• 대한치과보철학회지
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• 제57권3호
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• pp.312-320
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• 2019

디지털 방식을 이용한 치과 임플란트 진료에서 가장 주목받는 분야 중 하나가 디지털 소프트웨어와 컴퓨터 단층촬영을 이용하여 수술용 스텐트를 제작, 임플란트를 식립하는 분야이다. 컴퓨터를 이용한 디지털 임플란트 치료계획 시스템과 이를 이용한 수술용 가이드는 예지성과 심미성, 기능성을 갖춘 임플란트의 식립과 수복을 가능하게 한다. 특히 이러한 가이드 수술은 임플란트 수복물의 형태와 기능을 고려한 임플란트의 식립 시 더욱 유리하다. 최근 여러 제조사에서 보철물 제작을 위해 치과용 스캔부터 제작방법까지 다양한 디지털 방식의 제작과정을 제시하고 있다. 이러한 방법들은 정확하고 예지성 있는 예후를 위해 여러 연구자들에 의해 연구되어지고 있으며, 점차 발전하고 있다. 이번 증례는 완전무치악의 여성 환자에서 임플란트 고정성 보철물을 이용한 수복증례이다. 하악은 all-on-four 방식을 적용하여 4개의 임플란트를 식립하였으며, 상악은 이에 기초하여 6개의 임플란트를 식립하였다. 최종보철물에 기초한 임플란트의 식립을 위해 임플란트 수술용 스텐트를 이용하였으며, 환자는 치료 결과에 만족하였으며, 5년 추적관찰 결과, 임플란트와 보철물 모두 안정적으로 유지되고 있다.

• 대한치과의사협회지
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• 제56권12호
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• pp.695-706
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• 2018

Objectives: The purpose of this study was to investigate the ratio of 4 root canals and the incidence of Radix Entomolaris in mandibular first molars and find out anatomical difference according to number of roots by analysis of cone-beam CT images in a Korean population. Materials and Methods: Total 142 images containing mandibular first molars were selected from CBCT images taken from 2013 to 2017 at Gangneung-Wonju National University Dental Hospital. After reconstructing the image with reference to the Cemento-enamel junction, the root canals were detected at the bottom of the pulpal floor and the number of roots and root canals were analyzed. Various lengths and MLO-DLO-DBO angle were measured between each canal orifices and the external contour line of the tooth, and the distolingual canal wall thickness was measured. Student t-test was used for statistical significance. Results: Among the total 142 teeth, 4 canals were 42.2% and Radix Entomolaris was 25.3%. As the results of measuring various lengths and the angle, the distolingual canal orifice in Group 2(with Radix Entomolaris) tends to deviate to the lingual side than the mesiolingual canal orifice and to the mesial side than the distobuccal canal orifice. Besides, thickness of the distolingual canal wall in Group 2(with Radix Entomolaris) was significantly thinner than that of Group 1 at every level except pulpal floor level. Conclusion: It is necessary to consider the difference according to the presence of Radix Entomolaris in endodontic treatment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제48권5호
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• pp.297-302
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• 2022

Objectives: This retrospective study aimed to analyze data on nerve damage in patients who complained of sensory changes after dental implant surgery, the clinical results according to proximity of the implant fixture to the inferior alveolar nerve (IAN) canal, and the factors affecting recovery of sensation. Materials and Methods: The electronic medical records of 64 patients who had experienced sensory change after implant surgery were reviewed. Patients were classified by sex, age, implant installation sites, recovery rate and the distance between the implant fixture and IAN canal on computed tomography (CT). The distance was classified into Group I (D>2 mm), Group II (2 mm≥D>0 mm), and Group III (D≤0 mm). Results: The 64 patients were included and the mean age was 57.3±7.3 years. Among the 36 patients who visited our clinic more than two times, 21 patients (58.3%) reported improvement in sensation, 13 patients (36.1%) had no change in sensation, and 2 patients (5.6%) reported worsening sensation. In Group II, symptom improvement was achieved in all patients regardless of the removal of the implant fixture. In Group III, 8 patients (40.0%) had reported symptom improvement with removal of the implant fixture, and 2 patients (33.3%) of recovered patients showed improvement without removal. Removal of the implant fixture in Group III did not result in any significant difference in recovery (P=0.337), although there was a higher possibility of improvement in sensation in removal cases. Conclusion: Clinicians first should consider removing the fixture when it directly invades the IAN canal. However, in cases of sensory change after dental implant surgery where the drill or implant fixture did not invade the IAN canal, other indirect factors such as flap elevation and damage due to anesthesia should be considered as causes of sensory change. Removal of the implant should be considered with caution in these situations.

