• The Korean Journal of Pain
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• 제19권2호
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• pp.175-180
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• 2006

Background: A transforaminal epidural steroid injection has been used for the treatment of radicular arm or leg pain, which has the advantage of ventral epidural spreading compared to either an interlaminar or caudal approach. However, several factors are known to affect the epidural spread pattern of contrast dye; therefore, the injected medication can not be delivered to the target site. The objective of our study was to observe any differences in the contrast flow patterns according to several factors. Methods: A total of 34 epidurographies in 29 patients, who underwent fluoroscopically guided transforaminal epidural steroid injections, were evaluated. After confirming the location of the needle tip within the anterior superior aspect of the neural foramen in the lateral view, and at the 6 o'clock position to the pedicle in the anteroposterior view, 2 ml of contrast dye was injected. The contrast flow patterns of ventral, ventral and dorsal, and dorsal epidural filling were analyzed, according to age, gender, magnetic resonance imaging finding and history of previous back surgery. Results: Ventral contrast flow occurred in 30 out of the 34 epidurographies (88%). Both ventral and dorsal contrast flow patterns were observed 13 out of 16 (81%) patients in the older age group. Also, both ventral and dorsal contrast flow patterns were observed in 16 out of 18 (88%) patients with spinal stenosis. Conclusions: Transforaminal epidural steroid injections, performed uner fluoroscopy, provide excellent nerve root filling and ventral epidural spreading. Patients with spinal stenosis or an old age have both ventral and dorsal epidural spreading patterns.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.127-130
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• 1997

Phase-contrast(PC) methods have been used for quantitative measurements of velocity and volume flow rate. In addition, phase contrast cine magnetic resonance imaging (MRI) combines the flow dependent contrast of PC MRI with the ability of cardiac cine imaging to produce images throughout the cardiac cycle. In this method, the through-plane velocity has been encoded generally. However, the accuracy of the flow data can be reduced by the effect of flow direction, finite slice thickness, resolution, pulsatile flow pattern, and so on. In this study we calculated the error caused by misalignment of tomographic plane and flow directon. To reduce this error and encode the velocity for more complex flow, we suggested 3 directional velocity encoding method.

• 한국전문물리치료학회지
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• 제3권2호
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• pp.49-54
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• 1996

The purposes of this study were to measure skin temperature and blood flow on the contralateral upper extremity when heat is applied to one upper extremity, were to compare the effect of contrast bath. The subjects were 38 healthy adults with no history of peripheral vascular disease. The subjects of contrast bath were 18 persons and the subjects of warm bath were 20 persons. The subjects of one group were seated with their right arm in water($42^{\circ}C$) up to the mid-forearm. The subjects of the other group were seated with their right arm up to the mid-forearm in water which was changed from warm to cold using the contrast bath technique. The continually changing temperatures and blood flow were measured by an independent observer at intervals of 10, 15, 20, 25 and 30 minutes respectively after the start of the procedure. The results were as follows. The temperature of the warm bath group rose 4.28% over the pre-experimental temperatures and the temperature of the contrast bath group rose 3.41%. There was no statistically significant difference between the two groups. The blood flow of the warm bath group rose 8.31% over the pre-experimental blood flow and the blood flow of the contrast bath group rose 17.24%. There was a statistically significant between the two groups 20 minutes after the start of the procedure. Thus the contrast bath is a more effective method than the warm bath to increase blood flow.

• 대한의용생체공학회:의공학회지
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• 제20권2호
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• pp.165-172
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• 1999

본 연구에서는 MRI 영상에서 위상을 조절하여 영상 대조를 증가 시키는 방법을 제안 하였다 영상하고자 하는 물체 자체가 갖는 위상에 따라 영상의 대조가 변하기 때문에 본 방법은 자화율 영상이나 유속 영상에 유용하게 쓰일 수가 있다. 본 논문에서는 위상 분포에 따른 영상의 대조를 증가 시키기 위하여 RF 펄스를 복셀 내에서 위상을 갖도록 디자인 하였다. 따라서 복셀에서의 신호의 크기는 물체자체의 위상과 RF 펄스에의하여 가해준 위상이 결합에 의하여 결정된다. 외부위상 변화에 따른 신호의 변화를 분석하였고 그때 디자인된 RF 펄스를 이용하여 자화율만의 영상과 유속만의 영상을 얻었다. 컴퓨터 시뮬레이션의 결과는 제안된 알고리즘이 복셀내에 위상을 갖는 물체의 영상에 유용하고 그런 물체만을 영상하는데 유용함을 보였다.

• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.88-93
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• 2016

Recently laser speckle contrast (LSC) imaging has become a widely used optical method for in vivo assessment of blood flow in the animal brain. LSC imaging is useful for monitoring brain hemodynamics with relatively high spatio-temporal resolution. A speckle contrast imaging system has been implemented with electrical sensory stimulation apparatus. LSC imaging is combined with optical intrinsic signal imaging in order to measure changes in cerebral blood flow as well as neural activity in response to electrical sensory stimulation applied to the hindlimb region of the mouse brain. We found that blood flow and oxygen consumption are correlated and both sides of hindlimb activation regions are symmetrically located. This apparatus could be used to monitor spatial or temporal responses of cerebral blood flow in animal disease models such as ischemic stroke or cortical spreading depression.

• 한국산학기술학회논문지
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• 제14권5호
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• pp.2315-2321
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• 2013

본 연구는 혈류에 의한 조영제 peak time을 산출하는 새로운 방법을 개발하여 기존의 수식에 의한 부작용을 최소화 하고, 대체할 수 있는 새로운 검사법을 제시하고자 하였다. 시험적조영제주입법을 이용하여 CE MRA를 검사한 환자 127명을 대상으로, 기존의 수식에 의해 산출된 조영제 peak time이 조영제 주입 후 혈류에 의한 영상화 범위의 어느 뇌혈관 측정값과 일치하는지 각 뇌혈관의 조영제 inflow time과 peak time을 측정하였다. 연구결과, 유의수준 0.05에 대한 4개의 집단 간 차이가 존재하였으나 집단 1에서 수식에 의해 산출된 조영제 peak time과 S상 정맥동의 조영제 inflow time이 통계적으로 유의한 차이가 없어 일치하였으며, Bland Altman plot를 시행한 결과 일치도가 상당히 높은 것을 확인할 수 있었다. 따라서 본 연구의 혈류에 의한 새로운 방법을 적용한다면, 부작용 가능성을 최소화하고, 영상의 질은 유지하면서, 쉽고 빠르게 적용할 수 있어, 기존의 수식에 의해 산출된 조영제 peak time을 대체 할 수 있으리라 사료된다.

• The Korean Journal of Pain
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• 제25권1호
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• pp.22-27
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• 2012

Background: The common causes of lower back pain with or without leg pain includes disk disease and spinal stenosis. A definitive diagnosis is usually made by means of magnetic resonance imaging (MRI), but treatment is often difficult because the MRI findings are not consistent with the symptoms of the patient in many cases. The objective of this study was to observe the correlation between the patterns of epidurography performed in patients having lower back pain with or without leg pain and the position or severity of the pain as subjectively described by the patients. Methods: The subjects of this study were 69 outpatients with lower back pain with or without leg pain who visited our clinic and complained of predominant pain on one side. We performed caudal epidural block using an image intensifier. A mixture of the therapeutic drug and the contrast agent (10 ml) was injected to observe the contrast flow pattern. The patients who complained of predominant pain on one side were divided into the left side group and the right side group. A judgment of inconsistency was made if the contrast agent flowed to the side of the pain, while a judgment of consistency was made if the contrast agent flowed to the opposite side of the pain. The degree of the drug distribution was evaluated by counting the number of cells to which the contrast agent's flowed for evaluating the correlation between the contrasted cell and the severity of pain (one group ${\leq}$ VAS 7, the other group ${\geq}$ VAS 8) the degree of the contrast agent's contrast was evaluated by dividing and counting an image into 15 cells (the left, right, and middle sections at each level of L4, L5, S1, S2, and S3). Results: Thirty out of the 69 patients who had laterality in pain, that is, those who complained of predominant pain on one side, showed that the laterality of the pain and the contrast agent flow was consistent, while 39 patients showed that the laterality was inconsistent (P: 0.137). The evaluation of the correlation between the pain and the contrast agent flow showed that the mean number of contrasted cells was $9.0{\pm}2.2$ for the 46 patients in the group with a VAS of 7 or lower and $6.5{\pm}2.0$ for the 23 patients in the group with a VAS of 8 or higher, indicating that the former group showed a significantly greater number of contrasted cells (P < 0.001). Conclusions: This study, conducted with patients having lower back pain with or without leg pain, showed that the contrast flow pattern of caudal epidurography had a significant correlation with the severity of the pain but not with the laterality of the pain.

