• 대한치과의사협회지
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• 제57권11호
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• pp.700-707
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• 2019

On account of the dentistry mainly deals with hard tissues such as teeth and bones, CBCT and CT are common imaging modality in clinics. Recently, insurance coverage of MRI has been extended to head and neck region. In addition, unlike CBCT or CT, ionizing radiation is not used, the demand for MRI is gradually increasing in dentistry. Even though, many dentists still think that MRI is a difficult diagnostic tool and they are not confident when to use it. Therefore, the objective of this manuscript is to help the dental clinicians to access easily on MRI by introducing the overview, application and precautions of this imaging tool.

• 한국임상수의학회지
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• 제25권3호
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• pp.176-181
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• 2008

Fluid accumulation within the tympanic bulla is an important diagnostic indicator of canine otitis media although its identification can be a challenge using currently available imaging techniques. The purpose of this study was to compare radiography, computed tomography (CT) and magnetic resonance imaging (MRI) in the identification of fluid accumulation within canine tympanic bulla. Unilateral tympanic bulla in 10 beagles were experimentally filled with blood or saline. Quantitative analysis of CT images were obtained by using Hounsfield unit (HU). MR signal intensity was obtained by using region of interesting (ROI) and compared with those of gray matter. On the CT image, the presence of blood or saline produced a fluid opacity occupying the tympanic bulla. On the MR image, the appearance of blood in the tympanic bulla was isointense in T1-weighted images and hyperintense in T2-weighted images. However, the appearance of saline in the tympanic bulla was hypointense in T1-weighted images and hyperintense in T2-weighted images. This study suggest that CT and MR imaging are useful methods for detection and differentiation of fluid in canine tympanic bulla.

• Radiation Oncology Journal
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• 제30권4호
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• pp.173-181
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• 2012

Purpose: To evaluate the prognostic value of preoperative neck lymph node (LN) assessment with $^{18}F$-fluorodeoxyglucose positron emission tomography ($^{18}F$-FDG PET), computed tomography (CT), and magnetic resonance imaging (MRI) in oral cavity squamous cell carcinoma (OSCC) patients with pathologically positive LN. Materials and Methods: In total, 47 OSCC patients with pathologically positive LN were retrospectively reviewed with preoperative $^{18}F$-FDG PET and CT/MRI. All patients underwent surgical resection, neck dissection and postoperative adjuvant radiotherapy and/or chemotherapy between March 2002 and October 2010. Histologic correlation was performed for findings of $^{18}F$-FDG PET and CT/MRI. Results: Thirty-six (76.6%) of 47 cases were correctly diagnosed with neck LN metastasis by $^{18}F$-FDG PET and 32 (68.1%) of 47 cases were correctly diagnosed by CT/MRI. Follow-up ranged from 20 to 114 months (median, 56 months). Clinically negative nodal status evaluated by $^{18}F$-FDG PET or CT/MRI revealed a trend toward better clinical outcomes in terms of overall survival, disease-free survival, local recurrence-free survival, regional nodal recurrence-free survival, and distant metastasis-free survival rates even though the trends were not statistically significant. However, there was no impact of neck node standardized uptake value ($SUV_{max}$) on clinical outcomes. Notably, $SUV_{max}$ showed significant correlation with tumor size in LN (p < 0.01, $R^2$ = 0.62). PET and CT/MRI status of LN also had significant correlation with the size of intranodal tumor deposit (p < 0.05, $R^2$ = 0.37 and p < 0.01, $R^2$ = 0.48, respectively). Conclusion: $^{18}F$-FDG PET and CT/MRI at the neck LNs might improve risk stratification in OSCC patients with pathologically positive neck LN in this study, even without significant prognostic value of $SUV_{max}$.

• 대한한의학회지
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• 제17권1호
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• pp.171-189
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• 1996