• 대한치과보철학회지
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• 제60권1호
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• pp.44-54
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• 2022

다수 치아의 상실 상태로 장시간 지속시 구치부 지지의 부족 및 치아들의 과정출이 발생되어 교합 부조화, 수직고경 상실 및 기능 장애 등의 심각한 문제가 초래된다. 본 증례는 장기간 다수치아 결손으로 인하여 대합치가 정출하면서 교합평면의 붕괴가 일어난 환자의 완전 구강 회복에 관한 증례이다. 상기 환자는 서울대학교 치과병원 치과보철과로 내원한 68세 남환으로 오래된 상악 의치를 빼다가 치아가 함께 발거되었으며, 하악 전치부가 상악 전치부와 강하게 닿아서 불편함을 호소하며 내원하였다. 여러가지 평가를 통해 수직고경을 4 mm 거상하였으며, 무치악부는 진단 및 치료계획시 설계한 최종 보철 수복물 제작을 고려하여 정확한 임플란트 식립을 위해 CAD-CAM (Computer-aided design-computer-aided manufacturing) 기술을 이용한 Computer guided implant surgery를 시행하고, 임플란트 고정성 보철 수복으로 진행하였고, 환자는 저작, 기능 및 심미 모두 큰 개선에 만족하였다.

• 한국방사선학회논문지
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• 제17권3호
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• pp.375-384
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• 2023

간혈관종은 우리 몸에서 흔하게 발생하는 간병변 중 하나이다. 대부분 간혈관종은 증상이 없고 크기도 작기에 병리학적 검사로는 발견하기 어렵다. 따라서 간혈관종의 초기 발견 및 진단을 하기 위해서는 방사선 진단은 필수이다. 본 연구는 간혈관종에 대한 방사선진단인 전산화단층촬영, 자기공명영상, 핵의학, 초음파 검사의 방법에 대하여 연구하였다. 전산화단층촬영에서는 조영제를 이용한 삼중시기 기법, 자기공명영상 검사에서는 T1, T2 강조영상, 조영제를 이용한 동적 자기공명영상, 초고속 자기공명 영상기법, 확산강조영상의 방법, 핵의학에선 ^99mTc 표지 적혈구를 사용한 혈액풀 스캔방법, 초음파에선 색조도플러의 방법에 대해 연구하였다. 대부분의 간혈관종은 양성종양이기에 간세포암 등과 같은 악성 종양과 혼동하지 않게 주의하여 불필요한 시술을 방지해야 한다. 그러므로 정확한 진단을 하기 위해서는 간혈관종의 영상소견을 정확히 숙지하여 검사를 시행하는 것이 중요하다.

• Korean Journal of Radiology
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• 제22권12호
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• pp.1996-2005
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• 2021

Objective: To investigate the multidetector computed tomography (MDCT) features of fumarate hydratase-deficient renal cell carcinoma (FH-deficient RCC) with germline or somatic mutations, and compare them with those of papillary type II RCC (pRCC type II). Materials and Methods: A total of 24 patients (mean ± standard deviation, 40.4 ± 14.7 years) with pathologically confirmed FH-deficient RCC (15 with germline and 9 with somatic mutations) and 54 patients (58.6 ± 12.6 years) with pRCC type II were enrolled. The MDCT features were retrospectively reviewed and compared between the two entities and mutation subgroups, and were correlated with the clinicopathological findings. Results: All the lesions were unilateral and single. Compared with pRCC type II, FH-deficient RCC was more prevalent among younger patients (40.4 ± 14.7 vs. 58.6 ± 12.6, p < 0.001) and tended to be larger (8.1 ± 4.1 vs. 5.4 ± 3.2, p = 0.002). Cystic solid patterns were more common in FH-deficient RCC (20/24 vs. 16/54, p < 0.001), with 16 of the 20 (80.0%) cystic solid tumors having showed typical polycystic and thin smooth walls and/or septa, with an eccentric solid component. Lymph node (16/24 vs. 16/54, p = 0.003) and distant (11/24 vs. 3/54, p < 0.001) metastases were more frequent in FH-deficient RCC. FH-deficient RCC and pRCC type II showed similar attenuation in the unenhanced phase. The attenuation in the corticomedullary phase (CMP) (76.3% ± 25.0% vs. 60.2 ± 23.6, p = 0.008) and nephrographic phase (NP) (87.7 ± 20.5, vs. 71.2 ± 23.9, p = 0.004), absolute enhancement in CMP (39.0 ± 24.8 vs. 27.1 ± 22.7, p = 0.001) and NP (50.5 ± 20.5 vs. 38.2 ± 21.9, p = 0.001), and relative enhancement ratio to the renal cortex in CMP (0.35 ± 0.26 vs. 0.24 ± 0.19, p = 0.001) and NP (0.43 ± 0.24 vs. 0.29 ± 0.19, p < 0.001) were significantly higher in FH-deficient RCC. No significant difference was found between the FH germline and somatic mutation subgroups in any of the parameters. Conclusion: The MDCT features of FH-deficient RCC were different from those of pRCC type II, whereas there was no statistical difference between the germline and somatic mutation subgroups. A kidney mass with a cystic solid pattern and metastatic tendency, especially in young patients, should be considered for FH-deficient RCC.

