• Proceedings of the KOSOMBE Conference
• /
• v.1997 no.05
• /
• pp.127-130
• /
• 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.

• Korean Journal of Radiology
• /
• v.24 no.10
• /
• pp.960-973
• /
• 2023

The bicuspid aortic valve (BAV) is the most common congenital cardiovascular malformation. Patients with BAV are at higher risk of other congenital cardiovascular malformations and valvular dysfunction, including aortic stenosis/regurgitation and infective endocarditis. BAV may also be related to aortic wall abnormalities such as aortic dilatation, aneurysm, and dissection. The morphology of the BAV varies with the presence and position of the raphe and is associated with the type of valvular dysfunction and aortopathy. Therefore, accurate diagnosis and effective treatment at an early stage are essential to prevent complications in patients with BAV. This pictorial essay highlights the characteristics of BAV and its related congenital cardiovascular malformations, valvular dysfunction, aortopathy, and other rare cardiac complications using multimodal imaging.

• Proceedings of the KOSOMBE Conference
• /
• v.1996 no.11
• /
• pp.314-316
• /
• 1996

To diagnose cardiac malfunctions, various imaging techniques have been applied to heart : DSA(Digital Subtracted Angiography), Doppler Ultrasound, MR Angio. But it is difficult to observe three dimensional heart motion which is the most intuitive tool for diagnosis, only by using these methods. In this research, we have suggested 4-Dimensional reconstruction scheme of heart motion images that can be acquired by ECG-gated cine MR imaging. One cardiac cycle was devided into $9\sim15$ phases and for each phase 3D reconstructed volumn heart was made. We can observe 3D volumns along the cardiac cycle, time. So the results were 4-D reconstructed data.

• Korean Journal of Radiology
• /
• v.22 no.11
• /
• pp.1764-1776
• /
• 2021

Objective: This study aimed to validate a deep learning-based fully automatic calcium scoring (coronary artery calcium [CAC]_auto) system using previously published cardiac computed tomography (CT) cohort data with the manually segmented coronary calcium scoring (CAC_hand) system as the reference standard. Materials and Methods: We developed the CAC_auto system using 100 co-registered, non-enhanced and contrast-enhanced CT scans. For the validation of the CAC_auto system, three previously published CT cohorts (n = 2985) were chosen to represent different clinical scenarios (i.e., 2647 asymptomatic, 220 symptomatic, 118 valve disease) and four CT models. The performance of the CAC_auto system in detecting coronary calcium was determined. The reliability of the system in measuring the Agatston score as compared with CAC_hand was also evaluated per vessel and per patient using intraclass correlation coefficients (ICCs) and Bland-Altman analysis. The agreement between CAC_auto and CAC_hand based on the cardiovascular risk stratification categories (Agatston score: 0, 1-10, 11-100, 101-400, > 400) was evaluated. Results: In 2985 patients, 6218 coronary calcium lesions were identified using CAC_hand. The per-lesion sensitivity and false-positive rate of the CAC_auto system in detecting coronary calcium were 93.3% (5800 of 6218) and 0.11 false-positive lesions per patient, respectively. The CAC_auto system, in measuring the Agatston score, yielded ICCs of 0.99 for all the vessels (left main 0.91, left anterior descending 0.99, left circumflex 0.96, right coronary 0.99). The limits of agreement between CAC_auto and CAC_hand were 1.6 ± 52.2. The linearly weighted kappa value for the Agatston score categorization was 0.94. The main causes of false-positive results were image noise (29.1%, 97/333 lesions), aortic wall calcification (25.5%, 85/333 lesions), and pericardial calcification (24.3%, 81/333 lesions). Conclusion: The atlas-based CAC_auto empowered by deep learning provided accurate calcium score measurement as compared with manual method and risk category classification, which could potentially streamline CAC imaging workflows.

• Investigative Magnetic Resonance Imaging
• /
• v.17 no.1
• /
• pp.33-40
• /
• 2013

