• Korean Journal of Radiology
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• v.25 no.7
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• pp.673-683
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• 2024

Objective: To evaluate the role of visual and quantitative chest CT parameters in assessing treatment response in patients with severe asthma. Materials and Methods: Korean participants enrolled in a prospective multicenter study, named the Precision Medicine Intervention in Severe Asthma study, from May 2020 to August 2021, underwent baseline and follow-up chest CT scans (inspiration/expiration) 10-12 months apart, before and after biologic treatment. Two radiologists scored bronchiectasis severity and mucus plugging extent. Quantitative parameters were obtained from each CT scan as follows: normal lung area (normal), air trapping without emphysema (AT without emph), air trapping with emphysema (AT with emph), and airway (total branch count, Pi10). Clinical parameters, including pulmonary function tests (forced expiratory volume in 1 s [FEV1] and FEV1/forced vital capacity [FVC]), sputum and blood eosinophil count, were assessed at initial and follow-up stages. Changes in CT parameters were correlated with changes in clinical parameters using Pearson or Spearman correlation. Results: Thirty-four participants (female:male, 20:14; median age, 50.5 years) diagnosed with severe asthma from three centers were included. Changes in the bronchiectasis and mucus plugging extent scores were negatively correlated with changes in FEV1 and FEV1/FVC (ρ = from -0.544 to -0.368, all P < 0.05). Changes in quantitative CT parameters were correlated with changes in FEV1 (normal, r = 0.373 [P = 0.030], AT without emph, r = -0.351 [P = 0.042]), FEV1/FVC (normal, r = 0.390 [P = 0.022], AT without emph, r = -0.370 [P = 0.031]). Changes in total branch count were positively correlated with changes in FEV1 (r = 0.349 [P = 0.043]). There was no correlation between changes in Pi10 and the clinical parameters (P > 0.05). Conclusion: Visual and quantitative CT parameters of normal, AT without emph, and total branch count may be effective for evaluating treatment response in patients with severe asthma.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.592-600
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• 2016

AAPM CT performance for special medical equipment quality control checks using a standard phantom for evaluation, using the evaluator's subjective assessment as to minimize errors due computerized assessment program to evaluate their usefulness. Phantom for evaluation AAPM CT Performance Phantom: was used, the default shooting conditions are the same as quality control checks. And, we use IMAGE J to evaluate the program. Quantitative evaluation with CT attenuation coefficient and the noise measurement, the uniformity measurement, the slice thickness measurement, contrast resolution of the measurement, a phantom image of the spatial resolution determined by the evaluation program is evaluated as self-extracting the result after processing the image, CT uniformity measurement for the evaluation that was smaller and the standard deviation of a video image processing more uniform slice thickness measurements it is difficult to evaluate due to the difference of the ratio of the measured value of the phantom image. Contrast resolution was measured cylindrical diameter 6th evaluate the shape of a circle obtained a mean value and a standard deviation of diameters, the spatial resolution of the group of source, including acceptance criteria automatically extracted result as a result of both the number of the extracted circularIt appeared. Evaluate the source image and video processing, and video to qualitative evaluation by gross were processed video image is shown excellent results. If the evaluators in order to minimize the errors of subjective judgment based on the results of the above should be done with a quantitative evaluation and qualitative evaluation utilizes a computerized assessment program is considered that further evaluation be made more efficient.

• Journal of Veterinary Clinics
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• v.31 no.5
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• pp.376-381
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• 2014

In this study, we analyzed the computed tomography (CT) measurements of lung volume and density in dogs with relation to body weight, age, sex, and breed. The multi-detector CT examination of the thorax was performed on dogs without respiratory or cardiovascular diseases. Three-dimensional reconstruction of CT images facilitated measurement of lung volume and density. There was a statistical significant correlation between body weight and lung volume (p < 0.0001). Lung density significantly decreased with an increase in body weight (p = 0.0078). However, no correlation was seen between these lung parameters and either sex or age of the dogs. In conclusion, this study shows that body weight is an important factor to consider when interpreting total lung volume and density values measured by quantitative CT. We highlight the need for further study using quantitative CT in identifying the potential effects of sex, age, and disease status on these parameters.

