• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.461-463
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• 2002

Image quality and selection of optimized window for good quality reconstruction in coronary angiography using multi-detector row CT (MDCT) have not been studied by heart rate and its variation. Therefore, the effect of heart rate and its variation was systemically analyzed. Eighty-three patients were undergone contrast-enhanced coronary angiography using MDCT. In this study, sixty cases were enrolled. Two radiologists graded image quality as follows: 4, excellent; 3, good; 2, fair; l, bad. The starting points of the reconstruction window were chosen at seventy and forty percent of R wave interval. Optimized window was scored as 1 when 40% reconstruction was better quality than 70%, as 2 when 40% reconstruction is same as 70%, and as 3 when 70% reconstruction was better than 40%. Regression analysis was performed. The range of variation of beats per minute (BPM) was well correlated with image quality (r=-0.55, p=0.000), however correlation with optimized window percentage was not statistically significant (p=0.969). By contraries, median value of BPM was comparatively well correlated with optimized window grade (r=-0.24, p=0.086). Median value of BPM was not well correlated with image quality (r=0.l70, p=0.l97). Image quality is more affected by variation of heart rate (VHR) than by higher heart rate. Selection of optimized reconstruction window for good image quality is mainly affected by heart rate and there is a tendency that systolic phase reconstruction is better in image quality than diastolic reconstruction in higher heart rate.

• Korean Journal of Radiology
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• 제22권1호
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• pp.97-105
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• 2021

Objective: The present study aimed to investigate the association between myocardial blood flow (MBF) quantified by dynamic CT myocardial perfusion imaging (CT-MPI) and the increments in heart rate (HR) after stress in patients without obstructive coronary artery disease. Materials and Methods: We retrospectively included 204 subjects who underwent both dynamic CT-MPI and coronary CT angiography (CCTA). Patients with more than minimal coronary stenosis (diameter ≥ 25%), history of myocardial infarction/revascularization, cardiomyopathy, and microvascular dysfunction were excluded. Global MBF at stress was measured using hybrid deconvolution and maximum slope model. Furthermore, the HR increments after stress were recorded. Results: The median radiation dose of dynamic CT-MPI plus CCTA was 5.5 (4.5-6.8) mSv. The median global MBF of all subjects was 156.4 (139.8-180.4) mL/100 mL/min. In subjects with HR increment between 10 to 19 beats per minute (bpm), the global MBF was significantly lower than that of subjects with increment between 20 to 29 bpm (153.3 mL/100 mL/min vs. 171.3 mL/100 mL/min, p = 0.027). This difference became insignificant when the HR increment further increased to ≥ 30 bpm. Conclusion: The global MBF value was associated with the extent of increase in HR after stress. Significantly higher global MBF was seen in subjects with HR increment of ≥ 20 bpm.

• Korean Journal of Radiology
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• 제25권6호
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• pp.518-539
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• 2024

Coronary computed tomography angiography (CCTA) has emerged as a pivotal tool for diagnosing and risk-stratifying patients with suspected coronary artery disease (CAD). Recent advancements in image analysis and artificial intelligence (AI) techniques have enabled the comprehensive quantitative analysis of coronary atherosclerosis. Fully quantitative assessments of coronary stenosis and lumen attenuation have improved the accuracy of assessing stenosis severity and predicting hemodynamically significant lesions. In addition to stenosis evaluation, quantitative plaque analysis plays a crucial role in predicting and monitoring CAD progression. Studies have demonstrated that the quantitative assessment of plaque subtypes based on CT attenuation provides a nuanced understanding of plaque characteristics and their association with cardiovascular events. Quantitative analysis of serial CCTA scans offers a unique perspective on the impact of medical therapies on plaque modification. However, challenges such as time-intensive analyses and variability in software platforms still need to be addressed for broader clinical implementation. The paradigm of CCTA has shifted towards comprehensive quantitative plaque analysis facilitated by technological advancements. As these methods continue to evolve, their integration into routine clinical practice has the potential to enhance risk assessment and guide individualized patient management. This article reviews the evolving landscape of quantitative plaque analysis in CCTA and explores its applications and limitations.

• 대한방사선기술학회지:방사선기술과학
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• 제34권4호
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• pp.315-321
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• 2011

본 연구는 검사 기법에 따른 영상의 질과 방사선 피폭의 정도를 제시하여 검사자가 받는 방사선 피폭을 저감시키는 데 목적이 있다. 관상동맥 전산화 단층 혈관조영(Coronary CTA, coronary computed tomography angiography) 검사자를 대상으로 SnapShot Pulse의 전향적 동조화 기법과 SnapShot Segment의 후향적 동조화 기법으로 coronary CTA 검사에서 검사자가 받는 단면 피폭선량(CTDIvol, volume computed tomography dose index), 총 피폭선량(dose-length product; DLP)을 각각 측정하였다. 또한, Coronary CTA 촬영조건을 동일하게 팬텀을 이용하여 CT감약계수, 노이즈 및 균일도, 공간분해능을 측정하였다. 연구 결과 두기법에서 CT감약계수, 노이즈 및 균일도, 공간분해능의 질적 수준이 비슷하게 나타났으며, CTDIvol, DLP는 SnapShot Segment의 후향적 동조화 기법에 비해 피폭선량이 약 37.5%, 40.3% 감소되었다. 임상에서 coronary CTA 검사 시 SnapShot Pulse의 전향적 동조화 기법을 적극 채택하여 검사자가 받는 방사선 피폭을 감소시키기 위한 노력이 절실히 요구된다.

