• Journal of Korean Neurosurgical Society
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• v.39 no.6
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• pp.427-431
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• 2006

Objective : The purpose of this study is to assess the usefulness of three-dimensional computed tomography angiography [3D-CTA] as a postoperative follow-up examination after intracranial aneurysms have been clipped. Methods : Between January 2002 and June 2005, 522 consecutive patients received treatment for intracranial aneurysms. A retrospective analysis of 310 patients with postoperative 3D-CTAs was performed to evaluate aneurysmal remnants and de novo aneurysms. This study was conducted in 271 patients with at least immediate and 6-month routine 3D-CT As for postoperative clipped aneurysm and 39 patients with 3D-CTAs for clipped aneurysm before 2002 when there was no 3D-CTA in our hospital. Results : Eight patients had abnormal CT angiographic findings. Aneurysm remnants were revealed in 4 patients and de novo aneurysms were discovered in 5 patients. Two patients were found at the postoperative 6-month 3D-CTA performed routinely. In 1 patient, the aneurysm was demonstrated on the way to the examination of syncope. In 2 patients, the author recommended 3D-CTA although there was no symptom because the patients had visited our institute long time ago [5.1, 4.5 years]. Of the 8 patients, 2 remnants and 1 de novo aneurysm were treated by endovascular treatment. Three de novo aneurysms at the middle cerebral artery and 1 pericallosal artery aneurysm were treated by direct clipping because these aneurysms were not suitable for the endovascular treatment in point of anatomical configuration. One patient with both remnant and de novo aneurysm was treated conservatively. Conclusion : 3D-CTA is an available, non-invasive diagnostic tool for the postoperative follow-up examination of aneurysmal state in patients after clipping.

• Journal of Korean Neurosurgical Society
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• v.62 no.1
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• pp.35-45
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• 2019

Objective : To describe our experiences with a fully equipped high-end digital subtraction angiography (DSA) system within a hybrid operating room (OR). Methods : A single-plane DSA system with 3-dimensional rotational angiography, cone-beam computed tomography (CBCT), and real-time navigation software was used in our hybrid OR. Between April 2014 and January 2018, 191 sessions of cerebrovascular procedures were performed in our hybrid OR. After the retrospective review of all cases, the procedures were categorized into three subcategorical procedures : combined endovascular and surgical procedure, complementary rescue procedure during intervention and surgery, and frameless stereotaxic operation. Results : Forty-nine of 191 procedures were performed using hybrid techniques. Four cases of blood blister aneurysms and a ruptured posterior inferior cerebellar artery aneurysm were treated using bypass surgery and endovascular trapping. Eight cases of ruptured aneurysm with intracranial hemorrhage (ICH) were treated by partial embolization and surgical clipping. Six cases of ruptured arteriovenous malformation with ICH were treated by Onyx embolization of nidus and subsequent surgical removal of nidus and ICH. Two (5.4%) of the 37 cases of pre-mature rupture during clipping were secured by endovascular coil embolization. In one (0.8%) complicated case of 103 intra-arterial thrombectomy procedures, emergency surgical embolectomy with bypass surgery was performed. In 27 cases of ICH, frameless stereotaxic hematoma aspiration was performed using $XperGuide^{(R)}$ system (Philips Medical Systems, Best, the Netherlands). All procedures were performed in single sessions without any procedural complications. Conclusion : Hybrid OR with a fully equipped DSA system could provide precise and safe treatment strategies for cerebrovascular diseases. Especially, we could suggest a strategy to cope flexibly in complex lesions or unexpected situations in hybrid OR. CBCT with real-time navigation software could augment the usefulness of hybrid OR.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1021-1030
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• 2018

