• Annual Conference of KIPS
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• 2012.11a
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• pp.369-372
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• 2012

조영증강 의료 초음파 영상에서 조영제의 확산효과에 대한 분석은 간질환과 연관된 각종 병변을 검출하고 분석하는 과정에서 매우 유용한 정보를 제공한다. 본 연구에서는 초음파 영상에서 조영제의 확산 패턴을 분석하고 이를 영상화하는 방법을 제안한다. 이 과정에서 부수적으로 호흡에 의한 흔들림 현상을 보정하고 노이즈의 영향을 극복할 수 있는 방법론을 고찰한다. 호흡주기에 따른 모멘텀 요소를 고려한 ROI 추적 기법은 측정과정에서의 흔들림과 노이즈에 의한 오류를 최소화 할 수 있게 한다. 조영제의 확산 단계에 따라 서로 다른 노이즈 비율을 고려하여 동적 가중치를 할당하는 방법으로써 흔들림을 보정하였으며, 조영제의 전이 시간과 패턴을 분석하고 그 특성을 분류함으로써 간 병변 분석을 위한 효과적인 영상화기법을 구현하였다. 또한 생성된 영상에서 노이즈를 제거하고 영상을 개선하는 방법으로서 MRF 기반의 최적화 알고리즘을 적용하는 영상 개선 기법을 제시한다.

• Journal of Yeungnam Medical Science
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• v.38 no.1
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• pp.19-26
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• 2021

Adhesive capsulitis of the shoulder joint is a common disease characterized by pain at the insertional area of the deltoid muscle and decreased range of motion. The pathophysiological process involves fibrous inflammation of the capsule and intraarticular adhesion of synovial folds leading to capsular thickening and contracture. Regarding the multidirectional limitation of motion, a limitation in external rotation is especially prominent, which is related to not only global fibrosis but also to a localized tightness of the anterior capsule. Ultrasound and magnetic resonance imaging studies can be applied to rule out other structural lesions in the diagnosis of adhesive capsulitis. Hydraulic distension of the shoulder joint capsule provides pain relief and an immediate improvement in range of motion by directly expanding the capsule along with the infusion of steroids. However, the optimal technique for hydraulic distension is still a matter of controversy, with regards to the infusion volume and rupture of the capsule. By monitoring the real-time pressure-volume profile during hydraulic distension, the largest possible fluid volume can be infused without rupturing the capsule. The improvement in clinical outcomes is shown to be greater in capsule-preserved hydraulic distension than in capsule-ruptured distension. Moreover, repeated distension is possible, which provides additional clinical improvement. Capsule-preserved hydraulic distension with maximal volume is suggested to be an efficacious treatment option for persistent adhesive capsulitis.

• The Korean Journal of Medicine
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• v.99 no.4
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• pp.199-205
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• 2024

Benign small bowel strictures can occur in association with various conditions, including small bowel Crohn's disease, nonsteroidal anti-inflammatory drug-induced enteritis, ischemic enteritis, intestinal tuberculosis, radiation enteritis, postoperative adhesions, and anastomotic strictures. Benign small bowel strictures are classified into two categories, low-grade and high-grade. Low-grade small bowel strictures involve a partial reduction of the internal diameter of the small intestine, causing slight obstruction of the passage of food and digestive fluids without significant bowel obstruction symptoms. By contrast, high-grade small bowel strictures involve a severe narrowing of the intestinal lumen, leading to marked obstruction of the passage of food and digestive fluids and pronounced bowel obstruction symptoms. Small bowel strictures can be diagnosed using various methods, including abdominal plain radiography, abdominal computed tomography, computed tomography enterography, magnetic resonance enterography, balloon-assisted enteroscopy, and abdominal ultrasound. Each diagnostic method has unique advantages and disadvantages as well as differences in diagnostic specificity and sensitivity. Therefore, even if small bowel strictures are not observed using a single imaging technique, their presence cannot be completely excluded. A comprehensive diagnosis that combines clinical information from multiple diagnostic modalities is necessary. Therapeutic approaches for managing small bowel strictures include medical therapy, endoscopic balloon dilation using balloon-assisted enteroscopy, and surgical methods such as strictureplasty and segmental resection. Endoscopic balloon dilation, in particular, can help reduce complications associated with repeated surgeries for strictures.

