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  • Title/Summary/Keyword: Computed Tomography X-Ray

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Generalized Pulp Stones of Primary Dentition in a Patient with Molar-Incisor Malformation : A Case Report (Molar-Incisor Malformation 환자의 유치열 내 전반적인 치수석 관찰의 증례 보고)

  • Lee, Dongyun;Shin, Jisun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.47 no.3
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    • pp.337-343
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    • 2020
  • Molar-incisor malformation (MIM) is a new type of root anomaly reported recently. The characteristics of MIM are dysplastic root formations, constriction of pulp chambers and presence of calcified matrices at the level of cementoenamel junction in permanent first molars and primary second molars. In some cases, permanent maxillary incisors are also affected. The permanent first molars of the patient in this case report were affected with MIM. Generalized pulp stones were observed in overall primary dentition. Micro-computed tomography (micro-CT) imaging and scanning electron microscope-energy dispersive X-ray spectrometer analysis were performed on the extracted mandibular first molar and maxillary primary second molar of the patient. Micro-CT images revealed the discontinuity of enamel directly connected to an accessory canal of the root.

Correlation between Bone Mineral Density Measured by Dual-Energy X-Ray Absorptiometry and Hounsfield Units Measured by Diagnostic CT in Lumbar Spine

  • Lee, Sungjoon;Chung, Chun Kee;Oh, So Hee;Park, Sung Bae
    • Journal of Korean Neurosurgical Society
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    • v.54 no.5
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    • pp.384-389
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    • 2013
  • Objective : Use of quantitative computed tomography (CT) to evaluate bone mineral density was suggested in the 1970s. Despite its reliability and accuracy, technical shortcomings restricted its usage, and dual-energy X-ray absorptiometry (DXA) became the gold standard evaluation method. Advances in CT technology have reduced its previous limitations, and CT evaluation of bone quality may now be applicable in clinical practice. The aim of this study was to determine if the Hounsfield unit (HU) values obtained from CT correlate with patient age and bone mineral density. Methods : A total of 128 female patients who underwent lumbar CT for back pain were enrolled in the study. Their mean age was 66.4 years. Among them, 70 patients also underwent DXA. The patients were stratified by decade of life, forming five age groups. Lumbar vertebrae L1-4 were analyzed. The HU value of each vertebra was determined by averaging three measurements of the vertebra's trabecular portion, as shown in consecutive axial CT images. The HU values were compared between age groups, and correlations of HU value with bone mineral density and T-scores were determined. Results : The HU values consistently decreased with increasing age with significant differences between age groups (p<0.001). There were significant positive correlations (p<0.001) of HU value with bone mineral density and T-score. Conclusion : The trabecular area HU value consistently decreases with age. Based on the strong positive correlation between HU value and bone mineral density, CT-based HU values might be useful in detecting bone mineral diseases, such as osteoporosis.

Suggestion of the morphological characteristic parameters according to the Lee's physical constitution theory using X-ray computed tomography (X선 CT화상을 이용한 사상체질의 형태학적 특징 파라메타의 제안)

  • Jo, Bong-Kwan;Bae, Jong-Il;Ko, Byung-Hee;Saito, Masao
    • Proceedings of the KOSOMBE Conference
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    • v.1993 no.11
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    • pp.13-16
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    • 1993
  • In this paper the morphological characteristic parameters according to the Lee's physical constitution theory are suggested using the X-ray computed tomography. The Lee's physical constitution theory is classify into 4 physical constitutional types by the relative degree of visceral function: those are macro-negative(strong liver- weak lung), micro-negative(strong kidney- weak spleen), micro-positive(strong spleen- weak kidney) and macro-positive(string lung- weak liver). The morphological characteristic parameters are the following. The AA-line is the distance between Rt. & Lt. acupuncture point keug-cheun. The BB-line is the length of lung. The CC-line is the longest width of thorax. The DD-line is the vertical distance between the CC-line and the EE-line. The EE-line is the distance between the Rt. and Lt. anterior superior iliac spines. As the results macro-negative(strong liver-weak lung) has the longest CC-line and the short BB-line. Micro-negative(strong kidney-weak spleen) has the longest EE-line and the short CC-line. Micro-positive(strong spleen-weak kidney) has the longest DD-line and the short BB-line. And macro-positive(strong lung-weak kidney) has the longest BB-line and the short EE-line.

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An Analysis of Pore Network of Drilling Core from Pohang Basin for Geological Storage of CO2 (이산화탄소 지중저장을 위한 포항분지 시추코어의 공극구조 분석)

  • Park, Jihwan;Park, Hyeong-Dong
    • Tunnel and Underground Space
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    • v.26 no.3
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    • pp.181-191
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    • 2016
  • In geological storage of CO2, the behavior of CO2 is influenced by pore network of rock. In this study, the drilling cores from Pohang Basin were analyzed quantitatively using three-dimensional images acquired by X-ray micro computed tomography. The porosities of sandstone specimens around 740 m-depth (T1), 780 m-depth (T2) and 810 m-depth (T3) which were target strata were 25.22%, 23.97%, 6.28%, respectively. Equivalent diameter, volume, area, local thickness of pores inside the sandstone specimens were analyzed. As a result, the microstructural properties of T1 and T2 specimens were more suitable for geological storage of CO2 than those of T3 specimens. The result of the study can be used as input data of the site for decision of injection condition, flow simulation and so on.

