Pattern recognition analysis of dynamic susceptibility contrast (DSC)‐MRI curves automatically segments tissue areas with intact blood–brain barrier in a rat stroke model: A feasibility and comparison study

Jin, Seokha,Han, SoHyun,Stoyanova, Radka,Ackerstaff, Ellen,Cho, HyungJoon RADIOLOGICAL SOCIETY OF NORTH AMERICA INC 2020 JOURNAL OF MAGNETIC RESONANCE IMAGING Vol.51 No.5

<P><B>Background</B></P><P>The manual segmentation of intact blood–brain barrier (BBB) regions in the stroke brain is cumbersome, due to the coexistence of infarction, large blood vessels, ventricles, and intact BBB regions, specifically in areas with weak signal enhancement following contrast agent injection.</P><P><B>Hypothesis</B></P><P>That from dynamic susceptibility contrast (DSC)‐MRI alone, without user intervention, regions of weak BBB damage can be segmented based on the leakage‐related parameter <I>K</I><SUB><I>2</I></SUB> and the extent of intact BBB regions, needed to estimate <I>K</I><SUB><I>2</I></SUB> values, determined.</P><P><B>Study Type</B></P><P>Feasibility.</P><P><B>Animal Model</B></P><P>Ten female Sprague–Dawley rats (SD, 200–250g) underwent 1‐hour middle carotid artery occlusion (MCAO) and 1‐day reperfusion. Two SD rats underwent 1‐hour MCAO with 3‐day and 5‐day reperfusion.</P><P><B>Field Strength/Sequence</B></P><P>7T; ADC and T<SUB>1</SUB> maps using diffusion‐weighted echo planar imaging (EPI) and relaxation enhancement (RARE) with variable repetition time (TR), respectively. dynamic contrast‐enhanced (DCE)‐MRI using FLASH. DSC‐MRI using gradient‐echo EPI.</P><P><B>Assessment</B></P><P>Constrained nonnegative matrix factorization (cNMF) was applied to the dynamic ΔR2*‐curves of DSC‐MRI (<4 min) in a BBB‐disrupted rat model. Areas of voxels with intact BBB, classified by automated cNMF analyses, were then used in estimating <I>K</I><SUB><I>1</I></SUB> and <I>K</I><SUB><I>2</I></SUB> values, and compared with corresponding values from manually‐derived areas.</P><P><B>Statistical Tests</B></P><P>Mean ± standard deviation of ΔT<SUB>1</SUB>‐differences between ischemic and healthy areas were displayed with unpaired Student's <I>t</I>‐tests. Scatterplots were displayed with slopes and intercepts and Pearson's <I>r</I> values were evaluated between <I>K</I><SUB><I>2</I></SUB> maps obtained with automatic (cNMF)‐ and manually‐derived regions of interest (ROIs) of the intact BBB region.</P><P><B>Results</B></P><P>Mildly BBB‐damaged areas (indistinguishable from DCE‐MRI (10 min) parameters) were automatically segmented. Areas of voxels with intact BBB, classified by automated cNMF, matched closely the corresponding, manually‐derived areas when respective areas were used in estimating <I>K</I><SUB><I>2</I></SUB> maps (Pearson's <I>r</I> = 0.97, 12 slices).</P><P><B>Data Conclusion</B></P><P>Automatic segmentation of short DSC‐MRI data alone successfully identified areas with intact and compromised BBB in the stroke brain and compared favorably with manual segmentation.</P><P><B>Level of Evidence:</B> 3</P><P><B>Technical Efficacy:</B> Stage 1</P><P>J. Magn. Reson. Imaging 2020;51:1369–1381.</P>

차량용 시스템의 안개제거 영상처리를 위한 선예도기반 성능평가 방법

황석하(Seokha Hwang),김수환(Suhwan Kim),김지훈(Jihoon Kim),어진(Jin Eo),우동현(Donghyun Woo),정세환(Sehwan Jung),이영주(Youngjoo Lee) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.6

This paper presents a new comparison method of haze-removal algorithms for the next generation automotive. Compared to the previous PSNR-based comparison, which measures the similarity, the proposed MTF-based method checks the sharpness for selecting more suitable haze-removal algorithm for the following lane detection problem. Among the practical filtering schemes used for haze-removal algorithm, experimental results show that Gaussian filtering effectively preserves the sharpness of road images, enhancing the lane detection accuracy.

Ultrasonography for lumbar neuraxial block

Yoo Seokha,Kim Youngwon,Park Sun-Kyung,Ji Sang-Hwan,Kim Jin-Tae 대한마취통증의학회 2020 Anesthesia and pain medicine Vol.15 No.4

Ultrasonography can be useful to perform a lumbar neuraxial block. It aids in understanding the anatomy of the lumbar spine before the procedure. Pre-procedural ultrasound imaging provides information about the accurate intervertebral level for puncture, optimal needle insertion point, and depth of needle advancement for a successful neuraxial block. The key ultrasonographic views for lumbar neuraxial block include the transverse midline interlaminar and parasagittal oblique views. Ultrasonography can facilitate lumbar neuraxial block in difficult cases, such as the elderly, obese patients, and patients with anatomical abnormality of the lumbar spine. This review elucidates the basics of spinal ultrasonography for lumbar neuraxial block and the current evidence regarding ultrasound-guided neuraxial block in adults.

