Comparing the Clinical Manifestations of Bell's Palsy between Pre-COVID-19 Pandemic and COVID-19 Pandemic Periods.

BACKGROUND: COVID-19 has been shown to affect the onset and severity of various diseases. We examined whether the clinical characteristics of Bell's palsy differed between before and during the COVID-19 pandemic. METHODS: From January 2005 to December 2021, 1839 patients were diagnosed and treated for Bell's palsy at Kyung Hee University Hospital. These patients were divided into a pre-COVID period group and COVID-19 period group, and the clinical characteristics of the two groups were compared. RESULTS: There were 1719 patients in the pre-COVID period group and 120 patients in the COVID-19 period group. There were no between-group differences in sex (p = 0.103) or in the presence of underlying hypertension (p = 0.632) or diabetes (p = 0.807). Regarding symptoms, there were no significant between-group differences in otalgia, dizziness, tinnitus, hyperacusis, or hearing loss (p = 0.304, p = 0.59, p = 0.351, p = 0.605, and p = 0.949). There were also no significant between-group differences in electroneurography results (p = 0.398), electromyography results (p = 0.331), House-Brackmann Grade at visit (p = 0.634), or recovery rate after treatment (p = 0.525). CONCLUSIONS: Contrary to our expectation that Bell's palsy cases during the COVID-19 pandemic would show different clinical features than those occurring before COVID-19, the present study found no differences in clinical features or prognosis.

CT-quantified muscle and fat change in patients after surgery or endoscopic resection for early gastric cancer and its impact on long-term outcomes.

The purpose of this study was to evaluate the impact of the body composition changes on patients' long-term outcomes after endoscopic resection or surgery for mucosal gastric cancer.This case-control study included 96 patients who underwent endoscopic resection or surgery after propensity score matching. Areas of fat and muscle measured on CT were compared between the 2 groups. The effects of the variables on disease-free and overall survival were assessed using Cox-regression analysis and Kaplan-Meier survival analysis.The median overall survival of the surgical and endoscopic resection groups was 91.1 and 93.9 months (P = .080). Fat area was decreased significantly more after surgery (P < .001). The number of patients with sarcopenia was increased in the surgery group. Kaplan-Meier plot showed that overall survival was significantly correlated with post-treatment sarcopenia (P = .049).CT-based body composition analysis was helpful to evaluate the change in fat and muscle areas after treatment of early gastric cancer. The losses of fat and muscle after treatment were negatively associated with the patient overall survival.

Validation of intimate correlation between visceral fat and hepatic steatosis: Quantitative measurement techniques using CT for area of fat and MR for hepatic steatosis.

BACKGROUND & AIM: The relationship between obesity and hepatic steatosis is well known, and there are many methods to measure obesity and severity of hepatic steatosis. Because of advances in radiologic techniques, the areas of certain body components can be measured on computed tomography (CT) while the severity of hepatic steatosis can be measured by magnetic resonance spectroscopy (MRS) with high accuracy. The aim of this study is to investigate the relationship between degree of fatty infiltration of the liver measured by MRS and body composition measured from CT images. MATERIALS AND METHODS: We evaluated 95 potential liver donors who underwent abdomen CT and liver MRI (including MRS) between February 2014 and September 2015 in a tertiary university hospital. Body composition analysis was performed on CT images using commercial software. The areas of subcutaneous fat, visceral fat and abdominal circumference were measured automatically and the area of muscle was measured semi-automatically. The degree of hepatic steatosis was measured by MRS. RESULTS: The degree of hepatic steatosis showed a significant correlation with total fat area, visceral fat area, subcutaneous fat area, muscle area, abdominal circumference, BMI, and ratio of visceral fat to total fat. The strongest correlation was between hepatic steatosis and the area of visceral fat in all subjects (r=0.569). Multivariate regression analysis showed that male gender and visceral fat area were significantly associated with hepatic steatosis (P = 0.031, <0.001, respectively). CONCLUSIONS: The area of visceral fat has the most intimate correlation to the severity of hepatic steatosis among all significantly correlated parameters associated with body habitus. Accurate and quantitative body composition measurement and degree of hepatic steatosis can be noninvasively performed using advanced radiological techniques.

Educational Effects of Radiation Reduction During Fluoroscopic Examination of the Adult Gastrointestinal Tract.

