• Journal of Biomedical Engineering Research
• /
• v.28 no.6
• /
• pp.832-839
• /
• 2007

In this study, a new bicycle system was developed to improve muscular strength using the Magneto-Rheological(MR) rotary brake. The friction load of the MR rotary brake is adjusted according to muscle strength of the subjects. The characteristic of muscular strength was studied with various friction loads of MR rotary brake. The friction load was occurred with the current, applied to the MR. rotary brake. Experiments was composed of several cycling trials for various friction loads. In training programs involving muscle improvement, it is necessary to confirm muscle activity and fatigue. To measure the muscle activity and fatigue, EMG signals of rectus femoris (RF), biceps femoris (BF), tensor fasciae latae (TFL), vastus lateralis (VL), vastus medialis (VAS), gastrocnemius (GAS), tibialis anterior (TA) and soleus (SOL) muscles were collected with surface electromyography and analyzed into time and frequency domain. The experimental results showed that the muscle activity according to the applied current to the MR rotary brake was significantly different. The more the current was applied, the higher value of the integrated EMG (IEMG) was obtained. Especially, the magnitude of IEMG of the RF, BF, TFL and VL varied in direct proportion to the current. However, there was not significant in the median frequency as the cycling time continue.

• Imaging Science in Dentistry
• /
• v.45 no.1
• /
• pp.1-5
• /
• 2015

Purpose: Lateral pterygoid muscle (LPM) plays an important role in jaw movement and has been implicated in Temporomandibular disorders (TMDs). Migraine has been described as a common symptom in patients with TMDs and may be related to muscle hyperactivity. This study aimed to compare LPM volume in individuals with and without migraine, using segmentation of the LPM in magnetic resonance (MR) imaging of the TMJ. Materials and Methods: Twenty patients with migraine and 20 volunteers without migraine underwent a clinical examination of the TMJ, according to the Research Diagnostic Criteria for TMDs. MR imaging was performed and the LPM was segmented using the ITK-SNAP 1.4.1 software, which calculates the volume of each segmented structure in voxels per cubic millimeter. The chi-squared test and the Fisher's exact test were used to relate the TMD variables obtained from the MR images and clinical examinations to the presence of migraine. Logistic binary regression was used to determine the importance of each factor for predicting the presence of a migraine headache. Results: Patients with TMDs and migraine tended to have hypertrophy of the LPM (58.7%). In addition, abnormal mandibular movements (61.2%) and disc displacement (70.0%) were found to be the most common signs in patients with TMDs and migraine. Conclusion: In patients with TMDs and simultaneous migraine, the LPM tends to be hypertrophic. LPM segmentation on MR imaging may be an alternative method to study this muscle in such patients because the hypertrophic LPM is not always palpable.

• Journal of Biomedical Engineering Research
• /
• v.30 no.4
• /
• pp.333-340
• /
• 2009

MR compatible coaxial-slot antenna for microwave hyperthermia was developed while its structure and size of each part were determined by computer simulation using finite element method(FEM). Its local heating performance was evaluated using tissue-mimic phantom and swine muscles. 2% agarose gel mixed with 6mM/$\ell$ $MnCl_2$ as a biological tissue-mimic phantom was heated by the proposed antenna driven by a 2.45GHz microwave generator. The temperature changes of the phantom were monitored using multi-channel digital thermometer at the distance of 0mm, 5mm, 10mm and 20mm from the tip center of the antenna. Also muscle tissue of swine was heated for 2 and 5minutes with 50W and 30W of microwave generator powers, respectively, to evaluate the local heating performance of the antenna. MRI compatibility was also verified by acquiring MR images and MR temperature map. MR signals were acquired from the agarose gel phantom using $T2^*$ GRE sequence with 1.5T clinical MRI scanner(Signa Echospeed, GE, Milwaukee, WI, U.S.A.) at Pusan Paik Hospital and were transferred to PC in order to reconstruct MR images and temperature map using proton resonance frequency(PRF) method and laboratory-developed phase unwrapping algorithm. Authors found that it has no severe distortion due to the antenna inserted into the phantom. Finally, we can conclude that the suggested coaxial-slot antenna has an excellent local heating performance for both of tissue-mimic phantom and swine muscle, and it is compatible to 1.5T MRI scanner.

