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Jung-Gi Im

Publications and source records attributed to Jung-Gi Im.

At least 19 recordsLinked to original sources
PubMed2006

Characterization of benign and malignant solid breast masses: comparison of conventional US and tissue harmonic imaging.

PURPOSE: To prospectively compare the diagnostic performance of radiologists by using conventional ultrasonography (US) and tissue harmonic imaging for the differentiation of benign from malignant solid breast masses, with histologic results used as the reference standard. MATERIALS AND METHODS: The study was approved by the institutional review board, and informed consent was obtained from all patients. Images were obtained with conventional US and tissue harmonic imaging in 88 patients (age range, 25-67 years; mean age, 45 years) with 91 solid breast masses (30 cancers and 61 benign lesions) before excisional or needle biopsy. Three experienced radiologists, who did not perform the examinations, independently analyzed the US findings and provided a level of suspicion to indicate the probability of malignancy. Results were evaluated by using kappa statistics and receiver operating characteristic (ROC) analyses. RESULTS: Regarding the descriptions of US findings, echogenicity (kappa=0.205) was the most discordant between conventional US and tissue harmonic imaging, followed by margin (kappa=0.495), lesion boundary (kappa=0.495), calcifications (kappa=0.537), posterior acoustic transmission (kappa=0.546), echotexture (kappa=0.586), shape (kappa=0.591), and orientation (kappa=0.594). The area under the ROC curve (Az) for conventional US and tissue harmonic imaging was 0.84 and 0.79, respectively, for reader 1; 0.88 and 0.85, respectively, for reader 2; and 0.91 and 0.89, respectively, for reader 3. The overall Az value for the three readers was 0.88 for conventional US and 0.84 for tissue harmonic imaging (95% confidence interval: -0.0950, 0.1646; P=.595). CONCLUSION: The performance of the radiologists with respect to the characterization of solid breast masses as benign or malignant was not significantly improved with tissue harmonic imaging.

Adult↗
PubMed2006

Differentiating benign from malignant solid breast masses: comparison of two-dimensional and three-dimensional US.

PURPOSE: To compare prospectively obtained static two-dimensional (2D) and three-dimensional (3D) ultrasonographic (US) images in the diagnostic performance of radiologists with respect to the differentiation of benign from malignant solid breast masses with histopathologic examination as the reference standard. MATERIALS AND METHODS: This study had institutional review board approval, and patient informed consent was obtained. Conventional 2D and 3D US images were obtained from 141 patients (age range, 25-71 years; mean age, 46 years) with 150 solid breast masses (60 cancers and 90 benign lesions) before excisonal or needle biopsy. Four radiologists who had not performed the examinations independently reviewed 2D US images and stored 3D US data and provided a level of suspicion concerning probability of malignancy. The sensitivity, specificity, and negative predictive values of 2D images were compared with those of 3D US images. RESULTS: For all readers, 3D US images were the same as or better than 2D US images in terms of sensitivity (100% vs 100% for reader 1; 100% vs 98% for reader 2; 98% vs 93% for reader 3; 93% vs 92% for reader 4), specificity (58% vs 56% for reader 1; 51% vs 46% for reader 2; 83% vs 72% for reader 3; 86% vs 84% for reader 4), and negative predictive values (100% vs 100% for reader 1; 100% vs 98% for reader 2; 99% vs 94% for reader 3; 95% vs 94% for reader 4). These differences, however, were not statistically significant (P > .05). CONCLUSION: The performance of the radiologists with respect to the characterization of solid breast masses with static 2D US images was similar to that with 3D US data.

Adult↗
PubMed2006

Computer-aided detection in digital mammography: comparison of craniocaudal, mediolateral oblique, and mediolateral views.

