• Korean Journal of Radiology
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• 제22권10호
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• pp.1619-1627
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• 2021

Objective: This study used cardiac magnetic resonance imaging (MRI) to compare the characteristics of left ventricular remodeling in patients with primary aldosteronism (PA) with those of patients with essential hypertension (EH) and healthy controls (HCs). Materials and Methods: This prospective study enrolled 35 patients with PA, in addition to 35 age- and sex-matched patients with EH, and 35 age- and sex-matched HCs, all of whom underwent comprehensive clinical and cardiac MRI examinations. The analysis of variance was used to detect the differences in the characteristics of left ventricular remodeling among the three groups. Univariable and multivariable linear regression analyses were used to determine the relationships between left ventricular remodeling and the physiological variables. Results: The left ventricular end-diastolic volume index (EDVi) (mean ± standard deviation [SD]: 85.1 ± 13.0 mL/m² for PA, 75.9 ± 14.3 mL/m² for EH, and 77.3 ± 12.8 mL/m² for HC; p = 0.010), left ventricular end-systolic volume index (ESVi) (mean ± SD: 35.2 ± 9.8 mL/m² for PA, 30.7 ± 8.1 mL/m² for EH, and 29.5 ± 7.0 mL/m² for HC; p = 0.013), left ventricular mass index (mean ± SD: 65.8 ± 16.5 g/m² for PA, 56.9 ± 12.1 g/m² for EH, and 44.1 ± 8.9 g/m² for HC; p < 0.001), and native T1 (mean ± SD: 1224 ± 39 ms for PA, 1201 ± 47 ms for EH, and 1200 ± 44 ms for HC; p = 0.041) values were higher in the PA group compared to the EH and HC groups. Multivariable linear regression demonstrated that log (plasma aldosterone-to-renin ratio) was independently correlated with EDVi and ESVi. Plasma aldosterone was independently correlated with native T1. Conclusion: Patients with PA showed a greater degree of ventricular hypertrophy and enlargement, as well as myocardial fibrosis, compared to those with EH. Cardiac MRI T1 mapping can detect left ventricular myocardial fibrosis in patients with PA.

• 한국식품영양과학회지
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• 제43권3호
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• pp.341-348
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• 2014

본 연구에서는 두 품종의 원두커피와 이를 Monascus rubber 홍국균으로 발효시킨 원두커피 열수추출물의 체내 지질대사 개선 효과와 항비만 효과를 살펴보기 위하여 고지방 식이를 급여한 쥐에 커피추출물을 6주간 투여한 후 체중, 간 및 부고환 지방조직 무게, 혈액의 지질 농도 함량 등을 분석하였다. 실험 결과 HFD군에서는 고지방 식이로 인하여 체중이 유의하게 증가하였으나 커피추출물을 투여한 모든 실험군에서는 유의적으로 체중이 감소하였고 두 품종 중 에티오피아 모카 시다모 G2종을 홍국균으로 발효하였을 때 더 높은 체중 감소량을 보였다. 혈청 중성지방의 농도는 고지방 식이군이 정상 식이군에 비해 약 2배 정도 증가하였으나 커피추출물을 투여하였을 때 유의적으로 감소하였으며 부고환 지방 콜레스테롤 농도도 유의적으로 감소함을 보였다. LDL 콜레스테롤 저하효과 및 HDL 콜레스테롤 상승효과는 베트남 로부스타종에서만 관찰할 수 있었다. 본 실험결과 커피추출물이 고지방 식이를 급여한 쥐의 체중, 간 및 지방조직의 무게 감소와 더불어 혈장 및 간의 지질대사 개선에 긍정적으로 작용하는 유용한 체내 지질대사 개선 및 항비만 소재가 될 수 있을 것으로 사료된다. 또한 M. rubber 홍국균의 고체배양을 이용한 베트남산 로부스타 및 에티오피아 모카 시다모 G2 발효원두커피는 기능성 커피음료의 좋은 소재가 될 것으로 사료된다.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.360-362
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• 2002

