• Journal of Magnetics
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• 제21권4호
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• pp.603-615
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• 2016

In this study, in order to determine the validity and accuracy of MR imaging of 3D gradient dual echo 2-point DIXON technique for measuring abdominal adipose tissue volume and distribution, the measurements obtained by CT were set as a reference for comparison and their correlations were evaluated. CT and MRI scans were performed on each subject (17 healthy male volunteers who were fully informed about this study) to measure abdominal adipose tissue volume. Two skilled investigators individually observed the images acquired by CT and MRI in an independent environment, and directly separated the total volume using region-based thresholding segmentation method, and based on this, the total adipose tissue volume, subcutaneous adipose tissue volume and visceral adipose tissue volume were respectively measured. The correlation of the adipose tissue volume measurements with respect to the observer was examined using the Spearman test and the inter-observer agreement was evaluated using the intra-class correlation test. The correlation of the adipose tissue volume measurements by CT and MRI imaging methods was examined by simple regression analysis. In addition, using the Bland-Altman plot, the degree of agreement between the two imaging methods was evaluated. All of the statistical analysis results showed highly statistically significant correlation (p<0.05) respectively from the results of each adipose tissue volume measurements. In conclusion, MR abdominal adipose volumetry using the technique of 3D gradient dual echo 2-point DIXON showed a very high level of concordance even when compared with the adipose tissue measuring method using CT as reference.

• Child Health Nursing Research
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• 제28권1호
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• pp.62-69
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• 2022

Purpose: This study explored the validity of a new type of thermometer and parent satisfaction with the new device. This 24-hour continuous monitoring smart wearable wireless thermometer (TempTraq^®) uses a very small semiconductor sensor with a thin patch-like shape. Methods: We obtained 397 sets of TempTraq^® axillary temperatures and tympanic temperatures from 44 pediatric patients. Agreement between the axillary and tympanic measurements, as well as the validity of the TempTraq^® axillary temperatures, were evaluated. Satisfaction surveys were completed by 41 caregivers after the measurements. Results: The TempTraq^® axillary temperatures demonstrated a strong positive correlation with the tympanic temperatures. The Bland-Altman plot and analysis of TempTraq^® axillary temperatures and tympanic temperatures showed that the mean difference was +0.45 ℃, the 95% limits of agreement were -0.57 to +1.46 ℃. Based on a tympanic temperature of 38 ℃, the results of validity of fever detection were sensitivity 0.85 and specificity 0.86. Satisfaction scores for TempTraq^® temperature measurement were all > 4 points (satisfactory). Conclusion: TempTraq^® smart axillary temperature measurement is an appropriate method for measuring children's temperatures since it was highly correlated to tympanic temperatures, had a reliable level of sensitivity and specificity, and could be used safely and conveniently.

• Korean Journal of Radiology
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• 제22권5호
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• pp.688-698
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• 2021

Objective: To compare the lumen parameters measured by the location-adaptive threshold method (LATM), in which the inter- and intra-scan attenuation variabilities of coronary computed tomographic angiography (CCTA) were corrected, and the scan-adaptive threshold method (SATM), in which only the inter-scan variability was corrected, with the reference standard measurement by intravascular ultrasonography (IVUS). Materials and Methods: The Hounsfield unit (HU) values of whole voxels and the centerline in each of the cross-sections of the 22 target coronary artery segments were obtained from 15 patients between March 2009 and June 2010, in addition to the corresponding voxel size. Lumen volume was calculated mathematically as the voxel volume multiplied by the number of voxels with HU within a given range, defined as the lumen for each method, and compared with the IVUS-derived reference standard. Subgroup analysis of the lumen area was performed to investigate the effect of lumen size on the studied methods. Bland-Altman plots were used to evaluate the agreement between the measurements. Results: Lumen volumes measured by SATM was significantly smaller than that measured by IVUS (mean difference, 14.6 mm³; 95% confidence interval [CI], 4.9-24.3 mm³); the lumen volumes measured by LATM and IVUS were not significantly different (mean difference, -0.7 mm³; 95% CI, -9.1-7.7 mm³). The lumen area measured by SATM was significantly smaller than that measured by LATM in the smaller lumen area group (mean of difference, 1.07 mm²; 95% CI, 0.89-1.25 mm²) but not in the larger lumen area group (mean of difference, -0.07 mm²; 95% CI, -0.22-0.08 mm²). In the smaller lumen group, the mean difference was lower in the Bland-Altman plot of IVUS and LATM (0.46 mm²; 95% CI, 0.27-0.65 mm²) than in that of IVUS and SATM (1.53 mm²; 95% CI, 1.27-1.79 mm²). Conclusion: SATM underestimated the lumen parameters for computed lumen segmentation in CCTA, and this may be overcome by using LATM.