Objective: We evaluated the effect of various patient characteristics and time-density curve (TDC)-factors on the test bolus-affected vessel enhancement on coronary computed tomography angiography (CCTA). We also assessed the value of generalized linear regression models (GLMs) for predicting enhancement on CCTA. Materials and Methods: We performed univariate and multivariate regression analysis to evaluate the effect of patient characteristics and to compare contrast enhancement per gram of iodine on test bolus (${\Delta}HUTEST$) and CCTA (${\Delta}HUCCTA$). We developed GLMs to predict ${\Delta}HUCCTA$. GLMs including independent variables were validated with 6-fold cross-validation using the correlation coefficient and Bland-Altman analysis. Results: In multivariate analysis, only total body weight (TBW) and ${\Delta}HUTEST$ maintained their independent predictive value (p < 0.001). In validation analysis, the highest correlation coefficient between ${\Delta}HUCCTA$ and the prediction values was seen in the GLM (r = 0.75), followed by TDC (r = 0.69) and TBW (r = 0.62). The lowest Bland-Altman limit of agreement was observed with GLM-3 (mean difference, $-0.0{\pm}5.1$ Hounsfield units/grams of iodine [HU/gI]; 95% confidence interval [CI], -10.1, 10.1), followed by ${\Delta}HUCCTA$ ($-0.0{\pm}5.9HU/gI$; 95% CI, -11.9, 11.9) and TBW ($1.1{\pm}6.2HU/gI$; 95% CI, -11.2, 13.4). Conclusion: We demonstrated that the patient's TBW and ${\Delta}HUTEST$ significantly affected contrast enhancement on CCTA images and that the combined use of clinical information and test bolus results is useful for predicting aortic enhancement.

• Anatomy and Cell Biology
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• v.56 no.3
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• pp.360-366
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• 2023

Increased tortuosity of vessel is associated with high incidence of plaque formation leading to atherosclerosis. Surgical procedures are done after analyzing morphology of middle cerebral artery (MCA). However, literature describing MCA morphology using computed tomography angiography (CTA) is limited, so this study was planned to determine its incidence in Indian population. Datasets of CTA from 289 patients (180 males and 109 females), average age: 49.29±16.16 years (range: 11 to 85 years), from a tertiary care hospital were systematically reviewed for morphology of MCA. Cases involving aneurysms and infarcts were excluded. Four shapes of MCA were recognized: straight, U, inverted U, and S-shaped. MCA was straight in 44% (254/578), U-shaped in 37% (215/578), S shaped in 15% (89/578) and inverted U-shaped in 3% (20/578) cases. In males, MCA was straight in 46% (166/360), U-shaped in 37% (134/360), S-shaped in 16% (58/360) and inverted U-shaped in 4% (14/360) cases. In females, MCA was straight in 42% cases (92/218), U-shaped in 37% (81/218), S-shaped in 17% (36/218) and inverted U-shaped in 4% (9/218). On comparing shape with various age groups using chi square test, U shaped (P≤0.001) and S-shaped (P=0.003) MCA were found to be statistically significant. The incidence of straight shape was higher in advanced age group (>60 years). Knowledge of MCA shape will be useful for clinicians and surgeons in successful endovascular recanalization. Also, this data would help surgeons during neurointerventional procedures.

• Journal of Veterinary Clinics
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• v.41 no.3
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• pp.183-188
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• 2024

A 13-year-old male neutered Miniature Pinscher presented with coughing and dyspnea. The dog had been coughing for the past 4 weeks. The patient had mild dehydration on physical examination, and muffled heart sounds were detected. Thoracic radiographs revealed pleural effusion, which was consistent with chylous effusion based on cytological and biochemical evaluations. Computed tomography (CT) lymphangiography, which was performed via intrametatarsal pad injection, revealed no evidence of thoracic duct rupture or obvious leakage. On CT angiography (CTA), an intraluminal filling defect was identified in the cranial vena cava (CrVC). CrVC thrombosis with secondary chylothorax was diagnosed based on CT lymphangiography and CTA. Clopidogrel, rivaroxaban, and recombinant tissue-plasminogen activator were prescribed. The follow-up CTA, 4 months after diagnosis, revealed a decrease in the thrombus, and no pleural effusion was identified. Although CrVC thrombosis is an uncommon presentation in veterinary patients, thrombus in the CrVC should be considered as a differential diagnosis of chylothorax in dogs. CT lymphangiography and CTA could be helpful in identifying and differentiating the underlying etiologies of chylothorax.