Myocardial tagging technique such as spatial modulation of magnetization (SPAMM) allows the study of myocardial motion with high accuracy. Tagging contrast of such a tagging images can affect to the accuracy of the estimation of tag intersection in order to analyze the myocardial motion. Tagging contrast can be affected by tagline spacing. The aim of this study was to investigate the relationship between tagline spacing of SPAMM image and tagging contrast-to-noise ratio (CNR) experimentally. One healthy volunteer was undergone electrocardiographically triggered MR imaging with SPAMM-based tagging pulse sequence at a 1.5T MR scanner (Gyroscan Intera, Philips Medical System, Netherland). Horizontally modulated stripe patterns were imposed with a range from 3.6mm to 9.6mm of tagline spacing. Images of the left ventricle (LV) wall were acquired at the mid-ventricle level during cardiac cycle with FEEPI (TR/TE/FA=5.8/2.2/10). Tagging CNR for each image was calculated with a software which developed in our group. During contraction, tagging CNR was more rapidly decreased in case of short tagline spacing than in case of long tagline spacing. In the same heart phase, CNR was increased corresponding with tag line spacing. Especially, at the fully contracted heart phase, CNR was more rapidly increased than the other heart phases as a function of tagline spacing.

• Investigative Magnetic Resonance Imaging
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• 제5권1호
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• pp.38-42
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• 2001

2D TOF혈관조영술에서 presaturation RF펄스를 사용하여 정맥피에서 나오는 MR신호를 제거하고 얻은 동맥 angiogram에는 band형태로 동맥이 끊어져 나타나는 현상이 자주 보인다. 일부 동맥에서 피의 흐름은 한 심장 주기 동안에 3번의 펄스를 갖는데, 이 중 가운데 펄스는 짧은 기간 동안 역류를 한다. 이 역류하는 동맥피는 정맥피와 같은 방향이기 때문에 presaturation RF펄스에 의해 정맥피 처럼 saturation이 되어서 imaging slice로 흘러 들어가게 될 수 있다. 특히 이러한 경우가 phase encoding step의 dc 부근에서 발생하게 되면 그 때의 단면 영상에서 동맥이 강조가 될 수 없게 되어, 결과적으로 angiogram에는 그 단면을 지나는 동맥의 신호가 없어서 band 형태로 핏줄이 끊어져 나타나게 된다. Imaging slice와 saturation band와의 간격을 변화 시켜 가면서 angiogram을 얻어 봄으로서 이러한 현상을 실험적으로 확인하였다 나아가 saturation band를 rectangle형태에서 ramp 형태로 변경함으로써 이러한 artifacts를 제거 할 수 있는 방법을 제시하였다

• 대한의용생체공학회:의공학회지
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• 제28권3호
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• pp.338-343
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• 2007

BOLD T2*-weighted MR images reflects cortical blood flow and oxygenation alterations. fMRI study relies on the detection of localized changes in BOLD signal intensity. Since fMRI measures the very small modulations in BOLD signal intensity that occur during changes in brain activity, it is also very sensitive to small signal intensity variations caused by physiologic noise during the scan. Due to the complexity of movement of various organs associated with heart beat, it is important to reduce cardiac related noise rather than other physiological noise which could be required with relatively simple method. Therefore, a number of methods have been developed for the estimation and reduction of cardiac noise in fMRI study. But, each method has limitation. In this study, we proposed a new estimation method for brain activities influenced by blood pulsation effect using regression analysis with blood pulsation signal and the correspond slice of fMRI. We could find out that the right anterior cingulate cortex and right olfactory cortex and left olfactory cortex were largely influenced by blood pulsation effect for new method. These observed areas are mostly on the structure of anterior cerebral artery in the brain. That is convinced with that our method would be valid and our new method is easier to apply in practice and reduce computational burden than the retrospective method.

