• The Korean Journal of Pain
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• v.27 no.3
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• pp.253-259
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• 2014

Background: Caudal block is a common technique in children for reducing postoperative pain, and there have been several reports on the variations of the sacral canal in children. However, previous studies have mainly focused on the needle trajectory for caudal block, and there is limited information on the structural variations of the sacrum in children. The purpose of this study was to analyze the anatomic variations of sacral canals in children. Methods: Three-dimensional computed tomographic images were analyzed. The data from the images included (1) fusion of the sacral vertebral laminae and the sacral intervertebral space (2) existence of the sacral cornua and (3) the types of sacral hiatus. The types of sacral hiatus were classified into 3 groups: group I (fusion of S3 or S4 vertebral laminae), group II (unfused vertebral arch with the distance of the S3 and S4 vertebral laminae < 50% of the distance between the cornua), and group III (unfused vertebral arch with the distance of the S3 or S4 vertebral laminae ${\geq}50%$ of the distance between the cornua). Results: A total of 143 children were included in this study. All of the sacral vertebral arches were not fused in 22 children (15.4%). Cornua were not identified bilaterally in 5 (3.5%) and unilaterally in 6 (4.2%) children. In the sacral hiatus, group II and group III were identified in 22 (15.4%) and 31 (21.7%) children, respectively. Conclusions: The sacral canal has various anatomical variations in children. Careful attention must be paid to identify the correct anatomic landmark.

• Journal of Korean Neurosurgical Society
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• v.29 no.3
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• pp.345-352
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• 2000

Objective : The purpose of this study was to compare computed tomographic angiography(CTA) with conventional cerebral angiography(CCA) and to assess usefulness of CTA in detection and anatomic definition of intracranial aneurysms of the circle of Willis in subarachnoid hemorrhage. Patients and Methods : Fifty consecutive patients with known or suspected intracranial saccular aneurysms underwent CTA with preoperative CCA from 1997 to 1999. Using surface shaded display post-processing technique, CTA was interpreted for the presence, location of aneurysms and anatomic features. The image obtained with CTA was then compared with CCA image. Results : In 47 patients, CCA revealed 57 cerebral aneurysms and CTA revealed 54 aneurysms. Two of the 57 cerebral aneurysms were located outside of the imaging volume of CTA and one case was misdiagnosed. The sensitivity of CTA was 94.7% and the specificity was 100%. The results obtained with CTA were, compared with the results obtained with CCA, equal in determining dome shape, direction and lobularity. However, CTA provided a 3-dimensional representation of aneurysmal lesion very useful for surgical planning. Moreover, CTA was useful for rapid and relatively noninvasive detection of aneurysms in the circle of Willis. Conclusion : CTA can be a diagnostic tool for the patients with acute subarachnoid hemorrhage due to a ruptured aneurysm of the circle of Willis and provides adequate anatomic detail for surgical planning, especially to complex cerebral aneurysms. However, we think CCA is necessary because of CTA limitations including its difficulty in detecting unusually located aneurysms(including those in cavernous sinus or distal artery) and combined vascular lesion (including arteriovenous malformation) and acquiring dynamic flow information.

• Imaging Science in Dentistry
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• v.53 no.3
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• pp.177-191
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• 2023

Purpose: This systematic review examined the detection of the posterior superior alveolar artery, along with various anatomic characteristics, on cone-beam computed tomography images. Materials and Methods: Studies were identified electronically through the Web of Science, MEDLINE, Scopus, and Embase databases. The quality of the included studies was evaluated using a 5-item binary scale. The detection rate, location, and classified diameter of the posterior superior alveolar artery were estimated as prevalence values. The diameter of this artery, as well as the distances from the artery to the alveolar crest and sinus floor, were estimated as means with associated 95% confidence intervals. Results: Thirty-seven studies were enrolled, with 34 of these included in the meta-analysis. The mean detection rate was 79% (range: 72%-84%), and the mean diameter was 1.06±0.05 mm (range: 0.96-1.16 mm). The posterior superior alveolar artery was located intraosseously in 64% of cases. The mean distance of the artery from the alveolar crest was 16.71±0.49 mm (range: 15.75-17.68 mm), while the mean distance from the artery to the sinus floor was 8.85±0.4 mm (range: 8.05-9.64 mm). Conclusion: According to the findings of this meta-analysis regarding various anatomic characteristics of the posterior superior alveolar artery, severe hemorrhage after damage to this artery during sinus augmentation procedures is not a substantial clinical problem.