PURPOSE: To retrospectively compare the sensitivity of a computer-aided detection (CAD) system for depicting breast cancer in three digital mammographic views. MATERIALS AND METHODS: This study was conducted with institutional review board approval; informed consent was waived. A commercially available CAD system was applied to the craniocaudal, mediolateral oblique, and mediolateral digital mammographic views of 83 women (mean age, 48 years; range, 30-66 years) with 83 histologically proved breast cancers. Findings were 59 masses and 41 microcalcifications (17 lesions showed both findings; 42 lesions, mass only; and 24 lesions, microcalcification only). The paired t test was used to analyze sensitivity of the CAD system for the detection of cancer in these three mammographic views and in combinations of the views. RESULTS: The sensitivities of the CAD system were 92% (76 of 83) in the craniocaudal view, 83% (69 of 83) in the mediolateral oblique view, and 86% (71 of 83) in the mediolateral view; the differences were not significant (P = .07-.62). Sensitivity increased to 96% (80 of 83) in the craniocaudal plus mediolateral oblique views and to 99% (82 of 83) in the craniocaudal plus mediolateral oblique plus mediolateral views. For masses, the sensitivity of the CAD system was 76% (45 of 59) in the craniocaudal view and 75% (44 of 59) in the mediolateral oblique view and increased to 93% (55 of 59) when mediolateral oblique and craniocaudal views were combined (P < .001). For microcalcifications, sensitivity was 98% (40 of 41) in the craniocaudal view and 95% (39 of 41) in the mediolateral oblique view, and this increased to 100% (41 of 41) when the mediolateral oblique and craniocaudal views were combined (P = .31). CONCLUSION: The sensitivities of the CAD system were not significantly different among these three digital mammographic views. Sensitivity for depicting masses was significantly increased (P < .001) when the craniocaudal view was added to the mediolateral oblique view.

Adult↗
PubMed2005

Computer-aided diagnosis of localized ground-glass opacity in the lung at CT: initial experience.

The purpose of this study was to develop an automated scheme to facilitate detection of localized ground-glass opacity (GGO) in the lung at computed tomography (CT). Institutional review board approval and informed consent were not required. Two radiologists reviewed CT images from 14 patients (five men, nine women) who had lung cancer or metastasis and whose malignancy was classified as GGO. The lung region was sampled and completely covered with contiguous, 50% overlapping regions of interest (ROIs) measuring 30 x 30 pixels in size. The lung area within each ROI was analyzed to compute texture features and gaussian curve fitting features. Performance of the artificial neural networks (ANNs) measured by using the area under the receiver operating characteristic curve was 0.92. With a threshold of 0.9, the sensitivity of the ANN for detecting GGO ROIs was 94.3% (280 of 297 ROIs), and the positive predictive value was 29.1% (280 of 963 ROIs). A computerized scheme may hold promise in facilitating detection of localized GGO at CT.

Aged↗
PubMed2005

Diffractive ultrasound in the evaluation of solid breast masses: preliminary results.

PURPOSE: We sought to evaluate diffractive ultrasound (US) in the characterization of solid breast masses. MATERIALS AND METHODS: Forty-eight patients with solid breast masses (24 malignant and 24 benign) observed at conventional US underwent targeted diffractive US before needle biopsy or surgery. The process of locating the lesion was performed with knowledge of the mammography and conventional US. On diffractive US, imaging features, including shape, brightness, echotexture, margin, and boundary echo were analyzed and odds ratio (OR) were calculated to show how the risk of malignancy was altered by the presence of a given finding. RESULTS: Of the 48 solid breast masses seen on conventional US, 46 (96%) were seen at diffractive US. Diffractive US features suggestive of malignancy were irregular shape (OR 11.5), sono-opacity (OR 204), spiculated margin (OR 17.0), and absent boundary echo (OR 11.5) or thick rim (OR 5.5), whereas those of benignancy were round shape (OR 0.03), sonotransmission (OR 0.07) or isodensity (OR 0.01), well-defined margin (OR 0.03), and thin capsule (OR 0.03; P < 0.05). CONCLUSION: The finding of a sono-opaque mass on diffractive US was highly sensitive for malignancy. Further improvement of diffractive US equipment is needed to increase image quality and to permit inclusion of the axillary tail and deep portions of the breast.

Adult↗
PubMed2005

Differentiation of benign from malignant solid breast masses: conventional US versus spatial compound imaging.

PURPOSE: To compare prospectively the diagnostic performance of radiologists who used conventional ultrasonography (US) with that of radiologists who used spatial compound imaging for the differentiation of benign from malignant solid breast masses. MATERIALS AND METHODS: The study was approved by the institutional review board, and informed consent was obtained. Before excisional or needle biopsy was performed, conventional US and spatial compound images were obtained in 67 patients (age range, 25-67 years; mean age, 45 years) with 75 solid breast masses (21 cancers and 54 benign lesions). Three experienced radiologists who did not perform the examinations independently analyzed US findings and indicated the probability of malignancy. Results were evaluated with kappa statistics and receiver operating characteristic (ROC) analysis. RESULTS: For US findings, the presence of calcifications was the most discordant feature (kappa = 0.372) between conventional US and spatial compound imaging, followed by echotexture (kappa = 0.439), boundary echo (kappa = 0.496), orientation (kappa = 0.518), echogenicity (kappa = 0.523), shape (kappa = 0.526), margin (kappa = 0.569), and posterior acoustic transmission (kappa = 0.669). The area under the ROC curve for conventional US was 0.79 for reader 1, 0.88 for reader 2, and 0.82 for reader 3, and the area under the ROC curve for spatial compound imaging was 0.85 for reader 1, 0.88 for reader 2, and 0.89 for reader 3. The partial area index for conventional US was 0.29 for reader 1, 0.69 for reader 2, and 0.39 for reader 3, and the partial area index for spatial compound imaging was 0.29 for reader 1, 0.65 for reader 2, and 0.39 for reader 3. The difference between the diagnostic performances of the two techniques was not significant (P > .05). CONCLUSION: The performance of the radiologists with respect to the characterization of solid breast masses was not significantly improved with spatial compound imaging.

