Yoon Kyung Kim

Reduced Radiation Exposure of the Female Breast During Low-Dose Chest CT Using Organ-Based Tube Current Modulation and a Bismuth Shield: Comparison of Image Quality and Radiation Dose

OBJECTIVE The objective of our study was to evaluate the effect of organ-based tube current modulation and bismuth shielding on image quality and breast radiation dose in women undergoing low-dose chest CT. SUBJECTS AND METHODS From March 2011 through July 2011, 80 women prospectively underwent low-dose chest CT to screen for lung cancer. The patients were randomly assigned to a control group (n = 20), organ-based tube current modulation group (n = 20), breast shield group (n = 20), or breast shield plus organ-based tube current modulation group (n = 20). Axial slice images of the aortic arch, carina, and inferior pulmonary vein were used to analyze image quality. Three radiologists scored the image quality in terms of artifact and noise and then characterized the overall image quality as optimal (does not affect the diagnostic accuracy) or suboptimal (affects the diagnostic accuracy). Noise levels were measured in the anterior and posterior lung in each image. A phantom dose study was conducted to measure radiation dose. RESULTS Images with artifacts or noise were more frequently obtained in the breast shield groups; however, the overall image quality was not significantly different among the four groups. Measured noise levels in the anterior lung were significantly higher in the breast shield groups than the control group; however, no statistical significance was found among the four groups with regard to noise level in the posterior lung. In the phantom dose study, a 16-37.5% dose reduction in the breast was achieved using the breast shield, organ-based tube current modulation protocol, or both. CONCLUSION The radiation dose in the female breast may be reduced using a breast shield or organ-based tube current modulation during low-dose chest CT with acceptable image quality. The use of organ-based tube current modulation reduced the radiation dose in the breast without inducing image quality deterioration.

Multidetector CT and radiographic findings of lung injuries secondary to cardiopulmonary resuscitation

OBJECTIVES Lung injury is one of the complications of cardiopulmonary resuscitation (CPR). This is the first study to describe the MDCT and radiographic findings of lung injuries secondary to CPR. METHODS A total of 44 patients who underwent CPR for a non-traumatic cause of cardiac arrest were retrospectively included in this study. We evaluated the presence of lung injuries in the initial chest radiograph and MDCT performed immediately after CPR and described the MDCT and radiographic findings of the CPR-associated lung injuries. Finally, we evaluated the temporal pattern of lung injury on the follow-up radiographies. RESULTS Chest CT demonstrated lung injury in 54 lungs of 35 patients, while initial chest radiography detected lung abnormality in 37 lungs of 28 patients. The most common patterns of lung injuries on chest CT were bilateral (n=19), ground-glass opacity (n=30) and consolidation (n=26), distributed along the bronchovascular bundles (n=13). Most of the abnormalities were located in the posterior part of both upper lobes and both lower lobes (n=29). Among seven patients who did not have abnormalities in the initial chest radiograph, lung abnormalities were detected on the follow-up radiographies (mean follow-up duration=1.6 days, range=1-3 days) in five patients, and 28 patients who had lung abnormalities on initial radiograph were improved (n=19) or aggravated (n=8) on the follow-up radiographies. CONCLUSIONS Lung injuries are frequent complications in patients who underwent CPR. Compared with radiography, MDCT has benefits for the detection and characterisation of CPR-associated lung injuries. The most common findings of lung injuries after CPR were bilateral ground glass opacity and consolidation, usually in the dependent area of both lungs.

Pseudopathologic vertebral body enhancement in the presence of superior vena cava obstruction on computed tomography