• Journal of the Korean Society of Radiology
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• v.81 no.2
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• pp.337-350
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• 2020

The clinical manifestation of pericardial disease is similar to that of coronary artery disease and aortic disease. Therefore, a timely and accurate diagnosis is necessary. The pericardium is a 2-layered membrane that envelops the heart and great vessels, and there are numerous anatomic variations and pathologic conditions. Large or unusually located pericardial recesses can be easily mistaken for abnormal findings. Additionally, primary pericardial diseases resulting from infections, tumors, and injuries are possible; further, diseases can quickly spread along the pericardium. Echocardiography is generally the first imaging tool used to evaluate the pericardium. However, it has limited windows and poor resolution. Besides, the evaluation of postoperative echocardiography is sometimes limited. Currently, CT and MR imaging are useful for evaluating pericardial diseases. Detailed knowledge of the pericardium is important for interpreting the images and clinical results.

• The Journal of the Korean bone and joint tumor society
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• v.14 no.2
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• pp.86-94
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• 2008

$^{18}F$-FDG PET/CT has led to advancement in diagnostic imaging, providing correlation of both physiology and anatomic information, and to new and innovative ways to utilize PET/CT imaging for the evaluation of musculoskeletal tumors. Recently, the most widely utilized musculoskeletal application of PET/CT imaging is for the detection and characterization of bone metastases, staging and restaging of primary malignant bone tumors and soft tissue sarcomas. And it is also useful in evaluating response to therapy for malignant musculoskeletal tumors and in detecting local recurrences or distant metastases during follow up. The future likely holds even more unique and potentially quite useful applications of PET/CT imaging for primary bone and soft tissue tumors. This article will review the useful applications of $^{18}F$-FDG PET/CT imaging for evaluating musculoskeletal tumors.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.2
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• pp.98-111
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• 2008

This review introduces advances in clinical and pre-clinical single photon emission computed tomography (SPECT) and positron emission tomography (PET) providing noninvasive functional images of biological processes. Development of new collimation techniques such as multi-pinhole and slit-slat collimators permits the improvement of system spatial resolution and sensitivity of SPECT. Application specific SPECT systems using smaller and compact solid-state detector have been customized for myocardial perfusion imaging with higher performance. Combined SPECT/CT providing improved diagnostic and functional capabilities has been introduced. Advances in PET and CT instrumentation have been incorporated in the PET/CT design that provide the metabolic information from PET superimposed on the anatomic information from CT. Improvements in the sensitivity of PET have achieved by the fully 3D acquisition with no septa and the extension of axial field-of-view. With the development of faster scintillation crystals and electronics, time-of-flight (TOF) PET is now commercially available allowing the increase in the signal-to-noise ratio by incorporation of TOF information into the PET reconstruction process. Hybrid PET/SPECT/CT systems has become commercially available for molecular imaging in small animal models. The pre-clinical systems have improved spatial resolution using depth-of-interaction measurement and new collimators. The recent works on solid state detector and dual modality nuclear medicine instrumentations incorporating MRI and optical imagers will also be discussed.