Background and Purpose: The greater part of patients to visit Hospital of Oriental Medicine suffer from cerebrovascular accident(CVA). There is transcranial Doppler(TCD) in the diagnostic method to confirm cerebrovascular accident(CVA). Transcranial Doppler(TCD) is an accurate method of monitoring the blood flow velocities of the cerebral vessels and have been generally used to prevent symptomatic vasospasm and confirm cerebral infarction. So we studied, in the crebrovascular accident(CVA), to estimate whether transcranial Doppler(TCD) is useful to. Methods: Using transcranial doppler(Multigon Model 500M Transcranial Doppler System), we measured the mean and peak velocity and the direction of blood flow in 10 cerebrovascular accident(CVA)'s subjects who had been examined by Computed Tomography(CT) or Magnetic Resonance Imaging (MRI). Results : As an anticipation, in cerebrovascular accident(CVA)'s subject with Cb-infarction, the mean and peak velocity of blood flow fell down remarkably and the direction of blood flow was change or irritable. But didn't find out any signal in lacunar infarction. Also, in case with spontaneous hemorrhage, the velocity and direction of blood flow was change but this signal was short of diagnosis for Cb-hemorrhage. Besides, we found signals about embolism, stenosis, thrombosis and occlusion in cerebrovascular accident(CVA)'s subjects. Conclusion: In Cb-infarction, the result of TCD was equal to diagnosis with Computed Tomography(CT) or Magnetic Resonance Imaging (MRI). But about lacunar infarction or spontaneous hemorrhage, signals of TCD couldn't be found out or was insufficient more than Computed Tomography(CT) or Magnetic Resonance Imaging(MRI). In cerebrovascular accident(CVA)'s subject with embolism, stenosis, thrombosis or occlusion, signals of TCD were found out more than Computed Tomography(CT) or Magnetic Resonance Imaging(MRI). Therefore transcranial doppler(TCD) is necessary method which makes a diagnosis of cerebrovascular accident(CVA), with Computed Tomography(CT) or Magnetic Resonance Imaging(MRI).

• 한국방사선학회논문지
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• 제18권2호
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• pp.171-177
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• 2024

본 연구에서는 대전지역 종합병원 중 일반촬영장치, CT, MRI 검사 장치 각 2대씩 선정하여 시간대 별 검사 장치의 표면오염도를 측정하여 감염도를 예측하고 감염 예방을 위한 기초자료로 활용하고자 실험을 하였다. 그 결과 일반촬영장치와 MRI 검사장치의 시간대 별 표면 오염도는 13시>8시>16시 순이였으며, CT검사 장치는 13시>16시>8시 순이었으며 이는 검사 건수의 영향으로 나타났다. 또한 검사 장치 부위 별 표면 오염도 결과는 일반촬영장치는 Stand Bucky 손잡이, CT 검사장치는 머리받침대, MRI 검사 장치는 조작 스위치에서 ATP 오염도 수치가 가장 많이 나왔으며, 이는 접촉 건수와 밀접한 관계가 있었다. 소독 전후를 비교한 결과 소독 후 모든 장치에서 유의한 차이로 감소한 결과를 보였다. 실험 결과를 바탕으로 영상의학과 검사실의 오염도를 파악하고 감염질환을 예방할 수 있는 기초자료가 될 수 있을 것이라고 사료된다.

• 대한영상의학회지
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• 제81권5호
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• pp.1227-1233
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• 2020

윤활막육종은 주로 사지, 특히 무릎 근처에 발생하는 악성 연부조직 종양으로, 가슴벽에 발생한 경우는 매우 드물다. 저자들은 26세 여성에서 앞가슴벽에 발생한 윤활막육종의 증례를 CT 및 MRI 소견을 중심으로 보고하고자 한다. CT에서 흉막하에 위치한, 경계가 좋으며 석회화를 동반한 작은 종괴로 관찰되어, 처음에는 양성 종양으로 생각하였다. 하지만 갑자기 심한 통증과 함께 종괴의 출혈과 혈흉이 동반되어 악성의 가능성을 고려하였다. MRI에서는 다엽성 종괴 내부에 액체액체층이 보였고, 이는 윤활막육종의 특징적인 영상 소견이다.

• Korean Journal of Radiology
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• 제22권5호
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• pp.829-839
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• 2021

Objective: To compare the diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3-tesla (3T) magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of visceral pleural surface invasion (VPSI). Visceral pleural invasion by non-small-cell lung cancer (NSCLC) can be classified into two types: PL1 (without VPSI), invasion of the elastic layer of the visceral pleura without reaching the visceral pleural surface, and PL2 (with VPSI), full invasion of the visceral pleura. Materials and Methods: Thirty-three patients with pathologically confirmed VPSI by NSCLC were retrospectively reviewed. Multidetector CT and contrast-enhanced 3T MRI with a free-breathing radial three-dimensional fat-suppressed volumetric interpolated breath-hold examination (VIBE) pulse sequence were compared in terms of the length of contact, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. Supplemental evaluation of the tumor-pleura interface (smooth versus irregular) could only be performed with MRI (not discernible on CT). Results: At the tumor-pleura interface, radial VIBE MRI revealed a smooth margin in 20 of 21 patients without VPSI and an irregular margin in 10 of 12 patients with VPSI, yielding an accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F-score for VPSI detection of 91%, 83%, 95%, 91%, 91%, and 87%, respectively. The McNemar test and receiver operating characteristics curve analysis revealed no significant differences between the diagnostic accuracies of CT and MRI for evaluating the contact length, angle of mass margin, or arch distance-to-maximum tumor diameter ratio as predictors of VPSI. Conclusion: The diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3T MRI and CT were equal in terms of the contact length, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. The advantage of MRI is its clear depiction of the tumor-pleura interface margin, facilitating VPSI detection.