• Proceedings of the KSMRM Conference
• /
• 1996.10a
• /
• pp.26-26
• /
• 1996

• The Korean Journal of Zoology
• /
• v.29 no.3
• /
• pp.190-200
• /
• 1986

The male and female muscle of the 16 major bands in the protein patterns of the tissues of the mud-snail, Cipangopaludina chinensis malleata, were almost similar, and the bands E (Mr. 41,500), H (Mr. 52,100), L (Mr. 71,700), N(Mr. 98,500), O (Mr. 107,900) and P (Mr. 112,900) had the same molecular weights which appear in the muscles, testis and ovary. But it showed that the testis and the ovary had their characteristic patterns, and it was also observed that, besides the bands common to all tissues, the bands which appear both in the testis and the ovary are about five: the bands d (Mr. 15,600), k (Mr. 37,100), p (Mr. 57,000), s (Mr. 80,300), and v (Mr. 105,400). The result of the amino acid analysis showed that the quantity and composition of amino acid appeared, as the protein pattersn did, in the order of ovary, muscles and testis. This reveals that in the ovary a great quantity of protein which appears in the whole body was investigated, while the testis contained only little protein due to the phenomenon of morphogenesis in which sperms were developed through the condensation of the nuclei.

• Proceedings of the KSMRM Conference
• /
• 2001.11a
• /
• pp.167-167
• /
• 2001

Purpose： To obtain normative human skeletal muscle data and evaluate quantitative diffusion-ten anisotropy information using diffusion-tensor imaging technique. Method： Quantitative extremity muscle diffusion tensor MR images were obtained in 5 healt adults by using turbo STEAM sequence and a combination of tetrahedral and orthogon diffusion gradients. Relative anisotropy(RA) and fractional anisotropy(FA) values we measured in soleus and gastrocnemius muscle in addition to mean ADC value.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.6
• /
• pp.579-585
• /
• 2010

In this paper, an assistive device for a knee joint to help a disabled person to stand up by supporting power is presented. The device is designed and controlled by using damping characteristics of the MR (Magneto-Rheological) damper. The MR damper helps the person to sit slowly and safely. A DC motor supports muscle power in the case of standing motion. Thus the device helps the disabled person to sit down and stand up. Through the experiments, it is feasible that an assistive device can help the disabled person to standup according to the foot pressure change.

• Proceedings of the KOSOMBE Conference
• /
• v.1993 no.05
• /
• pp.28-30
• /
• 1993

We have investigated the feasibility study, especially for optimal TR, to obtain 3-D MR neurographic imaging (neurograms or nervography) which shows the distribution of peripheral nerve fibers at the human forearm using 4.7 T magnet. To peform a successful formation of MR neurographic imaging, nerve signal should be separated from the other signal comes from surrounding muscle or fat, because nerves are usually embeded in muscle or fat. Generally, it is well known that nerve has shoter T1 value than that of muscle. Thus, repetition time was optimized to maximize the signal intensity defference between the muscel and nerve. We have also used spin-echo(SE) sequence with long echo time($60{\sim}90\;msec$) to enhance the different signal intensity between muscles and pheriperal nerves base on the fact that muscle tissue has longer T2 relaxation lime than that or nerve.

• Investigative Magnetic Resonance Imaging
• /
• v.13 no.1
• /
• pp.101-105
• /
• 2009

We report radiological findings of ultrasonography (US), 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) computed tomography (CT), and magnetic resonance (MR) imaging for a rare case of skeletal muscle metastasis from an underlying known malignant phyllodes tumor. To our knowledge, there has been no previous published report of imaging findings of skeletal muscle metastasis from a sarcoma such as malignant phyllodes tumor.

• Journal of Chest Surgery
• /
• v.39 no.7 s.264
• /
• pp.549-552
• /
• 2006

In the mitral regurgitation (MR) accompanied with a serious ischemic cardiomyopathy (ICMP), coronary revascularization to viable myocardium, LV reduction and mitral reconstruction become the main surgery under the bad conditions that the cardiac transplantation is not so easy. The MR in ischemic cardiomyopathy appears as various pathologic factors, among them, the papillary muscle displacement in addition to the annular dilatation is pointed out as the important cause. Our hospital would like to report the experience of the surgery about coronary revascularization to the left main with 3-vessel coronary disease, severe ICMP patients accompanied with the MR, posterior mitral annuloplasty and papillary muscle plication through the LVtomy.