• Annals of Clinical Neurophysiology
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• v.4 no.1
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• pp.38-43
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• 2002

Background & Purpose : Dynamic susceptibility contrast MR imaging, one method of perfusion MRI, was developed to define cerebral hemodynamic status with good anatomical resolution. The authors investigated hemodynamic parameters using this imaging method, in an effort to identify hemodynamic changes on the remote crossed cerebellum of patients with a supratentorial infarct. Methods : Dynamic susceptibility contrast MR imaging was performed in 15 patients with only unilateral supratentorial infarcts. Imaging was obtained at the anatomic level of the cerebellum. rCBF, rCBV, MTT and TP were determined over both cerebellar hemispheres of interest. Results : The rCBF and rCBV values of the contralateral cerebellar hemisphere were significantly more decreased than those of the ipsilateral cerebellar hemisphere in 12 patients(p=0.028, 0.033). MTT and TP values of the contralateral and ipsilateral cerebellar hemispheres didn't reveal any differences(p=0.130, 0.121). Conclusions : The results of this work suggest that the region which are remote from the ischemic brain lesion shows no changes of MTT or TP but show decrease of rCBF and rCBV, mean to diaschisis, it also demonstrates that perfusion MRI is an easily available method to evaluate the hemodynamic status of the brain.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.5
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• pp.311-317
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• 2015

The aim of this study is to develop a 3D registration algorithm for positron emission tomography/computed tomography (PET/CT) and magnetic resonance (MR) images acquired from independent PET/CT and MR imaging systems. Combined PET/CT images provide anatomic and functional information, and MR images have high resolution for soft tissue. With the registration technique, the strengths of each modality image can be combined to achieve higher performance in diagnosis and radiotherapy planning. The proposed method consists of two stages: normalized mutual information (NMI)-based global matching and independent component analysis (ICA)-based refinement. In global matching, the field of view of the CT and MR images are adjusted to the same size in the preprocessing step. Then, the target image is geometrically transformed, and the similarities between the two images are measured with NMI. The optimization step updates the transformation parameters to efficiently find the best matched parameter set. In the refinement stage, ICA planes from the windowed image slices are extracted and the similarity between the images is measured to determine the transformation parameters of the control points. B-spline. based freeform deformation is performed for the geometric transformation. The results show good agreement between PET/CT and MR images.

• The Journal of the Korean dental association
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• v.53 no.12
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• pp.967-974
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• 2015

Purpose: This study was performed to investigate the characteristics of mandibular incisive canal (MIC) in Korean population. Materials and methods: A total of 97 subjects (60 males and 37 females) who underwent cone-beam computed tomography were included in the study. The anatomic features of MIC was assessed according to gender. Length, diameter and distance to inferior, lingual and buccal border were measured at the origin and the terminal. Also the distribution of MIC at each tooth position was evaluated. Results: Of 97 patients included, 75(77.3%) presented bilateral MIC and 13(13.4%) presented unilateral MIC. Of 194 hamimandibles, MIC was detected in 102(85%) sites in male and 61(82.4%) sites in female. Gender and side showed no statistically significant differences in detectability. The length, diameter and distance to adjacent structures were bigger in male than in female except the distance to lingual border. MIC travelled anteriorly in a slightly downward and lingual direction and usually terminated between the first premolar and the canine. On cross-sectional view, MIC showed individually scattered distribution both buccolingually and superoinferiorly. Conclusion: MIC is well detected with cone-beam computed tomography. Considered that the length and the location of MIC has large variations between individuals, its localization using cone-beam CT is highly recommended before performing surgical procedures such as implant placement and bone harvesting.

• Imaging Science in Dentistry
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• v.51 no.2
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• pp.217-222
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• 2021

Ewing sarcoma in the head and neck is rare, and metastasis from other bones to the mandible accounts for 0.7% of cases. This report presents a case of oral metastasis in a 24-year-old male patient diagnosed with Ewing sarcoma of the femur (p53 gene mutation and EWSR1-ERG fusion). The chief complaint was numbness in the mandible and pain for 1 month and a hardened, ulcerated exophytic lesion in the right retromolar region. Imaging exams revealed an unspecified thinning of the cortical bone of the inferior alveolar canal in the right mandibular ramus, associated with erosion of the alveolar bone. Histopathological analysis confirmed metastasis of Ewing sarcoma. The patient presented an aggressive disease progression and died 1 month after the oral diagnosis. It is important to recognize the signs and symptoms compatible with rare clinical outcomes, leading to an early diagnosis that can improve patients' quality of life and survival.