• 대한수의학회지
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• 제47권2호
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• pp.247-254
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• 2007

This study was performed to identify the normal anatomic orientation of pulmonary arteries and to obtain the normal baseline parameters and the optimal contrast material delivery methods of computed tomographic pulmonary angiography (CTPA) on normal beagle dogs. Based on the contrast injection flow rate, the contrast volume, and the administration methods, the experimental groups were divided into 4 groups such as group 1 : 2 ml/s, 3 ml/kg, and monophasic administration; group 2 : 5 ml/s, 3 ml/kg, and monophasic administration; group 3 : 5 ml/s, 4 ml/kg, and monophasic administration; group 4 : 5 ml/s and 2 ml/kg in first phase, 0.3 ml/s and 2 ml/kg in second phase, as biphasic administration. Normal anatomic orientation of pulmonary arteries in CTPA was evaluated through reformatted and 3D images after retro-reconstruction. Normal parameters for great arteries and peripheral pulmonary arteries were obtained on the factor of basement hounsfield unit (HU) values, contrast enhanced HU values, delay time, and peak time. And the optimal contrast delivery methods were evaluated on the factor of contrast enhanced HU values, image quality, and artifact. The monophasic administration with 5 ml/s contrast injection flow rate and 3 ml/kg contrast volume was optimal in canine CTPA.

• Korean Journal of Radiology
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• 제22권5호
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• pp.677-687
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• 2021

Microvascular ultrasound (US) techniques are advanced Doppler techniques that provide high sensitivity and spatial resolution for detailed visualization of low-flow vessels. Microvascular US imaging can be applied to breast lesion evaluation with or without US contrast agents. Microvascular US imaging without a contrast agent uses a sophisticated wall filtering system to selectively obtain low-flow Doppler signals from overlapped artifacts. Microvascular US imaging with second-generation contrast agents amplifies flow signals and makes them last longer, which facilitates hemodynamic evaluation of breast lesions. In this review article, we will introduce various microvascular US techniques, explain their clinical applications in breast cancer diagnosis and radiologic-histopathologic correlation, and provide a summary of a recent radiogenomic study using microvascular US.

• 순환기질환의공학회:학술대회논문집
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• 순환기질환의공학회 2006년도 춘계학술강연회
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• pp.28-36
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• 2006

The x-ray PIV method was improved for measuring quantitative velocity fields of real blood flows using a coherent synchrotron x-ray source. Without using any contrast media or seeding particles, this method can visualize flow pattern of blood by enhancing the phase-contrast and interference characteristics of blood cells based on a synchrotron x-ray imaging mechanism. The enhanced x-ray images were achieved by optimizing the sample-to-scintillator distance, the sample thickness, and hematocrit. The quantitative velocity fields of blood flows inside opaque tubes were obtained by applying a 2-frame PIV algorithm to the x-ray images of the blood flows. The measured velocity field data show typical features of blood flows such as the yield stress effect. The non-Newtonian flow characteristics of blood flows were analyzed using the x-ray PIV method and the experimental results were compared with hemodynamic models.