Current digital radiography systems are rapidly growing in clinical applications. The purpose of this study was to evaluate the characteristics of a mobile digital radiographic system. The performance of the mobile DR system was evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). Measurements were made on a LISTEM Mobix-1000 generator and a Teleoptic PRA Alpha-R4000 detector. Imaging characteristics were measured for these two systems using the IEC-61267 defined RQA5 (kVp: 74, additional filtration: 21 mmAl) radiographic condition. The MTF at 10% was measured as 2.4 cycles/mm and the DQE(0) values for radiation exposure 0.19, 0.5, and 1.3 mR were measured as 54%, 55%, and 76%, respectively. The NPS curves gradually decreased at high spatial frequencies. This high DQE at low frequencies, may be useful for low frequency information. The results suggested that mobile DR system could be integrated with emergency ambulance system in teleradiologic imaging applications.
Ambulances ; Emergencies ; Filtration ; Noise ; Radiographic Image Enhancement

Cardiogenic dysphagia is a rare type of esophageal dysphagia caused by external compression of the esophagus by an enlarged left atrium. Long-term comparisons between the degree of cardiogenic dysphagia and heart failure have not been reported due to its low incidence. We hereby report the case of a 74-year-old woman with valvular heart disease, suspected of having oropharyngeal dysphagia following a recent intracerebral hemorrhage, who performed a swallowing function test. Videofluoroscopic swallowing study (VFSS) revealed a supraglottic penetration, confirming the oropharyngeal dysphagia. Furthermore, post-VFSS chest radiograph revealed esophageal residual barium, suggestive of reduced esophageal food transition secondary to external compression, at the level of the T6 vertebral body. Chest computed tomography showed mid-esophageal compression caused by left atrial enlargement. She had pulmonary edema which was managed with diuretics. Post-VFSS chest radiographs also revealed a direct association between the diameter of the esophageal barium residue and body weight. A reduction in body weight led to the resolution of the barium residue and vice versa. Development of cardiac dysphagia may be one of the signs of acute exacerbation of heart failure.

Objective: To investigate esophageal motility disorders in patients with esophageal residual barium on chest x-rays after videofluoroscopic swallowing studies (VFSS) through high-resolution esophageal manometry (HREM). Methods: We reviewed the records of 432 patients who underwent VFSS from September 2019 to May 2021, and 85 patients (19.7%) with large residual barium (diameter ≥1 cm) were included. As a result of HREM, motility disorders were classified as major or minor motility disorders according. Esophagogastroduodenoscopy and chest computed tomography results available were also reviewed. Results: Among 85 patients with large residual barium in the esophagus, 16 patients (18.8%) underwent HREM. Abnormal esophageal motilities were identified in 68.8% patient: three patients (18.8%) had major motility disorders—achalasia (n=1), esophagogastric junction (EGJ) outflow obstruction (n=2)—and eight patients (50%) had minor motility disorders—ineffective esophageal motility (n=7), fragmented peristalsis (n=1). In those with normal esophageal motility, three patients of esophageal structure disorders (18.8%)—esophageal cancer (n=1), cardiogenic dysphagia (n=1), slight narrowing without obstruction of EGJ (n=1)—and two patients (12.5%) with chronic atrophic gastritis (n=2) were confirmed. Conclusion Esophageal motility disorders were identified in 68.8% of 16 patients with large esophageal residual barium with three patients in the major and eight patients in the minor categories. Residual barium in the esophagus was not rare and can be a sign of significant esophageal motility disorders.

Objective: To evaluate the prevalence rate, types, characteristics, and associated factors of esophageal dysphagia detected on chest X-ray images after videofluoroscopic swallowing study (VFSS). Methods: The medical records of 535 adults were reviewed retrospectively. Chest X-ray images taken after barium swallow study were analyzed and presence of any residual barium in the esophagus was considered as esophageal dysphagia. Esophageal dysphagia was classified based on the largest width of barium deposit (mild, <2 cm; severe ≥2 cm) and the anatomic level at which it was located (upper and lower esophagus). Results: Esophageal residual barium on chest X-ray images was identified in 40 patients (7.5%, 40/535). Esophageal dysphagia was more frequent in individuals aged 65–79 years (odds ratio=4.78, p<0.05) than in those aged <65 years. Mild esophageal dysphagia was more frequent (n=32) than its severe form (n=8). Lower esophageal dysphagia was more frequent (n=31) than upper esophageal dysphagia (n=9). Esophageal residual barium in patients diagnosed with esophageal cancer or lung cancer was significantly associated with severe esophageal dysphagia (p<0.05) and at the upper esophagus level (p<0.01). Conclusion Esophageal residual barium was observed on chest X-ray imaging after VFSS. Esophageal barium in the upper esophagus with a diameter of ≥2 cm is an important indicator of malignancy, and chest X-ray image taken after VFSS is an important step to evaluate the presence of esophageal disorder.