Adult↗
PubMed2005

High-resolution sonography of the rib: can fracture and metastasis be differentiated?

OBJECTIVE: Our aim was to evaluate whether high-resolution sonography can provide additional information concerning rib lesions compared with radiography or bone scintigraphy. MATERIALS AND METHODS: Fifty-eight patients with high-uptake rib lesions seen on bone scintigraphy were selected. Radiography and rib high-resolution sonography were performed on these patients. High-resolution sonography was performed using a linear 5-12 MHz transducer. By means of clinical history, histopathologic examination, and follow-up observation, these patients were classified into rib fracture (n = 37), rib metastasis (n = 18), or unknown (n = 3) groups. High-resolution sonography images of the 55 proven cases were reviewed for the presence of five representative findings: cortical disruption, callus formation, cortical deformity, mass, or bone destruction. The frequencies of these findings were compared between the groups with fracture and metastasis. RESULTS: Rib lesions were matched by bone scintigraphy and high-resolution sonography in 53 (96%) of 55 patients and by bone scintigraphy and plain radiography in 23 (42%) of 55 patients. High-resolution sonography revealed 17 (94%) of 18 patients with metastasis and 36 (97%) of 37 patients with rib fractures. Metastatic lesions were seen as mass formation (n = 13) and irregular bone destruction (n = 7) on high-resolution sonography. Fracture was seen as cortical disruption with or without hematoma (n = 17), callus formation (n = 9), or cortical deformity, such as angling or stepping (n = 12). CONCLUSION: High-resolution sonography of the ribs is a useful method of characterizing rib lesions in patients who have hot-uptake lesions on bone scintigraphy.

Adult↗
PubMed2004

Value of high-resolution ultrasound in detecting a pneumothorax.

This study was designed to compare the detectability of high-resolution ultrasound (HRUS) and bedside chest radiography (CR) for a pneumothorax. During the last 14 months, 97 consecutive patients who were admitted to our institute to undergo a transthoracic needle aspiration and biopsy (TNAB) of the lung were included. Both HRUS and CR were performed immediately after the TNAB procedure. The HRUS images were saved in sequence using the cine-review mode and displayed as an animation on a workstation. Four radiologists independently analyzed both HRUS images and a soft copy of the CR on a diagnostic monitor and identified the pneumothorax. With CT as the reference standard, statistical parameters were calculated. From 97 patients, 35 pneumothorax cases were found on CT after the TNAB. The sensitivities in detecting the pneumothorax were 80 and 47% in HRUS and CR, respectively. The specificities were 94 and 94%. The diagnostic accuracies were 89 and 77%. The inter-observer agreement was excellent (kappa=0.85) in the HRUS images and moderate (kappa=0.49) in the CR. The results of this study suggest that HRUS is a more sensitive and confident method for diagnosing a pneumothorax when compared to bedside chest radiography.

Biopsy, Needle↗
PubMed2004

Acute lung injury: effects of prone positioning on cephalocaudal distribution of lung inflation--CT assessment in dogs.

