• Journal of Chest Surgery
• /
• v.51 no.3
• /
• pp.216-219
• /
• 2018

We report the case of a 16-year-old male patient who was involved in a traffic accident and transferred to the emergency department with mild chest pain. We initially did not find evidence of tracheal injury on computed tomography (CT). Within an hour after presentation, the patient developed severe dyspnea and newly developed subcutaneous emphysema and pneumoperitoneum were discovered. Abdominal CT showed no intra-abdominal injury. However, destruction of the right main bronchus was identified on coronal images of the initially performed CT scan. Emergency exploratory surgery was performed. The amputated right main bronchus was identified. End-to-end tracheobronchial anastomosis was performed, and the patient recovered without any complications.

• Tuberculosis and Respiratory Diseases
• /
• v.40 no.4
• /
• pp.345-352
• /
• 1993

The role of magnetic resonance(MR) imaging in the evaluation of thoracic disease has been limited Nontheless, MR has inherent properties of better contrast resolution than CT allowing tissue-specific diagnosis. MR has capability of direct imaging in sagittal, coronal, and oblique planes which provide better anatomic information than axial images of CT such as lesions in the pulmonary apex, aorticopulmonary window, peridiaphragmatic region, and subcarinal region. MR is sensitive to blood flow making it an ideal imaging modality for the evaluation of cardiovascular system of the thorax without the need for intravenous contrast media. Technical developments and better control of motion artifacts have resulted in improved image quality, and clinical applications of MR imaging in thoracic diseases have been expanded. Although MR imaging is considered as a problem-solving tool in patients with equivocal CT findings, MR should be used as the primary imaging modality in the following situations: 1) Evaluation of the cardiovascular abnormalities of the thorax 2) Evaluation of the superior sulcus tumors 3) Evaluation of the chest wall invasion or mediastinal invasion by tumor 4) Evaluation of the posterior mediastinal mass, especially neurogenic tumor 5) Differentiation of fibrosis and residual or recurrent tumor, especially in lymphoma 6) Evaluation of brachial plexopathy With technical developments and fast scan capabilities, clinical indications for MR imaging in thorax will increase in the area of pulmonary parenchymal and pulmonary vascular imaging.

• Restorative Dentistry and Endodontics
• /
• v.49 no.1
• /
• pp.1.1-1.18
• /
• 2024

The implementation of imaging methods that enable sensitive and specific observation of anatomical structures has been a constant in the evolution of endodontic therapy. Cone-beam computed tomography (CBCT) enables 3-dimensional (3D) spatial anatomical navigation in the 3 volumetric planes (sagittal, coronal and axial) which translates into great accuracy for the identification of endodontic pathologies/conditions. CBCT interpretation consists of 2 main components: (i) the generation of specific tasks of the image and (ii) the subsequent interpretation report. A systematic and reproducible method to review CBCT scans can improve the accuracy of the interpretation process, translating into greater precision in terms of diagnosis and planning of endodontic clinical procedures. MEDLINE (PubMed), Web of Science, Google Scholar, Embase and Scopus were searched from inception to March 2023. This narrative review addresses the theoretical concepts, elements of interpretation and applications of the CBCT scan in endodontics. In addition, the contents and rationale for reporting 3D endodontic imaging are discussed.

• The Journal of Korean Academy of Prosthodontics
• /
• v.53 no.2
• /
• pp.111-119
• /
• 2015

Purpose: The objective of this study was to evaluate the accuracy of a stereolithographic surgical guide that was made with information from intraoral digital impressions and cone beam CT (CBCT). Materials and methods: Six sets of resin maxilla and mandible models with missing teeth were used in this study. Intraoral digital impressions were made. The virtual models provided by these intraoral digital impressions and by the CBCT scan images of the resin models were used to create a surgical guide. Implant surgery was performed on the resin models using the surgical guide. After implant placement, the models were subjected to another CBCT scan to compare the planned and actual implant positions. Deviations in position, depth and axis between the planned and actual positions were measured for each implant. Results: The mean deviation of the insertion point and angulation were 0.28 mm and $0.26^{\circ}$, apex point were 0.11 mm and 0.14 mm respectively. The implants were situated at a mean of 0.44 mm coronal to the planned vertical position. Conclusion: This study demonstrates that stereolithographic surgical guides created without the use of impressions and stone models show promising accuracy in implant placement.