RATIONALE AND OBJECTIVES: This study aimed to evaluate the effects of educating radiology residents and radiographers about radiation exposure on reduction of dose area product (DAP) and fluoroscopy time in diagnostic fluoroscopy of the gastrointestinal (GI) tract in adult patients. MATERIALS AND METHODS: In April 2015, we offered 1 hour of education to radiology residents and radiographers on how to reduce radiation doses during fluoroscopic examinations. Fluoroscopic examinations of the GI tracts of adult patients performed from June 2014 to February 2016 were evaluated. A total of 2326 fluoroscopic examinations (779 and 1547 examinations before and after education, respectively) were performed, including 10 kinds of examinations. Fluoroscopy time and DAP were collected. A radiologist evaluated the number of spot images, captured images, cine video, captured video, and the use of collimation or magnification. We used the Mann-Whitney U test to assess the difference in fluoroscopy-related factors before and after education. RESULTS: Median DAP decreased significantly after education, from 21.1 to 18.2 Gy∙cm2 (P < .001) in all examinations. After education DAP decreased significantly in defecography (P < .001) and fluoroscopy time decreased significantly in upper gastrointestinal series with water-soluble contrast (P < .001). Spot and cine images that increased the radiation dose were used less frequently after education than before in some kinds of examinations, especially in defecography (P < .001). More images were collimated after education in barium swallow than before (P < .001). CONCLUSIONS: Educating radiologist residents and radiographers could reduce DAP in fluoroscopy examinations of the GI tract in adult patients.

A standardization model based on image recognition for performance evaluation of an oral scanner.

PURPOSE: Accurate information is essential in dentistry. The image information of missing teeth is used in optically based medical equipment in prosthodontic treatment. To evaluate oral scanners, the standardized model was examined from cases of image recognition errors of linear discriminant analysis (LDA), and a model that combines the variables with reference to ISO 12836:2015 was designed. MATERIALS AND METHODS: The basic model was fabricated by applying 4 factors to the tooth profile (chamfer, groove, curve, and square) and the bottom surface. Photo-type and video-type scanners were used to analyze 3D images after image capture. The scans were performed several times according to the prescribed sequence to distinguish the model from the one that did not form, and the results confirmed it to be the best. RESULTS: In the case of the initial basic model, a 3D shape could not be obtained by scanning even if several shots were taken. Subsequently, the recognition rate of the image was improved with every variable factor, and the difference depends on the tooth profile and the pattern of the floor surface. CONCLUSION: Based on the recognition error of the LDA, the recognition rate decreases when the model has a similar pattern. Therefore, to obtain the accurate 3D data, the difference of each class needs to be provided when developing a standardized model.

Prediction of Therapeutic Response of Hepatocellular Carcinoma to Transcatheter Arterial Chemoembolization Based on Pretherapeutic Dynamic CT and Textural Findings.

OBJECTIVE: The objective of our study was to assess the value of CT texture analysis for prediction of therapeutic response of hepatocellular carcinoma (HCC) to transcatheter arterial chemoembolization (TACE) with pretherapeutic dynamic CT. MATERIALS AND METHODS: We retrospectively analyzed 132 HCCs in 96 patients treated with TACE who underwent dynamic CT before initial TACE. Imaging findings and arterial enhancement ratios were analyzed. All HCCs were manually segmented, and their texture features were quantitatively extracted using in-house software. CT texture was quantified with 2D and 3D analysis. HCCs were classified as with and without complete response (CR) according to modified Response Evaluation Criteria in Solid Tumors. Predictive factors for CR were assessed with multivariate analysis. Radiologic responses were correlated with time to progression (TTP). RESULTS: Of the 132 HCCs, CR was achieved in 75 (56.8%). Tumor size, subjective arterial tumor attenuation, and arterial enhancement ratios were significantly associated with CR. On 2D and 3D analysis, tumors with CR showed significantly lower homogeneity and higher mean attenuation, gray-level co-occurrence matrix (GLCM) moments, and CT number percentiles (p < 0.05). On multivariate analysis, higher subjective tumor attenuation (adjusted odds ratio [OR] = 23.35), arterial enhancement ratio (OR = 14.07), GLCM moments (OR = 6.57), smaller tumor size (OR = 17.26), and lower homogeneity (OR = 0.69) were significant predictors of CR compared with incomplete response (p < 0.05). Median survival value for TTP was significantly longer in tumors with CR (p < 0.001). CONCLUSION: Pretherapeutic dynamic CT texture analysis can be valuable to predict CR of HCC to TACE. Higher arterial enhancement and GLCM moments, lower homogeneity, and smaller tumor size are significant predictors of CR after TACE.