• Investigative Magnetic Resonance Imaging
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• v.25 no.2
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• pp.109-117
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• 2021

Purpose: To investigate the reliability of CT and MRI for quantitative and qualitative analyses of lumbar paraspinal muscle fatty infiltration (PSFI) and correlation of PSFI with intervertebral disc pathology. Materials and Methods: Lumbar spine CT and MRI of 36 subjects were reviewed retrospectively. Two observers independently outlined lumbar paraspinal muscles at each mid-intervertebral disc level. Paraspinal muscles on CT and MRI were graded according to the Goutallier grading system (GGS). The area, mean value, and standard deviation (SD) of the Hounsfield unit (HU) were obtained. Intervertebral discs were assessed on axial image of T2WI at each level. Correlations between qualitative and quantitative data and intervertebral disc pathology, age, and sex were evaluated. Results: Inter- and intra-observer agreements for results of GGS on MRI were substantial (κ = 0.79) and moderate (κ = 0.59), respectively. Inter- and intra-observer agreements for results of GGS on CT were almost perfect (κ = 0.88) and substantial (κ = 0.66), respectively. Quantitative measurements of HU showed almost perfect inter- and intra-observer reliabilities (κ = 0.82 and κ = 0.99, respectively). There were statistically significant correlations between intervertebral disc pathology and PSFI at L1-2, L2-3, and L4-5 levels on MRI and at L1-2 and L3-4 levels on CT. Age showed significant correlation with results of GGS at all levels on CT and MRI. Conclusion: This study showed that GGS results and HU measurements could be useful for evaluating PSFI because they showed correlations with intervertebral disc pathology results at certain levels.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.385-390
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• 2023

The uterus, one of women's reproductive organs, is also closely related to women's health. Among them, hemorrhagic luteal cysts, one of the causes of pelvic pain that women often experience, were observed through CT and ultrasound, and the quality of images was evaluated through quantitative and qualitative evaluations. This study sought to find out whether the test method is more helpful to patients during CT and ultrasound. This study was conducted on 15 adolescent women and 15 adult women(21.31±3.45 average age). The equipment used for filming used EC3-10X (3~10 MHZ) and Philips Mx8000 iCT 256 among Endocavity Probes among Ecube Platinum. After setting a constant ROI on the cyst and the interface as a quantitative analysis method, SNR and CNR values were measured on a 5-point scale based on image quality, lesion clarity, image distortion, clarity of the interface, and motion artifacts (p<0.05). Independent t-test and Mann Whiteny U were performed, and the statistical program used was noted when SPSS (Version 22.0 for windows software package, Chicago, IL, USA) was statistically less than 0.05. Comparing the SNR and CNR values for this experiment, it can be seen that the SNR value was higher in the case of CT images(p<0.05). As a result of the qualitative evaluation, the quality of the image, the clarity of the lesion, the distortion of the image, the clarity of the interface, and the clarity of the boundary were measured on a 5-point scale based on the movement artifact. Comparing each score, CT images scored higher with a finer difference than ultrasound images(p<0.05). In conclusion, both test methods showed excellent results in finding the patient's lesions. However, in quantitative and qualitative evaluations, CT produced higher results in detecting lesions than ultrasound. However, for cyst tests that require continuous observation, ultrasonography, a non-invasive method that is advantageous for patients, will be clinically useful. Therefore, observing the patient's lesions by appropriately distributing these two test methods will provide optimal diagnostic information. These results will be useful for providing clinical basic data and educational materials to CT and US users in the future.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.211-217
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• 2010

A micro-focus X-ray computed tomography (CT) was employed to determine quantitative phase analysis of skarn Zn-Pb-Cu ore by nondestructive visualization of the internal mineral distribution of a skarn ore. The micro CT images of the ore were calibrated to remove beam hardening artifacts, and compared with its scanning electron microscope (SEM) images to set the threshold of CT number range covering sulfide ore minerals. The volume ratio of sulfide and gangue minerals was calculated 20.5% and 79.5%, respectively. The quantitative 3D X-ray CT could be applied to analyse the distribution of economic minerals and their recovery.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.68-80
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• 2012