• Clinics in Shoulder and Elbow
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• v.22 no.1
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• pp.9-15
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• 2019

Background: Latissimus dorsi (LD) tendon transfer is used as a treatment option for massive irreparable posterosuperior rotator cuff tears, and recently, an arthroscopic-assisted technique was introduced. This study was undertaken to evaluate the clinical and radiological outcomes of arthroscopic-assisted LD tendon transfer for the management of irreparable rotator cuff tears in active middle-aged patients. Methods: The records of five patients (two males) with irreparable tears involving the supraspinatus and infraspinatus tendons managed by arthroscopic-assisted LD tendon transfer were retrospectively reviewed. Clinical outcomes were assessed using the visual analogue scale (VAS) pain scale, American Shoulder and Elbow Surgeon's (ASES) scores, the University of California Los Angeles (UCLA) scale, and ranges of motion. Postoperative integrities of transferred tendon were evaluated by magnetic resonance imaging in 4 patients and by ultrasound in one. Results: Mean patient age was 55 years (range, 48-61 years), and mean follow-up period was 20 months (range, 12.0-27.2 months). Mean VAS score significantly improved from $6.6{\pm}2.6$ preoperatively to $1.8{\pm}2.5$ postoperatively (p=0.009), mean ASES score increased from $67.6{\pm}9.2$ to $84.6{\pm}15.1$, and mean UCLA score from $18.0{\pm}1.4$ to $28.8{\pm}8.5$ (all p<0.001). Postoperative imaging of the transferred LD tendon showed intact repair in 4 patients. The remaining patient experienced LD transfer rupture and a poor outcome. Conclusions: Arthroscopic-assisted LD tendon transfer improved shoulder pain and function in patients with massive, irreparable rotator cuff tears, and may be an option for this condition, especially in physically active patients.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.175-182
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• 2015

Objective : The purpose of this study was to investigate difference in fascicle behavior of the medial gastrocnemius during the locomotion with varying intensities, such as gait and one-legged and two-legged vertical jumping. Methods : Six subjects (3 males and 3 females; age: $27.2{\pm}1.6yrs.$, body mass: $62.8{\pm}9.8kg$, height: $169.6{\pm}8.5cm$) performed normal gait (G) at preferred speed and maximum vertical jumping with one (OJ) and two (TJ) legs. While subjects were performing the given tasks, the hip, knee and ankle joint motion and ground reaction force was monitored using a 8-infrared camera motion analysis system with two forceplates. Simultaneously, electromyography of the triceps surae muscles, and the fascicle length of the medial gastrocnemius were recorded using a real-time ultrasound imaging machine. Results : Comparing to gait, the kinematic and kinetic parameters of TJ and OJ were found to be significantly different. Along with those parameters, change in the medial gastrocnemius (MG) muscle-tendon complex (MTC) length ($50.57{\pm}6.20mm$ for TJ and $44.14{\pm}5.39mm$ for OJ) and changes in the fascicle length of the MG ($18.97{\pm}3.58mm$ for TJ and $20.31{\pm}4.59mm$ for OJ) were observed. Although the total excursion of the MTC and the MG fascicle length during the two types of jump were not significantly different, however the pattern of length changes were found to be different. For TJ, the fascicle length maintained isometric longer during the propulsive phase than OJ. Conclusion : One-legged and two-legged vertical jumping use different muscle-tendon interaction strategies.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.61-72
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• 2002

In this parer, a new harmonic imaging technique is Proposed and evaluated experimentally. In the Proposed method. a weighted chirp signal with a hanning window is transmitted. The RF samples obtained on each array element are individually compressed by correlating with the reference signal defined as the 2nd harmonic component($2f_0$) of a transmitted chirp signal generated in a square-law system. The correlator output will then consist of the compressed version of the $2f_0$ component generated in tissue and the crosscorrelation sequence of the fundamental($f_0$) and 2f$_{0}$components. The Proposed method uses the compressed $2f_0$ component to form an image. for which the crosscorrelation term should be suppressed below at least -50dB. The Proposed method has two process, 2f$_{0}$-correlation and $2f_0$-correlation(PI) . $2f_0$-correlation can successfully eliminate the $f_0$ component with a single transmit-receive events and therefore is more efficient than the conventional Pulse inversion method in terms of the frame rate. 2i)-correlation(Pl) Performs pulse compression after applying pulse inversion method for the 2nd harmonic image with high resolution and SNR. Another advantage of the proposed method is that the SNR of 2nd harmonic imaging can be improved without limitation by increasing the duration of the chirp signal. The proposed method was verified through both the computer simulations and actual experiments .ts .

• Korean Journal of Applied Biomechanics
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• v.24 no.4
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• pp.399-415
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• 2014

The aim of this study was to investigate the effect of resistance training with and without whole-body vibration(WBV) on the biomechanical properties of the plantarflexor in the elderly women (>60 yrs., n=35). Thirty-five volunteers were randomly assigned to a resistance training with WBV group (RVT, n=14), a resistance training without WBV (RT, n=11), and a non-training control group (CON, n=10). The RVT and the RT groups participated in the training sessions three times a week for 8 weeks, followed by a 4-week detraining period. The CON group was instructed to refrain from any type of resistance training. To assess strength and activation of the plantarflexor muscles, maximum isometric ankle plantarflexion torque and muscle activation of the triceps surae muscles were measured using dynamometry, twitch interpolation technique and electromyography at four different ankle joint angles. Also, the lower extremity function was assessed by vertical jumping. The measurements were performed prior to, 2 and 8 weeks after the training and after a 4-week detraining period. Following the 8-week training sessions, an increase in the isometric plantarflexion strength was found to be greater for the RVT compared with the RT group (p<.05). Muscle inhibition was significantly decreased after training than before training only for the RVT (p<.05). Following the detraining period, a decrease in isometric plantarflexors strength and a increases in muscle inhibition were significantly less in the RVT compared with the RT group. In conclusion, the exercise with WBV is a feasible training modality for the elderly and seems to have a boosting effect when used with conventional resistance training.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.192-198
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• 2008

