• Proceedings of the KSMRM Conference
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• 2005.09a
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• pp.35-35
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• 2005

• Investigative Magnetic Resonance Imaging
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• v.24 no.3
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• pp.141-153
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• 2020

Purpose: Myocardial T1 and T2 relaxation times are affected by technical factors such as cardiovascular magnetic resonance platform/vendor. We aimed to validate T1 and T2 mapping sequences using a phantom; establish reference T1, T2, and extracellular volume (ECV) measurements using two sequences at 3T in normal Koreans; and compare the protocols and evaluate the differences from previously reported measurements. Materials and Methods: Eleven healthy subjects underwent cardiac magnetic resonance imaging (MRI) using 3T MRI equipment (Verio, Siemens, Erlangen, Germany). We did phantom validation before volunteer scanning: T1 mapping with modified look locker inversion recovery (MOLLI) with 5(3)3 and 4(1)3(1)2 sequences, and T2 mapping with gradient echo (GRE) and TrueFISP sequences. We did T1 and T2 mappings on the volunteers with the same sequences. ECV was also calculated with both sequences after gadolinium enhancement. Results: The phantom study showed no significant differences from the gold standard T1 and T2 values in either sequence. Pre-contrast T1 relaxation times of the 4(1)3(1)2 protocol was 1142.27 ± 36.64 ms and of the 5(3)3 was 1266.03 ± 32.86 ms on the volunteer study. T2 relaxation times of GRE were 40.09 ± 2.45 ms and T2 relaxation times of TrueFISP were 38.20 ± 1.64 ms in each. ECV calculation was 24.42% ± 2.41% and 26.11% ± 2.39% in the 4(1)3(1)2 and 5(3)3 protocols, respectively, and showed no differences at any segment or slice between the sequences. We also calculated ECV from the pre-enhancement T1 relaxation time of MOLLI 5(3)3 and the post-enhancement T1 relaxation time of MOLLI 4(1)3(1)2, with no significant differences between the combinations. Conclusion: Using phantom-validated sequences, we reported the normal myocardial T1, T2, and ECV reference values of healthy Koreans at 3T. There were no statistically significant differences between the sequences, although it has limited statistical value due to the small number of subjects studied. ECV showed no significant differences between calculations based on various pre- and post-mapping combinations.

• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.55-60
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• 2003

For quantitative analysis of the cardiac diseases. it is necessary to segment the left-ventricle (LY) in MR (Magnetic Resonance) cardiac images. Snake or active contour model has been used to segment LV boundary. However, the contour of the LV front these models may not converge to the desirable one because the contour may fall into local minimum value due to image artifact inside of the LY Therefore, in this paper, we Propose the Preprocessing method using k-means clustering and merging algorithms that can improve the performance of the active contour model. We verified that our proposed algorithm overcomes local minimum convergence problem by experiment results.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.238-241
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• 2017

Background: We investigated the difference in right ventricle (RV) volume and ejection fraction (EF) according to the pulmonary valve (PV) annular extension technique during Tetralogy of Fallot (TOF) total correction. Methods: We divided patients who underwent the procedure from 1993 to 2003 into two groups according to PV extension technique (group I: PV annular extension, group II: no PV annular extension) during TOF total correction. We then analyzed the three segmental (RV inlet, trabecular and outlet) and whole RV volume and EF by cardiac magnetic resonance imaging (MRI). Results: Fourteen patients were included in this study (group I: 10 patients, group II: four patients; male: nine patients, female: five patients). Cardiac MRI was conducted after a 16.1 years TOF total correction follow-up period. There was no statistical difference in RV segmental volume index or EF between groups (all p>0.05). Moreover, the total RV volume index and EF did not differ significantly between groups (all p>0.05). Conclusion: The RV volume and EF of the PV annular extension group did not differ from that of the PV annular extension group. Thus, PV annular preservation technique did not show the surgical advantage compared to PV annular extension technique in this study.