PURPOSE: To quantify cephalocaudal gradient of lung inflation in acute lung injury in a dog model in prone versus supine position. MATERIALS AND METHODS: Experiments were performed in accordance with Guide for the Care and Use of Laboratory Animals, as approved by National Research Council (National Institutes of Health), and were approved by committee on care and use of animals in research at Seoul National University Hospital. After induction of acute lung injury with intravenous injection of oleic acid, dogs were randomized to be ventilated in either prone (n = 6) or supine (n = 6) position. Spiral computed tomography (CT) and hemodynamic measurement were performed sequentially on an hourly basis. Volume and mean attenuation of lung were measured quantitatively by using software to evaluate each CT section. Cephalocaudal gradient of mean lung attenuation, distribution of gas and tissue, and alveolar expansion were assessed. Functional residual capacity and net alveolar expansion of entire lung were measured. Statistical analysis was performed with Friedman, sign, and Mann-Whitney tests. RESULTS: Mean lung attenuation increased gradually from apex to base of lung in supine position. Thus, inflation gradient along cephalocaudal axis was found. Gas was located predominantly in upper lung, whereas tissue was dominant in lower lung in supine position. In supine group, cephalocaudal inflation gradient showed no significant change from baseline up to 4 hours. After prone positioning, cephalocaudal inflation gradient was reduced, and gas and tissue proportions became more uniform along cephalocaudal axis. In prone group, absolute values of cephalocaudal inflation gradient at time points of prone positioning for 1, 2, and 3 hours were significantly lower than baseline values (P < .05) and those in supine group (P < .05). Alveolar expansion occurred in caudal regions, and alveolar contraction occurred in cephalic regions; accordingly, net alveolar volume of entire lung was not altered significantly. Functional residual capacity was unchanged by prone positioning. CONCLUSION: In acute lung injury, prone positioning induced more uniform distribution of gas and tissue along cephalocaudal axis by reducing cephalocaudal inflation gradient.

Animals↗
PubMed2004

Effect of monitor luminance and ambient light on observer performance in soft-copy reading of digital chest radiographs.

PURPOSE: To examine the combined effects of monitor luminance and ambient light on observer performance for detecting abnormalities in a soft-copy interpretation of digital chest radiographs. MATERIALS AND METHODS: A total of 254 digital chest radiographs were displayed on a high-resolution cathode ray tube monitor at three luminance levels (25, 50, and 100 foot-lamberts) under three ambient light levels (0, 50, and 460 lux). Six chest radiologists reviewed each image in nine modes of combined luminance and ambient light. The observers were allowed to adjust the window width and level of the soft-copy images. The abnormalities included nodule, pneumothorax, and interstitial disease. Observer performance was analyzed in terms of the receiver operating characteristics. The observers reported their subjective level of visual fatigue with each viewing mode. A statistical test was conducted for each of the abnormalities and for fatigue score by using repeated-measures two-way analysis of variance with an interaction. RESULTS: The detection of nodules was the only reading that was affected by the ambient light with a statistically significant difference (P <.05). Otherwise, observer performance for detecting a nodule, pneumothorax, and interstitial disease was not significantly different in the nine-mode comparison. There was no evidence that the luminance of the monitors was related to the ambient light for any of the abnormalities. The fatigue score showed a statistically significant difference due to both the luminance and ambient light. CONCLUSION: When adequate window width and level are applied to soft-copy images, the primary diagnosis with chest radiographs on the monitor is unlikely to be affected under low ambient light and a monitor luminance of 25 foot-lamberts or more.

Computer Terminals↗
PubMed2004

Pleomorphic carcinoma of lung: comparison of CT features and pathologic findings.

PURPOSE: To retrospectively evaluate computed tomographic (CT) features of pleomorphic carcinoma of the lung and to compare these features with pathologic findings. MATERIALS AND METHODS: Ten patients (10 men, three women; mean age at diagnosis, 64.1 years; range, 43-75 years) with pleomorphic carcinoma treated from June 2000 to January 2003 were selected from two institutions. Two radiologists retrospectively reviewed CT features, which included size and location of tumor, presence of calcification, attenuation values and internal architecture of the mass, and invasion of pleura and chest wall. Attenuation values of the mass on CT scans were compared with pathologic findings in tumors in available gross specimens. Follow-up CT scans were not routinely obtained except in two patients with progressive pleural effusion and rapid growth of the tumor as seen on serial chest radiographs. RESULTS: On unenhanced CT scans, attenuation of the tumor was similar to that of the surrounding muscle. Calcification within the tumor was visible in one patient. Invasion of chest wall was noted in two patients. Seven patients had pleural invasion. Tumors were located at the lung periphery in nine patients. On contrast material-enhanced CT scans, lesions with the longest diameter larger than 5 cm showed central low-attenuation areas with substantial enhancement in the tumor periphery; in comparison, lesions with the longest diameter smaller than 5 cm showed homogeneous enhancement. Size of two lesions with the longest diameter larger than 5 cm increased rapidly after a follow-up of shorter than 3 weeks. Low-attenuation areas on contrast-enhanced CT scans were found to correspond to areas of myxoid degeneration, necrosis, or hemorrhage in pathologic specimens. CONCLUSION: Findings of this study suggest that pleomorphic carcinomas of the lung preferentially manifest as large peripheral lung neoplasms with a central low-attenuation area and frequently invade the pleura and chest wall.