BACKGROUND CONTEXT Superior vena cava (SVC) obstruction can cause the development of collateral vessels. During contrast-enhanced thoracic computed tomography (CT), contrast material may reflux into the collaterals such as paravertebral venous plexus. However, an unusual pseudopathologic vertebral body enhancement on CT in the presence of SVC obstruction has not been studied previously. PURPOSE To demonstrate clinical presentation and imaging findings of pseudopathologic vertebral body enhancement in patients with SVC obstruction. STUDY DESIGN Retrospective study of diagnostic CT images examined at our clinic. PATIENT SAMPLE From March, 2009 to September, 2012, a retrospective radiologic database review was performed to identify patients with obstruction of SVC causing contrast reflux into collateral vessels and presented with an unusual vertebral body enhancement on thoracic CT. Thirteen patients (11 men, mean age 51.4 years) with vertebral body enhancement were enrolled. OUTCOME MEASURES Enhancement patterns of vertebral bodies were classified as nodular enhancement with round shape occupying less than one-third of vertebral body or polygonal enhancement occupying greater than or equal to one-third of vertebral body on axial image. The locations of enhanced areas within vertebral bodies were described using right lateral/central/left lateral, anterior/posterior, and upper/middle/lower in the x-, y-, or z-axis directions, respectively. MATERIALS AND METHODS Enhancement patterns, locations, and the presence of a connection between vertebral body enhancement and the paravertebral venous plexus were evaluated. RESULTS A total of 39 vertebral body enhancements were found in the 13 patients, involving cervical (n=12), thoracic (n=25), or lumbar (n=2) vertebrae. Vertebral body enhancements showed a nodular (n=19) or a polygonal (n=20) pattern. The central portions of vertebral bodies were more frequently involved. The connection to the paravertebral venous plexus was observed in 34 lesions (87.2%). CONCLUSIONS Patients with SVC obstruction with extensive collateral vessels might exhibit a pseudopathologic vertebral enhancement. They tended to involve the central portion of the vertebral body, and most of them showed connection to the paravertebral venous plexus.

Annual Change in Pulmonary Function and Clinical Characteristics of Combined Pulmonary Fibrosis and Emphysema and Idiopathic Pulmonary Fibrosis: Over a 3-Year Follow-up

Background Combined pulmonary fibrosis and emphysema (CPFE) have different pulmonary function tests (PFTs) and outcomes than idiopathic pulmonary fibrosis (IPF). The intention of this study was to identify unknown differences between CPFE and IPF by a retrospective comparison of clinical data including baseline and annual changes in pulmonary function, comorbidities, laboratory findings, clinical characteristics and cause of hospitalization. Methods This study retrospectively enrolled patients with CPFE and IPF who had undergone PFTs once or several times per year during a follow-up period of three years. Baseline clinical characteristics and the annual changes in the pulmonary function during the follow-up period were compared between 26 with CPFE and 42 patients with IPF. Results The baseline ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC%) in patients with CPFE was lower than that in patients with IPF (78.6±1.7 vs. 82.9±1.1, p=0.041). The annual decrease in FEV1/FVC in the CPFE was significantly higher than in the IPF. The annual decreases in diffusion capacity of carbon monoxide and FVC showed no significant differences between the two groups. The symptom durations of cough and sputum were in the CPFE significantly lower than in the IPF. The serum erythrocyte sedimentation rate level at the acute stage was significantly higher than in the IPF. There were no significant differences in the hospitalization rate and pneumonia was the most common cause of hospitalization in both study groups. Conclusion The annual decrease of FEV1/FVC was in patients with CPFE significantly higher than in the patients with IPF.

CT Characteristics of Pleural Plaques Related to Occupational or Environmental Asbestos Exposure from South Korean Asbestos Mines.

Objective This study evaluated the CT characteristics of pleural plaques in asbestos-exposed individuals and compared occupational versus environmental exposure groups. Materials and Methods This study enrolled 181 subjects with occupational exposure and 98 with environmental exposure from chrysotile asbestos mines, who had pleural plaques confirmed by a chest CT. The CT scans were analyzed for morphological characteristics, the number and distribution of pleural plaques and combined pulmonary fibrosis. Furthermore, the CT findings were compared between the occupational and environmental exposure groups. Results Concerning the 279 subjects, the pleural plaques were single in 2.2% and unilateral in 3.6%, and showed variable widths (range, 1-20 mm; mean, 5.4 ± 2.7 mm) and lengths (5-310 mm; 72.6 ± 54.8 mm). The chest wall was the most commonly involved (98.6%), with an upper predominance on the ventral side (upper, 77.8% vs. lower, 55.9%, p < 0.001) and a lower predominance on the dorsal side (upper, 74.9% vs. lower, 91.8%, p = 0.02). Diaphragmatic involvement (78.1%) showed a right-side predominance (right, 73.8% vs. left, 55.6%, p < 0.001), whereas mediastinal plaques (42.7%) were more frequent on the left (right, 17.6% vs. left, 39.4%, p < 0.001). The extent and maximum length of plaques, and presence and severity of combined asbestosis, were significantly higher in the occupational exposure group (p < 0.05). Conclusion Pleural plaques in asbestos-exposed individuals are variable in number and size; and show a predominant distribution in the upper ventral and lower dorsal chest walls, right diaphragm, and left mediastinum. Asbestos mine workers have a higher extent of plaques and pulmonary fibrosis versus environmentally exposed individuals.