• The Journal of the Korea Contents Association
• /
• v.17 no.6
• /
• pp.81-85
• /
• 2017

The aim of this study was to evaluate the usability of applied Low dose Computed Tomography(LDCT) protocol in examining urinary calculus using computed tomography. The subjects of this study were urological patients who visited a medical institution located in Busan from June to December 2016 and the protocol used in this study was Adaptive Statistical Iterative Reconstruction: low-dose CT with 50% Adaptive Statistical Iterative Reconstruction (ASIR). As results of quantitative analysis, the mean pixel value and standard deviation within kidney region of image(ROI)of the axial image were $26.21{\pm}7.08$ in abdomen CT pre scan and $20.03{\pm}8.16$ in low-dose CT. Also the mean pixel value and standard deviation within kidney ROI of the coronal image were $22.07{\pm}7.35$ in abdomen CT pre scan and $21.67{\pm}6.11$ in low dose CT. The results of qualitative analysis showed that four raters' mean values of observed kidney artifacts were $19.14{\pm}0.36$ when using abdomen CT protocol and $19.17{\pm}0.43$ in low-dose CT, and the mean value of resolution and contrast was $19.35{\pm}0.70$ when using abdomen CT protocol and $19.29{\pm}0.58$ in low-dose CT. Also the results of a exposure dose analysis showed that the mean values of CTDIvol and DLP in abdomen CT pre scan were 18.02 mGy and $887.51mGy{\cdot}cm$ respectively and the mean values of CTDIvol and DLP when using low-dose CT protocol were 7.412 mGy and $361.22mGy{\cdot}cm$ respectively. The resulting dose reduction rate was 58.82% and 59.29%, respectively.

• Childhood Kidney Diseases
• /
• v.5 no.1
• /
• pp.22-29
• /
• 2001

Purpose : 99mTc DMSA renal scan have been widely used not only for tile evaluation of renal scars but also for the diagnosis of acute pyelonephritis. Recent studies have shown SPECT images have higher accuracy than the planar images with some controversy. We evaluated the availability of the SPECT images adding to planar images for the diagnosis of acute pyelonephritis(APN) and renal scar in children with urinary tract infection (UTI). Methods : 130 children with UTI (260 kidney units) and 22 follow-up children (44 kidney units) were included between January 1, 1997 and July 31, 1999 at Ewha University Mokdong Hospital. Planar Anterior and posterior images and SPECT axial and coronal images of 99mTc DMSA renal scan were obtained with Starcam 4000-i U.S.A. GE at 3 hours after 99mTc DMSA I.V. injection. The data were analyzed by Chi square test after Yates's correction. Results : The detection rate of the acute pyelonephritis by SPECT images was 12.3$\%$ higher than that of planar images ($47.7\%\;vs\;35.4\%$) by the patient and 6.9$\%$ higher also ($31.9\%\;vs\;25.4\%$) by the kidney unit. 18 kidney units with negative planar images had focal defect in 10 kidney units (3.8$\%$) and multifocal defect in 8 kidney units (3.1$\%$) on SPECT images, but 1 kidney unit with positive planar image had negative SPECT image. SPECT images were superior to tile planar images in 17.3$\%$. identical in 82.3$\%$ and inferior in 0.4$\%$ to planar image. The detection rate of tile renal scars by SPECT images was 13.7$\%$ higher than planar images by the patient ($68.2\%\;vs\;54.5\%$) and 6.8$\%$ higher also ($43.2\%\;vs\;36.4\%$) by the kidney unit. SPECT images were superior to the planar images in 17.3$\%$ and identical in 82.3$\%$ to planar image. Conclusion SPECT images had shown higher detection rate and better image than planar images for the diagnosis of the acute pyelonephritis and the evaluation of the renal scars. (J. Korean Soc Pediatr Nephrol 5 : 22- 9, 2001)

• The Korean Journal of Nuclear Medicine Technology
• /
• v.16 no.2
• /
• pp.18-24
• /
• 2012