• Korean Journal of Radiology
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• 제22권9호
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• pp.1547-1554
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• 2021

Objective: We aimed to investigate whether repeated intravascular administration of iodinated contrast media (ICM) or gadolinium-based contrast agents (GBCAs) within a short interval was associated with an increased risk of post-contrast acute kidney injury (PC-AKI). Materials and Methods: This retrospective study included 300 patients (mean age ± standard deviation, 68.5 ± 8.1 years; 131 male and 169 female) who had undergone at least one ICM-enhanced perfusion brain CT scan, had their baseline and follow-up serum creatinine levels available, and had not undergone additional contrast-enhanced examinations 72 hours before and after a time window of interest were included. The study population was divided into three groups: single-dose group and groups of patients who had received multiple contrast administrations in the time window of interest with the minimum contrast repeat interval either within 4 hours (0-4-hour group) or between 4 to 48 hours (4-48-hour group). Multivariable logistic regression analysis was conducted to evaluate the association between AKI and repeated ICM administrations. A similar supplementary analysis was performed including both ICM and GBCA. Results: When ICM was only considered ignoring GBCA, among 300 patients, 207 patients received a single dose of ICM, 58 had repeated doses within 4 hours (0-4-hour group), and 35 patients had repeated doses between 4 to 48 hours (4-48-hour group). Most patients (> 95%) had a baseline estimated glomerular filtration rate (eGFR) of ≥ 30 mL/min/1.73 m². AKI occurred in 7.2%, 13.8%, and 8.6% of patients in the single-dose, 0-4-hour, and 4-48-hour groups, respectively. In the 0-4-hour and 4-48-hour groups, additional exposure to ICM was not associated with AKI after adjusting for comorbidities and nephrotoxic drugs (all p values > 0.05). Conclusion: Repeated intravascular administrations of ICM within a short interval did not increase the risk of AKI in our study patients suspected of acute stroke with a baseline eGFR of ≥ 30 mL/min/1.73 m².

• Korean Journal of Radiology
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• 제22권11호
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• pp.1875-1885
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• 2021

Objective: Central nervous system involvement in coronavirus disease 2019 (COVID-19) has been increasingly reported. We performed a systematic review and meta-analysis to evaluate the incidence of radiologically demonstrated neurologic complications and detailed neuroimaging findings associated with COVID-19. Materials and Methods: A systematic literature search of MEDLINE/PubMed and EMBASE databases was performed up to September 17, 2020, and studies evaluating neuroimaging findings of COVID-19 using brain CT or MRI were included. Several cohort-based outcomes, including the proportion of patients with abnormal neuroimaging findings related to COVID-19 were evaluated. The proportion of patients showing specific neuroimaging findings was also assessed. Subgroup analyses were also conducted focusing on critically ill COVID-19 patients and results from studies that used MRI as the only imaging modality. Results: A total of 1394 COVID-19 patients who underwent neuroimaging from 17 studies were included; among them, 3.4% of the patients demonstrated COVID-19-related neuroimaging findings. Olfactory bulb abnormalities were the most commonly observed (23.1%). The predominant cerebral neuroimaging finding was white matter abnormality (17.6%), followed by acute/subacute ischemic infarction (16.0%), and encephalopathy (13.0%). Significantly more critically ill patients had COVID-19-related neuroimaging findings than other patients (9.1% vs. 1.6%; p = 0.029). The type of imaging modality used did not significantly affect the proportion of COVID-19-related neuroimaging findings. Conclusion: Abnormal neuroimaging findings were occasionally observed in COVID-19 patients. Olfactory bulb abnormalities were the most commonly observed finding. Critically ill patients showed abnormal neuroimaging findings more frequently than the other patient groups. White matter abnormalities, ischemic infarctions, and encephalopathies were the common cerebral neuroimaging findings.