• Korean Journal of Radiology
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• 제20권5호
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• pp.729-738
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• 2019

Objective: To assess the effects of iterative model reconstruction (IMR) on image quality for demonstrating non-calcific high-risk plaque characteristics of coronary arteries. Materials and Methods: This study included 66 patients (53 men and 13 women; aged 39-76 years; mean age, 55 ± 13 years) having single-vessel disease with predominantly non-calcified plaques evaluated using prospective electrocardiogram-gated 256-slice CT angiography. Paired image sets were created using two types of reconstruction: hybrid iterative reconstruction (HIR) and IMR. Plaque characteristics were compared using the two algorithms. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the images and the CNR between the plaque and adjacent adipose tissue were also compared between the two reformatted methods. Results: Seventy-seven predominantly non-calcified plaques were detected. Forty plaques showed napkin-ring sign with the IMR reformatted method, while nineteen plaques demonstrated napkin-ring sign with HIR. There was no statistically significant difference in the presentation of positive remodeling, low attenuation plaque, and spotty calcification between the HIR and IMR reconstructed methods (all p > 0.5); however, there was a statistically significant difference in the ability to discern the napkin-ring sign between the two algorithms (χ² = 12.12, p < 0.001). The image noise of IMR was lower than that of HIR (10 ± 2 HU versus 12 ± 2 HU; p < 0.01), and the SNR and CNR of the images and the CNR between plaques and surrounding adipose tissues on IMR were better than those on HIR (p < 0.01). Conclusion: IMR can significantly improve image quality compared with HIR for the demonstration of coronary artery and atherosclerotic plaques using a 256-slice CT.

• Korean Circulation Journal
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• 제52권7호
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• pp.558-559
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• 2022

• Nuclear Medicine and Molecular Imaging
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• 제43권3호
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• pp.222-228
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• 2009

Risk stratification and assessment of prognosis in patients with known or suspected CAD is of crucial important for the practice of contemporary medicine. Noninvasive testing such as myocardial perfusion scintigraphy, coronary artery calcium scoring or CT coronary angiography is increasingly being used to determine the need for aggressive medical therapy and to select patients for catheterization. The integrated anatomic and functional information may provide more additional information for the cardiologist or other clinician by the improved risk stratification and diagnostic accuracy of integrated techniques. The development of SPECT/CT or PET/CT hybrid systems is therefore of important value for the nuclear cardiology.

• Korean Journal of Radiology
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• 제21권12호
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• pp.1305-1316
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• 2020

In approximately 10% of patients with acute myocardial infarction (MI), angiography does not reveal an obstructive coronary stenosis. This is known as myocardial infarction with non-obstructive coronary arteries (MINOCA), which has complex and multifactorial causes. However, this term can be confusing and open to dual interpretation, because MINOCA is also used to describe patients with acute myocardial injury caused by ischemia-related myocardial necrosis. Therefore, with regards to this specific context of MINOCA, the generic term for MINOCA should be replaced with troponin-positive with non-obstructive coronary arteries (TpNOCA). The causes of TpNOCA can be subcategorized into epicardial coronary (causes of MINOCA), myocardial, and extracardiac disorders. Cardiac magnetic resonance imaging can confirm MI and differentiate various myocardial causes, while cardiac computed tomography is useful to diagnose the extracardiac causes.

• 한국컴퓨터그래픽스학회논문지
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• 제23권1호
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• pp.49-55
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• 2017

심장 CT 혈관 조영 영상은 심혈관의 전체 해부학 구조를 3D 로 보여줄 뿐 아니라 병변의 정보를 제공하기 때문에 관상동맥 질환 진단 및 치료에 많이 사용되고 있다. 하지만 영상의 방대한 크기로 인해 수동으로 정보를 추출하는 데는 한계가 있어 자동으로 심혈관을 정확하게 추출하는 연구들이 활발히 진행되고 있다. 심혈관 자동 추출 알고리즘을 개발하는데 있어 심혈관의 시작점인 상행대동맥의 심문을 검출하는 방법은 필수적인 부분이다. 본 논문에서는 심혈관의 시작점인 심문을 분할하는 방법을 제안한다. 첫째, 상행대동맥의 크기와 위치를 고려한 허프변환으로 대동맥 초기영역을 검출한다. 둘째, 초기영역을 기반으로 탐색범위를 줄일 수 있도록 관심 볼륨 영역을 설정한다. 셋째, 지오데식 활성외곽선 모델을 기반으로 정제된 대동맥 영역을 검출한다. 마지막으로 검출된 대동맥 영역에서 심문을 분할한다. 제안방법의 평가를 위해 20 개의 심장 CT 혈관 조영 영상에서 전문가가 수동으로 표기한 시작점과 비교 분석하였다. 실험 결과 제안방법을 통해 시작점이 제대로 추출 됨을 확인할 수 있었다.

• Anatomy and Cell Biology
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• 제56권1호
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• pp.155-159
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• 2023

Studies describing the vascular systems and their variations in Situs inversus totalis (SIT) from a whole-body computed tomographic (CT) angiography perspective are lacking. We report a case of SIT in which postmortem CT angiography (PMCTA) was performed as a part of the forensic death investigation and incidentally detected several vascular variations in it. The PMCTA procedure was performed using the multiphase PMCTA protocol. Almost all major vessels were visualized, indeed in a completely reversed pattern. Contrast mixture flow interruptions were noted in the right coronary arterial branches suggesting possible blockage, upon which autopsy revealed >90% vessel occlusions at several locations. As such the cause of death was due to ischemic heart disease. Anomalous origins of the right internal mammary artery; abnormal left thyrocervical trunk and variations in the drainage of testicular veins were noted. Our findings might be helpful to clinicians and add to the body of literature on SIT.