• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.6
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• pp.538-542
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• 2010

Acute mediastinitis is a fatal infection which occurs related to connective tissue of mediastium, in the thoratic organs. Occurrence of mediastinitis due to craniocervical infection is very rare, and is defined as descending necrotizing mediastinitis. November 8th, 2008, man in his early fifties visited ER due to severe swelling on left neck area and dyspnea. Antibiotic were administered immediately, and vast amount of abscess formation on pneumomediastinum and adjacent tissues were observed via chest computed tomography. With cooperation of thoracic and cardiovascular surgery department, emergency incision and drainage with drain insertion was done to remove abscess, and control the infection. After surgery, everyday saline irrigation through drain was done during hospitalization, with continues antibiotic therapy. Descending necrotising mediastinitis is a most rare and dangerous infection which occurs on oropharyngeal area. In case of descending necrotising mediastinitis, accurate diagnosis, airway maintenance, remove of abscess by incision and drainage, aggressive antibiotic therapy and continuous saline irrigation is necessary to increase patient survivability. Also, computed tomography with contrast media is essential to figure out the size and location of the infection and abscess formation.

• Korean Journal of Radiology
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• v.2 no.4
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• pp.210-215
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• 2001

Objective: To investigate the efficacy of gadobenate dimeglumine (GdBOPTA) enhanced MR imaging for the detection of liver lesions in patients with primary malignant hepatic neoplasms. Materials and Methods: Thirty-one patients with histologically proven primary malignancy of the liver were evaluated before and after administration of GdBOPTA at dose 0.05 or 0.10 mmol/kg. T1-weighted spin echo (T1W-SE) and gradient echo (T1W-GRE) images were evaluated for lesion number, location, size and confidence by three off-site independent reviewers and the findings were compared to reference standard imaging (intraoperative ultrasound, computed tomography during arterial portography or lipiodol computed tomography). Results were analyzed for significance using a two-sided McNemar's test. Results: More lesions were identified on Gd-BOPTA enhanced images than on unenhanced images and there was no significant difference in lesion detection between either concentration. The largest benefit was in detection of lesions under 1 cm in size (7 to 21, 9 to 15, 16 to 18 for reviewers A, B, C respectively). In 68% of the patients with more than one lesion, Gd-BOPTA increased the number of lesions detected. Conclusion: Liver MR imaging after Gd-BOPTA increases the detection of liver lesions in patients with primary malignant hepatic neoplasm.

• Journal of the Korean Society of Radiology
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• v.14 no.1
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• pp.61-68
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• 2020

The purpose of this study is to investigate the correlation of blooming artifacts according to dilution ratio of contrast agent on CT angiography images. A total of 10 sets were prepared by differently setting the ratio of contrast media and saline in a ball phantom made by a 3D printer. CT scan images were obtained and reconstructed by MIP and MPR techniques to obtain axial, sagittal and coronal images, respectively. After, the diameter of the ball phantom of the image obtained after the test was measured each 30 times, a total 1800 times. As a result, the dilution of 20:80 in the coronal plane was the smallest (p<0.05). Similarly, when dilute to 20:80 in the sagittal plane of MIP, it was the smallest as 20.39 ± 0.08 mm (p<0.05). Correlation analysis between dilution ratio and measurement size confirmed strong negative correlations in all reconstructed images (p<0.05). In conclusion, the higher the dilution ratio of the contrast agent, the more difficult it is to measure actual blood vessel measurement. Therefore, this study may provide basic data in future studies on actual measurement.

• Journal of Veterinary Clinics
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• v.38 no.3
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• pp.159-162
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• 2021

A 5-year-old, intact male, poodle dog with right external auditory canal obstruction and subaural mass was presented. Physical examination revealed that right external auditory canal opening was absent and right head tilt was identified. Aspiration in right subaural mass revealed a small amount of dark brown exudate. Streptococcus canis and Staphylococcus spp. were identified on the microbial culture. Radiography of the skull was revealed absence of air-filled ear canal at the right external ear canal (EEC) level. Computed tomography (CT) revealed well capsulated, hypoattenuated mass in the right EEC region. On the contrast enhanced CT images, rim enhancement around the mass and ear canal obstruction were identified. Fluid attenuated material filled with right bulla. Mild thickening of the right tympanic bulla wall with mild lytic lesion of the ventral wall were found. Based on the images findings, the case was tentatively diagnosed as right external auditory canal atresia with otitis media. Total ear canal ablation and lateral bulla osteotomy was performed. The entire ear canal was removed, numerous hair in the canal and the thickening wall were founded. Right ear canal was sent for histopathological evaluation and found to otitis externa. The patient was followed up for two weeks and there were no complications. This report described the CT diagnosis of right EEC atresia with otitis media rarely reported in small breed dogs.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.235-240
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• 2008

