• Journal of Biomedical Engineering Research
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• v.27 no.2
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• pp.53-58
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• 2006

In this study, transverse relaxation time (T2) measurement and the evaluation of the characteristics of the spectral peak related to stomach tissue metabolites were performed using ex vivo proton magnetic resonance spectroscopic imaging (MRSI) at 1.5-T MRI/S instruments. Thirty-two gastric tissues resected from 12 patients during gastric cancer surgery, of which 19 were normal tissue and 13 were cancerous tissue, were used to measure the $T_2$ of the magnetic resonance spectroscopy (MRS) peaks. The volume of interest data results from the MRSI measurements were extracted from the proper muscle (MUS) layer and the composite mucosa/submucosa (MC/SMC) layer and were statistically analyzed. MR spectra were acquired using the chemical shift imaging (CSI) point resolved spectroscopy (CSI-PRESS) technique with the parameters of pulse repetition time (TR) and echo times (TE) TR/(TE1,TE2)=1500 msec/(35 msec, 144 msec), matrix $size=24{\times}24$, NA=1, and voxel $size=2.2{\times}2.2{\times}4mm^3$. In conclusion, the measured $T_2$ of the metabolite peaks, such as choline (3.21ppm) and lipid (1.33ppm), were significantly decreased (p<0.01 and p<0.05, respectively) in the cancerous stomach tissue.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.517-527
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• 1997

Magnetic Resonance Spectroscopic Imaging is a methodology combining the imaging and spectroscopy. It can provide the spectrum of each areas of image so that one can easily compare the spectrum of one position to another position of the image. In this study, we developed pulse sequence or the spectroscopic imaging method, RF wave forms or the saturation of water signal, computer simulations to validate our method, and confirmed the methodology with phantom experiment. Then we applied the spectroscopic method to human subject and identified a few important metabolites in in vivo. To develope a water saturating RF waveform, we used Shinnar-Le-Roux algorithm and obtained maximum phase RF waveform. With this RF pulse, it could suppress the water signal to 1:1000. The magnet is shimmed to under 1.0ppm with auto-shimming technique. The saturation bandwidth is 80Hz(2ppm). The water and fat seperation is 3.3ppm(about 140Hz at 1 Tesla magnet), the bandwidth is enough to resolve the difference. But we are more concerned about the narrow window in between the two peaks, in which the small quantity of metabolites reside. We performed the computer simulation and phantom experiments in 8*8 matrix form and showed good agreement in the image and spectrum. Finally we applied spectroscopic imaging to the brain of human subject. Only the lipid signal was shown in the periphery region which agrees with the at distribution in human head surface area. The spectrum inside the brain shows the important metabolites such as NAA, Cr/PCr, Choline. We here have shown the spectroscopic imaging which is normally done above 1.5 Tesla machine can be performed in the 1 Tesla Magnetic Resonance Imaging Unit.

• Investigative Magnetic Resonance Imaging
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• v.23 no.1
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• pp.17-25
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• 2019

We discuss recent advances in Gd-based $T_1$-weighted MR contrast agents for the mapping of cellular pH. The pH plays a critical role in various biological processes. During the past two decades, several MR contrast agents of strategic importance for pH-mapping have been developed. Some of these agents shed light on the pH fluctuation in the tumor microenvironment. A pH-responsive self-assembled contrast agent facilitates the visualization of tumor size as small as $3mm^3$. Optimization of various parameters is crucial for the development of pH-responsive contrast agents. In due course, the new contrast agents may provide significant insight into pH fluctuations in the human body.

• Investigative Magnetic Resonance Imaging
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• v.17 no.4
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• pp.326-333
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• 2013

On $H^1$ MRS (magnetic resonance spectroscopy), malignant tumors show higher concentration of metabolite than benign lesions. Lactate double peak was detected in malignant tumor and endometriosis, and more prominent high concentration was demonstrated in endometriosis. Tuboovarian abscesses and salpingitis do not show prominent peak. Dermoid cysts show high levels of lipid peak. Paratubal cyst and follicular cyst can be showed the lipid peak, however, the concentration of lipid is lower than that of dermoid cyst. $H^1$ MRS of ovarian cystic lesions can give valuable information about the presence of metabolites of ovarian cystic lesions.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.25-25
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• 2003

Purpose： In order to characterise primary central nervous system Iymphomas (PCNSL) and to evaluate if 1H spectroscopy improves the preoperative differential diagnosis of other diseases. Method： We reviewed 11 MR imaging and 7 MR spectroscopy of 9 patient with Iymphoma confirmed by stereotatic biopsy.