• 한국방사선학회논문지
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• 제15권5호
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• pp.591-602
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• 2021

급성 허혈성 뇌졸중(Acute ischemic stroke; AIS) 환자는 증상발현 수 시간 이내 영상의학 검사를 통해 뇌경색(Infarction)을 조기 진단하여야 한다. 본 연구에서 SVD와 Bayesian 알고리즘을 이용한 뇌경색의 부피측정을 관류 전산화단층촬영(Computed tomography perfusion; CTP)과 확산 강조 자기공명영상(Magnetic resonance diffusion weighted image; MR DWI)을 비교하여 임상적 유용성을 알고자 하였다. 2017년 9월부터 2020년 9월까지 급성 허혈성 뇌졸중 증상으로 응급실을 내원한 환자 중 50명(남 : 여 = 33 : 17)의 영상의학 검사 정보를 후향적으로 이용하였다. SVD와 Bayesian 알고리즘으로 측정된 뇌경색 부피는 윌콕슨 부호순위검정(Wilcoxon signed rank test) 통계분석을 하여 중앙값(Median)과 사분위수(Iter quartile range; IQR) 25 - 75% 범위로 나타내었다. CTP 검사로 측정한 core volume(단위 : cc)은 SVD가 18.07 (7.76 - 33.98), Bayesian은 47.3 (23.76 - 79.11)으로 측정되었고 penumbra volume은 SVD가 140.24 (117.8 - 176.89), Bayesian은 105.05 (72.52 - 141.98)로 측정되었다. Mismatch ratio (%)는 SVD가 7.56 (4.36 - 15.26), Bayesian은 2.08 (1.68 - 2.77)로 측정되었으며 모든 측정값은 통계적으로 유의미한 차이가 있었다(p < 0.05). 스피어만 상관 분석(Spearman's correlation analysis) 결과는 CT Bayesian과 MR로 측정한 뇌경색 부피의 상관계수(r = 0.915)가 CT SVD와 MR의 상관계수(r = 0.763)보다 더욱 높은 양의 상관관계를 보였다(p < 0.01). 블랜드 알트만 산점도(Bland altman plot) 분석 결과는 CT Bayesian과 MR로 측정한 뇌경색 부피의 산점도 기울기(y = - 0.065)가 CT SVD와 MR의 산점도 기울기(y = - 0.749)보다 완만하게 측정되어 Bayesian이 더 높은 신뢰성을 나타내었다. 따라서 뇌경색 부피의 측정에서 Bayesian 알고리즘이 SVD보다 높은 정확도를 보였으므로 임상에서 유용하게 사용될 것으로 사료된다.

• Imaging Science in Dentistry
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• 제50권1호
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• pp.37-43
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• 2020

Purpose: The purpose of this study was to evaluate the accuracy of linear measurements in the horizontal and vertical dimensions based on object position and slice inclination in cone-beam computed tomography (CBCT) images. Materials and Methods: Ten dry sheep hemi-mandibles, each with 4 sites (incisor, canine, premolar, and molar), were evaluated when either centrally or peripherally positioned within the field of view (FOV) with the image slices subjected to either oblique or orthogonal inclinations. Four types of images were created of each region: central/cross-sectional, central/coronal, peripheral/cross-sectional, and peripheral/coronal. The horizontal and vertical dimensions were measured for each region of each image type. Direct measurements of each region were obtained using a digital caliper in both horizontal and vertical dimensions. CBCT and direct measurements were compared using the Bland-Altman plot method. P values <0.05 were considered to indicate statistical significance. Results: The buccolingual dimension of the incisor and premolar areas and the height of the incisor, canine, and molar areas showed statistically significant differences on the peripheral/coronal images compared to the direct measurements (P<0.05). Molar area height in the central/coronal slices also differed significantly from the direct measurements (P<0.05). Cross-sectional images of either the central or peripheral position had no marked difference from the gold-standard values, indicating sufficient accuracy. Conclusion: Peripheral object positioning within the FOV in combination with applying an orthogonal inclination to the slices resulted in significant inaccuracies in the horizontal and vertical measurements. The most undesirable effect was observed in the molar area and the vertical dimension.

