• 한국자기공명학회논문지
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• 제14권1호
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• pp.9-17
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• 2010

The water proton relaxation rates increase linearly with concentrations of contrast agents, and could be expressed as a function of the concentrations. In this paper, we have investigated MR properties of two different contrast agents, $GdCl_3$ and $CoCl_2$. Relaxivity coefficients were calculated from individual contrast agent solutions, and used for predicting relaxation rates at mixtures of two contrast agents. From the experimental results, we have discussed the feasibility of constructing water solutions with the desired relaxation times using specific mixtures of contrast agents.

• 대한디지털의료영상학회논문지
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• 제11권2호
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• pp.51-57
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• 2009

The purpose of this study would evaluate if having clinical effects on diffusion image with quantitative analysis through ADC values of brain's normal tissue and lesions before and after contrast injections using a 3.0T. From November in 2007 until December in 2008, a total of 32 patient was performed on 3.0T(Signa Excite, GE Medical System, USA) with the normal or lesions in the patient who requests diffusion weighted image with 8channel head coil. The pulse sequence was used with spin echo EPI(TR: 10000msec, TE: 72.2 msec, Matrix: 128*128, FOV: 240 mm, NEX: 1, diffusion direction: 3, b-value: 1000). Measurement results of ADC values on lesions, CSF, white matter, gray matter, lesions after contrast injection were measured less 75% than before contrast injection, infarction: 100%, CSF: 78%(high), white matter: 71.4%(low), gray matter: 50%(high, low). The results of paired t-test on the deference of ADC values which statically is significant in three(lesions, CSF, white matter)regions except for white matter(p<0.05). Quantitative analysis of lesions, CSF, white matter, gray matter have difference on all regions. ADC values were low in lesions and white matter, normal CSF after contrast injection commonly is high than before contrast injection, ADC values which white matter were high and low (50:50) after contrast injection. 3.0T diffusion weighted image clinically supposed that performing DWI examination after contrast injection was not desirable because of having effects on brain tissue.

• 대한핵의학회지
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• 제38권2호
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• pp.205-208
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• 2004

The two major classes of magnetic resonance (MR) contrast agents are paramagnetic contrast agents, usually based on chelates of gadolinium generating T1 positive signal enhancement, and super-paramagnetic contrast agents that use mono- or polycrystalline iron oxide to generate strong T2 negative contrast in MR images. These paramagnetic or super-paramagnetic complexes are used to develop new contrast agents that can target the specific molecular marker of the cells or tan be activated to report on the physiological status or metabolic activity of biological systems. In molecular imaging science, MR imaging has emerged as a leading technique because it provides high-resolution three-dimension maps of the living subject. The future of molecular MR imaging is promising as advancements in hardware, contrast agents, and image acquisition methods coalesce to bring high resolution in vivo imaging to the biochemical sciences and to patient care.

• 한국자기공명학회논문지
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• 제9권2호
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• pp.93-102
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• 2005

Purpose: To develop an advanced non-linear curve fitting (NLCF) algorithm for dynamic susceptibility contrast study of brain. Materials and Methods: The first pass effects give rise to spuriously high estimates of $K^{trans}$ in voxels with large vascular components. An explicit threshold value has been used to reject voxels. Results: By using this non-linear curve fitting algorithm, the blood perfusion and the volume estimation were accurately evaluated in T2*-weighted dynamic contrast enhanced (DCE)-MR images. From the recalculated each parameters, perfusion weighted image were outlined by using modified non-linear curve fitting algorithm. This results were improved estimation of T2*-weighted dynamic series. Conclusion: The present study demonstrated an improvement of an estimation of kinetic parameters from dynamic contrast-enhanced (DCE) T2*-weighted magnetic resonance imaging data, using contrast agents. The advanced kinetic models include the relation of volume transfer constant $K^{trans}\;(min^{-1})$ and the volume of extravascular extracellular space (EES) per unit volume of tissue $\nu_e$.