Purpose: The scan time reduction helps to yield more accurate results and induce the minimization of patient's motion. Also we can expect that satisfaction of examination will increase. Nowdays medical equipment companies have developed various programs to reduce scan time. We used Onco. Flash (Pixon method, SIEMENS) that is an image processing technique gated cardiac blood pool scan and going to evaluate its clinical usefullness. Materials and Method: We analyzed the 50 patients who were examined by gated blood pool scan in nuclear medicine department of Asan Mediacal Center from June $20^{th}$ 2008 to August $14^{th}$ 2008. We acquired the Full-time (6000 Kcounts) and Half-time (3000 Kcounts) LAO image in same position. And we acquired LVEF values ten times from Full-time, Half-time images acquired by the image processing technique and analyzed its mean and standard deviation values. To estimate LVEF in same conditions, we set automatic location of the LV ROI and background ROI based on same X and Y-axis. Also we performed blinding tests to physician. Results: After making a quantitative analysis of the 50 patients EF values, each mean${\pm}$standard deviation is shown at Full-time image $68.12{\pm}7.84%$, Half- time (acquired by imaging processing technique) $68.49{\pm}8.73%$. In the 95% confidence limit, there was no statistically significant difference (p>0.05). After blinding test with a physician for making a qualitative analysis, there was no difference between Full-time image and Half-time image acquired by the image processing technique for observing LV myocardial wall motion. Conclusion: Gated cardiac blood pool scan has been reported its relatively exact EF measured results than ultrasound or CT. But gated cardiac blood pool scan takes relatively longer time than other exams and now it needs to improve time competitive power. If we adapt Half-time technique to gated cardiac blood pool scintigraphy based on this study, we expect to reduce possible artifacts and improve accessibility as well as flexibility to exam. Also we expect patient's satisfaction.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3185-3190
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• 2016

Background: This study was designed to compare radioguided versus routine wire localization of nonpalpable non-malignant breast lesions in terms of efficacy for complete excision, ease of use, time saving, and cosmetic outcome. Materials and Methods: Patients with non-palpable breast masses and non-malignant core biopsy results who were candidates for complete surgical lumpectomy were enrolled and randomly assigned to radioguided or wire localization groups. Radiologic, surgical, and pathologic data were collected and analyzed to determine the difficulty and duration of each procedure, ease of use, accuracy, and cosmetic outcomes. Results: This prospective randomized study included 60 patients, randomly divided into wire guided localization (WGL) or radioguided occult lesion localization (ROLL) groups. The mean duration of localization under ultrasound guidance was shorter in the ROLL group (14.4 min) than in the WGL group (16.5 min) (p<0.001). The ROLL method was significantly easier for radiologists (p=0.0001). The mean duration of the surgical procedure was 22.6 min (${\pm}10.3min$) for ROLL and 23.6 min (${\pm}9.6min$) for WGL (p=0.6), a non-significant difference. Radiography of the surgical specimens showed 100% lesion excision with clear margins, as proved by pathologic examination, with both techniques. The surgical specimens were slightly heavier in the ROLL group, but the difference was not significant (p=0.06). Conclusions: The ROLL technique provides effective, fast, and simple localization and excision of non-palpable non-malignant breast lesions.

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.135-142
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• 2016

Objective: The purpose of this study was to investigate the acute effect of walking on high heels on the behavior of fascicle length and activation of the lower limb muscles. Methods: Twelve healthy inexperienced high heel wearers (age: $23.1{\pm}2.0yr$, height: $162.4{\pm}4.9cm$, weight: $54.4{\pm}8.5kg$) participated in this study. They walked in high heels (7 cm) and barefoot on a treadmill at their preferred speed. During the gait analysis, the lower limb joint kinematics were obtained using a motion analysis system. In addition, the changes in fascicle length and the level of activation of the medial gastrocnemius (MG) were simultaneously monitored using a real-time ultrasound imaging technique and surface electromyography, respectively. Results: The results of this study show that the MG fascicle operates at a significantly shorter length in high heel walking ($37.64{\pm}8.59mm$ to $43.99{\pm}8.66mm$) in comparison with barefoot walking ($48.26{\pm}9.02mm$ to $53.99{\pm}8.54mm$) (p < .05). In addition, the MG fascicle underwent lengthening during high heel walking with relatively low muscle activation while it remained isometric during barefoot walking with relatively high muscle activation. Conclusion: Wearing high heels alters the operating range of the MG fascicle length and the pattern of muscle activation, suggesting that prolonged wearing of high heels might induce structural alterations of the MG that, in turn, hinder normal functioning of the MG muscle during walking.