Sterile Pyometra in Two Dogs.

Two young dogs were referred to the Veterinary Medical Teaching Hospital of Konkuk University, one for examination of vaginal discharge and the other after being hit by a car. Dog 1 exhibited a high neutrophil count on Gram-stained vaginal smears, marked leukocytosis on a complete blood count, and uterine enlargement on ultrasonography. In dog 2, a markedly enlarged right uterine horn containing echogenic debris was found incidentally on ultrasonography. A tentative diagnosis of pyometra was made in both cases and ovariohysterectomy was performed. Purulent material was collected from each uterine horn and submitted separately for aerobic and anaerobic bacterial culture; all culture results were negative. The white blood cell count revealed normal limits 2 days post operation in dog 1 and 4 days post operation in dog 2. Positive bacterial cultures are usually obtained from dogs with pyometra, and antibiotic selection is based on the results of culture and sensitivity testing in the event of failure of empiric antibiotic therapy. However, in the cases reported here, no bacterial growth was identified from the uterine samples despite the presence of purulent material. A short course of empiric antibiotic therapy was administered. This is the first known report describing sterile pyometra in dogs.

Location of Disease on Imaging may Predict Radiation Exposure During Endoscopic Retrograde Cholangiopancreatography.

Endoscopic retrograde cholangiopancreatography (ERCP) is performed for various diseases. The aim of this study is to evaluate the difference of dose-area product (DAP) during the ERCP procedures according to location of the lesion. We performed a retrospective study of consecutive 217 therapeutic ERCP examinations performed between November 2014 and April 2015 at a tertiary care center. ERCP procedures divided into two groups according to location of the lesion identified on imaging: lesions in the common hepatic duct (CHD) or the common bile duct (CBD) and lesions in the hepatic hilum or the intrahepatic duct (IHD). The mean DAP of the hilum-IHD group (48.7 Gy cm2) was significantly higher than that of the CBD-CHD group (34.9 Gy cm2) (P = 0.003). Radiation exposure during ERCP was significantly different according to location of bile duct lesion.

Diaphragmatic Hernia After Living-Donor Right Hepatectomy: An Important Late Donor Complication.

OBJECTIVE: This study was performed to evaluate the incidence and clinical outcome of diaphragmatic hernia after living-donor right hepatectomy. METHODS: Three hundred thirty-six patients (202 men, 134 women; mean age, 37.6 years) who underwent abdominal computed tomography (CT) after right donor hepatectomy were enrolled in this study. The CT images and the electronic medical records were reviewed. We evaluated the associations between diaphragmatic hernia and patient characteristics. RESULTS: Diaphragmatic hernia developed in 9 (2.7%) of 336 patients at a median time interval of 173 days (range, 98-488 days) after hepatectomy. In all 6 patients with available follow-up CT images, diaphragmatic hernia increased in size. Three patients presented with abdominal pain and underwent diaphragmatic repair. Diaphragmatic hernia was associated with older age but not with body mass index or sex. CONCLUSIONS: Clinicians and radiologists should not overlook the possibility of diaphragmatic hernia after living-donor right hepatectomy, especially in old liver donors.

Performance of Gadoxetic Acid-Enhanced Liver Magnetic Resonance Imaging for Predicting Patient Eligibility for Liver Transplantation Based on the Milan Criteria.

PURPOSE: This study aimed to evaluate the accuracy of gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI) in predicting eligibility for liver transplantation in patients with hepatocellular carcinoma (HCC) based on Milan criteria (MC). MATERIALS AND METHODS: We reviewed Gd-EOB-MRI of 44 patients who underwent liver transplantation for HCC with cirrhosis for the presence/size of HCCs, vascular invasion, and transplant eligibility based on MC. Hepatocellular carcinoma was diagnosed based on conventional radiological hallmarks (arterial enhancement and washout) or the modified criteria. RESULTS: Among 44 patients, 16 was beyond MC. Sensitivity, specificity, and accuracy of conventional radiological hallmark and the modified criteria for predicting eligibility by MC were 31.3%, 96.3%, and 72.7%, and 68.8%, 96.3%, and 86.4%, respectively. CONCLUSIONS: Gd-EOB-MRI showed high specificity but poor sensitivity for assessing transplant eligibility based on MC when adopting the conventional radiological hallmarks of HCC. Our modified criteria showed significantly better sensitivity and accuracy than the conventional radiological hallmarks.