Purpose: At the beginning of PET/CT, Computed Tomography was mainly used only for Attenuation Correction (AC), but as the performance of the CT have been increase, it could give improved diagnostic information with Contrast Media. But it was controversial that Contrast Media could affect AC on PET/CT scan. Some submitted thesis' show that Contrast Media could overestimate when it is for AC data processing. On the contrary, the opinion that Contrast Media could be possible to affect the alteration of SUV because of the overestimated AC. But it does not have a definite effect on the diagnosis. Thus, the affection of Contrast Media on AC was investigated in this study. Materials and Methods: Patient inclusion criteria required a history of a malignancy and performance of an integrated PET/CT scan and contrast- enhanced CT scan within a 1-day period. Thirty oncologic patients who had PET/CT scan from December 2007 to June 2008 underwent staging evaluation and met these criteria. All patients fasted for at least 6 hr before the IV injection of approximately 5.6 MBq/kg (0.15 mCi/kg) of $^{18}F$-FDG and were scanned about 60 min after injection. All patients had a whole body PET/CT performed without IV contrast media followed by a contrast-enhanced CT on the Discovery STe PET/CT scanner. CT data were used for AC and PET images came out after AC. The ROIs drew and measured SUV. A paired t-test of these results was performed to assess the significance of the difference between the SUV obtained from the two attenuation corrected PET images. Results: The mean and maximum Standardized Uptake Values (SUV) for different regions averaged over all Patients. Comparing before using Contrast Media and after using, Most of ROIs have the increased SUV when it did Contrast Enhanced CT compare to Non-Contrast enhanced CT. All regions have increased SUV and also their p value was under 0.05 except the mean SUV of the Heart region. Conclusion: In this regard, the effect on SUV measurements that occurs when a contrast-enhanced CT is used for attenuation correction could have significant clinical ramifications. But some submitted thesis insisted that the percentage change in SUV that can determine or modify clinical management of oncology patients is small. Because there was not much difference that could be discovered by interpreter. But obviously the numerical change was occurred and on the stage finding primary region, small change would be base line, such as the region of liver which has greater change than the other regions needs more attention.

• Journal of the Korean Society of Radiology
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• v.84 no.4
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• pp.911-922
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• 2023

Purpose To compare small bowel distension and side effects between a diluted polyethylene glycol (PEG) solution and a low-density (0.1% w/v) barium sulfate suspension (LDBSS) for CT enterography (CTE) preparation. Materials and Methods Total 173 consecutive patients who underwent CTE were enrolled in this study. The LDBSS (1 L) was used in 50 patients, and the diluted iso-osmotic PEG solution (1 L) was used in 123 patients. Two blinded radiologists independently scored jejunal and ileal distensions on a 5-point scale. To compare side effects between the two groups, the patients reported whether they had immediate complications after the administration of the oral contrast media. Results For ileal and jejunal distension, the diluted PEG solution showed no difference from the LDBSS for either reader (ileum: reader 1, median, 4; 4, interquartile range, 3-4; 3-4, p = 0.997; reader 2, median, 4; 4, interquartile range, 3.3-4.0; 3-4, p = 0.064; jejunum: reader 1, median, 2; 2, interquartile range, 2-3; 2-3, p = 0.560; reader 2, median, 3; 2, interquartile range, 2-3; 2-3, p = 0.192). None of the patients complained of immediate complications following administration of either of the oral contrast media. Conclusion The diluted PEG solution showed comparable bowel distension compared to LDBSS and no immediate side effects; thus, it can be a useful alternative.

• Korean Journal of Radiology
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• v.25 no.7
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• pp.634-643
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• 2024

Objective: This study aimed to evaluate the diagnostic efficacy and safety of low-contrast-dose, dual-source dual-energy CT before transcatheter aortic valve replacement (TAVR) in patients with compromised renal function. Materials and Methods: A total of 54 consecutive patients (female:male, 26:38; 81.9 ± 7.3 years) with reduced renal function underwent pre-TAVR dual-energy CT with a 30-mL contrast agent between June 2022 and March 2023. Monochromatic (40- and 50-keV) and conventional (120-kVp) images were reconstructed and analyzed. The subjective quality score, vascular attenuation, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were compared among the imaging techniques using the Friedman test and post-hoc analysis. Interobserver reliability for aortic annular measurement was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. The procedural outcomes and incidence of post-contrast acute kidney injury (AKI) were assessed. Results: Monochromatic images achieved diagnostic quality in all patients. The 50-keV images achieved superior vascular attenuation and CNR (P < 0.001 in all) while maintaining a similar SNR compared to conventional CT. For aortic annular measurement, the 50-keV images showed higher interobserver reliability compared to conventional CT: ICC, 0.98 vs. 0.90 for area and 0.97 vs. 0.95 for perimeter; 95% limits of agreement width, 0.63 cm² vs. 0.92 cm² for area and 5.78 mm vs. 8.50 mm for perimeter. The size of the implanted device matched CT-measured values in all patients, achieving a procedural success rate of 92.6%. No patient experienced a serum creatinine increase of ≥ 1.5 times baseline in the 48-72 hours following CT. However, one patient had a procedural delay due to gradual renal function deterioration. Conclusion: Low-contrast-dose imaging with 50-keV reconstruction enables precise pre-TAVR evaluation with improved image quality and minimal risk of post-contrast AKI. This approach may be an effective and safe option for pre-TAVR evaluation in patients with compromised renal function.