Purpose : To evaluate late gadolinium enhancement (LGE) pattern of left ventricular (LV) myocardium and presence or absence of LGE in other regions of the heart on cardiac magnetic resonance (CMR) imaging in patients diagnosed with cardiac amyloidosis. Materials and Methods: From 2009 to 2011, 9 patients who were suspected cardiac amyloidosis underwent CMR. We retrospectively analyzed the presence or absence of LGE and enhancement pattern in LV myocardium, and the presence or absence of LGE in other chambers as well. Also we measured interatrial septal thickness (IST), relative signal intensities of atrial septum and epicardial fat over the left atrial (LA) cavity on delayed enhanced images. MRI parameters in these patients were compared to those of control group of patients with ischemic heart disease by Wilcoxon rank sum test. Results: Of nine patients, LGE were found in 8; subendocardial circumferential pattern in 4 and diffuse pattern in 4. LGE in right ventricle was observed in 7. IST was significantly increased in patients with cardiac amyloidosis (P = 0.02). Ratio of atrial septum to LA cavity and ratio of epicardial fat to LA cavity showed a significant difference (P = 0.0002 and P = 0.0006, respectively). Conclusion: In LGE CMR, subendocardial or diffuse enhancement pattern is a typical finding for patients with cardiac amyloidosis. Atrial septum and epicardial fat show relatively increased signal intensities over LA blood cavity.

• Nuclear Medicine and Molecular Imaging
• /
• v.43 no.3
• /
• pp.203-206
• /
• 2009

Nuclear cardiac imaging has been widely used to assess viable myocardium in patients with ischemic heart disease, The assessment of viable myocardium is important in selecting patients who will be benefit from revascularization. Although revascularization is indicated in patients with sufficient myocardium, patients with scar tissue should be treated medically. Nuclear imaging methods including myocardial perfusion SPECT and FDG PET have been shown to be effective modalities for identifying viable myocardium.

• Korean Journal of Radiology
• /
• v.20 no.1
• /
• pp.102-113
• /
• 2019

Objective: To assess the accuracy and potential bias of computed tomography (CT) ventricular volumetry using semiautomatic three-dimensional (3D) threshold-based segmentation in repaired tetralogy of Fallot, and to compare them to those of two-dimensional (2D) magnetic resonance imaging (MRI). Materials and Methods: This retrospective study evaluated 32 patients with repaired tetralogy of Fallot who had undergone both cardiac CT and MRI within 3 years. For ventricular volumetry, semiautomatic 3D threshold-based segmentation was used in CT, while a manual simplified contouring 2D method was used in MRI. The indexed ventricular volumes were compared between CT and MRI. The indexed ventricular stroke volumes were compared with the indexed arterial stroke volumes measured using phase-contrast MRI. The mean differences and degrees of agreement in the indexed ventricular and stroke volumes were evaluated using Bland-Altman analysis. Results: The indexed end-systolic (ES) volumes showed no significant difference between CT and MRI (p > 0.05), while the indexed end-diastolic (ED) volumes were significantly larger on CT than on MRI (93.6 ± 17.5 mL/m² vs. 87.3 ± 15.5 mL/m² for the left ventricle [p < 0.001] and 177.2 ± 39.5 mL/m² vs. 161.7 ± 33.1 mL/m² for the right ventricle [p < 0.001], respectively). The mean differences between CT and MRI were smaller for the indexed ES volumes (2.0-2.5 mL/m²) than for the indexed ED volumes (6.3-15.5 mL/m²). CT overestimated the stroke volumes by 14-16%. With phase-contrast MRI as a reference, CT (7.2-14.3 mL/m²) showed greater mean differences in the indexed stroke volumes than did MRI (0.8-3.3 mL/m²; p < 0.005). Conclusion: Compared to 2D MRI, CT ventricular volumetry using semiautomatic 3D threshold-based segmentation provides comparable ES volumes, but overestimates the ED and stroke volumes in patients with repaired tetralogy of Fallot.

• Korean Journal of Radiology
• /
• v.20 no.6
• /
• pp.1001-1002
• /
• 2019

• The Korean Journal of Nuclear Medicine
• /
• v.39 no.2
• /
• pp.69-74
• /
• 2005

Ever since it was first introduced as a method of scintigraphically measuring regional myocardial perfusion, myocardial perfusion study has been widely used in patients diagnosed or suspected with coronary artery diseases, and continuously improved upon. In addition to the technological enhancement of nuclear medicine equipments, the innovation of radiopharmaceuticals used in the cardiac exams were important contributors to such improvement. Besides the cardiac perfusion studies, new radiopharmaceuticals that visualize fat metabolism or receptors of the sympathetic nervous system have successfully been applied to clinical practice. More information can be collected before diagnosing coronary vascular disease, evaluating the patient's condition, or assessing therapeutic effects. In this review article, the clinical efficacy and characteristics of radiopharmaceutical products tailored for cardiac SPECT that are commonly used in Korea currently, plus the ones not being used yet but have proven value are briefly described.

• Journal of Cardiovascular Imaging
• /
• v.31 no.2
• /
• pp.83-84
• /
• 2023