• Journal of Cardiovascular Imaging
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• v.30 no.3
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• pp.202-211
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• 2022

BACKGROUND: This study aims to investigate normal changes throughout aging of the heart in cardiac magnetic resonance (CMR) imaging in healthy volunteers. While type 2 diabetes mellitus is a frequent finding in the elderly population, also the influence of this circumstance in otherwise healthy persons is part of our study. METHODS: In this prospective single-center trial, 75 healthy subjects in distinct age groups and 10 otherwise healthy diabetics were enrolled. All subjects underwent functional, flow sensitive, native T2- and T1-mapping in a 1.5T CMR scanner. RESULTS: No differences in right and left ventricular ejection fractions were observed between aging healthy groups. Bi-ventricular volumes lowered significantly (p<0.001) between the age groups. There was also a significant decrease in myocardial T1 values, aortic distensibility, and left ventricular peak diastolic strain rates. There were no differences in T2 mapping and the other deformation parameters. Patients with type 2 diabetes mellitus had lower end-diastolic volume indexes; all the other measurements were comparable. CONCLUSIONS: Aging processes in the healthy heart involve a decrease in ventricular volumes, with ejection fractions remaining normal. Stiffening of the myocardium and aorta and a decrease in T1 values are potential indications of age-related remodeling. Type 2 diabetes mellitus seems to have no major influence on aging processes of the heart.

• Investigative Magnetic Resonance Imaging
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• v.21 no.1
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• pp.20-27
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• 2017

Purpose: To evaluate quantification results of single breath-hold (SBH) magnetic resonance (MR) cine imaging compared to results of conventional multiple breath-hold (MBH) technique for left ventricular (LV) function in patients with cardiac arrhythmia. Materials and Methods: MR images of patients with arrhythmia who underwent MBH and SBH cine imaging at the same time on a 1.5T MR scanner were retrospectively reviewed. Both SBH and MBH cine imaging were performed with balanced steady state free precession. SBH scans were acquired using temporal parallel acquisition technique (TPAT). Fifty patients ($65.4{\pm}12.3years$, 72% men) were included. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), myocardial mass, and LV regional wall motion were evaluated. Results: EF, myocardial mass, and regional wall motion were not significantly different between SBH and MBH acquisition techniques (all P-values > 0.05). EDV, ESV, and SV were significant difference between the two techniques. These parameters for SBH cine imaging with TPAT tended to lower than those in MBH. EF and myocardial mass of SBH cine imaging with TPAT showed good correlation with values of MBH cine imaging in Passing-Bablok regression charts and Bland-Altman plots. However, SBH imaging required significantly shorter acquisition time than MBH cine imaging ($15{\pm}7sec$ vs. $293{\pm}104sec$, P < 0.001). Conclusion: SBH cine imaging with TPAT permits shorter acquisition time with assessment results of global and regional LV function comparable to those with MBH cine imaging in patients with arrhythmia.

• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.296-315
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• 2019

Cardiac magnetic resonance (CMR) imaging is widely used in many areas of cardiovascular disease assessment. This is a practical, standard CMR protocol for beginners that is designed to be easy to follow and implement. This protocol guideline is based on previously reported CMR guidelines and includes sequence terminology used by vendors, essential MR physics, imaging planes, field strength considerations, MRI-conditional devices, drugs for stress tests, various CMR modules, and disease/symptom-based protocols based on a survey of cardiologists and various appropriate-use criteria. It will be of considerable help in planning and implementing tests. In addressing CMR usage and creating this protocol guideline, we particularly tried to include useful tips to overcome various practical issues and improve CMR imaging. We hope that this document will continue to standardize and simplify a patient-based approach to clinical CMR and contribute to the promotion of public health.

