromosome analysis is the classification of human chromosomes. The feature parameter of chromosome is very important information for chromosome analysis. The special preprocessing algorithm is required to extracting them. In this paper, we performed quantitative analysis for preprocessing algorithm of observation of chromosomal aberrations. Two algorithms is used MAT and reconstruction. The morphological feature parameters were centromeric index(C.I.), relative length ratio(R.L.), relative area ratio(R.A.) and chromosome length(C.L.), and the density and width profiles. The reconstruction of chromosome images by this reconstruction algorithm was appeared as effective algorithms to observe and extract chromosome parameter.

A Quantitative Analysis for Pre-processing Algorithm of Aberration Chromosome Observation / 대한의료정보학회지

The task of chromosome analysis is the classification of human chromosomes. The feature parameter of chromosome is very important information for chromosome analysis. The special preprocessing algorithm is required to extracting them. In this paper, we performed quantitative analysis for preprocessing algorithm of observation of chromosomal aberrations. Two algorithms is used MAT and reconstruction. The morphological feature parameters were centromeric index(C.I.), relative length ratio(R.L.), relative area ratio(R.A.) and chromosome length(C.L.), and the density and width profiles. The reconstruction of chromosome images by this reconstruction algorithm was appeared as effective algorithms to observe and extract chromosome parameter.

Extraction of the Quantative Parameter for EMG Signal Analysis / 대한의료정보학회지

In this paper, we studied a signal processing method which extracts each MUAP(motor unit action potential) from EMG(Electromyogram) interference pattern for clinical diagnostic purposes. First of all, differential digital filtering is selected for eliminating the spike components of the MUAP' s from the backgroud noise. And the algorithm identifies the spikes over the certanin threshold by template matching in frequency domain. After missing or false firing factor is cut off at the IPJ(inter pulse interval) histogram, we average the MUAP waveforms from the raw signal using the identified spikes as triggers, and finally, measure their amplitudes, durations, and numbers of phases. Specially, we introduce algorithm performed by template matching in the frequency domain. This algorithm performed as follows. A typical 3 second signal recorded from the biceps brachii muscle using a conventional needle electrode during a isometric contraction. And decomposed active MUAP' s decomposed from original EMG signal.

Measurement of Regional Cerebral Blood Volume in Normal Rabbits on Perfusion-weighted MR Image

PURPOSE: To evaluate the usefulness of cerebral blood flow measurement applied to perfusion weighted image with short-scan time single shot gradient echo-planar technique in measuring cerebral blood volume(rCBV) of normal rabbits. MATERIALS AND METHODS: With 2.1-3.6 kg weighted rabbits, image is acquired when they are in supine position in children positioner. Perfusion weighted image is acquired to 44 seconds per 1 second successively. After 4 seconds later, Gd-DTPA 2ml are injected into int. jugular vein with 2 ml per second and normal saline is also injected after that. Same technique is applied 2 times per 30 minites in same rabbit. After Image is obtained in two part of cerebral cortex at vertex, convexity, in one of basal ganglia with choosing about 3-5mm2 areas. Curve of signal intensity changes in time sequence is drawn. After this images are transmitted by PC and software IDL, regional cerebral blood volume is measured with imaging processing program made by us. RESULTS: With 22 of 24 rabbits, satisfactory 1-2 signal intensity versus time curve is made. Cerebral blood capacity and contrast media stay time (ST) is measured in two cerebral cortex and basal ganglia refering in parietal cerebral cortex. Mean focal cerebral blood flow capacity ratio in cortex was 0.97+/-0.35 and in basal ganglia, 0.99+/-0.37, mean contrast media stay time in cortex was 9.83+/-1.63 sec and in basal ganglia, 9.42+/-1.14 sec, but there was no statistically significant difference between two areas (p=0.05). CONCLUSION: In cerebral cortex and basal ganglia, there is no difference in mean focal blood volume and mean contrast stay time. Therefore, PWI is useful in cerebral blood flow and early diagnosis, prognosis of cerebral ischemic disease. Hereafter, it is helpful in analysing cerebral blood flow changes with comparison difference in rCBV between normal tissue and ischemic tissue, and that with DWI finding in infarcted patient.