• The Korean Journal of Pain
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• v.19 no.2
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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.

• 순환기질환의공학회:학술대회논문집
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• 2006.04a
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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.

• International Journal of Vascular Biomedical Engineering
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• v.4 no.1
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• pp.1-8
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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.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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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.

• The Korean Journal of Pain
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• v.25 no.1
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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.

• The Korean Journal of Pain
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• v.21 no.3
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• pp.217-223
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• 2008

Background: Lumbar transforaminal epidural injections (LTEIs) have been utilized in the treatment of radicular pain, and LTEIs have the advantage of target-specificity. However, there have not been enough studies on the contrast patterns in LTEIs with using fluoroscopy. The purpose of this study was to evaluate the spreading epidural contrast patterns that are seen during real-time fluoroscopic guided LTEIs. Methods: A total of 131 patients who underwent fluoroscopic guided LTEIs were studied. The inclusion criteria were those patients with low back pain and/or lower extremity pain that was caused by a herniated nucleus pulposus, lumbar spinal stenosis, failed back surgery syndrome, and herpes zoster-associated pain. We classified the contrast patterns in regard to the contrast flow spreading to the nerve root and/or the unilateral, bilateral or cylinderic type of epidural spreading on the AP view of the fluoroscopy and the ventral or dorsal epidural filling on the lateral view. In addition to the pattern analysis, we evaluated the range of contrast spreading from the cranial to the caudal epidural filling and the incidence of an intravascular flow pattern. Results: Epidural spreading was seen in 126 cases (96.2%) of the total patients through the nerve root. Ventral spreading occurred in 120 cases (95.2%). On the AP view, a nerve root with unilateral, bilateral and cylinderic epidural filling was noted for 108 (85.7%), 9 (7.1%) and 9 (7.1%) cases, respectively. The contrast spreading to vertebral segments was smaller for the patients with lumbar spinal stenosis and failed back surgery syndrome than for the other groups (P < 0.0083). The incidence of intravascular injection was 11.1% (14/126). Conclusions: LTEIs using fluoroscopic visualization provided excellent assessment of the ventral epidural filling as well as nerve root filling. However, unilateral epidural spreading was prominent for the LTEIs.

• Journal of Korean Neurosurgical Society
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• v.29 no.12
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• pp.1634-1641
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• 2000

Objective : The cerebrospinal fluid(CSF) pulsates within the craniospinal axis in response to rhythmic cerebral blood volume variation during the cardiac cycle. The aim of this study is to characterize the normal and abnormal CSF flow and its waveforms in the cervical spinal subarachnoid space. Methods : The magnetic resonance(MR) images were obtained with 1.5 T(GE Signa, GE Medical Systems, Milwaukee, USA) unit using the 2 dimensional cine PC(phase contrast) sequence with cardiac gating and gradient recalled echo imaging. This pulse sequence yielded 16 quantitative flow-encoded images per cardiac cycle. Sagittal and axial images of the cervical spinal CSF space were obtained, and target sites were analyzed for characteristic CSF flow (TR=50ms, TE=12.5-15ms). The region of interest(ROI) was 1mm 3 in volume. Twenty six persons were included in this study : 10 healthy volunteers and 16 patients with cervical myelopathy. The post-operative cine MR study were also done in five patients. Results : The normal CSF pulsation dynamics in the cervical spine showed discrete systolic and diastolic components. The CSF flow revealed a sine wave pattern, in which the systolic phase was shorter than the diastolic phase(ratio=2 : 3). The patient group revealed decreased amplitudes of the CSF flow and irregularly distored flow waves. The systolic phase was elongated in the ROI above the stenotic level, whereas the diastolic phase was lengthened below the level. In the postoperative images, the abnormal pattern and amplitude were found to be corrected. Conclusion : From these results, the authors believe that the CSF flow study provides valuable informations regarding the extent of cervical stenosis and may be useful for the surgical planning and post-operative evaluation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.11 s.242
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• pp.1182-1188
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• 2005

An x-ray PIV (Particle Image Velocimetry) technique was developed to measure quantitative information on flows inside opaque conduits and on opaque-fluid flows. At first, the developed x-ray PIV technique was applied to flow in an opaque Teflon tube. To acquire x-ray images suitable for PIV velocity field measurements, refraction-based edge enhancement mechanism was employed using detectable tracer particles. The optimal distance between with the sample and detector was experimentally determined. The resulting amassed velocity field data were in reasonable agreement with the theoretical prediction. The x-ray PIV technique was also applied to blood flow in a microchannel. The flow pattern of blood was visualifed by enhancing the diffraction/interference -bas ed characteristic s of blood cells on synchrotron x-rays without any contrast agent or tracer particles. That is, the flow-pattern image of blood was achieved by optimizing the sample (blood) to detector distance and the sample thickness. Quantitative velocity field information was obtained by applying PIV algorithm to the enhanced x-ray flow images. The measured velocity field data show a typical flow structure of flow in a macro-scale channel.