• 대한영상의학회지
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• 제83권6호
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• pp.1286-1297
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• 2022

목적 고관절 인공치환물을 가진 환자에서 여러 가지 금속인공물 감소 효과를 비교하였다. 대상과 방법 이 연구는 고관절 인공치환술과 이중에너지 전산화단층촬영을 시행한 47명 환자에서 시행하였다. 금속에서 발생한 인공물 감소효과는 서로 다른 3개의 영상(고식적 영상, 금속인공물 감소영상, 가상 단일에너지 영상)에서 비교하였다. 이를 위해 인공관절 주변 7곳에서 금속인공물에 대한 정량적 분석과 정성적 분석을 시행하였다. 결과 금속인공물 감소영상에서 가장 낮은 영상잡음과 인공물 지수를 보였고, 다음으로는 가상 단일에너지 영상이었다. 금속인공물 감소영상은 저음영 인공물이 매우 심한 영역에서만 높은 대조도를 보인 반면, 가상 단일에너지 영상은 인공물 주변 골조직과 그 외 영역에서 높은 대조도를 보였다. 연부조직 분석에서도 금속인공물 감소영상이 더 우수함을 보여 주었다. 정성적 분석에서도 금속인공물 감소영상이 가상 단일에너지 영상보다 인공물 감소 효과가 뛰어남을 밝혔지만, 이차적인 인공물 발생도 가장 흔히 발생하였다. 결론 금속인공물 감소영상이 심한 금속인공물감소에 가장 뛰어난 효과를 보였지만 새로운 이차적 인공물을 발생시켰다. 가상 단일에너지 영상은 인공물 주변 골조직 평가에서 우수함을 보였다.

• Korean Journal of Radiology
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• 제21권11호
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• pp.1230-1238
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• 2020

Objective: We aimed to assess the effects of remote ischemic pre-conditioning (RIPC) on the incidence of contrast-induced nephropathy (CIN) after an intravenous (IV) or intra-arterial injection of contrast medium (CM) in patient and control groups. Materials and Methods: This prospective, randomized, single-blinded, controlled trial included 26 patients who were hospitalized for the evaluation of the feasibility of transcatheter aortic valve implantation and underwent investigations including contrast-enhanced computed tomography (CT), with Mehran risk scores greater than or equal to six. All the patients underwent four cycles of five minute-blood pressure cuff inflation followed by five minutes of total deflation. In the RIPC group (n = 13), the cuff was inflated to 50 mm Hg above the patient's systolic blood pressure (SBP); in the control group (n = 13), it was inflated to 10 mm Hg below the patient's SBP. The primary endpoint was the occurrence of CIN. Additionally, variation in the serum levels of cystatin C was assessed. Results: One case of CIN was observed in the control group, whereas no cases were detected in the RIPC group (p = 0.48, analysis of 25 patients). Mean creatinine values at the baseline, 24 hours after injection of CM, and 48 hours after injection of CM were 88 ± 32 μmol/L, 91 ± 28 μmol/L and 82 ± 29 μmol/L, respectively (p = 0.73) in the RIPC group, whereas in the control group, they were 100 ± 36 μmol/L, 110 ± 36 μmol/L, and 105 ± 34 μmol/L, respectively (p = 0.78). Cystatin C values (median [Q1, Q3]) at the baseline, 24 hours after injection of CM, and 48 hours after injection of CM were 1.10 [1.08, 1.18] mg/L, 1.17 [0.97, 1.35] mg/L, and 1.12 [0.99, 1.24] mg/L, respectively (p = 0.88) in the RIPC group, whereas they were 1.11 [0.97, 1.28] mg/L, 1.13 [1.08, 1.25] mg/L, and 1.16 [1.03, 1.31] mg/L, respectively (p = 0.93), in the control group. Conclusion: The risk of CIN after an IV injection of CM is very low in patients with Mehran risk score greater than or equal to six and even in the patients who are unable to receive preventive hyperhydration. Hence, the Mehran risk score may not be an appropriate method for the estimation of the risk of CIN after IV CM injection.