• Journal of the Korean Society of Radiology
• /
• v.84 no.2
• /
• pp.332-344
• /
• 2023

The role of ultrasound-guided interventions in the diagnosis and treatment of breast lesions is gaining importance and prevalence, particularly as the instances of non-palpable breast lesion detection, breast-conserving surgery, and neoadjuvant chemotherapy are increasing. This review attempts to summarize the types and techniques of breast ultrasound-guided interventional procedures, such as biopsy, tissue marker insertion, and preoperative localization, and their indications. Furthermore, we highlight the pro and cons of the most commonly used procedures with the intention of promoting their use in clinical practice.

• Korean Journal of Radiology
• /
• v.24 no.7
• /
• pp.681-689
• /
• 2023

Objective: Three-dimensional rotational angiography (3D-RA) is increasingly used for the evaluation of intracranial aneurysms (IAs); however, radiation exposure to the lens is a concern. We investigated the effect of head off-centering by adjusting table height on the lens dose during 3D-RA and its feasibility in patient examination. Materials and Methods: The effect of head off-centering during 3D-RA on the lens radiation dose at various table heights was investigated using a RANDO head phantom (Alderson Research Labs). We prospectively enrolled 20 patients (58.0 ± 9.4 years) with IAs who were scheduled to undergo bilateral 3D-RA. In all patients' 3D-RA, the lens dose-reduction protocol involving elevation of the examination table was applied to one internal carotid artery, and the conventional protocol was applied to the other. The lens dose was measured using photoluminescent glass dosimeters (GD-352M, AGC Techno Glass Co., LTD), and radiation dose metrics were compared between the two protocols. Image quality was quantitatively analyzed using source images for image noise, signal-to-noise ratio, and contrast-to-noise ratio. Additionally, three reviewers qualitatively assessed the image quality using a five-point Likert scale. Results: The phantom study showed that the lens dose was reduced by an average of 38% per 1 cm increase in table height. In the patient study, the dose-reduction protocol (elevating the table height by an average of 2.3 cm) led to an 83% reduction in the median dose from 4.65 mGy to 0.79 mGy (P < 0.001). There were no significant differences between dose-reduction and conventional protocols in the kerma area product (7.34 vs. 7.40 Gy·cm², P = 0.892), air kerma (75.7 vs. 75.1 mGy, P = 0.872), and image quality. Conclusion: The lens radiation dose was significantly affected by table height adjustment during 3D-RA. Intentional head off-centering by elevation of the table is a simple and effective way to reduce the lens dose in clinical practice.

• Korean Journal of Radiology
• /
• v.21 no.7
• /
• pp.812-828
• /
• 2020

Objective: To provide an evidence-based guide for the MRI interpretation of complete tumor response after neoadjuvant chemoradiation therapy (CRT) for rectal cancer using visual assessment on T2-weighted imaging (T2) and diffusion-weighted imaging (DWI). Materials and Methods: PubMed MEDLINE, EMBASE, and Cochrane Library were searched on November 28, 2019 to identify articles on the following issues: 1) sensitivity and specificity of T2 or DWI for diagnosing pathologic complete response (pCR) and the criteria for MRI diagnosis; 2) MRI alone vs. MRI combined with other test(s) in sensitivity and specificity for pCR; and 3) tests to select patients for the watch-and-wait management. Eligible articles were selected according to meticulous criteria and were synthesized. Results: Of 1615 article candidates, 55 eligible articles (for all three issues combined) were identified. Combined T2 and DWI performed better than T2 alone, with a meta-analytic summary sensitivity of 0.62 (95% confidence interval [CI], 0.43-0.77; I² = 80.60) and summary specificity of 0.89 (95% CI, 0.80-0.94; I² = 92.61) for diagnosing pCR. The criteria for the complete response on T2 in most studies had the commonality of remarkable tumor decrease to the absence of mass-like or nodular intermediate signal, although somewhat varied, as follows: (near) normalization of the wall; regular, thin, hypointense scar in the luminal side with (near) normal-appearance or homogeneous intermediate signal in the underlying wall; and hypointense thickening of the wall. The criteria on DWI were the absence of a hyperintense signal at high b-value (≥ 800 sec/mm²) in most studies. The specific algorithm to combine T2 and DWI was obscure in half of the studies. MRI combined with endoscopy was the most utilized means to select patients for the watch-and-wait management despite a lack of strong evidence to guide and support a multi-test approach. Conclusion: This systematic review and meta-analysis provide an evidence-based practical guide for MRI assessment of complete tumor response after CRT for rectal cancer.