Kimura disease(KD) is a chronic inflammatory disorder of unknown etiology and results from an abnormal proliferation of lymphoid follicles and vascular endothelium and rarely has been reported in Korea. Clinical findings of Kimura disease include solitary or multiple, firm, subcutaneous nodules, which usually are located on the head or neck but parotid region is the most common site. The clinical course of the disease is chronic, with lesions frequently persisting or recurring despite treatment. The prognosis for KD is good, with no potential for malignant transformation. Our case is a 45-years-old man who had huge mass on left cheek which had slowly grown since about 10 years before. We planned to perform superficial parotidectomy but the mass was poorly demarcated due to extensive fibrosis and adhesion and had easy bleeding tendency. After frozen biopsy, we performed tumor debulking operation followed by cyclosporin therapy by the dose of 2.5 mg/Kg/day. The lesion was almostly cleared successfully after 3 months later. We report important aspects of clinical findings, histologic features, and therapeutic options of the rare case of KD with review of the previous articles.
Angiolymphoid Hyperplasia with Eosinophilia* ; Biopsy ; Cheek ; Cyclosporine ; Endothelium, Vascular ; Fibrosis ; Head ; Hemorrhage ; Korea ; Neck ; Parotid Gland* ; Parotid Region ; Prognosis

With recent advancement of the medical imaging systems and picture archiving and communication system (PACS), installation of digital radiography has been accelerated over past few years. Moreover, Computed Radiography (CR) which was well established for the foundation of digital x-ray imaging systems at low cost was widely used for clinical applications. This study analyzes imaging characteristics for two systems with different pixel sizes through the Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE). In addition, influence of radiation dose to the imaging characteristics was also measured by quantitative assessment. A standard beam quality RQA5 based on an international electro-technical commission (IEC) standard was used to perform the x-ray imaging studies. For the results, the spatial resolution based on MTF at 10% for Agfa CR system with I.P size of 8x10 inches and 14x17 inches was measured as 3.9 cycles/mm and 2.8 cycles/mm, respectively. The spatial resolution based on MTF at 10% for Fuji CR system with I.P size of 8X10 inches and 14x17 inches was measured as 3.4 cycles/mm and 3.2 cycles/mm, respectively. There was difference in the spatial resolution for 14x17 inches, although radiation dose does not effect to the MTF. The NPS of the Agfa CR system shows similar results for different pixel size between 100 micrometer for 8x10 inch I.P and 150 micrometer for 14x17 inch I.P. For both systems, the results show better NPS for increased radiation dose due to increasing number of photons. DQE of the Agfa CR system for 8X10 inch I.P and 14x17 inch I.P resulted in 11% and 8.8% at 1.5 cycles/mm, respectively. Both systems show that the higher level of radiation dose would lead to the worse DQE efficiency. Measuring DQE for multiple factors of imaging characteristics plays very important role in determining efficiency of equipment and reducing radiation dose for the patients. In conclusion, the results of this study could be used as a baseline to optimize imaging systems and their imaging characteristics by measuring MTF, NPS, and DQE for different level of radiation dose.
Diagnostic Imaging ; Humans ; Noise ; Photons ; Radiographic Image Enhancement

This study aims to conduct the comparative analysis of the radiation dose according to before and after the calibration of the ionization chamber used for measuring radiation dose in the MDCT, as well as of CTDIW according to temperature and pressure correction factors in the CT room. A comparative analysis was conducted based on the measured MDCT (GE light speed plus 4 slice, USA) data using head and body CT dosimetric phantom, and Model 2026C electrometer (RADICAL 2026C, USA) calibrated on March 21, 2007. As a result, the CTDIW value which reflected calibration factors, as well as correction factors of temperature and pressure, was found to be the range of 0.479~3.162 mGy in effective radiation dose than the uncorrected values. Also, under the routine abdomen routine CT image acquisition conditions used in reference hospitals, patient effective dose was measured to indicate the difference of the maximum of 0.7 mSv between before and after the application of such factors. These results imply that the calibration of the ion chamber, and the correction of temperature and pressure of the CT room are crucial in measuring and calculating patient effective dose. Thus, to measure patient radiation dose accurately, the detailed information should be made available regarding not only the temperature and pressure of the CT room, but also the humidity and recombination factor, characteristics of X-ray beam quality, exposure conditions, scan region, and so forth.
Abdomen ; Calibration ; Head ; Humans ; Humidity ; Light ; Recombination, Genetic