Prognostic CT findings of diplopia after surgical repair of pure orbital blowout fracture.

PURPOSE: Diplopia is a common sequela of blowout fracture even after proper surgical management. We investigated the prognostic factors of diplopia after surgery of pure blowout fracture. MATERIALS AND METHODS: We retrospectively reviewed CT images of 181 patients with pure orbital blowout fracture who underwent at least six months of postoperative follow-up. We evaluated the following CT factors: (1) fracture site (orbital floor, medial wall of the orbit, or both), (2) fracture type (closed flap, open flap), (3) fracture size, (4) volume of herniated orbital soft tissue, (5) ratio of volume of herniated orbital soft tissue to fracture size, (6) number of points of contact between extraocular muscle (EOM) and bony edge, (7) presence of EOM thickening, (8) EOM swelling ratio, (9) presence of displacement of EOM, (10) presence of deformity of EOM, (11) presence of tenting of EOM, and (12) presence of entrapment of EOM. The associations between diplopia at six months after surgical repair and various risk factors were analyzed using logistic regression models for univariable and multivariable analyses. RESULTS: EOM tenting and deformity and ratio of volume of herniated orbital soft tissue to fracture size were found to be statistically significant risk factors of diplopia at six months after repair on univariable analysis (all P < 0.05). Patients who showed EOM tenting or deformity on CT images had 5.22 and 10.85 times greater probability of diplopia after surgery, respectively (P-value, <0.001 and 0.026; 95% confidence interval of odds ratio, 2.071-13.174 and 1.323-88.915, respectively). On the other hand, ratio of volume of herniated orbital soft tissue to fracture size was not significant on multivariable analysis (P = 0.472). CONCLUSION: The prognosis of patients was predicted by CT evaluation. Patients who have tenting or deformity of EOM on CT scan are more likely to have postoperative diplopia.

Optimization of beam-flow angles for Doppler ultrasound flow velocity measurements using slanted gel pads.

The aim of this study was to assess whether slanted gel pads can be used to optimize beam-flow angles and flow velocity measurements for Doppler ultrasound. The right carotid artery of a single healthy female volunteer was measured alternatively five times without and with an 18° angled slanted gel pad between the ultrasound transducer and skin by 13 radiologists. Beam-flow angles and peak systolic flow velocities (PSV) were measured along with assessment of spectral broadening. Beam-flow angles (P = 0.001) and PSV (P = 0.001) measurements showed a significant decrease when using slanted gel pads. The mean (±SD) beam-flow angles without and with the use of slanted gel pads were 66.7 (±4.2) and 56.1 (±5.8) degrees, respectively. The mean (±SD) PSVs without and with the use of slanted gel pads were 92.0 (±17.4) and 76.9 (±10.9) cm/s, respectively. There was a noticeable decrease in spectral broadening when using slanted gel pads. There was a significant linear correlation between beam-flow angle and peak systolic velocity. Coefficients of variation for peak systolic velocity without and with the use of gel pads were 18.9 and 14.2 %, respectively. These results demonstrate that slanted gel pads decrease beam-flow angles and overestimation of Doppler flow velocity measurements while potentially increasing the reliability of measurements.

Factors Related to Radiation Exposure during Lumbar Spine Intervention.

Fluoroscopy guidance is useful to confirm anatomical landmark and needle location for spine intervention; however, it can lead to radiation exposure in patients, physicians, and medical staff. Physicians who used fluoroscopy should be cognizant of radiation exposure and intend to minimize radiation dose. We retrospectively reviewed three lumbar spine intervention procedures (nerve root block, medial branch block, and facet joint block) at our institution between June and December, 2014. We performed 268 procedures on 220 patients and found significant difference in radiation dose between two groups classified by performing physicians. The physician who controlled the fluoroscopy unit directly used significantly shorter fluoroscopy (6 seconds) that resulted in a smaller radiation dose (dose area product [DAP] 0.59 Gy∙cm(2)) than the physician supervising the radiographer controlling the fluoroscopy unit (72 seconds, DAP 5.31 Gy∙cm(2), P < 0.001). The analysis indicates that the difference in fluoroscopy time depends on whether a physician or a radiographer controls the fluoroscopy unit.

Magnetic resonance imaging findings of undifferentiated carcinoma with osteoclast-like giant cells of pancreas.