• Journal of Cardiovascular Imaging
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• v.31 no.1
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• pp.26-38
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• 2023

BACKGROUND: Dobutamine and adenosine stress cardiac magnetic resonance (CMR) imaging is relatively contraindicated in patients with moderate to severe aortic valve stenosis (AS). We aimed to determine the safety of dobutamine and adenosine stress CMR in patients with moderate to severe AS. METHODS: In this retrospective study patients with AS who underwent either dobutamine or adenosine stress CMR for exclusion of obstructive coronary artery disease were enrolled. We recorded clinical data, CMR and echocardiography findings, and complications as well as minor symptoms. Patients with AS were compared to matched individuals without AS. RESULTS: A total of 187 patients with AS were identified and compared to age-, gender- and body mass index-matched 187 patients without AS. No severe complications were reported in the study nor the control group. The reported frequency of non-severe complications and minor symptoms were similar between the study and the control groups. Nineteen patients with AS experienced non-severe complications or minor symptoms during dobutamine stress CMR compared to eighteen patients without AS (p = 0.855). One patient with AS and two patients without AS undergoing adenosine stress CMR experienced minor symptoms (p = 0.562). Four examinations were aborted because of chest pain, paroxysmal atrial fibrillation and third-degree atrioventricular block. Inducible ischaemia, prior coronary artery bypass grafting, prior stroke and age were associated with a higher incidence of complications and minor symptoms. CONCLUSIONS: Moderate to severe AS was not associated with complications during CMR stress test. The incidence of non-severe complications and minor symptoms was greater with dobutamine.

• Journal of Chest Surgery
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• v.57 no.4
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• pp.360-368
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• 2024

Background: The left pulmonary artery (LPA) may be kinked and stenotic, especially in tetralogy of Fallot, because of ductal tissue and anterior deviation of the conal septum. If LPA stenosis is not effectively treated during total correction, surgical angioplasty is occasionally performed. However, whether pulmonary artery (PA) angioplasty in adolescents or adults improves perfusion in the ipsilateral lung remains unclear. Methods: This retrospective review enrolled patients who underwent PA angioplasty for LPA stenosis between 2004 and 2019. Among patients who underwent a lung perfusion scan (LPS) or cardiac magnetic resonance imaging (cMRI) pre- and post-pulmonary angioplasty, those aged >13 years with <40% left lung perfusion (p-left) in the pre-angioplasty study were included. Preoperative and postoperative computed tomography, LPS, and cMRI data were collected. The perfusion ratio was analyzed according to the LPA's anatomical characteristics. Results: Seventeen adolescents and 16 adults (≥18 years old) were finally included (median age, 17 years). The most common primary diagnosis was tetralogy of Fallot (87.9%). In all patients, LPA angioplasty was performed concomitantly with right ventricular outflow tract reconstruction. No patients died. Preoperative p-left was not significantly different between adolescents and adults; however, adolescents had significantly higher postoperative p-left than adults. P-left significantly increased in adolescents, but not in adults. Seven patients had significant stenosis (z-score <-2.0) confined only to the proximal LPA and demonstrated significantly increased p-left. Conclusion: PA angioplasty significantly increased ipsilateral lung perfusion in adolescents. If focal stenosis is confined to the proximal LPA, PA angioplasty may improve ipsilateral lung perfusion, regardless of age.

• Journal of Neurocritical Care
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• v.11 no.2
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• pp.143-147
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• 2018

Background: Hypoglycemia is uncommon in people without diabetes. There have been only a few reports of cardiac arrest in conjunction with hypoglycemia in non-diabetic patients. Case Report: A 66-year-old man visited the emergency room with dizziness. He was a chronic alcoholic. Laboratory test showed no evidence of diabetes mellitus. Brain magnetic resonance imaging revealed a left cerebellar infarction. Abdomen computed tomography demonstrated liver cirrhosis with minimal ascites. During his hospital stay, he consumed only a small amount of food because of nausea and headache. On hospital day 4, he had a cardiac arrest after two seizure episodes. His blood glucose was 10 mg/dL. The combination of liver cirrhosis, renal failure and poor oral intake was presumed to be the causes of the severe hypoglycemia. Conclusion: We report a rare case of cardiac arrest occurring in conjunction with severe hypoglycemia in a non-diabetic patient with cerebral infarction.