• Korean Journal of Radiology
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• v.21 no.9
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• pp.1095-1103
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• 2020

Objective: The present study aimed to investigate whether quantitative dual-energy computed tomography (DECT) parameters offer an incremental risk stratification benefit over the CT ventricular diameter ratio in patients with acute pulmonary embolism (PE) by using propensity score analysis. Materials and Methods: This study was conducted on 480 patients with acute PE who underwent CT pulmonary angiography (CTPA) or DECT pulmonary angiography (DE CT-PA). This propensity-matched study population included 240 patients with acute PE each in the CTPA and DECT groups. Altogether, 260 (54.1%) patients were men, and the mean age was 64.9 years (64.9 ± 13.5 years). The primary endpoint was all-cause death within 30 days. The Cox proportional hazards regression model was used to identify associations between CT parameters and outcomes and to identify potential predictors. Concordance (C) statistics were used to compare the prognoses between the two groups. Results: In both CTPA and DECT groups, right to left ventricle diameter ratio ≥ 1 was associated with an increased risk of all-cause death within 30 days (hazard ratio: 3.707, p < 0.001 and 5.573, p < 0.001, respectively). However, C-statistics showed no statistically significant difference between the CTPA and DECT groups for predicting death within 30 days (C-statistics: 0.759 vs. 0.819, p = 0.117). Conclusion: Quantitative measurement of lung perfusion defect volume by DECT had no added benefit over CT ventricular diameter ratio for predicting all-cause death within 30 days.

• Journal of radiological science and technology
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• v.38 no.2
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• pp.121-126
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• 2015

To image diagnosis in neurovascular diseases using Multi-Detector Computed Tomography(MDCT), injected the same contrast material when inspecting Brain Computed Tomography Angiography(BCTA) to examine radiation dose and Image quality on changing Cerebral Artery CT number by tube voltage. Executed an examination with same condition[Beam Collimation $128{\times}0.6mm$, Pitch 0.6, Rotation Time 0.5s, Slice Thickness 5.0mm, Increment 5.0mm, Delay Time 3.0sec, Care Dose 4D(Demension ; D)] except for tube voltage on 50 call patients for BCTA and divided them into two groups (25 people for a group, group A: 80, group B: 120kVp). From all the acquired images, set a ROI(Region of Interest) on four spots such as left cerebral artery, right cerebral artery, posterior cerebral artery and cerebral parenchyma to compare quantitative evaluation, qualitative evaluation and effective dose after measuring CT number value from Picture Archiving Communications System(PACS). Evaluating images with CT number acquired from BCTA examination, images with 80 kVp was 18% higher in Signal to Noise Ratio and 19% in Contrast to Noise Ratio than those with 120 kVp. It was seen that expose dose was decreased by over 50% with tube voltage 80 kVp than with 120 kVp. Group A (25 patients) was examination with tube voltage 80kVp while group B with 120 kVp to examine radiation dose and Image quality. It is considered effective to inspect with lower tube voltage than with conventional high kVp, which can reduce radiation dose without any affect on diagnosis.

• Tuberculosis and Respiratory Diseases
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• v.72 no.4
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• pp.352-359
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• 2012

Background: The purpose of this study was to evaluate whether measuring the ratio of descending aortic enhancement (DAE) to main pulmonary artery enhancement (MPAE) on pulmonary computed tomography angiography (PCTA) can predict poor outcome in patients with acute massive or submassive pulmonary embolism (PE). Methods: We retrospectively, reviewed computed tomgraphy findings and charts of 37 patients with acute PE and right ventricular dysfunction. We divided the enrolled patients into 3 groups; group Ia (n=8), comprised of patients with major adverse event (MAE); group Ib (n=5), consisted of those with PE-related MAE; and group II (n=29), those without MAE. We analyzed the right ventricular diameter (RVD)/left ventricular diameter (LVD) and DAE/MPAE on PCTA. Results: For observer 1, RVD/LVD in group Ia ($1.9{\pm}0.36$ vs. $1.44{\pm}0.38$, p=0.009) and group Ib ($1.87{\pm}0.37$ vs. $1.44{\pm}0.38$, p=0.044) were significantly higher than that of group II. For observer 2, RVD/LVD in group Ia ($1.71{\pm}0.18$ vs. $1.41{\pm}0.47$, p=0.027) was significantly greater than that of group II, but RVD/LVD of group Ib was not ($1.68{\pm}0.2$ vs. $1.41{\pm}0.47$, p=0.093). For both observers, there was a significant difference of DAE/MPAE between group Ib and group II ($0.32{\pm}0.15$ vs. $0.64{\pm}0.24$, p=0.005; $0.34{\pm}0.16$ vs. $0.64{\pm}0.22$, p=0.004), but no significant difference of DAE/MPAE between group Ia and group II ($0.51{\pm}0.3$ vs. $0.64{\pm}0.24$, p=0.268; $0.53{\pm}0.29$ vs. $0.64{\pm}0.22$, p=0.302). Intra-class correlation coefficient (ICC) for the measurement of DAE/MPAE (ICC=0.97) was higher than that of RVD/LVD (ICC=0.74). Conclusion: DAE/MPAE measured on PCTA may predict PE-related poor outcomes in patients with massive or submassive PE with an excellent inter-observer agreement.