• Investigative Magnetic Resonance Imaging
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• 제16권2호
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• pp.189-194
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• 2012

40세 남성에서 상대정맥의 폐쇄와 우폐동맥 협착을 동반한 종격동 종괴가 발견되어 병리학적 소견에 경화성 종격동염으로 진단되었고, 6개월 후 심장 자기공명영상(MRI)에서 비허혈성 심근병증으로 의심된 심장림프종의 예를 보고하고자 한다. 심장 초음파에서 제한적 양상의 심장 생리현상을 보였고 구혈율이 매우 감소되어 있었다. MRI에서 전반적인 심근비대와 조영제 주입 후 광범위한 지연조영증강이 있어 비허혈성 심근병증이 의심되었으며 심장근육 생검 후 림프종으로 확진되었다. 조영제 주입후 MRI에서 심근 기저부는 침범되지 않았고 전반적인 심내막 보존이 있었으므로 아밀로이드증과 구별되는 양상이고 종괴를 형성하지 않았기 때문에 심장종양 보다는 심근병증에 더 유사한 영상 소견을 보인 특이한 증례로서 심장림프종의 자기공명영상에서의 특징을 문헌고찰과 함께 보고하고자 한다.

• 한국임상수의학회지
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• 제29권5호
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• pp.416-421
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• 2012

10살령의 4 kg 암컷 치와와가 심한 울혈성심부전의 수술적 치료를 위해서 내원하였다. 여러 가지 진단을 통해 이 환자는 심한 이첨판 폐쇄부전과 중등도의 삼천판 폐쇄부전이 확인되었다. 약물에 대한 치료적인 반응이 여의치 않아, 수술적으로 이첨판을 교정하는 치료방법으로 지시되었다. 체외순환을 이용한 심폐순환기하에서 이첨판교정술이 실시되었다. 하지만 이 환자는 교정 후에 마취에서 회복되지 못하고 사망하였다. 심장수술에 있어 실패를 유발하는 여러 가지 원인들에는 심폐순환기 운용, 저체온증, 장기부전, 출혈, 저혈압, 전해질과 산-염기 불균형, 그리고 감염 등이 있다. 비록 이 환자는 사망하였지만, 그 원인을 밝혀 내는 일은 수의학 분야에서 중요한 일이다. 이 증례의 사망원인을 고찰해 본 결과, 심한 저체온증에 의한 가스환기와 산소공급의 이상 그리고 심장수술과 관련한 저심박출량 증후군으로 인한 낮은 심박동수를 동반한 저혈압으로 사망한 것으로 생각되었다. 이 증례의 원인 규명을 위한 고찰은 이첨판성형술의 성공을 위해서는 좀더 세심한 주의가 요구됨을 알 수 있게 해주었고, 나아가 앞으로의 수술에서 성공률을 높일 수 있는 중요한 계기가 될 것이다.

• Korean Journal of Radiology
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• 제24권12호
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• pp.1221-1231
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• 2023

Objective: To clinically validate the feasibility and accuracy of cine images acquired through the multitasking method, with no electrocardiogram gating and free-breathing, in measuring left ventricular (LV) function indices by comparing them with those acquired through the balanced steady-state free precession (bSSFP) method, with multiple breath-holds and electrocardiogram gating. Materials and Methods: Forty-three healthy volunteers (female:male, 30:13; mean age, 23.1 ± 2.3 years) and 36 patients requiring an assessment of LV function for various clinical indications (female:male, 22:14; 57.8 ± 11.3 years) were enrolled in this prospective study. Each participant underwent cardiac magnetic resonance imaging (MRI) using the multiple breath-hold bSSFP method and free-breathing multitasking method. LV function parameters were measured for both MRI methods. Image quality was assessed through subjective image quality scores (1 to 5) and calculation of the contrast-to-noise ratio (CNR) between the myocardium and blood pool. Differences between the two MRI methods were analyzed using the Bland-Altman plot, paired t-test, or Wilcoxon signed-rank test, as appropriate. Results: LV ejection fraction (LVEF) was not significantly different between the two MRI methods (P = 0.222 in healthy volunteers and P = 0.343 in patients). LV end-diastolic mass was slightly overestimated with multitasking in both healthy volunteers (multitasking vs. bSSFP, 60.5 ± 10.7 g vs. 58.0 ± 10.4 g, respectively; P < 0.001) and patients (69.4 ± 18.1 g vs. 66.8 ± 18.0 g, respectively; P = 0.003). Acceptable and comparable image quality was achieved for both MRI methods (multitasking vs. bSSFP, 4.5 ± 0.7 vs. 4.6 ± 0.6, respectively; P = 0.203). The CNR between the myocardium and blood pool showed no significant differences between the two MRI methods (18.89 ± 6.65 vs. 18.19 ± 5.83, respectively; P = 0.480). Conclusion: Multitasking-derived cine images obtained without electrocardiogram gating and breath-holding achieved similar image quality and accurate quantification of LVEF in healthy volunteers and patients.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1989년도 춘계학술대회
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• pp.27-28
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• 1989