• Journal of Magnetics
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• 제21권1호
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• pp.115-124
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• 2016

The present study analyzes T1 TSE and T1 slice sel. IR (dark_fluid) signal strength according to the degree of gadolinium contrast agent dilution and analyzes the turbo factors with regard to changes in the maximum and overall signal strength to study correlations between changes and signal-to-noise ratios (SNRs) and compare peak-to-peak SNR (PSNR) enhancement in order to improve the quality of T1-weighted images. Enhancement TR (600 msec) evaluated to determine the T1 TSE turbo factor and obtain the maximum signal strength, T1WI were used sequentially to experiment with turbo factors_1-4. T1 slice sel. IR (dark-fluid) was used to sequentially test turbo factors_2-5 but not turbo factor_1 at a TR (1500 msec) and compare data at an increase in T1 of 900 msec. The T1 TSE was reduced according to the contrast agent concentration. Phantom signal strength increased, whereas turbo factors_1-4 exhibited maximum signal strength at a concentration of 3 mmol, followed by a gradual decrease. In the turbo factors_2-5, the signal strength increased sharply to maximum signal strength at 0.7 mmol, followed by a reduction. T1 TSE had a greater maximum signal strength than did T1 slice sel. IR (dark_fluid). A comparison of SNR found that T1 TSE imaging was superior (33.3 dB) in turbo factor_1 and T1 slice sel. IR (dark_fluid) was highest (33.9 dB) at turbo factor_5. A PSNR comparison analysis was not sufficient to distinguish between the images obtained with both techniques at 30 dB or higher under all experimental conditions.

• The Korean Journal of Pain
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• 제7권2호
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• pp.211-216
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• 1994

Celiac plexus block is performed to relieve intractable upper abdominal cancer pain. Generally, celiac plexus blocks have been performed under control of X-ray fluoroscopy to determine the position of the needle tip and the spread of contrast media. During the period from March 1992 to February 1994, we have performed 21 cases of neurolytic celiac plexus block to alleviate pain of intra-abdominal malignancy. We retrospectively evaluated the location of the needle tip and the spread of contrast media. P-A views of simple abdomen demonstrated the locations of the needle tip: 66.7% of the left needle tips were in upper 3/1 of L1 (6 cases) and $T_{12}-L_1$ interspace (8 cases), 50% of the right needle tips were in upper 1/3 of $L_1$, (6 cases) and $T_{12}-L_1$ interspace (4 cases). Contrast media from the right needle spread upward to middle 1/3 of $T_{10}$ (5 cases) and middle 1/3 of $T_{11}$ (5 cases), downward to middle 1/3 of $L_1$ (6 cases) and lower 1/3 of $L_1$ (3 cases). Contrast media from the left needle were spread upward to middle 1/3 of $T_{10}$ (5 cases) and evenly to other spaces, downward to middle 1/3 of $L_1$, (4 cases) and $L_1-L_2$ interspace (6 cases). We analyze the spread of contrast media according to distance from needle tip by authors score system. Contrast media of right needle spread upward 6.1 and downward 3.4, that of left needle spread upward 6.5 and downward 3.7.

• 대한디지털의료영상학회논문지
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• 제15권1호
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• pp.27-31
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• 2013

Perfusion MR imaging is how to use exogenous and endogenous contrast agent. Exogenous perfusion MRI methods which are dynamic susceptibility contrast using $T2^*$ effect and dynamic contrast-enhanced using T1 weighted image after injection contrast media. An endogenous perfusion MRI method which is arterial spin labeling using arterial blood flow in body. In order to exam perfusion MRI in human, technical access are very important according to disease conditions. For instance, dynamic susceptibility contrast is used in patients with acute stroke because of short exam time, while dynamic susceptibility contrast or dynamic contrast enhancement provides the various perfusion information for patients with tumor, vascular stenosis. Arterial spin labeling is useful for children, women who are expected to be pregnant. In this regard, perfusion MR imaging is required to understanding, and the author would like to share information with clinical users

• Investigative Magnetic Resonance Imaging
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• 제22권2호
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• pp.102-109
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• 2018