Purpose : More recently, combined PET/MR scanners have been developed in which the MR data can be used for both anatometabolic image formation and attenuation correction of the PET data. For quantitative PET information, correction of tissue photon attenuation is mandatory. The attenuation map is obtained from the CT scan in the PET/CT. In the case of PET/MR, the attenuation map can be calculated from the MR image. The purpose of this study was to assess the quantitative differences between MR-based and CT-based attenuation corrected PET images. Materials and Methods : Using the uniform cylinder phantom of distilled water which has 199.8 MBq of $^{18}F$-FDG put into the phantom, we studied the effect of MR-based and CT-based attenuation corrected PET images, of the PET-CT using time of flight (TOF) and non-TOF iterative reconstruction. The images were acquired from 60 minutes at 15-minute intervals. Region of interests were drawn over 70% from the center of the image, and the Scanners' analysis software tools calculated both maximum and mean SUV. These data were analyzed by one way-anova test and Bland-Altman analysis. MR images are segmented into three classes(not including bone), and each class is assigned to each region based on the expected average attenuation of each region. For clinical diagnostic purpose, PET/MR and PET/CT images were acquired in 23 patients (Ingenuity TF PET/MR, Gemini TF64). PET/CT scans were performed approximately 33.8 minutes after the beginnig of the PET/MR scans. Region of interests were drawn over 9 regions of interest(lung, liver, spleen, bone), and the Scanners' analysis software tools calculated both maximum and mean SUV. The SUVs from 9 regions of interest in MR-based PET images and in CT-based PET images were compared. These data were analyzed by paired t test and Bland-Altman analysis. Results : In phantom study, MR-based attenuation corrected PET images generally showed slightly lower -0.36~-0.15 SUVs than CT-based attenuation corrected PET images (p<0.05). In clinical study, MR-based attenuation corrected PET images generally showed slightly lower SUVs than CT-based attenuation corrected PET images (excepting left middle lung and transverse Lumbar) (p<0.05). And percent differences were -8.01.79% lower for the PET/MR images than for the PET/CT images. (excepting lung) Based on the Bland-Altman method, the agreement between the two methods was considered good. Conclusion : PET/MR confirms generally lower SUVs than PET/CT. But, there were no difference in the clinical interpretations made by the quantitative comparisons with both type of attenuation map.

• Imaging Science in Dentistry
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• v.31 no.2
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• pp.85-91
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• 2001

Purpose: To evaluate the effect of the slice thickness and the size of region of interest (ROI) on CT number using quantitative CT phantom Materials and Methods: The phantom containing 150 mg/cc, 75 mg/cc and 0 mg/cc calcium hydroxyapatite was scanned with 1, 3, 5 and 10 mm slice thicknesses by single energy quantitative computed tomography (QCT). CT numbers were measured on center position of the phantom. Shape of ROI was circular and sizes were 1, 3, 5, 11, 16, 21, 26 and 33 mm². ANOVA and Tukey's multiple comparison method were performed for statistical comparison of CT numbers according to different slice thicknesses. Coefficient of variation of CT number measured in each size of ROI was evaluated in same slice thickness. Results : CT numbers had statistically significant difference according to slice thicknesses (p<0.05). As the slice thickness increased, CT number also increased. As the density of phantom became lower and the size of ROI became smaller, the coefficient of variation of CT number increased. When the size of ROI was more than 11 mm² in 1 mm slice thickness, 5 mm² in 3 mm slice thickness and 3 mm² in 5 mm slice thickness, the coefficient of variation became consistent. In 10 mm slice thickness, the size of ROI had little effect on the coefficient of variation. Conclusion: CT number had variation according to the slice thickness and the size of ROI although the object was homogeneous. The slice thickness and the size of ROI are critical factors in precision of the CT number measurements.