• Progress in Medical Physics
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• v.17 no.4
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• pp.238-245
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• 2006

To assess the ability of an extravasation defection accessory (EDA) to detect the clinically important extravascular Injection of iodinated contrast material that was delivered with an automated mechanical power injector. The purpose of this study was to assess the ability of this device during clinically important episodes of extravasation. The EDA system was composed of a strain gage, an amplifier and a computer-based system. In the rabbit experimental cases, there were seven true-positive cases (range of the extravasation volumes: $14{\sim}23 ml$). The algorithm results showed seven true-positive cases (range of the extravasation volumes: $7{\sim}16ml$), nineteen true-negative cases, two false-positive cases and no false-negative cases. The EDA system had a sensitivity of 100% and a specificity of 90% for the detection of clinically important extravasation. The EDA system had good sensitivity for the detection of clinically important extravasation and the EDA system has the clinical potential for the early detection of extravasation of the contrast medium that is administered with power injectors.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.519-526
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• 1996

Background : Clinical and Radiographic studies to differentiate benign from malignant pulmonary nodules have previously focused on clinical status and the morphologic and the computed tomographic attenuation characteristics of the lung nodules. Distinctive differences in the vascularity and pathophysiology of malignant versus benign pulmonary nodules were identified. We evaluated the diagnostic method for differentiating malignant from benign solitary pulmonary nodule by contrast enhancement on the spiral CT. Method : Sixteen patients with solitary pulmonary nodule were examined(Tuberculoma 8, primary lung cancer 8). Serial thin section on the spiral CT was performed before and after(45second, 2min, 5min) the onset of the injection of 100mL of nonionic contrast material(2mL/sec). Results : There was no difference in size of nodule and pre-contrast CT number (Hounsfield unit) between benign and malignant nodules. At forty-five second after the onset of the injection, malignant neoplasms($19.6{\pm}7.9$ HU) enhanced significantly more than tuberculomas($4.9{\pm}9.4$ HU, p=0.008). At 2minute and 5 minute after, malignant neoplasms($34.0{\pm}19.2$HU, $34.0{\pm}15.4$HU) enhanced significantly more than tuberculomas ($6.7{\pm}9.7$HU, p=0.007 and $7.7{\pm}11.5$HU, p=0.011). On cut-off value 20HU(contrast enhancement) 2minute after the injection of contrast media, sensitivity was 87% and specificity was 87%. No correlation between the contrast enhancement and size of the nodules was observed. Conclusion : Studies with the use of an intravenously administered noniodinated contrast medium in examining the enhancement properties of lung nodules was performed. The contrast enhancement was useful in differential diagnosis of solitary pulmonary nodules.

• Progress in Medical Physics
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• v.23 no.4
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• pp.252-260
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• 2012

The reduction of radiation dose from x-ray is a main concern in computed tomography (CT) imaging due to the side-effect of the dose on human body. Recently, the various methods for dose reduction have been studied in CT and one of the method is a iterative reconstruction based on total variation (TV) minimization at few-views data. In this paper, we evaluated the image quality between total variation (TV) minimization algorithm and Feldkam-Davis-kress (FDK) algorithm in micro computed tomography (CT). To evaluate the effect of TV minimization algorithm, we produced a cylindrical phantom including contrast media, water, air inserts. We can acquire maximum 400 projection views per rotation of the x-ray tube and detector. 20, 50, 90, 180 projection data were chosen for evaluating the level of image restoration by TV minimization. The phantom and mouse image reconstructed with FDK algorithm at 400 projection data used as a reference image for comparing with TV minimization and FDK algorithm at few-views. Contrast-to-noise ratio (CNR), Universal quality index (UQI) were used as a image evaluation metric. When projection data are not insufficient, our results show that the image quality of reconstructed with TV minimization is similar to reconstructed image with FDK at 400 view. In the cylindrical phantom study, the CNR of TV image was 5.86, FDK image was 5.65 and FDK-reference was 5.98 at 90-views. The CNR of TV image 0.21 higher than FDK image CNR at 90-views. UQI of TV image was 0.99 and FDK image was 0.81 at 90-views. where, the number of projection is 90, the UQI of TV image 0.18 higher than FDK image at 90-views. In the mouse study UQI of TV image was 0.91, FDK was 0.83 at 90-views. the UQI of TV image 0.08 higher than FDK image at 90-views. In cylindrical phantom image and mouse image study, TV minimization algorithm shows the best performance in artifact reduction and preserving edges at few view data. Therefore, TV minimization can potentially be expected to reduce patient dose in clinics.