Purpose: The purpose of this study is to compare the performance of the T1 3D subtraction technique and the conventional 2D dynamic contrast enhancement (DCE) technique in diagnosing Cushing's disease. Materials and Methods: Twelve patients with clinically and biochemically proven Cushing's disease were included in the study. In addition, 23 patients with a Rathke's cleft cyst (RCC) diagnosed on an MRI with normal pituitary hormone levels were included as a control, to prevent non-blinded positive results. Postcontrast T1 3D fast spin echo (FSE) images were acquired after DCE images in 3T MRI and image subtraction of pre- and postcontrast T1 3D FSE images were performed. Inter-observer agreement, interpretation time, multiobserver receiver operating characteristic (ROC), and net benefit analyses were performed to compare 2D DCE and T1 3D subtraction techniques. Results: Inter-observer agreement for a visual scale of contrast enhancement was poor in DCE (${\kappa}=0.57$) and good in T1 3D subtraction images (${\kappa}=0.75$). The time taken for determining contrast-enhancement in pituitary lesions was significantly shorter in the T1 3D subtraction images compared to the DCE sequence (P < 0.05). ROC values demonstrated increased reader confidence range with T1 3D subtraction images (95% confidence interval [CI]: 0.94-1.00) compared with DCE (95% CI: 0.70-0.92) (P < 0.01). The net benefit effect of T1 3D subtraction images over DCE was 0.34 (95% CI: 0.12-0.56). For Cushing's disease, both reviewers misclassified one case as a nonenhancing lesion on the DCE images, while no cases were misclassified on T1 3D subtraction images. Conclusion: The T1 3D subtraction technique shows superior performance for determining the presence of enhancement on pituitary lesions compared with conventional DCE techniques, which may aid in diagnosing Cushing's disease.

• Journal of Magnetics
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• 제17권2호
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• pp.158-162
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• 2012

Although 3.0T magnetic resonance imaging (MRI) has the advantages of a higher signal to noise ratio (SNR) and contrast than 1.5T MRI, there are limitations on the contrast between white and grey matter because of the long T1 recovery time when T1 images are obtained using the Spin Echo Technique. To overcome this, T1 weighted images are obtained occasionally using the inversion recovery (IR) technique, which employs a relatively long TR. The aim of this study was to determine the optimal TI in a brain examination when a T1 weighted image is obtained using the IR technique. Eight participants (male: 7, female: 1, average age: $34{\pm}14.11$) with a normal diagnosis were targeted from February 18, 2012 to February 27, 2012, and the contrast between white and grey matter as well as the contrast to noise ratio (CNRs) in each participant were measured. The CNRs of white matter and grey matter were highest at TI = 600, 650, 750, 900, 1050 and 1100 ms when the TR was 1100, 1400, 1700, 2000, 2300 and 2600 ms, respectively. Therefore, as the TIs were $44.425{\pm}0.877%$ of the TRs in the TR range of 1400-2300 ms, the optimal T1 weighted images that describe the contrast between white and grey matter can be obtained if the TIs are compensated for with $44.425{\pm}0.877%$ of the TRs in the time of setting TIs.

• 호스피스학술지
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• 제1권1호
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• pp.1-17
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• 2001

The purpose of this study was to elucidate the effects of spiritual nursing intervention on pain and anxiety of the hospice patients. This study was devised with a quasi-experimental design using non-equivalent contrast group non-synchronized design. The data were collected during the period from July 10 to September 25 in 2000 at the general hospital in CheonJu city. The subjects were sixty-seven patients who referred the hospice service. They were assigned to two groups, 36 members of the experimental group and 30 members of the contrast group. They also did not any complication, were alert enough tobe interviewed and agree willingly to participate in this study. The tools used were Yoon's Korean Version of Brief Pain Inventory and Spielberger's State Anxiety Scale. The spiritual care intervention was carried out through Hymn, Scripture, Prayer, the therapeutic use of self over a period of three weeks. Data were analyzed by mean, standard deviation, $x^2$-test, t-test, paired t-test and Pearson's Correlation Coefficients. The results of this study were as follows: 1.The examination of the same quality showed that there were not significant differences in the general characters, disease and therapeutic characters, religional characters between the experimental group and the contrast group. 2.After the spiritual nursing intervention pain scores of the experimental group were remarkably lower than those of the contrast group(right now pain: t=-2.634, p=0.012). 3.Decreasing rate in the pain scores of the experimental group were remarkably lower than those of the contrast group(right now pain: t=5.017, p=0.000). 4. After the spiritual nursing intervention state anxiety of the experimental group were remarkably lower than those of the contrast group(t=-5.987, p=0.000). 5. A positive correlation was found between reported pain and depression following the spiritual nursing intervention. In conclusion, the hospice patients who were offered spiritual care became lower than those who were not offered spiritual care and confirmed to decrease pain. According to these results, spiritual nursing intervention can be regarded as an effective nursing intervention that relieved pain and anxiety of the hospice patients.