The current PET/CT system with high quality CT images not only increases diagnostic value by providing anatomic localization, but also shortens the acquisition time for attenuation correction than primary PET system. All commercially available PET/CT system uses the CT scan for attenuation correction instead of the transmission scan using radioactive source such as 137Cs, 68Ge. However the CT scan may substantially increase the patient dose. The purpose of this study was to evaluate quality of PET images reconstructed by CT attenuation map using various tube currents. In this study, images were acquired for 3D Hoffman brain phantom and cylindrical phantom using GE DSTe PET/CT system. The emission data were acquired for 10 min using phantoms after injecting 44.03 MBq of 18F-FDG. The CT images for attenuation map were acquired by changing tube current from 10 mA to 95 mA with fixed exposure time of 8 sec and fixed tube voltage of 140 kVp. The PET images were reconstructed using these CT attenuation maps. Image quality of CT images was evaluated by measuring SD (standard deviation) of cylindrical phantom which was filled with water and 18F-FDG solution. The PET images were evaluated by measuring the activity ratio between gray matter and white matter in Hoffman phantom images. SDs of CT images decrease by increasing tube current. When PET images were reconstructed using CT attenuation maps with various tube currents, the activity ratios between gray matter and white matter of PET images were almost same. These results indicated that the quality of the PET images using low dose CT data were comparable to the PET images using general dose CT data. Therefore, the use of low dose CT is recommended than the use of general dose CT, when the diagnostic high quality CT is not required. Further studies may need to be performed for other system, since this study is limited to the GE DSTe system used in this study.
Brain ; Fluorodeoxyglucose F18 ; Humans ; Positron-Emission Tomography and Computed Tomography* ; Tomography, X-Ray Computed ; Water

PURPOSE: To validate the use of harmonic ultrasonography (US) in the detection of gallbladder microlithiasis. METHODS: From November 30, 2012, to January 18, 2014, fundamental US (FUS) and harmonic US with a high background noise (HUS-N) were performed for evaluation of gallbladder during the routine abdomen US. During the US, a dot-like stone (or stones) with Brownian motion was regarded as a positive finding of microlithiasis. Fifty-five patients with microlithiasis in the gallbladder detected on US were enrolled as the subjects of a retrospective review. With respect to the obtained images, two abdominal radiologists independently scored the conspicuity of gallbladder microlithiasis on FUS and HUS-N by using a 4-grade scale. The statistical analysis employed a kappa test and a Wilcoxon rank-sum test. RESULTS: For FUS, the conspicuity grades of gallbladder microlithiasis were G1 in 25 and 37, G2 in 21 and 9, G3 in 6 and 6, G4 in 3 and 3 patients, while HUS-N showed G1 in 0 and 0, G2 in 3 and 2, G3 in 12 and 15, and G4 in 40 and 38 patients, respectively, by each of the two radiologists. The kappa value was 0.633 for FUS between the two radiologists and 0.708 for HUS-N. HUS-N showed better conspicuity of gallbladder microlithiasis than FUS with significant P-values of less than 0.001 and 0.001 for the two radiologists, respectively. CONCLUSION: Compared with FUS, HUS-N enables better detection of microlithiasis in the gallbladder.
Abdomen ; Cholecystolithiasis ; Gallbladder* ; Humans ; Noise ; Retrospective Studies ; Ultrasonography*

Objective: To translate the 22-item Longer-term Unmet Needs after Stroke (LUNS) questionnaire, validate it in the Korean stroke population, and assess the reliability of face-to-face and telephone surveys. Methods: Sixty-six adult patients with stroke from Seoul National University Bundang Hospital and Kangwon National University Hospital were involved in the validation. Participants were interviewed twice using the LUNS Korean version: first, a face-to-face survey for validation, and second, a telephone survey for test-retest reliability. Participants completed the Frenchay Activities Index (FAI) and Short Form 12 (SF-12) Mental and Physical Component Summary (MCS and PCS) scores at the first interview. For concurrent validity, the differences in health status (FAI, SF-12 MCS and PCS) between the groups that reported unmet needs and those that did not were analyzed for each item. Cohen’s kappa and percentage of agreement between the first and second administrations were calculated for each item to determine the test-retest reliability. Results: The average age of the participants was 61.2±12.8 years and 74.2% were male. Fifty-seven patients were involved in the second interview. Depending on the unmet needs, SF-12 MCS, PCS, and FAI were significantly different in 12 of 22 items. In the test-retest reliability test, 12 items had a kappa of 0.6 or higher, and two had a kappa of <0.4. Conclusion The LUNS instrument into Korean (LUNS-K) is a reliable and valid instrument for assessing unmet health needs in patients with stroke. In addition, telephone surveys can be considered reliable.