Aortic Stent-Graft for a Giant Bronchial Artery Aneurysm with Ultrashort Neck

Bronchial artery aneurysms are rarely encountered, but they can cause life-threatening hemorrhages when they rupture. The authors report a case of a giant bronchial artery aneurysm with ultrashort neck in a 73-year-old woman who presented with massive hemoptysis. The aneurysm was successfully treated by a combination of transcatheter arterial embolization and aortic stent-graft placement, and the patient made an uneventful recovery. Follow-up computed tomography (CT) obtained 24 months after aortic stent-graft placement confirmed continued exclusion of the aneurysm, with no evidence of an endoleak.

The value of chest CT for prediction of breast tumor size: comparison with pathology measurement.

BackgroundLittle information is available on the use of chest computed tomography (CT) to predict breast tumor size in breast cancer, despite the fact that chest CT examinations are being increasingly used. The purpose of this study was to evaluate the value of chest CT for predicting breast tumor size using pathology measurements as reference standards.MethodsTumor sizes (defined as greatest diameter) were retrospectively measured on the preoperative chest CT images of 285 patients with surgically proven unifocal, invasive breast carcinoma. Greatest tumor diameters as determined by chest CT and pathologic examinations were compared by linear regression and Spearman’s rho correlation analysis. Concordance between CT and pathology results was defined as a diameter difference of <5 mm. Subgroup analyses were also performed with respect to tumor size (<20 mm or ≥20 mm) and histological subtype (invasive ductal carcinoma(IDC) or non-IDC).ResultsCT and pathology measured diameters were found to be linearly related (size at pathology = 1.086 × CT determined tumor size - 1.141; Spearman’s rho correlation coefficient = 0.84, P<0.001). Most tumors (n = 228, 80.0%) were concordant by chest CT and pathology, but 36 tumors (12.7%) were underestimated by CT (average underestimation, 11 mm; range, 6–36 mm) and 21 tumors (7.4%) were overestimated (average overestimation by CT, 10 mm; range, 6–19 mm). The concordance rate between the two sets of measurements was greater for tumor of <20 mm and for IDC (P<0.001 and P = 0.011, respectively).ConclusionsTumor size by chest CT is well correlated with pathology determined tumor size in breast cancer patients, and the diameters of the majority of tumors by chest CT and pathology differed by <5 mm. In addition, the concordance rate was higher for breast tumors of <20 mm and for tumors of the IDC histologic subtype.

Multidetector CT Findings and Differential Diagnoses of Malignant Pleural Mesothelioma and Metastatic Pleural Diseases in Korea

