1.Principle, Development, and Application of Electrical Conductivity Mapping Using Magnetic Resonance Imaging
Geon-Ho JAHNG ; Mun Bae LEE ; Oh In KWON
Progress in Medical Physics 2024;35(4):73-88
Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.
2.Principle, Development, and Application of Electrical Conductivity Mapping Using Magnetic Resonance Imaging
Geon-Ho JAHNG ; Mun Bae LEE ; Oh In KWON
Progress in Medical Physics 2024;35(4):73-88
Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.
3.Principle, Development, and Application of Electrical Conductivity Mapping Using Magnetic Resonance Imaging
Geon-Ho JAHNG ; Mun Bae LEE ; Oh In KWON
Progress in Medical Physics 2024;35(4):73-88
Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.
4.Principle, Development, and Application of Electrical Conductivity Mapping Using Magnetic Resonance Imaging
Geon-Ho JAHNG ; Mun Bae LEE ; Oh In KWON
Progress in Medical Physics 2024;35(4):73-88
Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.
5.Principle, Development, and Application of Electrical Conductivity Mapping Using Magnetic Resonance Imaging
Geon-Ho JAHNG ; Mun Bae LEE ; Oh In KWON
Progress in Medical Physics 2024;35(4):73-88
Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.
6.The Pattern of Care for Brain Metastasis from Breast Cancer over the Past 10 Years in Korea: A Multicenter Retrospective Study (KROG 16-12)
Jae Sik KIM ; Kyubo KIM ; Wonguen JUNG ; Kyung Hwan SHIN ; Seock-Ah IM ; Hee-Jun KIM ; Yong Bae KIM ; Jee Suk CHANG ; Jee Hyun KIM ; Doo Ho CHOI ; Yeon Hee PARK ; Dae Yong KIM ; Tae Hyun KIM ; Byung Ock CHOI ; Sea-Won LEE ; Suzy KIM ; Jeanny KWON ; Ki Mun KANG ; Woong-Ki CHUNG ; Kyung Su KIM ; Ji Ho NAM ; Won Sup YOON ; Jin Hee KIM ; Jihye CHA ; Yoon Kyeong OH ; In Ah KIM
Cancer Research and Treatment 2022;54(4):1121-1129
Purpose:
We aimed to investigate manifestations and patterns of care for patients with brain metastasis (BM) from breast cancer (BC) and compared their overall survival (OS) from 2005 through 2014 in Korea.
Materials and Methods:
We retrospectively reviewed 600 BC patients with BM diagnosed between 2005 and 2014. The median follow-up duration was 12.5 months. We categorized the patients into three groups according to the year when BM was initially diagnosed (group I [2005-2008], 98 patients; group II [2009-2011], 200 patients; and group III [2012-2014], 302 patients).
Results:
Over time, the median age at BM diagnosis increased by 2.2 years (group I, 49.0 years; group II, 48.3 years; and group III, 51.2 years; p=0.008). The percentage of patients with extracranial metastasis was 73.5%, 83.5%, and 86.4% for group I, II, and III, respectively (p=0.011). The time interval between BC and BM was prolonged in patients with stage III primary BC (median, 2.4 to 3 years; p=0.029). As an initial brain-directed treatment, whole-brain radiotherapy alone decreased from 80.0% in 2005 to 41.1% in 2014. Meanwhile, stereotactic radiosurgery or fractionated stereotactic radiotherapy alone increased from 13.3% to 34.7% during the same period (p=0.005). The median OS for group I, II, and III was 15.6, 17.9, and 15.0 months, respectively, with no statistical significance.
Conclusion
The manifestations of BM from BC and the pattern of care have changed from 2005 to 2014 in Korea. However, the OS has remained relatively unchanged over the 10 years.
7.Neurodevelopmental Outcomes of Very-Low-Birth-Weight Infants without Severe Brain Lesions and Impact of Postnatal Steroid Use: A Single-Center Korean Study
Mun Hui JEONG ; Seong Hee JEONG ; Su Jeong PARK ; Narae LEE ; Mi-Hye BAE ; Kyung-Hee PARK ; Shin-Yun BYUN ; Choongrak KIM ; Young Mi HAN
Neonatal Medicine 2022;29(1):36-45
Purpose:
We used the Bayley Scales of Infant and Toddler Development (BSID)-III to analyze the incidence and risk factors of developmental delay in very-low-birth-weight infants without severe brain lesions. We further examined the correlation between the cumulative dexamethasone dose and developmental assessment results.