Undifferentiated carcinoma with osteoclast-like giant cells is a rare pancreatic and periampullary neoplasm with less than 50 cases reported in the literature. Pathologically, this tumor mimics a giant cell tumor in bones. We report a case of undifferentiated carcinoma with osteoclast-like giant cells in a 55-year-old man presenting as a pancreatic mass with associated regional and distant lymphadenopathy. On T1- and T2-weighted images, the mass shows dark signal intensity which was atypical for a pancreatic adenocarcinoma.

Differentiation of benign and malignant thyroid nodules based on the proportion of sponge-like areas on ultrasonography: imaging-pathologic correlation.

PURPOSE: The purpose of this study was to determine whether it is possible to differentiate benign from malignant thyroid nodules according to the proportion of sponge-like appearance within the nodules. METHODS: A total of 201 thyroid nodules containing sponge-like appearance from 195 patients (157 women and 38 men) were included this study. Each thyroid nodule was classified into one of three grades by real-time ultrasonography (US) based on the areas with a sponge-like appearance within nodule: grade I had sponge-like areas occupying <50%; grade II, between 50% and 75%; and grade III, >75%. We evaluated whether a correlation existed between these grades and cytopathologic diagnoses. RESULTS: Of the 201 nodules, 196 were benign and five were malignant, and according to the US classification, 101 nodules were grade I, 45 were grade II, and 55 were grade III. Of the five malignant nodules, four were grade I, and one was grade II. No statistically significant difference was found in the rate of malignancy between grade III and grades I and II, due to insufficient statistical power. A sponge-like appearance was correlated with follicles filled with colloid and cholesterol granules in benign nodules and with papillary fronds around the dilated cystic spaces in malignant nodules. CONCLUSION: No malignancies were found in thyroid nodules with >75% sponge-like appearance. Due to the overall low incidence of malignancy and the limited number of patients, a statistically significant difference could not be found in the prevalence of malignancy depending on the proportion of sponge-like areas within the nodule.

Diffusion-weighted MRI of epithelial ovarian cancers: correlation of apparent diffusion coefficient values with histologic grade and surgical stage.

OBJECTIVE: The purpose of this article is to correlate the apparent diffusion coefficient (ADC) values of epithelial ovarian cancers with histologic grade and surgical stage. MATERIALS AND METHODS: We enrolled 43 patients with pathologically proven epithelial ovarian cancers for this retrospective study. All patients underwent preoperative pelvic magnetic resonance imaging (MRI) including diffusion-weighted images with b value of 0 and 1000 s/mm2 at 3.0-T unit. The mean ADC values of the solid portion of the tumor were measured and compared among different histologic grades and surgical stages. RESULTS: The mean ADC values of epithelial ovarian cancers differed significantly between grade 1 (well-differentiated) and grade 2 (moderately-differentiated) (P=0.013) as well as between grade 1 and grade 3 (poorly-differentiated) (P=0.01); however, no statistically significant difference existed between grade 2 and grade 3 (P=0.737). The receiver-operating characteristic analysis indicated that a cutoff ADC value of less than or equal to 1.09×10(-3)mm2/s was associated with 94.4% sensitivity and 85.7% specificity in distinguishing grade 1 and grade 2/3 cancer. The difference in mean ADC values was statistically significant for early stage (FIGO stage I) and advanced stage (FIGO stage II-IV) cancer (P=0.011). The interobserver agreement for the mean ADC values of epithelial ovarian cancers was excellent. CONCLUSION: The mean ADC values of the solid portion of epithelial ovarian cancers negatively correlated to histologic grade and surgical stage. The mean ADC values may be useful imaging biomarkers for assessment of tumor grade of epithelial ovarian cancer.

CT and MR imaging findings of hepatic epithelioid hemangioendotheliomas: emphasis on single nodular type.