• Journal of Korean Neurosurgical Society
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• 제53권2호
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• pp.102-107
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• 2013

Objective : The Leksell Gamma Knife$^{(R)}$ (LGK) is based on a single-fraction high dose treatment strategy. Therefore, independent verification of the Leksell GammaPlan$^{(R)}$ (LGP) is important for ensuring patient safety and minimizing the risk of treatment errors. Although several verification techniques have been previously developed and reported, no method has ever been tested statistically on multiple LGK target treatments. The purpose of this study was to perform and to evaluate the accuracy of a verification method (modified variable ellipsoid modeling technique, MVEMT) for multiple target treatments. Methods : A total of 500 locations in 10 consecutive patients with multiple brain tumor targets were included in this study. We compared the data from an LGP planning system and MVEMT in terms of dose at random points, maximal dose points, and target volumes. All data was analyzed by t-test and the Bland-Altman plot, which are statistical methods used to compare two different measurement techniques. Results : No statistical difference in dose at the 500 random points was observed between LGP and MVEMT. Differences in maximal dose ranged from -2.4% to 6.1%. An average distance of 1.6 mm between the maximal dose points was observed when comparing the two methods. Conclusion : Statistical analyses demonstrated that MVEMT was in excellent agreement with LGP when planning for radiosurgery involving multiple target treatments. MVEMT is a useful, independent tool for planning multiple target treatment that provides statistically identical data to that produced by LGP. Findings from the present study indicate that MVEMT can be used as a reference dose verification system for multiple tumors.

• 전기학회논문지P
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• 제59권1호
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• pp.58-63
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• 2010

In this paper, we proposed a wearable respiration measurement system with textile capacitive pressure sensor. Belt typed textile capacitive pressure sensor approach of respiration measurement, from which respiration signatures and rates can be derived in real-time for long-term monitoring, are presented. Belt typed textile capacitive pressure sensor has been developed for this measurement system. the distance change of two plates by the pressure of motion has been used for the respiration measurement in chest area. Respiration rates measured with the textile capacitive pressure sensor was compared with standard techniques on 8 human subjects. Accurate measurement of respiration rate with developed sensor system is shown. The data from the method comparison study is used to confirm theoretical estimates of change in capacitance by the distance change. The current version of respiratory rate detection system using textile capacitive pressure sensor can successfully measure respiration rate. It showed upper limit agreement of $3.7997{\times}10^{-7}$ RPM, and lower limit of agreement of $-3.8428{\times}10^{-7}$ RPM in Bland-Altman plot. From all subject, high correlation were shown(p<0.0001). The proposed measurement method could be used to monitor unconscious persons, avoiding the need to apply electrodes to the directly skin or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using textile capacitive pressure sensor offers a promising possibility of convenient measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range and quality of the rate-finding, broadening the potential application areas of this technology.

• Investigative Magnetic Resonance Imaging
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• 제24권2호
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• pp.76-84
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• 2020