Effect of Sedatives on In-hospital and Long-term Mortality of Critically Ill Patients Requiring Extended Mechanical Ventilation for ≥ 48 Hours

Lee Hannah,Choi Seongmi,Jang Eun Jin,Lee Juhee,Kim Dalho,Yoo Seokha,Oh Seung-Young,Ryu Ho Geol 대한의학회 2021 Journal of Korean medical science Vol.36 No.34

Background: The purpose of this study was to assess the correlation between sedatives and mortality in critically ill patients who required mechanical ventilation (MV) for ≥ 48 hours from 2008 to 2016. Methods: We conducted a nationwide retrospective cohort study using population-based healthcare reimbursement claims database. Data from adult patients (aged ≥ 18) who underwent MV for ≥ 48 hours between 2008 and 2016 were identified and extracted from the National Health Insurance Service database. The benzodiazepine group consisted of patients who were administered benzodiazepines for sedation during MV. All other patients were assigned to the non-benzodiazepine group. Results: A total of 158,712 patients requiring MV for ≥ 48 hours were admitted in 55 centers in Korea from 2008 to 2016. The benzodiazepine group had significantly higher in-hospital and one-year mortality compared to the non-benzodiazepine group (37.0% vs. 34.3%, 55.0% vs. 54.4%, respectively). Benzodiazepine use decreased from 2008 to 2016, after adjusting for age, sex, and mean Elixhauser comorbidity index in the Poisson regression analysis (incidence rate ratio, 0.968; 95% confident interval, 0.954–0.983; P < 0.001). Benzodiazepine use, older age, lower case volume (≤ 500 cases/year), chronic kidney disease, and higher Elixhauser comorbidity index were common significant risk factors for in-hospital and oneyear mortality. Conclusion: In critically ill patients undergoing MV for ≥ 48 hour, the use of benzodiazepines for sedation, older age, and chronic kidney disease were associated with higher in-hospital mortality and one-year mortality. Further studies are needed to evaluate the impact of benzodiazepines on the mortality in elderly patients with chronic kidney disease requiring MV for ≥ 48 hours.

Retrospective analysis of the incidence and predictors of postoperative nausea and vomiting after orthopedic surgery under spinal anesthesia

Ju Jae-Woo,Kwon Jina,Yoo Seokha,Lee Ho-Jin 대한마취통증의학회 2023 Korean Journal of Anesthesiology Vol.76 No.2

Background: Postoperative nausea and vomiting (PONV) commonly occurs after spinal anesthesia; however, its incidence rate and predictors have been scarcely studied. Therefore, we aimed to investigate its incidence rate and potential predictors.Methods: The electronic medical records of 6,610 consecutive patients undergoing orthopedic surgery under spinal anesthesia were reviewed between January 2016 and December 2020. The primary outcome was PONV incidence within 24 h after spinal anesthesia. Along with its incidence rate, we investigated its predictors using multivariable logistic regression analysis.Results: Among the 5,691 patients included in the analysis, 1,298 (22.8%) experienced PONV within 24 h after spinal anesthesia. Female sex (odds ratio [OR]: 3.23, 95% CI [2.72, 3.83], P < 0.001), nonsmoker (OR: 2.12, 95% CI [1.46, 3.07], P < 0.001), history of PONV (OR: 1.52, 95% CI [1.26, 1.82], P < 0.001), prophylactic 5-hydroxytryptamine receptor antagonist use (OR: 0.35, 95% CI [0.24, 0.50], P < 0.001), prophylactic steroid use (OR: 0.53, 95% CI [0.44, 0.62], P < 0.001), baseline heart rate ≥ 60 beats/min (OR: 1.38, 95% CI [1.10, 1.72], P = 0.005), and postoperative opioid use (OR: 2.57, 95% CI [1.80, 3.67], P < 0.001), were significant predictors of the primary outcome.Conclusions: Our study showed the common incidence of PONV after spinal anesthesia and its significant predictors. A better understanding of its predictors may provide important information for its management.

Simulation of microvascular signal changes used on a gadolinium-chelated contrast agent at 3 T MRI in the presence of amyloid-beta plaques

Yoo Chang Hyun,Goh Junghwan,Jahng Geon-Ho,Jin Seokha,Lee DongKyu,Cho HyungJoon 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.81 No.11

It is important to understand microvascular alterations in the brain of Alzheimer disease (AD) patients which usually has amyloid-beta plaques in an imaging voxel, causing a phase dispersion in an MRI signal. The objective of this study was to simulate the changes of transverse relaxation rates and microvascular indexes with and without the presence of amyloid-beta plaques in an imaging voxel with using a clinically available contrast agent. The Monte Carlo simulations with the fnite perturber method were used to calculate microvascular indices of mean vessel diameter (mVD), vessel size index (VSI), mean vessel density (Q), blood volume fraction (BVf), and microvessel-weighted imaging (MvWI) with and without the presence of amyloid-beta plaques in an imaging voxel. The simulation was performed with the conditions of three diferent magnetic feld strengths (1.5 T, 3 T and 7 T), several diferent echo times for gradient-echo (15, 40, and 60 ms) and spin-echo (20, 80, and 100 ms) images, and two diferent contrast agents (gadolinium (Gd)-chelated and superparamagnetic iron oxide nanoparticles (SPION)-based contrast agents). The changes of relaxation rates and microvascular indexes were evaluated with increasing the microvascular vessel sizes and with increasing the amyloid plaque loads. In the microvascular structures without amyloid plaques, ΔR2* and ΔR2 increased as the B0 feld became stronger, the susceptibility diference of the contrast agent became larger, and the echo time was increased. Both mVD and VSI increased with increasing microvessel sizes, but Q decreased with increasing microvessel sizes. In the microvascular structures with amyloid plaques, ΔR2* and ΔR2 were not varied with increasing the vessel radius, but higher in the 3.81% concentration of amyloid plaque than 1.83% of that. BVf and MvWI were increased with increasing the plaque load. The BVf and MvWI indices were sensitive to evaluate the integrity of the microvascular in the AD brain since those values were increased with increasing the plaque load. Therefore, it is worthwhile to evaluate microvascular structure changes in the AD human brain using 3 T MRI with a Gd contrast agent.