Adult↗
PubMed2004

Pulmonary tuberculosis in patients with idiopathic pulmonary fibrosis.

OBJECTIVES: Patients with idiopathic pulmonary fibrosis (IPF) have an increased risk of pulmonary tuberculosis. However, detecting pulmonary tuberculosis may be difficult due to the underlying fibrosis. The aim of this report is to describe the radiological and clinical findings of pulmonary tuberculosis in patients with idiopathic pulmonary fibrosis. MATERIALS AND METHODS: We reviewed 143 consecutive patients in whom IPF was diagnosed by either the histological or radio-clinical criteria. Among them, nine patients were histologically (n=2) or bacteriologically (n=7) confirmed to have active pulmonary tuberculosis. The location and patterns of pulmonary tuberculosis were examined on a thin section CT scan. RESULTS: The most common thin section CT findings were subpleural nodules (n=6; mean diameter, 3.2 cm) and a lobar or segmental consolidation (n=3). The lesions were located most commonly in the right lower lobe (n=4). The incidence of tuberculosis in patients with idiopathic pulmonary fibrosis was more than five times higher than that of the general population. CONCLUSION: The atypical manifestation of pulmonary tuberculosis is common in patients with idiopathic pulmonary fibrosis, which may mimic lung cancer or bacterial pneumonia.

Aged↗
PubMed2004

Endobronchial metastasis from renal cell carcinoma: CT findings in four patients.

PURPOSE: To describe the CT findings of an endobronchial metastasis from a renal cell carcinoma (RCC). MATERIALS AND METHODS: The CT findings and clinical features of a histologically proven endobronchial metastasis from a RCC in four patients (three male, one female; age range, 64-80 years; mean age, 69 years) were reviewed retrospectively. The location of the metastasis in the airway, shape, the degree of tumor enhancement, and the associated pulmonary parenchymal abnormalities were analyzed. RESULTS: The histological subtype of the endobronchial metastases from the RCC was conventional in all cases. The tumors were located at the lobar (n = 1), both the lobar and segmental (n = 2), or the segmental (n = 1) bronchus. On the CT scan, the tumors were polypoid (n = 1), had a glove-finger appearance (n = 2), and exhibited branching in the airways and bronchial wall thickening (n = 1). The endobronchial metastasis from the RCC showed very high attenuation (84-128 HU), and strong enhancement (51.6-93.3 HU) on the contrast-enhanced CT images. The lung parenchymal lesions that had reticular opacities and ground glass opacities (n = 3). CONCLUSIONS: An endobronchial metastasis from a RCC appears as a strong-enhancing mass or bronchial wall thickening, accompanied by reticular opacities and ground glass opacities.

Aged↗
PubMed2004

CT perfusion image of the lung: value in the detection of pulmonary embolism in a porcine model.

RATIONALE AND OBJECTIVES: We assess the value of computed tomography perfusion image (CTPI) obtained by postprocessing the CT data in the diagnosis of pulmonary embolism. METHODS: An experimental pulmonary embolism model was made in 6 pigs by injecting 2 types of emboli into the pulmonary arteries. For each pig, 5 type-A (diameter 3.5 x 8 mm) and 5 type-B (diameter 2.5 x 6 mm) emboli were injected through a catheter with the distal tip located in the inflow tract of the right atrium. After obtaining precontrast and postcontrast CT data during a single breath-hold using a 4-slice multidetector CT, perfusion images were generated by data subtraction. Approximately 150 to 180 mL of contrast material was injected at an injection rate of 6 mL/s to obtain postcontrast CT. Three independent observers twice analyzed CT images for the presence of emboli: once with postcontrast CT scans (CT angiography: CTA) alone and again with both CTA and CTPI. The locations of the emboli in the pulmonary arteries were confirmed by examining the killed porcine lungs. RESULTS: The sensitivity and positive predictive value in the detection of pulmonary emboli with CTA alone were 59% (106/180) and 87% (106/122), respectively. The sensitivity and positive predictive value with both CTA and CTPI were 87% (156/180) and 85% (156/184), respectively. For type-A emboli, the sensitivity with both CTA and CTPI (76/90, 85%) was better than that with CTA alone (63/90, 70%) (P < 0.001). For type-B emboli, the sensitivity with both CTA and CTPI (80/90, 89%) was also better than that of CTA alone (43/90, 48%) (P < 0.001). CONCLUSIONS: CTPI could be obtained using digital subtraction of the CT data. It appeared to be an adjunct in enhancing the diagnostic accuracy of pulmonary embolism, particularly when detecting small pulmonary emboli.

Animals↗