• Investigative Magnetic Resonance Imaging
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• 제23권4호
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• pp.283-295
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• 2019

Perirectal cystic lesions are rare entities, for which only a relatively few research publications are available. These lesions are heterogeneous in nature and can range from benign lesions to malignant lesions; thus, they are sometimes difficult to differentiate. Some studies have reported on retrorectal or presacral cystic lesions, but to our knowledge, there have been only a few reports on perirectal cystic lesions. Cystic lesions arise from the retrorectal space as well as the rectal lumen or adjacent organ, and they should be differentiated based on their characteristics and anatomic location. Thus, we comprehensively studied diseases with a cystic component around the rectum, which are perirectal cystic lesions. A clinical challenge with perirectal cystic lesions is that it is sometimes difficult to distinguish malignant lesions from benign lesions and is thus difficult to determine the extent for surgical excision. We thus attempted to identify benign and malignant imaging features of perirectal cystic lesions.

• Imaging Science in Dentistry
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• 제52권1호
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• pp.67-74
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• 2022

Purpose: To focus on the effects of the presence of mesiodens on adjacent teeth and to investigate the timing of its safe removal. Materials and Methods: Cone-beam computed tomography examinations, obtained at Okayama University Hospital over a three-year period, were inspected. Data were recorded including the number of mesiodens; associated abnormalities; and the relationship with neighboring structures. Depending on multiple factors, the risk of developing complications due to early extraction of a mesiodens was divided into three categories: high, medium, and low risk. Results: A total of 5,958 cone-beam computed tomography exams were obtained, 460 patients aged 3-85 years were diagnosed with a total of 568 mesiodens, 382 (67.3%) of which were discovered in young patients (age <10 years), and 333 (87.2%) of these were associated with abnormalities. Regarding the risk categories, 11 (1.9%) were considered to be in the high-risk, five (0.9%) in the medium-risk and 552 (97.2%) in the low-risk categories. Moreover, eight out of 11 high-risk mesiodens were extracted and no post-operative complications have been seen. Conclusion: As the results showed that no postoperative complications were seen in all the extracted cases of high-risk mesiodens, this indicates the possibility of safe extraction at an early age which could reduce related future complications.

• Korean Journal of Radiology
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• 제22권9호
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• pp.1579-1586
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• 2021

Objective: To evaluate the diagnostic performance of the modified Korean Thyroid Imaging Reporting and Data System (K-TIRADS), and compare it with the 2016 version of K-TIRADS using the Thyroid Imaging Network of Korea. Materials and Methods: Between June and September 2015, 5708 thyroid nodules (≥ 1.0 cm) from 5081 consecutive patients who had undergone thyroid ultrasonography at 26 institutions were retrospectively evaluated. We used a biopsy size threshold of 2 cm for K-TIRADS 3 and 1 cm for K-TIRADS 4 (modified K-TIRADS 1) or 1.5 cm for K-TIRADS 4 (modified K-TIRADS 3). The modified K-TIRADS 2 subcategorized the K-TIRADS 4 into 4A and 4B, and the cutoff sizes for the biopsies were defined as 1 cm for K-TIRADS 4B and 1.5 cm for K-TIRADS 4A. The diagnostic performance and the rate of unnecessary biopsies of the modified K-TIRADS for detecting malignancy were compared with those of the 2016 K-TIRAD, which were stratified by nodule size (with a threshold of 2 cm). Results: A total of 1111 malignant nodules and 4597 benign nodules were included. The sensitivity, specificity, and unnecessary biopsy rate of the benign nodules were 94.9%, 24.4%, and 60.9% for the 2016 K-TIRADS; 91.0%, 39.7%, and 48.6% for the modified K-TIRADS 1; 84.9%, 45.9%, and 43.5% for the modified K-TIRADS 2; and 76.1%, 50.2%, and 40.1% for the modified K-TIRADS 3. For small nodules (1-2 cm), the diagnostic sensitivity of the modified K-TIRADS decreased by 5.2-25.6% and the rate of unnecessary biopsies reduced by 19.2-32.8% compared with those of the 2016 K-TIRADS (p < 0.001). For large nodules (> 2 cm), the modified K-TIRADSs maintained a very high sensitivity for detecting malignancy (98%). Conclusion: The modified K-TIRADSs significantly reduced the rate of unnecessary biopsies for small (1-2 cm) nodules while maintaining a very high sensitivity for malignancy for large (> 2 cm) nodules.

• Korean Journal of Radiology
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• 제25권3호
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• pp.267-276
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• 2024