Background: Determination of inter-method differences between clinically available volumetry methods are essential for the clinical application of brain volumetry in a wider context. Purpose: The purpose of this study was to examine the inter-method reliability and differences between the Siemens morphometry (SM) software and the NeuroQuant (NQ) software. Materials and Methods: MR images of 86 subjects with subjective or objective cognitive impairment were included in this retrospective study. For this study, 3D T1 volume images were obtained in all subjects using a 3T MR scanner (Skyra 3T, Siemens). Volumetric analysis of the 3D T1 volume images was performed using SM and NQ. To analyze the inter-method difference, correlation, and reliability, we used the paired t-test, Bland-Altman plot, Pearson's correlation coefficient, intraclass correlation coefficient (ICC), and effect size (ES) using the MedCalc and SPSS software. Results: SM and NQ showed excellent reliability for cortical gray matter, cerebral white matter, and cerebrospinal fluid; and good reliability for intracranial volume, whole brain volume, both thalami, and both hippocampi. In contrast, poor reliability was observed for both basal ganglia including the caudate nucleus, putamen, and pallidum. Paired comparison revealed that while the mean volume of the right hippocampus was not different between the two software, the mean difference in the left hippocampus volume between the two methods was 0.17 ml (P < 0.001). The other brain regions showed significant differences in terms of measured volumes between the two software. Conclusion: SM and NQ provided good-to-excellent reliability in evaluating most brain structures, except for the basal ganglia in patients with cognitive impairment. Researchers and clinicians should be aware of the potential differences in the measured volumes when using these two different software interchangeably.

• 한국전문물리치료학회지
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• 제17권4호
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• pp.49-54
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• 2010

The reliability of the thickness measurement of the lumbar multifidus (LMD using real-time ultrasonography (US) was determined in only the superficial fiber of the lumbar multifidus (SM). However, previous studies have not examined the reliability of the deep fiber of the LM (DM). The purpose of this study was to determine the intrarater and the interrater reliability of the thickness measurements of DM using US. Eleven heathy males participated in the study. The thickness of the DM was measured with an US in the prone position. Reliability was examined using intraclass correlation coefficients (ICC), standard error of the measurement (SEM), and the Bland and Altman plot. ICC(3,1) was used to calculate the interrater reliability of the thickness measurement of DM using the values from both the first and second test sessions. Additionally, ICC(3,1) was used to calculate the intrarater reliability of the measurements over two days using the measurements obtained in test session 1 and lest session 2. The results of this study were as follows: 1) the ICC(3,1) value for interrater reliability was .94 in the first test session, and .93 in the second test session. 2) the ICC(3,1) values for intrarater reliability of the measurements over two days was .90 in both the first examiner and the second examiner. The interrater reliability and interrater reliability of the DM measurements, obtained via the US protocol used in this research was excellent. Therefore, we conclude that the thickness measurement of the DM obtaioned from the US protocol used in this research would be useful for clinician assessment of the thickness of the DM.

• 대한지역사회영양학회지
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• 제19권6호
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• pp.568-580
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• 2014

Objectives: The purpose of this study was to measure the resting metabolic rate (RMR) and to assess the accuracy of RMR predictive equations for Korean farmers. Methods: Subjects were 161 healthy Korean farmers (50 males, 111 females) in Gangwon-area. The RMR was measured by indirect calorimetry for 20 minutes following a 12-hour overnight fasting. Selected predictive equations were Harris-Benedict, Mifflin, Liu, KDRI, Cunningham (1980, 1991), Owen-W, F, FAO/WHO/UNU-W, WH, Schofield-W, WH, Henry-W, WH. The accuracy of the equations was evaluated on the basis of bias, RMSPE, accurate prediction and Bland-Altman plot. Further, new RMR predictive equations for the subjects were developed by multiple regression analysis using the variables highly related to RMR. Results: The mean of the measured RMR was 1703 kcal/day in males and 1343 kcal/day in females. The Cunningham (1980) equation was the closest to measured RMR than others in males and in females (males Bias -0.47%, RMSPE 110 kcal/day, accurate prediction 80%, females Bias 1.4%, RMSPE 63 kcal/day, accurate prediction 81%). Body weight, BMI, circumferences of waist and hip, fat mass and FFM were significantly correlated with measured RMR. Thus, derived prediction equation as follow : males RMR = 447.5 + 17.4 Wt, females RMR = 684.5 - 3.5 Ht + 11.8 Wt + 12.4 FFM. Conclusions: This study showed that Cunningham (1980) equation was the most accurate to predict RMR of the subjects. Thus, Cunningham (1980) equation could be used to predict RMR of Korean farmers studied in this study. Future studies including larger subjects should be carried out to develop RMR predictive equations for Korean farmers.