Objective To compare the multidetector CT (MDCT) features of malignant pleural mesothelioma (MPM) and metastatic pleural disease (MPD). Materials and Methods The authors reviewed the MDCT images of 167 patients, 103 patients with MPM and 64 patients with MPD. All 167 cases were pathologically confirmed by sonography-guided needle biopsy of pleura, thoracoscopic pleural biopsy, or open thoracotomy. CT features were evaluated with respect to pleural effusion, pleural thickening, invasion of other organs, lung abnormality, lymphadenopathy, mediastinal shifting, thoracic volume decrease, asbestosis, and the presence of pleural plaque. Results Pleural thickening was the most common CT finding in MPM (96.1%) and MPD (93.8%). Circumferential pleural thickening (31.1% vs. 10.9%, odds ratio [OR] 3.670), thickening of fissural pleura (83.5% vs. 67.2%, OR 2.471), thickening of diaphragmatic pleura (90.3% vs. 73.4%, OR 3.364), pleural mass (38.8% vs. 23.4%, OR 2.074), pericardial involvement (56.3% vs. 20.3%, OR 5.056), and pleural plaque (66.0% vs. 21.9%, OR 6.939) were more frequently seen in MPM than in MPD. On the other hand, nodular pleural thickening (59.2% vs. 76.6%, OR 0.445), hilar lymph node metastasis (5.8% vs. 20.3%, OR 0.243), mediastinal lymph node metastasis (10.7% vs. 37.5%, OR 0.199), and hematogenous lung metastasis (9.7% vs. 29.2%, OR 0.261) were less frequent in MPM than in MPD. When we analyzed MPD from extrathoracic malignancy (EMPD) separately and compared them to MPM, circumferential pleural thickening, thickening of interlobar fissure, pericardial involvement and presence of pleural plaque were significant findings indicating MPM than EMPD. MPM had significantly lower occurrence of hematogenous lung metastasis, as compared with EMPD. Conclusion Awareness of frequent and infrequent CT findings could aid in distinguishing MPM from MPD.

2018 Korean Clinical Imaging Guideline for Hemoptysis

In 2014, the American College of Radiology (ACR) announced the guideline for the appropriate diagnostic approach and treatment of patients according to the severity of hemoptysis and risk for lung cancer. However, the application of the ACR guideline in Korea may not be appropriate, because many patients in Korea have active tuberculosis or pulmonary fibrosis due to previous tuberculosis. The Korean Society of Radiology and Korean Society of Thoracic Radiology have proposed a new guideline suitable for Korean practice. This new guideline was prepared through the consensus of a development committee, working party, and an advisory committee. The guideline proposal process was based on an evidence-based clinical imaging guideline proposed by the development committee. Clinical imaging guideline for adult patients with hemoptysis is as follows: Chest radiography is an initial imaging modality to evaluate hemoptysis. Contrast-enhanced chest CT is recommended in patients with two risk factors for lung cancer (> 40 years old and > 30 pack-year smoking history), moderate hemoptysis (> 30 mL/24 hours) or recurrent hemoptysis. Contrast-enhanced chest CT is also recommended in patients with massive hemoptysis (> 400 mL/24 hours) without cardiopulmonary compromise.

Prognostic significance of CT-determined emphysema in patients with small cell lung cancer

Background Although emphysema and small cell lung cancer (SCLC) are prevalent in smokers, no previous study has investigated the prognostic impact of computed tomography (CT)-determined emphysema in SCLC. This study was undertaken to analyze the prognostic value of emphysema scores as determined by baseline CT scans in patients with SCLC. Methods The data of 149 consecutive patients with SCLC were analyzed. Emphysema severity was semi-quantitatively scored on baseline chest CT images using the Goddard scoring system (possible scores for individual patients ranged from 0 to 24). Data on clinical characteristics and survival were retrospectively collected. Survivals were estimated using the Kaplan-Meier method and compared using the log-rank test. A multivariable Cox proportional hazard model was used to identify prognostic factors. Results Most of the 149 patients were male (85.2%) and current/ex-smokers (87.2%). The median CT emphysema score was 4 (range, 0 to 23). Univariable analysis, patients with a higher CT emphysema score (≥8) had significantly poorer overall survivals (OS) than those with lower scores (5.0 vs. 12.3 months, P<0.001). Multivariable analysis showed a higher CT emphysema score (treated as a continuous variable) was a significant independent prognostic factor of poor survival [hazard ratio (HR), 1.85; 95% confidence interval (CI), 1.14 to 3.00; P=0.012], along with extensive stage (HR, 2.27; 95% CI, 1.45-3.53; P<0.001), elevated lactate dehydrogenase (LDH) (HR, 1.52; 95% CI, 1.03-2.23; P=0.034), and supportive care only (HR, 6.46; 95% CI, 3.64-11.48; P<0.001). Conclusions Emphysema severity, as determined by baseline CT, is significantly associated with poor prognosis in SCLC.