• Journal of the Korean Society of Radiology
• /
• v.9 no.6
• /
• pp.409-416
• /
• 2015

This study is to examine the infection management cognition and to practice of dental hygienists about their general characteristics, type of workplace. 354 dental hygienists in Daegu and Kyungbuk cities. The questionnaire survey was performed from April to May, 2015. These showed that factors of dental infection management according to workplace depended existence and nonexistence that chief of station and program of infection management, education of infection control(p<.001). Also cognition of dental infection control according to workplace drawed the protection individual(p<.05), asepsis procedure(p<.01), control of dental equipment(p<.001), control of infectious waste(p<.01) and laundry(p<.001), to practice of dental infection control according to workplace drawed the protection individual and asepsis procedure(p<.001), methods of disinfected and sterilized(p<.05), control of dental equipment and laundry(p<.001), control of infectious waste(p<.05). As above results, in order to minimize the infection prevention in the dental clinic, the regular infection control education for infection control of dental hygienists required, infection control guidelines place at the dental office.

• Journal of the Korean Society of Radiology
• /
• v.17 no.5
• /
• pp.775-782
• /
• 2023

In order to overcome practical limitations in installing, managing and operating MRI machines with expensive equipment, this study developed and utilized virtual reality (VR) experience education by combining virtual reality (VR) with magnetic resonance imaging devices. The Students who experienced virtual reality-based educational systems were surveyed to identify possible side effects during the experience and self-directed learning ability and academic self-efficacy surveys were conducted to analyze the impact of virtual reality-based practice on learning. In the analysis of the self-directed learning ability survey there was no difference in the average between the student group who experienced education and the student group who did not but there was a significant difference in the average for each group. Virtual Reality-based practical education is expected to provide an efficient practice system by providing new learning methods and opportunities for education that can be repeated anytime, anywhere regardless of time and space.

• Imaging Science in Dentistry
• /
• v.52 no.3
• /
• pp.283-288
• /
• 2022

Purpose: This study was conducted to measure the radiation exposure and image quality of various cone-beam computed tomography (CBCT) machines under common clinical conditions and to analyze the correlation between them. Materials and Methods: Seven CBCT machines used frequently in clinical practice were selected. Because each machine has various sizes of fields of view (FOVs), 1 large FOV and 1 small FOV were selected for each machine. Radiation exposure was measured using a dose-area product (DAP) meter. The quality of the CBCT images was analyzed using 8 image quality parameters obtained using a dental volume tomography phantom. For statistical analysis, regression analysis using a generalized linear model was used. Results: Polymethyl-methacrylate (PMMA) noise and modulation transfer function (MTF) 10% showed statistically significant correlations with DAP values, presenting positive and negative correlations, respectively (P<0.05). Image quality parameters other than PMMA noise and MTF 10% did not demonstrate statistically significant correlations with DAP values. Conclusion: As radiation exposure and image quality are not proportionally related in clinically used equipment, it is necessary to evaluate and monitor radiation exposure and image quality separately.

• Korean Journal of Radiology
• /
• v.21 no.10
• /
• pp.1150-1160
• /
• 2020

Objective: To describe the experience of implementing a deep learning-based computer-aided detection (CAD) system for the interpretation of chest X-ray radiographs (CXR) of suspected coronavirus disease (COVID-19) patients and investigate the diagnostic performance of CXR interpretation with CAD assistance. Materials and Methods: In this single-center retrospective study, initial CXR of patients with suspected or confirmed COVID-19 were investigated. A commercialized deep learning-based CAD system that can identify various abnormalities on CXR was implemented for the interpretation of CXR in daily practice. The diagnostic performance of radiologists with CAD assistance were evaluated based on two different reference standards: 1) real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) results for COVID-19 and 2) pulmonary abnormality suggesting pneumonia on chest CT. The turnaround times (TATs) of radiology reports for CXR and rRT-PCR results were also evaluated. Results: Among 332 patients (male:female, 173:159; mean age, 57 years) with available rRT-PCR results, 16 patients (4.8%) were diagnosed with COVID-19. Using CXR, radiologists with CAD assistance identified rRT-PCR positive COVID-19 patients with sensitivity and specificity of 68.8% and 66.7%, respectively. Among 119 patients (male:female, 75:44; mean age, 69 years) with available chest CTs, radiologists assisted by CAD reported pneumonia on CXR with a sensitivity of 81.5% and a specificity of 72.3%. The TATs of CXR reports were significantly shorter than those of rRT-PCR results (median 51 vs. 507 minutes; p < 0.001). Conclusion: Radiologists with CAD assistance could identify patients with rRT-PCR-positive COVID-19 or pneumonia on CXR with a reasonably acceptable performance. In patients suspected with COVID-19, CXR had much faster TATs than rRT-PCRs.