• Korean Journal of Radiology
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• v.21 no.11
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• pp.1256-1264
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• 2020

Objective: Lung segmentation using volumetric quantitative computed tomography (CT) analysis may help predict outcomes of patients with coronavirus disease (COVID-19). The aim of this study was to investigate the relationship between CT volumetric quantitative analysis and prognosis in patients with COVID-19. Materials and Methods: CT images from patients diagnosed with COVID-19 from February 18 to April 15, 2020 were retrospectively analyzed. CT with a negative finding, failure of quantitative analysis, or poor image quality was excluded. CT volumetric quantitative analysis was performed by automated volumetric methods. Patients were stratified into two risk groups according to CURB-65: mild (score of 0-1) and severe (2-5) pneumonia. Outcomes were evaluated according to the critical event-free survival (CEFS). The critical events were defined as mechanical ventilator care, ICU admission, or death. Multivariable Cox proportional hazards analyses were used to evaluate the relationship between the variables and prognosis. Results: Eighty-two patients (mean age, 63.1 ± 14.5 years; 42 females) were included. In the total cohort, male sex (hazard ratio [HR], 9.264; 95% confidence interval [CI], 2.021-42.457; p = 0.004), C-reactive protein (CRP) (HR, 1.080 per mg/dL; 95% CI, 1.010-1.156; p = 0.025), and COVID-affected lung proportion (CALP) (HR, 1.067 per percentage; 95% CI, 1.033-1.101; p < 0.001) were significantly associated with CEFS. CRP (HR, 1.164 per mg/dL; 95% CI, 1.006-1.347; p = 0.041) was independently associated with CEFS in the mild pneumonia group (n = 54). Normally aerated lung proportion (NALP) (HR, 0.872 per percentage; 95% CI, 0.794-0.957; p = 0.004) and NALP volume (NALPV) (HR, 1.002 per mL; 95% CI, 1.000-1.004; p = 0.019) were associated with a lower risk of critical events in the severe pneumonia group (n = 28). Conclusion: CRP in the mild pneumonia group; NALP and NALPV in the severe pneumonia group; and sex, CRP, and CALP in the total cohort were independently associated with CEFS in patients with COVID-19.

• Journal of radiological science and technology
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• v.45 no.2
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• pp.135-143
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• 2022

In SPECT image, scatter count is the cause of quantitative count error and image quality degradation. This study is to evaluate the accuracy of CT based SC(CTSC) and energy window based SC(EWSC) as the comparison with existing Non SC. SPECT/CT images were obtained after filling air in order to acquire a reference image without the influence of scatter count inside the Triple line insert phantom setting hot rod(^99mTc 74.0 MBq) in the middle and each SPECT/CT image was obtained each separately after filling water instead of air in order to derive the influence of scatter count under the same conditions. For EWSC, 9 sub-energy windows were set additionally in addition to main energy window(140 keV, 20%) and then, images were acquired at the same time and five types of EWSC including DPW(dual photo-peak window)10%, DEW(dual energy window)20%, TEW(triple energy window)10%, TEW5.0%, TEW2.5% were used. Under the condition without fluctuations in primary count, total count was measured by drawing volume of interest (VOI) in the images of the two conditions and then, the ratio of scatter count of total counts was calculated as percent scatter fraction(%SF) and the count error with image filled with water was evaluated with percent normalized mean-square error(%NMSE) based on the image filled with air. Based on the image filled with air, %SF of images filled with water to which each SC method was applied is non scatter correction(NSC) 37.44, DPW 27.41, DEW 21.84, TEW10% 19.60, TEW5% 17.02, TEW2.5% 14.68, CTSC 5.57 and the scatter counts were removed the most in CTSC and %NMSE is NSC 35.80, DPW 14.28, DEW 7.81, TEW10% 5.94, TEW5% 4.21, TEW2.5% 2.96, CTSC 0.35 and the error in CTSC was found to be the lowest. In SPECT/CT images, the application of each scatter correction method used in the experiment could improve the quantitative count error caused by the influence of scatter count. In particular, CTSC showed the lowest %NMSE(=0.35) compared to existing EWSC methods, enabling relatively accurate scatter correction.