Methods:
We retrospectively analyzed data of preterm infants (birth weight <1,500 g) admitted to our neonatal intensive care unit between January 2014 to December 2020. The BSID-III scores obtained between the corrected ages of 12 and 24 months and after 24 months were analyzed. Developmental delay was defined as a composite score of <85 for the cognition, language, and motor domains. Univariate and multivariate analyses of developmental delay risk factors and developmental changes from the first to second BSID-III were performed. Correlations between the accumulated dexamethasone dose used for bronchopulmonary dysplasia (BPD) and the first and second test scores were analyzed.
Results:
Seventy-one and thirty-six infants completed the first and second tests, respectively. In both tests, developmental delay was most commonly observed in the language domain (26.8%, 47.2%). In multivariate analysis, mild BPD was identified as a developmental delay risk factor (P<0.05), whereas prenatal steroid use reduced the developmental delay risk (P<0.05). All domain scores were lower in the second test than in the first test. The cognition and language domain scores in the second test decreased with increasing cumulative dexamethasone doses.
Conclusion
Very-low-birth-weight infants typically experience language delay, which can persist as they age.
8.Implementing the Golden Hour Protocol to Improve the Clinical Outcomes in Preterm Infants
Seong Hee JEONG ; Mun Hui JEONG ; Su Jeong PARK ; Narae LEE ; Mi Hye BAE ; Young Mi HAN ; Kyung Hee PARK ; Shin Yun BYUN
Neonatal Medicine 2022;29(1):10-17
Purpose:
Since premature infants are sensitive to the changes in blood glucose levels and body temperature, maintaining these parameters is important to avoid the risk of infections. The authors implemented the Golden Hour protocol (GHP) that aims to close the final incubator within one hour of birth by implementing early treatment steps for premature infants after birth, such as maintaining body temperature, securing airway, and rapidly administering glucose fluid and prophylactic antibiotics by securing breathing and rapid blood vessels. This study investigated the effect of GHP application on the short- and long-term clinical outcomes.
Methods:
We retrospectively analyzed the medical records between 2017 and 2018 before GHP application and between 2019 and 2020 after GHP application in preterm infants aged 24 weeks or older and those aged less than 33 weeks who were admitted to the neonatal intensive care unit.
Results:
Overall, 117 GHP patients and 81 patients without GHP were compared and analyzed. Peripheral vascularization time and prophylactic antibiotic administration time were shortened in the GHP-treated group (P=0.007 and P=0.008). In the short-term results, the GHP-treated group showed reduced hypothermia upon arrival at the neonatal intensive care unit (P=0.002), and the blood glucose level at 1 hour of hospitalization was higher (P=0.012). Furthermore, the incidence of neonatal necrotizing enteritis decreased (P=0.043). As a long-term result, the incidence of BPD was reduced (P=0.004).
Conclusion
We confirmed that applying GHP improved short- and long-term clinical outcomes in premature infants aged <33 weeks age of gestation, and we expect to improve the treatment quality by actively using it for postnatal treatment.
9.Perinatal Prognostic Factors for Congenital Diaphragmatic Hernia: A Korean Single-Center Study
Sungrok JEON ; Mun Hui JEONG ; Seong Hee JEONG ; Su Jeong PARK ; Narae LEE ; Mi-Hye BAE ; Kyung-Hee PARK ; Shin-Yun BYUN ; Soo-Hong KIM ; Yong-Hoon CHO ; Choongrak KIM ; Young Mi HAN
Neonatal Medicine 2022;29(2):76-83
Purpose:
This study aimed to identify prognostic factors based on treatment outcomes for congenital diaphragmatic hernia (CDH) at a single-center and to identify factors that may improve these outcomes.