In conventional line scan angiography, flow signal has been enhanced by the time_of_flight effect while the signal from stationary tissues has been suppressed by the saturation rf pulse followed by spoiling gradients. Due to the inhomogeneous rf field and the tissue dependent T1 relaxation time, however, stationary tissues can not be suppressed completely or uniformly, and the remnant stationary signal deteriorates the resultant angiogram. Here, the complete cancellation of stationary tissues is made possible by the spectral analysis of a series of repetitive line images of the same slice. The Fourier transformation of a set of line images results in the spectrum images, where stationary tissues are collected into the dc component while arteries are included in harmonic components because of the variation of the flow velocity and the resultant flow signal in arteries according to the cardiac cycle. The summation of harmonic components excluding the dc component results in the angiogram of arteries with the complete cancellation of stationary tissues.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2003년도 제8차 학술대회 초록집
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• pp.103-105
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• 2003

After fifteen years of development, Magnetic Resonance (MR) technology for human imaging and spectroscopy is reaching a refined state with FDA approved 3T clinical products from Siemens, GE, and Philips. Broker has cleared CE approval with a 4T system. Varian supports a 4T system platform as well. Shielded magnets are standard at 3T from GE, Oxford, Magnex, and IGC. A shielded 4T whole body magnet is available from Oxford. Stronger switched gradients and dynamic shim coils, desired at any field, areespecially useful at higher static magnetic fields B0. In addition to the higher currents required for higher resolution slice or volume selection afforded by higher SNR, whole body gradient coils will be driven at increasing slew rates to meet the needs of new cardiac applications and other requirements. For example 3T and 4T systems are now being equipped with 2kV, 500A gradient coils and amplifiers capable of generating 4G/cm in 200msec, over a 67+/-cm bore diameter. High field EPI applications require oscillation rates at 1 kHz and higher. To achieve a benchmark 0.2 ppm shim over a 30cm sphere in a high field magnet, at least four stages of shimming need to be considered. 1) A good high field magnet will be built to a homogeneity spec. falling in the range of 100 to 150 ppm over this 30cm spherical "sweet spot" 2) Most modern high field magnets will also have superconducting shim coils capable of finding 1.5 ppm by their adjustment during system installation. 3) Passive ferro-magnetic shimming combined with 4) active, high order room temperature shim coils (as many as five orders are now being recommended) will accomplish 0.2 ppm over the 30cm sphere, and 0.1 ppm over a human brain in even the highest field magnets for human studies. Safety concerns for strong, fast gradients at any B0 field include acoustic noise and peripheral nerve stimulation. One or more of the mechanical decoupling methods may lead to quieter gradients. Patient positioning relative to asymmetric or short gradient coils may limit peripheral nerve stimulation at higher slew rates. Gradient designs combining a short coil for local speed and strength with a longer coil for coverage are being developed for 3T systems. Local gradients give another approach to maximizing performance over a limited region while keeping within the physiologically imposed dB0/dt performance limits.