• The Korean Journal of Nuclear Medicine
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• v.19 no.2
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• pp.25-41
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• 1985

간흡충증은 한국 및 동남아세아에 널리 분포되어 있는 중요한 풍토병의 하나로서 진단은 전통적으로 분변검사에 의존하여 오고 있다. 최근 들어 담관내 간흡충 및 이의 합병증의 진단을 위해 ERCP 및 contrast cholangiogram등이 시도되었으나 실제에 이용하기에는 많은 제약이 있다 하겠다. 저자는 간흡충증에 있어서 최근 소개된 $^{99m}Tc-DISIDA$ hepatobiliary scintigraphy의 진단적 의의를 규명하고자 1982년부터 1983년까지 고신의대 부속 복음병원에서 검진한 간흡충증 환자 90명을 대상으로 하여 $^{99m}Tc-DISIDA$ hepatobiliary scintigraphy와 formalin-ether 원침법에 의한 분변검사를 시행하였다. $^{99m}Tc-DISIDA$ scintigram소견은 간내 담관 bile flow 및 총수담관 bile flow defect, 그리고 간세포기능의 정도에 따라 자료를 분석하였고 그외 합병증의 진단은 병록 기록, 수술 소견, ERCP 등에 의존하여 결론을 얻었다. $^{99m}Tc-DISIDA$ scintigraphy는 특이한 양상의 bile flow dynamics를 나타내었으며 간내 주담관의 intermittent irregular focal bile flow defect 및 tile flow stasis를 나타내고 말초담관의 bile flow defect는 경미하고 60분 내에 담관 bile flow activity의 완전한 배설을 나타내는 경우를 mild pattern, 간내 담관의 심한 irregular bile flow dynamics 및 간내담관의 심한 irregularity (담관내벽의 심한 불규칙성), 총수담관, 간내 주담관 및 말초 담관까지 심하게 irregular bile flow stasis를 나타내며 bile flow activity의 완전 베설이 $60\sim90$분사이 혹은 90분이상까지 인지된 경우를 moderate-severe pattern으로 분류하였다. 1) 분변검사상 간흡충증은 95검사중 70검사(환자 86명중 67명)에서 양성을 보여 분변 충난검사의 양성율은 73.7%였고 음성율은 26.3%였다. 2) $^{99m}Tc-DISIDA$ hepatobiliary scintigraphy는 90명중 70명에서 특이한 Cs-bile flow양성을 보였으며 양성율은 77.8%였으며 음성율은 22.2%였다. 3) $^{99m}Tc-DISIDA$ hepatobiliary scintigram양성율을 나타낸 환자 70명중 11명은 mild pattern, 59명은 moderate-severe pattern을 나타냈으며 그중 21명은 여러가지 간세포 기능 및 담관에 영향을 미치는 질환과 합병했지만 특이한 Cs-bile flow pattern을 dominent하게 나타내었으며 합병된 여러 질환들도 bile flow pattern상 인지 할 수 있었다. 4) $^{99m}Tc-DISIDA$ hepatobiliary scintigram 음성율을 나타낸 환자 20명중 8명은 만성간염, 5명은 간경변증, 3명은 재발성 농양성담관염(recurrent pyogenic cholangitis)과 간내담도의 stricture 및 담관담석증이 합병되었으며 scintigram상 합병증의 pattern을 나타냈고 4명에서는 low CBD obstruction을 나타내었으며 후에 CBD stone, CBD carcinoma, gall bladder Ca.의 porta hepatis 전이 및 clonorchis worms의 cluster에 의한 obstruction이 operation 및 ERCP로서 진단 되었다. 5) $^{99m}Tc-DISIDA$ hepatobiliary scintigraphy pattern은 현재의 자각증상과 관계된 dominent disease를 나타내었으며, 공간 점유병소도 multiple project images를 시행하므로서 쉽게 발견할 수 있었다. 이와 같이 간흡충증에 있어서 $^{99m}Tc-DISIDA$ hepatobiliary scintigram은 환자의 자각증상과 관계된 질환을 규명하는 데 필요한 정보를 얻었을 수 있었으며 간내담관의 damage정도를 규명하는데 필요한 procedure임이 판명되었다.

• The Korean Journal of Pain
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• v.22 no.1
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• pp.52-57
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• 2009

Background: Transforaminal epidural injection (TEI) may be useful to treat unilateral pain that has a dermatomal distribution. In this approach, the needle tip can be placed closer to the dorsal root ganglion and ventral aspect of the nerve root. However many studies have reported that serious complications following TEI occurred more frequently when it was conducted at the cervical level. One of the presumptive mechanisms of the complication is intravascular injection. Therefore this study was conducted to identify the incidence of complications in response to intravascular injections at cervical segments. Methods: This study included all patients, who visited our pain clinic and had radicular symptoms or herpes zoster associated pain. All procedures were conducted under fluoroscopic guidance with contrast enhancement by one of the authors. After the ideal needle position was confirmed by biplanar fluoroscopy, the blood aspiration through the needle hub was evaluated, and a 3 ml mixture of nonionic contrast (2 ml) with normal saline (1 ml) was injected at a rate of 0.3-0.5 ml/sec continuously under real time fluoroscopic visualization. We then classified the contrast spreading pattern as neural, simultaneous neural and vascular, or vascular. Results: A total 71 cervical TEIs were performed. In 26 cases (36.6%), the contrast only spread to the nerve sheath. However, 45 cases (63.4%) showed an intravascular spreading pattern, 37 (52.1%) of which showed a neural and vascular pattern and 8 (11.3%) of which showed only a vascular pattern. Conclusions: Approximately two thirds of the cases of cervical TEI were found to lead to intravascular spreading, which is much higher than the incidence reported in previous studies.