Methods:
Thirty-five neonates diagnosed with CDH between January 2011 and December 2021 were retrospectively analyzed. Pre- and postnatal factors were correlated and analyzed with postnatal clinical outcomes to determine the prognostic factors. Highest oxygenation index (OI) within 24 hours of birth was also calculated. Treatment strategy and outcome analysis of published literatures were also performed.
Results:
Overall survival rate of this cohort was 60%. Four patients were unable to undergo anesthesia and/or surgery. Three patients who commenced extracorporeal membrane oxygenation (ECMO) post-surgery were non-survivors. Compared to the survivor group, the non-survivor group had a significantly higher occurrence of pneumothorax on the first day, need for high-frequency ventilator and inhaled nitric oxide use, and high OI within the first 24 hours. The non-survivor group showed an early trend towards the surgery timing and a greater number of patch closures. Area under the receiver operating characteristic curve was 0.878 with a sensitivity of 76.2% and specificity of 92.9% at an OI cutoff value of 7.75.
Conclusion
OI within 24 hours is a valuable predictor of survival. It is expected that the application of ECMO based on OI monitoring may help improve the opportunity for surgical repair, as well as the prognosis of CDH patients.
10.Long-term follow-up results of cytarabine-containing chemotherapy for acute promyelocytic leukemia
Young Hoon PARK ; Dae-Young KIM ; Yeung-Chul MUN ; Eun Kyung CHO ; Jae Hoon LEE ; Deog-Yeon JO ; Inho KIM ; Sung-Soo YOON ; Seon Yang PARK ; Byoungkook KIM ; Soo-Mee BANG ; Hawk KIM ; Young Joo MIN ; Jae Hoo PARK ; Jong Jin SEO ; Hyung Nam MOON ; Moon Hee LEE ; Chul Soo KIM ; Won Sik LEE ; So Young CHONG ; Doyeun OH ; Dae Young ZANG ; Kyung Hee LEE ; Myung Soo HYUN ; Heung Sik KIM ; Sung-Hyun KIM ; Hyukchan KWON ; Hyo Jin KIM ; Kyung Tae PARK ; Sung Hwa BAE ; Hun Mo RYOO ; Jung Hye CHOI ; Myung-Ju AHN ; Hwi-Joong YOON ; Sung-Hyun NAM ; Bong-Seog KIM ; Chu-Myong SEONG
The Korean Journal of Internal Medicine 2022;37(4):841-850
Background/Aims:
We evaluated the feasibility and long-term efficacy of the combination of cytarabine, idarubicin, and all-trans retinoic acid (ATRA) for treating patients with newly diagnosed acute promyelocytic leukemia (APL).
Methods:
We included 87 patients with newly diagnosed acute myeloid leukemia and a t(15;17) or promyelocytic leukemia/retinoic acid receptor alpha (PML-RARα) mutation. Patients received 12 mg/m2/day idarubicin intravenously for 3 days and 100 mg/m2/day cytarabine for 7 days, plus 45 mg/m2/day ATRA. Clinical outcomes included complete remission (CR), relapse-free survival (RFS), overall survival (OS), and the secondary malignancy incidence during a 20-year follow-up.
Results:
The CR, 10-year RFS, and 10-year OS rates were 89.7%, 94.1%, and 73.8%, respectively, for all patients. The 10-year OS rate was 100% for patients that achieved CR. Subjects were classified according to the white blood cell (WBC) count in peripheral blood at diagnosis (low-risk, WBC < 10,000/mm3; high-risk, WBC ≥ 10,000/mm3). The low-risk group had significantly higher RFS and OS rates than the high-risk group, but the outcomes were not superior to the current standard treatment (arsenic trioxide plus ATRA). Toxicities were similar to those observed with anthracycline plus ATRA, and higher than those observed with arsenic trioxide plus ATRA. The secondary malignancy incidence after APL treatment was 2.7%, among the 75 patients that achieved CR, and 5.0% among the 40 patients that survived more than 5 years after the APL diagnosis.
Conclusions
Adding cytarabine to anthracycline plus ATRA was not inferior to anthracycline plus ATRA alone, but it was not comparable to arsenic trioxide plus ATRA. The probability of secondary malignancy was low.

Result Analysis
Print
Save
E-mail