• Korean Journal of Radiology
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• 제19권6호
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• pp.1053-1065
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• 2018

Objective: To evaluate the clinical impact of using registration software for ablative margin assessment on pre-radiofrequency ablation (RFA) magnetic resonance imaging (MRI) and post-RFA computed tomography (CT) compared with the conventional side-by-side MR-CT visual comparison. Materials and Methods: In this Institutional Review Board-approved prospective study, 68 patients with 88 hepatocellulcar carcinomas (HCCs) who had undergone pre-RFA MRI were enrolled. Informed consent was obtained from all patients. Pre-RFA MRI and post-RFA CT images were analyzed to evaluate the presence of a sufficient safety margin (${\geq}3mm$) in two separate sessions using either side-by-side visual comparison or non-rigid registration software. Patients with an insufficient ablative margin on either one or both methods underwent additional treatment depending on the technical feasibility and patient's condition. Then, ablative margins were re-assessed using both methods. Local tumor progression (LTP) rates were compared between the sufficient and insufficient margin groups in each method. Results: The two methods showed 14.8% (13/88) discordance in estimating sufficient ablative margins. On registration software-assisted inspection, patients with insufficient ablative margins showed a significantly higher 5-year LTP rate than those with sufficient ablative margins (66.7% vs. 27.0%, p = 0.004). However, classification by visual inspection alone did not reveal a significant difference in 5-year LTP between the two groups (28.6% vs. 30.5%, p = 0.79). Conclusion: Registration software provided better ablative margin assessment than did visual inspection in patients with HCCs who had undergone pre-RFA MRI and post-RFA CT for prediction of LTP after RFA and may provide more precise risk stratification of those who are treated with RFA.

• Korean Journal of Radiology
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• 제20권8호
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• pp.1266-1274
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• 2019

Objective: To determine whether radiologic extranodal extension (ENE) appearing on pretreatment CT and MRI could predict the prognosis in patients with human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC). Materials and Methods: The study population was obtained from a historical cohort diagnosed with HPV-related OPSCC. A total of 134 OPSCC patients who had a metastatic lymph node on pretreatment CT or MRI were included, and radiologic ENE was evaluated by two experienced head and neck radiologists. Kaplan-Meier and multivariate Cox regression analyses were performed to evaluate the impact of radiologic ENE on progression-free survival (PFS). The diagnostic performance of CT and MRI for the diagnosis of ENE was also evaluated in patients who underwent neck dissection. Results: Seventy patients (52.2%) showed radiologic ENE-positive findings. Although patients showing radiologic ENE had a worse 3-year PFS (83.7% vs. 95.3%, p = 0.023), the association between radiologic ENE and PFS was not statistically significant on multivariate analysis (p = 0.141; hazard ratio, 2.68; 95% confidence interval, 0.72-9.97). CT or MRI had a sensitivity of 62%, specificity of 77.8%, and accuracy of 71.9% for predicting pathologic ENE. Conclusion: Radiologic ENE on CT or MRI did not predict poor PFS in patients with HPV-related OPSCC, although there was a trend towards worse PFS. Further studies are warranted to determine whether radiologic ENE is a useful imaging biomarker to risk-stratify patients with HPV-related OPSCC.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1177-1181
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• 2010

The synthesis and characterization of gold nanoparticles coated by Gd-chelate (GdL@Au) is described, where L is a conjugate of DTPA (DTPA = diethylenetriamine-N,N,N',N",N"-pentaacetic acid) and 4-aminothiophenol. These particles are obtained by the replacement of citrate from the gold nanoparticle surfaces with gadolinium chelate (GdL). The average size of GdL@Au is 12 nm with a loading of GdL reaching up to $1.4{\times}10^3$ per particles, and they demonstrate very high r1 relaxivity (${\sim}10^4mM^{-1}s^{-1}$) and the r1 relaxivity per [Gd] is as high as $10mM^{-1}s{-1}$. Here, we also describe the use of bimodality of this contrast agent (CA) as a highly efficient CT contrast agent based on gold nanoparticles (GNPs) that overcome the limitations of iodine based contrast agent. The MTT assay performed on this CAs reveals the cytotoxicity as low as that for Omniscan$^{(R)}$ in the concentration range required to obtain intensity enhancement in the in vivo MRI study.