• Journal of the Korean Magnetic Resonance Society
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• v.10 no.1
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• pp.105-114
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• 2006

Purpose: We achieved high resolution MR imaging and spectra of human skin in vitro with using a 14.1 T MRI/MRS system, and evaluated the hydration effect of various cosmetic products by measuring the skin's. moisture concentration. Materials and Methods: We used the Bruker 14.1 T MRI/MRS system with a vertical standard bore that was equipped with a DMX spectrometer gradient system (200 G/cm at a maximum 40 A), RF resonators (2, 5 and 10 mm) and Para Vision software. Spin echo and fast spin echo pulse sequences were employed for obtaining the high resolution MR images. The 3D-localized point resolved spectroscopy (PRESS) method was used to acquire the MR spectra. Results: The high resolution MR images and spectra of human skin in vitro were successfully obtained on a 14.1 T system. The water concentration of human skin after applying a moisturizer was higher than that before applying a moisturizer. Conclusions: The present study demonstrated that the high-resolution MR images and spectra of human skin from a high field NMR instrument could be applicable to evaluating the hydration state of the stratum corneum.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3243-3248
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• 2013

The tissue inhibitor of metalloproteinase-2 (TIMP-2) inhibits matrix metalloproteinases activity and modulates cellular proliferation and apoptosis. The human serum albumin-TIMP-2 with folic acid conjugate (termed HT2-folate) was synthesized to promote uptake through folate receptors (FRs), and a corresponding radio-labeled compound was prepared for tumor diagnosis by positron emission tomography (PET). $^{68}Ga$-NOTA-HT2-folate was synthesized from $^{68}Ga$ and the NOTA chelator with HT2-folate. The fusion protein was identified using MALDI-TOF mass spectrometry. The radioligand was prepared with a high radiochemical yield. Cell-surface association of $^{68}Ga$-NOTA-HT2-folate significantly increased over time in FR-positive tumor cells. In animal PET and biodistribution studies, tumor uptake was very high as early as 1 h after radioligand injection. Folate conjugation enhanced the selective receptor-targeting efficacy of HT2 in FRexpressing tumors, and its radioligand will be useful as an in vitro tool and for in vivo tumor diagnosis by PET imaging.

• Journal of Korean Neurosurgical Society
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• v.45 no.1
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• pp.1-4
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• 2009

Objective : In the present study, the authors investigated the clinical and imaging features as well as the therapeutic outcomes of SIH (spontaneous intracranial hypotension) patients. Methods : A retrospective review of 12 SIH patients was carried out. The diagnostic work-up included lumbar tapping and measurement of CSF opening pressure, radioisotope cisternography, brain and spinal magnetic resonance imaging (MRI), and computed tomography (CT) myelography. Autologous epidural blood patching was performed in patients who did not respond to conservative therapies, including analgesics, steroids, hydration and rest. Results : Typical postural headache was found in 11 (91%) patients. Nine (75%) patients showed pachymeningeal enhancement on their initial T1-weighted MR images. The CSF opening pressure was less than 60 mm$H_2O$ in 9 of 11 patients. Autologous epidural blood patching was performed in 7 patients, and all of them showed good responses. Conclusion : SIH can present with various clinical presentations and neuroimaging findings. Autologous epidural blood patching is thought to be the treatment of choice for patients with SIH.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.75-78
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• 1997

A dual birdcage RF coil is proposed for MRI and MRA of the human leg. The proposed coil c can be used to cover the whole human leg by imaging upper and lower parts of the leg separately. In the conventional leg imaging scheme using a single RF coil, the leg has to be r relocated when changing the position of the RF coil thus causing problems in matching the i images from two sets of coils. When using the proposed dual RF coil, however, only the bed h has to be moved to select the imaging region while only one part of the dual coil is used each t time by using current switching and PIN diodes. The utility of proposed coil has been verified b by volunteer MRI and MRA and the imaging results show that the coil is useful for the clinical MRI and MRA of the leg.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.124-127
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• 1995

Due to the self-diffusion of nuclear spins, the edge of phantoms is enhanced in the magnetic resonance imaging (MRI), especially in the case of microscopy [1]. According to several published works, theory has been established that the edge enhancement is caused by the motion narrowing around bounded regions due to diffusions of nuclear spins during data acquisition. It is found, however, that the signal decreases due to the diffusion attenuation and image is distorted as edge of the image is sharpened. In this paper, we wilt investigate this signal loss during data acquisition and its effects on image, i.e., image edge enhancement due to the diffusion phenomenon. This result is new and different from the previously discussed edge enhancement due to the diffusion, namely, by motion narrowing effect or spin bouncing effect at the boundary.