• Korean Journal of Digital Imaging in Medicine
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• v.15 no.2
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• pp.45-53
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• 2013

Purpose : Fixed way of mAs previously Low Extremity Computed Tomography Angiography(LECTA) examination were used. Automatic Current Selection(ACS) to use for the purpose of reducing the dose when Low Extremity Computed Tomography Angiography examining patients. Materials and methods : Were analyzed from July 2011 to July 2012 MDCT examination of Dose Length Product(DLP) LECTA 116 Case. It was defined as previous inspection methods(Old protocol). CT workstation is set to 100 mAs and 150 mAs protocol based on the patient's weight 70kg examined by LECTA. We defined as 'New protocol' that applies to ACS. The data collection period are 76 cases from October 2012 to January 2013 Results : 1. Average Total DLP of 'Old protocol' is 3602.943 $mGy^*cm$. 2. Average Total DLP of 'New protocol' is 1762.977 $mGy^*cm$. 3. Due to the 'New Protocol' use of Total DLP was reduced by approximately 51 %. Phase-specific dose reduction is as follows. Pre(33.62 %), Artery(64.63 %), Delay(49.0 %) 4. Using One way ANOVA Analysis of fluctuations obtained DLP is as follows. 'Old protocol', 'New protocol' a value of P < 0.001, P = 0.882 values were obtained. Conclusions : Dose reduction of 51 % is a useful study that proves. The results obtained using the ACS, the effects of a dose reduction of 51 % was obtained. Therefore, it has been proven to be a useful way. Statistics using SPSS version came out of the 'Old protocol' P-value P < 0.0001. This result means that the DLP a large difference values. On the other hand, The results of the 'New protocol' was P = 0.882. These results means to that small and regularly was fluctuations of the dose. The use of ACS, you can get a reduction of the dose and will able to get the effect of reducing the dose errors.

• Korean Journal of Radiology
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• v.21 no.10
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• pp.1165-1177
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• 2020

Objective: To assess the feasibility of applying a deep learning-based denoising technique to coronary CT angiography (CCTA) along with iterative reconstruction for additional noise reduction. Materials and Methods: We retrospectively enrolled 82 consecutive patients (male:female = 60:22; mean age, 67.0 ± 10.8 years) who had undergone both CCTA and invasive coronary artery angiography from March 2017 to June 2018. All included patients underwent CCTA with iterative reconstruction (ADMIRE level 3, Siemens Healthineers). We developed a deep learning based denoising technique (ClariCT.AI, ClariPI), which was based on a modified U-net type convolutional neural net model designed to predict the possible occurrence of low-dose noise in the originals. Denoised images were obtained by subtracting the predicted noise from the originals. Image noise, CT attenuation, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were objectively calculated. The edge rise distance (ERD) was measured as an indicator of image sharpness. Two blinded readers subjectively graded the image quality using a 5-point scale. Diagnostic performance of the CCTA was evaluated based on the presence or absence of significant stenosis (≥ 50% lumen reduction). Results: Objective image qualities (original vs. denoised: image noise, 67.22 ± 25.74 vs. 52.64 ± 27.40; SNR [left main], 21.91 ± 6.38 vs. 30.35 ± 10.46; CNR [left main], 23.24 ± 6.52 vs. 31.93 ± 10.72; all p < 0.001) and subjective image quality (2.45 ± 0.62 vs. 3.65 ± 0.60, p < 0.001) improved significantly in the denoised images. The average ERDs of the denoised images were significantly smaller than those of originals (0.98 ± 0.08 vs. 0.09 ± 0.08, p < 0.001). With regard to diagnostic accuracy, no significant differences were observed among paired comparisons. Conclusion: Application of the deep learning technique along with iterative reconstruction can enhance the noise reduction performance with a significant improvement in objective and subjective image qualities of CCTA images.