Purpose : Although lung ventilation SPECT (LV-SPECT) has a good sensitivity in detection of deep lung lesions, it is difficult to apply the LV-SPECT to patients having breathing problems due to limited examination time. In this study, we evaluated the usefulness of LEAP collimator, which provides high detection sensitivity and tolerable resolution, for the LV-SPECT in terms of diagnostic accuracy and examination time. Materials and Methods : Four volunteers inhaled Technegas (370 MBq) and the lung ventilation planar scan (LVPS, 300 counts/view (cpv)) with LEHR collimator was performed using Siemens E.cam scanner as a reference test. LV-SPECT scans were performed with three collimators, LEHR, LEUHR, and LEAP, in low (7 kcpv) and high (70 kcpv) counting modes. The count ratios of left (LT) and right (RT) lung segments were calculated on the geometric mean view of anterior and posterior images for LVPS and on the summed coronal images of LV-SPECT, respectively. Comparing to LVPS, the usefulness of three different collimators for LV-SPECT was evaluated through statistical analysis (paired t-test), on count ratios of lung segments. Results : The average LT:RT ratio in LVPS was 47:53. For LV-SPECT, there were negligible difference of the LT:RT ratios (48:52 on average) among three different collimators in low and high counting modes. Comparing to standard LVPS with LEHR, all LV-SPECTs with different collimators resulted in similar diagnostic accuracy through paired t-test (p>0.05). The scan time in LVPS (6 views) was 17.3 min. For LV-SPECT (128 views) in low counting mode, it took 18.7 (LEUHR), 15.0 (LEHR), and 12.3 min (LEAP), respectively. Conclusion : Comparing to standard LVPS, the LV-SPECT with LEAP in low counting mode provided the comparable diagnostic accuracy in addition to shortened scan time.

• The korean journal of orthodontics
• /
• v.35 no.4 s.111
• /
• pp.320-329
• /
• 2005

The three-dimensional (3D) changes of bone, soft tissue and the ratio of soft tissue to bony movement was investigated in 8 skeletal Class III patients treated by mandibular setback surgery. CT scans of each patient at pre- and post-operative states were taken. Each scan was segmented by a threshold value and registered to a universal three-dimensional coordinate system, consisting of an FH plane, a mid-sagittal plane, and a coronal plane defined by PNS. In the study, the grid parallel to the coronal plane was proposed for the comparison of the changes. The bone or soft tissue was intersected by the projected line from each point on the gird. The coordinate values of intersected point were measured and compared between the pre- and post-operative models. The facial surface changes after setback surgery occurred not only in the mandible, but also in the mouth corner region. The soft tissue changes of the mandibular area were measured relatively by the proportional ratios to the bone changes. The ratios at the mid-sagittal plane were $77\~102\%(p<0.05)$. The ratios at all other sagittal planes had similar patterns to the mid-sagittal plane, but with decreased values. And, the changes in the maxillary region were calculated as a ratio, relative to the movement of a point representing a mandibular movement. When B point was used as a representative point, the ratios were $14\~29\%$, and when Pog was used, the ratios were $17\~37\%(9<0.05)$. In case of the 83rd point of the grid, the ratios were $11\~22\%(p<0.05)$.

• The Journal of Korean Academy of Prosthodontics
• /
• v.56 no.1
• /
• pp.8-16
• /
• 2018

Purpose: The purpose of this study is to evaluate the accuracy of surgical stent according to the supported type. Materials and methods: 5 sets of dental models which have tooth supported edentulous area and tooth-tissue supported edentulous area were made. Dental model were scanned with model scanner, and CBCT was taken. CT data and model scan data were overlapped using In2Guide software, implant were virtually planned in the software. Surgical stents are fabricated by 3D printing. The implant fixture were installed using the surgical stent, CBCT were retaken. CBCT before surgery and after surgery were overlapped, and the differences (angle difference, coronal difference, apical difference) were evaluated using statistical analysis. Results: In the assessment of the accuracy of surgical guides according to arch type, there are no statistically significant differences between maxilla and mandible. In the case of support type, tooth supported stents showed lower angle difference and length difference than tooth-tissue supported stents, which are statistically significant. Conclusion: Arch type does not affect the accuracy of surgical stents. But tooth support stents are more accurate than tooth-tissue support stents in the case of angle and length difference.

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