Comparison of Based on Histogram Equalization Techniques by Using Normalization in Thoracic Computed Tomography (흉부 컴퓨터 단층 촬영에서 정규화를 사용한 다양한 히스토그램 평준화 기법을 비교)

  • Lee, Young-Jun;Min, Jung-Whan
    • Journal of radiological science and technology
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    • v.44 no.5
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    • pp.473-480
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    • 2021
  • This study was purpose to method that applies for improving the image quality in CT and X-ray scan, especially in the lung region. Also, we researched the parameters of the image before and after applying for Histogram Equalization (HE) such as mean, median values in the histogram. These techniques are mainly used for all type of medical images such as for Chest X-ray, Low-Dose Computed Tomography (CT). These are also used to intensify tiny anatomies like vessels, lung nodules, airways and pulmonary fissures. The proposed techniques consist of two main steps using the MATLAB software (R2021a). First, the technique should apply for the process of normalization for improving the basic image more correctly. In the next, the technique actively rearranges the intensity of the image contrast. Second, the Contrast Limited Adaptive Histogram Equalization (CLAHE) method was used for enhancing small details, textures and local contrast of the image. As a result, this paper shows the modern and improved techniques of HE and some advantages of the technique on the traditional HE. Therefore, this paper concludes that various techniques related to the HE can be helpful for many processes, especially image pre-processing for Machine Learning (ML), Deep Learning (DL).

Fractal dimension analysis on CBCT scans for detecting low bone mineral density in postmenopausal women

  • Carvalho, Bruno Fontenele;de Castro, Julia Goncalves Koehne;de Melo, Nilce Santos;Figueiredo, Paulo Tadeu de Souza;Moreira-Mesquita, Carla Ruffeil;de Paula, Ana Patricia;Sindeaux, Rafael;Leite, Andre Ferreira
    • Imaging Science in Dentistry
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    • v.52 no.1
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    • pp.53-60
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    • 2022
  • Purpose: The aim of this study was to compare the fractal dimension (FD) measured at 2 bone sites (second cervical vertebra and mandible) on cone-beam computed tomography (CBCT). The research question was whether FD could serve as an accessory tool to refer postmenopausal women for densitometric analysis. Therefore, the reliability and accuracy of FD were evaluated. Materials and Methods: In total, 103 postmenopausal women were evaluated, of whom 52 had normal bone mineral density and 51 had osteoporosis, according to dual X-ray absorptiometry of the lumbar spine and hip. On the CBCT scans, 2 regions of interest were selected for FD analysis: 1 at the second cervical vertebra and 1 located at the mandible. The correlations between both measurements, intra- and inter-observer agreement, and the accuracy of the measurements were calculated. A P value less than 0.05 was considered to indicate statistical significance for all tests. Results: The mean FD values were significantly lower at the mandibular region of interest in osteoporotic patients than in individuals with normal bone mineral density. The areas under the curve were 0.644 (P=0.008) and 0.531 (P=0.720) for the mandibular and vertebral sites, respectively. Conclusion: FD at the vertebral site could not be used as an adjuvant tool to refer women for osteoporosis investigation. Although FD differed between women with normal BMD and osteoporosis at the mandibular site, it demonstrated low accuracy and reliability.

Development of pre-procedure virtual simulation for challenging interventional procedures: an experimental study with clinical application

  • Seong, Hyunyoung;Yun, Daehun;Yoon, Kyung Seob;Kwak, Ji Soo;Koh, Jae Chul
    • The Korean Journal of Pain
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    • v.35 no.4
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    • pp.403-412
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    • 2022
  • Background: Most pain management techniques for challenging procedures are still performed under the guidance of the C-arm fluoroscope although it is sometimes difficult for even experienced clinicians to understand the modified three-dimensional anatomy as a two-dimensional X-ray image. To overcome these difficulties, the development of a virtual simulator may be helpful. Therefore, in this study, the authors developed a virtual simulator and presented its clinical application cases. Methods: We developed a computer program to simulate the actual environment of the procedure. Computed tomography (CT) Digital Imaging and Communications in Medicine (DICOM) data were used for the simulations. Virtual needle placement was simulated at the most appropriate position for a successful block. Using a virtual C-arm, the authors searched for the position of the C-arm at which the needle was visualized as a point. The positional relationships between the anatomy of the patient and the needle were identified. Results: For the simulations, the CT DICOM data of patients who visited the outpatient clinic was used. When the patients revisited the clinic, images similar to the simulated images were obtained by manipulating the C-arm. Transforaminal epidural injection, which was difficult to perform due to severe spinal deformity, and the challenging procedures of the superior hypogastric plexus block and Gasserian ganglion block, were successfully performed with the help of the simulation. Conclusions: We created a pre-procedural virtual simulation and demonstrated its successful application in patients who are expected to undergo challenging procedures.