PURPOSE: To evaluate imaging findings of hepatic epithelioid hemangioendothelioma (HEH), with emphasis on solitary form at the initial presentation. MATERIALS AND METHODS: Ten cases of pathologically confirmed HEH were retrospectively reviewed; seven patients had CT and MR images and three had only CT images. Two radiologists assessed the followings in consensus: lesion number, size, location, presence of capsular retraction and calcification, attenuation, signal intensity, and enhancement pattern. RESULTS: Initially, HEHs manifested as a single mass (n = 5) or multiple masses (n = 5). One case demonstrated a solitary nodule at first, which subsequently transformed to multifocal nodules on serial follow-up. The maximal diameter of the lesions ranged from 1.8 to 10 cm (mean 4.2 cm). All cases showed predominant subcapsular location. Capsular retraction was seen in multinodular types, but not in solitary types. Two patients had intra-lesional calcifications. HEHs showed minimal enhancement (7/7 patients) on the hepatic arterial phase CT and rim-like enhancement (5/10 patients), minimal enhancement (2/10 patients), multilayered target enhancement (2/10 patients), and peripheral nodular enhancement (1/10 patients) on the portal venous phase CT. On MR images (n = 7), HEHs showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images. Dynamic contrast-enhanced MR images revealed progressive centripetal fill-in enhancement (7/7 patients). On Gd-EOB-DTPA-enhanced hepatobiliary phase images, HEH manifested as homogeneous hypointensity (3/5 patients) and target-shaped hypointensity (2/5 patients). CONCLUSION: HEH can manifest as single nodular, multinodular, or diffuse type. Common imaging features of HEH are multiple subcapsular nodules with coalescence, capsular retraction, peripheral, and delayed enhancement. However, HEH can manifest as a solitary subcapsular mass with minimal or rim-like enhancement at early phase and progressive centripetal fill-in enhancement during dynamic phase imaging, representing early stage of HEH. A single nodular type can progress to multifocal nodular type during follow-up.

Correlation of dynamic contrast-enhanced MRI perfusion parameters with angiogenesis and biologic aggressiveness of rectal cancer: Preliminary results.

PURPOSE: To investigate whether quantitative parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) are correlated with angiogenesis and biologic aggressiveness of rectal cancer. MATERIALS AND METHODS: A total of 46 patients with rectal cancer underwent DCE-MRI. Using a two-compartmental model, quantitative parameters (K(trans) , kep , ve , and iAUC) were calculated from the whole-transverse region of interest (ROI) and high K(trans) area ROI of entire tumors. Histological specimens were analyzed for tumor size; T/N stage; lymphatic, vascular, perineural invasion; expression of epidermal growth factor receptor (EGFR); and KRAS gene mutations. Tumor angiogenesis was evaluated based on the microvessel density (MVD) and the expression level of the vascular endothelial growth factor. Correlations of the DCE-MRI parameters with histological markers and angiogenesis were determined using Student's t-test and analysis of variance (ANOVA). RESULTS: The mean kep from high K(trans) area ROIs showed a significantly positive correlation with MVD (P = 0.030, r = 0.514, R(2) = 0.264). The mean kep from the whole-transverse ROIs showed a significant inverse correlation with T stage (T1 vs. T2-4, P = 0.021). EGFR-positive cancer displayed higher mean K(trans) (P = 0.045) and kep (P = 0.038) than EGFR-negative cancer in whole-transverse ROIs. CONCLUSION: These preliminary results suggest that the determination of kep of high K(trans) area permits the noninvasive estimation of tumor angiogenesis in rectal cancer and that DCE-MRI parameters can be used as imaging biomarkers to predict the biologic aggressiveness of the tumor and patient prognosis.

Intra- and interobserver reliability of gray scale/dynamic range evaluation of ultrasonography using a standardized phantom.

PURPOSE: To evaluate intra- and interobserver reliability of the gray scale/dynamic range of the phantom image evaluation of ultrasonography using a standardized phantom, and to assess the effect of interactive education on the reliability. METHODS: Three radiologists (a resident, and two board-certified radiologists with 2 and 7 years of experience in evaluating ultrasound phantom images) performed the gray scale/dynamic range test for an ultrasound machine using a standardized phantom. They scored the number of visible cylindrical structures of varying degrees of brightness and made a 'pass or fail' decision. First, they scored 49 phantom images twice from a 2010 survey with limited knowledge of phantom images. After this, the radiologists underwent two hours of interactive education for the phantom images and scored another 91 phantom images from a 2011 survey twice. Intra- and interobserver reliability before and after the interactive education session were analyzed using K analyses. RESULTS: Before education, the K-value for intraobserver reliability for the radiologist with 7 years of experience, 2 years of experience, and the resident was 0.386, 0.469, and 0.465, respectively. After education, the K-values were improved (0.823, 0.611, and 0.711, respectively). For interobserver reliability, the K-value was also better after the education for the 3 participants (0.067, 0.002, and 0.547 before education; 0.635, 0.667, and 0.616 after education, respectively). CONCLUSION: The intra- and interobserver reliability of the gray scale/dynamic range was fair to substantial. Interactive education can improve reliability. For more reliable results, double- checking of phantom images by multiple reviewers is recommended.