Objective: To evaluate the diagnostic performance of susceptibility map-weighted imaging (SMwI) taken in different acquisition planes for discriminating patients with neurodegenerative parkinsonism from those without. Materials and Methods: This retrospective, observational, single-institution study enrolled consecutive patients who visited movement disorder clinics and underwent brain MRI and ¹⁸F-FP-CIT PET between September 2021 and December 2021. SMwI images were acquired in both the oblique (perpendicular to the midbrain) and the anterior commissure-posterior commissure (AC-PC) planes. Hyperintensity in the substantia nigra was determined by two neuroradiologists. ¹⁸F-FP-CIT PET was used as the reference standard. Inter-rater agreement was assessed using Cohen;s kappa coefficient. The diagnostic performance of SMwI in the two planes was analyzed separately for the right and left substantia nigra. Multivariable logistic regression analysis with generalized estimating equations was applied to compare the diagnostic performance of the two planes. Results: In total, 194 patients were included, of whom 105 and 103 had positive results on ¹⁸F-FP-CIT PET in the left and right substantia nigra, respectively. Good inter-rater agreement in the oblique (κ = 0.772/0.658 for left/right) and AC-PC planes (0.730/0.741 for left/right) was confirmed. The pooled sensitivities for two readers were 86.4% (178/206, left) and 83.3% (175/210, right) in the oblique plane and 87.4% (180/206, left) and 87.6% (184/210, right) in the AC-PC plane. The pooled specificities for two readers were 83.5% (152/182, left) and 82.0% (146/178, right) in the oblique plane, and 83.5% (152/182, left) and 86.0% (153/178, right) in the AC-PC plane. There were no significant differences in the diagnostic performance between the two planes (P > 0.05). Conclusion: There are no significant difference in the diagnostic performance of SMwI performed in the oblique and AC-PC plane in discriminating patients with parkinsonism from those without. This finding affirms that each institution may choose the imaging plane for SMwI according to their clinical settings.

• Korean Journal of Radiology
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• 제22권12호
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• pp.1946-1963
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• 2021

Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (CMR) can reveal the detailed anatomy and function of the tricuspid valve and right ventricle (RV). Quantification of tricuspid regurgitation (TR) and analysis of RV function have prognostic implications. With the recently available transcatheter treatment options for diseases of the tricuspid valve, evaluation of the tricuspid valve using CT and CMR has become important in terms of patient selection and procedural guidance. Moreover, CT enables post-procedural investigation of the causes of valve dysfunction, such as pannus or thrombus. This review describes the anatomy of the tricuspid valve and CT and CMR imaging protocols for right heart evaluation, including RV function and TR analyses. We also demonstrate the pre-procedural planning for transcatheter treatment of TR and imaging of postoperative complications using CT.

• 대한영상의학회지
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• 제85권1호
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• pp.210-214
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• 2024

심실간 막 중격류는 드문 질환이다. 이 동맥류는 우심실 유출 폐색이나 혈전색전증과 같은 합병증을 유발할 수 있으므로 이 동맥류를 발견하는 것은 임상적으로 의의가 있다. 우리는 뇌경색의 원인으로 생각되는 심실간 막 중격류에 생긴 혈전을 보고하고자 한다.

• 한국임상수의학회:학술대회논문집
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• 한국임상수의학회 2007년도 추계국제학술대회 및 컨퍼런스
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• pp.555-555
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• 2007

• Imaging Science in Dentistry
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• 제34권4호
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• pp.215-218
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• 2004

Neurilemmoma is a benign tumor of the nerve sheath that arises on cranial and spinal nerve roots as well as along the course of peripheral nerves. A case of a neurilemmoma that arose in the left infratemporal fossa of a 29-year-old male was presented. Plain radiographs, enhanced computed tomography scan, and magnetic resonance imaging demonstrated a large, well-circumscribed, heterogeneously enhanced mass with extension into the pterygopalatine fossa. Displaced by the large mass, bowing-in of the posterior maxillary antral wall was noted and a provisional diagnosis of a benign soft tissue tumor was made. The mass was completely excised and a diagnosis of neurilemmoma was confirmed.

• Imaging Science in Dentistry
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• 제52권4호
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• pp.435-440
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• 2022

Mucormycosis is a rare, invasive fungal infection that progresses aggressively and requires prompt surgery and appropriate treatment. The number of cases of mucormycosis in coronavirus disease 2019 (COVID-19) patients has recently increased, and patients with uncontrolled diabetes mellitus are particularly at an elevated risk of infection. This report presents a case of mucormycosis-related osteomyelitis of the maxilla in a 37-year-old man with diabetes mellitus. The patient complained of severe and persistent pain in the right maxilla, accompanied by increased tooth mobility and headache. On contrast-enhanced computed tomographic images, gas-forming osteomyelitis of the right maxilla was observed. Destruction of the maxilla and palatine bone then proceeded aggressively. Sequestrectomy was performed on the right maxilla, and the histopathological diagnosis was mucormycosis. Further investigation after the first operation revealed the patient's history of COVID-19 infection.

• Imaging Science in Dentistry
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• 제53권3호
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• pp.257-263
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• 2023

Fibrodysplasia ossificans progressiva is a rare hereditary disorder characterized by progressive heterotopic ossification in muscle and connective tissue, with few reported cases affecting the head and neck region. Although plain radiographic findings and computed tomography features have been well documented, limited reports exist on magnetic resonance findings. This report presents 2 cases of fibrodysplasia ossificans progressiva, one with limited mouth opening due to heterotopic ossification of the lateral pterygoid muscle and the other with restricted neck movement due to heterotopic ossification of the platysma muscle. Clinical findings of restricted mouth opening or limited neck movement, along with radiological findings of associated heterotopic ossification, should prompt consideration of fibrodysplasia ossificans progressiva in the differential diagnosis. Dentists should be particularly vigilant with patients diagnosed with fibrodysplasia ossificans progressiva to avoid exposure to diagnostic biopsy and invasive dental procedures.