3D Medical Image Data Augmentation for CT Image Segmentation (CT 이미지 세그멘테이션을 위한 3D 의료 영상 데이터 증강 기법)

  • Seonghyeon Ko;Huigyu Yang;Moonseong Kim;Hyunseung Choo
    • Journal of Internet Computing and Services
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    • v.24 no.4
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    • pp.85-92
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    • 2023
  • Deep learning applications are increasingly being leveraged for disease detection tasks in medical imaging modalities such as X-ray, Computed Tomography (CT), and Magnetic Resonance Imaging (MRI). Most data-centric deep learning challenges necessitate the use of supervised learning methodologies to attain high accuracy and to facilitate performance evaluation through comparison with the ground truth. Supervised learning mandates a substantial amount of image and label sets, however, procuring an adequate volume of medical imaging data for training is a formidable task. Various data augmentation strategies can mitigate the underfitting issue inherent in supervised learning-based models that are trained on limited medical image and label sets. This research investigates the enhancement of a deep learning-based rib fracture segmentation model and the efficacy of data augmentation techniques such as left-right flipping, rotation, and scaling. Augmented dataset with L/R flipping and rotations(30°, 60°) increased model performance, however, dataset with rotation(90°) and ⨯0.5 rescaling decreased model performance. This indicates the usage of appropriate data augmentation methods depending on datasets and tasks.

Evaluation of the postoperative maxillary sinus with computed tomography

  • Kim Hee-Kyung;Heo Min-Suk;Lee Sam-Sun;Choi Hyun-Bae;Choi Soon-Chul;Park Tae-Won
    • Imaging Science in Dentistry
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    • v.32 no.4
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    • pp.195-200
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    • 2002
  • Purpose: To evaluate the computed tomographic appearances of post-operative maxillary sinuses. Materials and Methods: 33 asymptomatic cases of post-operative maxillary sinus without evidence of any pathologic changes and clinical symptoms were selected. CT images were classified as opacification, soft tissue shadow, anterior wall depression, naso-antral communication, and compartmentalization. The relationships between the CT image and the age of patients at the time of operatation, and between the CT image and the duration of time elapsed since the surgical procedure were evaluated. Results: The most commonly presented radiological characteristics that occurred after the Caldwell-Luc procedure were opacification and soft tissue shadow. Anterior wall depression and naso-antral communication were radiographic indications that a Caldwell-Luc operation had been carried out. The age of patients when they had been first operated on, and the duration between the surgical procedure and the time of evaluation had no effect on the CT appearances of normal changes. In cases involving a longer time interval between the antral surgery and evaluation, the anterior wall depression with bony healing was more commonly observed than soft tissue healing. Conclusion: The radiographic information regarding the normal healing state using computed tomography can distinguish post-operative changes from inflammatory and cystic disease in patients who have undergone a Caldwell-Luc type of radical maxillary antrostomy.

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Comparison of Volumes between Four-Dimensional Computed Tomography and Cone-Beam Computed Tomography Images using Dynamic Phantom (호흡동조전산화단층촬영과 콘빔전산화단층촬영의 팬텀 영상 체적비교)

  • Kim, Seong-Eun;Won, Hui-Su;Hong, Joo-Wan;Chang, Nam-Jun;Jung, Woo-Hyun;Choi, Byeong-Don
    • The Journal of Korean Society for Radiation Therapy
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    • v.28 no.2
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    • pp.123-130
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    • 2016
  • Purpose : The aim of this study was to compare the differences between the volumes acquired with four-dimensional computed tomography (4DCT)images with a reconstruction image-filtering algorithm and cone-beam computed tomography (CBCT) images with dynamic phantom. Materials and Methods : The 4DCT images were obtained from the computerized imaging reference systems (CIRS) phantom using a computed tomography (CT) simulator. We analyzed the volumes for maximum intensity projection (MIP), minimum intensity projection (MinIP) and average intensity projection (AVG) of the images obtained with the 4DCT scanner against those acquired from CBCT images with CT ranger tools. Results : Difference in volume for node of 1, 2 and 3 cm between CBCT and 4DCT was 0.54~2.33, 5.16~8.06, 9.03~20.11 ml in MIP, respectively, 0.00~1.48, 0.00~8.47, 1.42~24.85 ml in MinIP, respectively and 0.00~1.17, 0.00~2.19, 0.04~3.35 ml in AVG, respectively. Conclusion : After a comparative analysis of the volumes for each nodal size, it was apparent that the CBCT images were similar to the AVG images acquired using 4DCT.

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