• Journal of Korean society of Dental Hygiene
• /
• v.11 no.2
• /
• pp.169-178
• /
• 2011

Objectives : This study was conducted to investigate the actual state of dental hygienist's behavior for infection control during dental practice and radiologic examination and to evaluate the dental hygienist's awareness of the importance of infection control in dental office. Methods : A survey on 218 dental hygienists was carried out. The respondents to complete a questionnaire were the dental hygienists who were in dental office on Gwang-ju area or attended complementary training conducted by the Seoul Branch of Korean Dental Hygienists Association in April 2010. The data were collected and analyzed with $x^2$ test, t-test, ANOVA using SPSS program. Results : The ratios of educational experience for infection control in dental practice and radiologic examination room accounted for 87.6% and 30.3% respectively. Behavior degree of mask-wearing in the dental practice and radiologic examination room were $4.60{\pm}0.70$ and $3.77{\pm}1.09$ respectively. Behavior degree of glove-wearing in the dental practice and radiologic examination room were $4.40{\pm}0.91$ and $3.68{\pm}1.17$ respectively. In case of the relation between educational experience and behavior degree in mask-wearing or glove-wearing, there was no significant difference in the performance of mask or glove wearing during dental practice, and mask-wearing during radiologic examination. However, there was a significant difference (p<0.05) in the performance of glove-wearing during radiologic examination, which revealed that behavior degree between the respondents having educational experience and the others no having it were $3.92{\pm}1.19$ and $3.58{\pm}1.14$ respectively. The surface disinfection control for radiation and protective equipments used in radiologic examination room was done by occasional needs without premeditated schedules. Conclusions : The result of this study shows lower behavior degree during radiologic examination compared with one during dental practice. We suggest that there are needs to raise the awareness of infection control and to improve infection control behavior, and through this study, the importance of education was verified.

• Journal of the Korea Convergence Society
• /
• v.11 no.7
• /
• pp.51-57
• /
• 2020

This study was conducted to examine the type of subjective perceptions and characteristics of the type toward the image of students enrolled in the Department of Radiology who experienced clinical training by applying Q Methodology which is aiming at the research of human subjectivity, and provide basic data for educational programs for the Department of Radiology to establish the image of a radiological technologist based on the result. This study conducted convenience sampling with 30 students of the Department of Radiology who experienced their first clinical training for 8 weeks as a P sample, forcing 33 Q samples to be distributed on the nine-point scale Q distribution chart. After that, this study processed collected data with principal factor analysis by QUANL program. Study results show that Eigen value was more than 1.0, which was divided into 2 types. Type 1 was "Patient-oriented" and type 2 was "Organization-oriented". These results can be helpful as a basic resources to understand Radiology Students who will choose a job by using different sense of value of their job.

• Imaging Science in Dentistry
• /
• v.51 no.1
• /
• pp.1-7
• /
• 2021

Purpose: The aim of this study was to assess artifacts generated in cone-beam computed tomography (CBCT) of 3 types of dental implants using 3 metal artifact reduction (MAR) algorithm conditions (pre-acquisition MAR, post-acquisition MAR, and no MAR), and 2 peak kilovoltage (kVp) settings. Materials and Methods: Titanium-zirconium, titanium, and zirconium alloy implants were placed in a dry mandible. CBCT images were acquired using 84 and 90 kVp and at normal resolution for all 3 MAR conditions. The images were analyzed using ImageJ software (National Institutes of Health, Bethesda, MD) to calculate the intensity of artifacts for each combination of material and settings. A 3-factor analysis of variance model with up to 3-way interactions was used to determine whether there was a statistically significant difference in the mean intensity of artifacts associated with each factor. Results: The analysis of all 3 MAR conditions showed that using no MAR resulted in substantially more severe artifacts than either of the 2 MAR algorithms for the 3 implant materials; however, there were no significant differences between pre- and post-acquisition MAR. The 90 kVp setting generated less intense artifacts on average than the 84 kVp setting. The titanium-zirconium alloy generated significantly less intense artifacts than zirconium. Titanium generated artifacts at an intermediate level relative to the other 2 implant materials, but was not statistically significantly different from either. Conclusion: This in vitro study suggests that artifacts can be minimized by using a titanium-zirconium alloy at the 90 kVp setting, with either MAR setting.