PubMed Health⌕ Search

Biomedical subjects

Jin Mo Goo

Publications and source records attributed to Jin Mo Goo.

At least 19 recordsLinked to original sources
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

CT depiction of pulmonary emboli: display window settings.

PURPOSE: To compare computed tomographic (CT) window settings selected by radiologists with those determined by using two alternative approaches for depiction of pulmonary emboli (PE). MATERIALS AND METHODS: Institutional review board approval was obtained; informed consent was not required. This study was compliant with the Health Insurance Portability and Accountability Act. Twenty-five clinical chest CT studies were obtained with a standardized PE protocol and retrospectively evaluated by five chest and two body CT radiologists. Of these studies, 13 were positive for PE, and 12 were negative. At the main pulmonary artery (PA), mean attenuations (MPA) and standard deviations (SDPA) were measured. Initially, images were displayed with a standard mediastinal window setting (window width, W = 400 HU; window center, C = 30 HU), and each observer adjusted the setting to a personally preferred setting (eg, "personal") for PE detection. Images displayed at this setting were compared in a side-by-side fashion with the "modified" (W = MPA + 2 . SDPA, C = W/2) and "double-half" (W = 2 . MPA, C = MPA/2) window setting. Each observer rated images from 1 (ie, most preferred) to 3 (ie, least preferred). For quantitative analysis, window width and center value of each setting were divided by corresponding MPA to compute a width ratio and a center ratio. Window settings and ratings were compared with repeated-measures analysis of variance, paired t tests, and Wilcoxon signed-rank tests. RESULTS: Ratings for all three types of window settings were significantly different (P < .001). Observers preferred their personal settings the most and the modified settings the least. Mean ratios for the seven observers were 1.68 +/- 0.20 for window width and 0.47 +/- 0.08 for window center. Window width ratios for all settings were significantly different from each other (P < .001). Window center ratios were significantly higher for the modified setting than for the double-half setting (P = .013). Values for mean PA attenuation were correlated with window width ratios for six (86%) observers (mean r2 value = 0.29 +/- 0.19, P < or = .03) and with window center ratios for four (57%) observers (mean r2 value = 0.16 +/- 0.14, P < or = .02), thus indicating a trend of setting window width and window center higher when contrast enhancement is lower and vice versa. CONCLUSION: On average, observers selected CT window settings for PE detection at a window width of slightly less than twice the mean PA attenuation and at a window center of about half the mean PA attenuation. Observers tended to use larger window widths and centers as the degree of PA enhancement was lower.

Adult↗
PubMed2005

Volumetric measurement of synthetic lung nodules with multi-detector row CT: effect of various image reconstruction parameters and segmentation thresholds on measurement accuracy.

PURPOSE: To evaluate the effect of various multi-detector row computed tomographic (CT) reconstruction parameters and nodule segmentation thresholds on the accuracy of volumetric measurement of synthetic lung nodules. MATERIALS AND METHODS: Synthetic lung nodules of four different diameters (3.2, 4.8, 6.4, and 12.7 mm) were scanned with multi-detector row CT. Images were reconstructed at various section thicknesses (0.75, 1.0, 2.0, 3.0, and 5.0 mm), fields of view (30, 20, and 10 cm), and reconstruction intervals (0.5, 1.0, and 2.0 mm). The nodules were segmented from the simulated background lung region by using four segmentation thresholds (-300, -400, -500, and -600 HU), and their volumes were estimated and compared with a reference standard (measurements according to fluid displacement) by computing the absolute percentage error (APE). APE was regressed against nodule size, and multivariate analysis of variance (MANOVA) was performed with APE as the dependent variable and with four within-subject factors (field of view, reconstruction interval, threshold, and section thickness). RESULTS: The MANOVA demonstrated statistically significant effects for threshold (P = .02), section thickness (P < .01), and interaction of threshold and section thickness (P = .04). The regression of mean APE values on nodule size indicates that APE progressively increases with decreasing synthetic nodule size (R2 = 0.99, P < .01). CONCLUSION: For accurate measurement of lung nodule volume, it is critical to select a section thickness and/or segmentation threshold appropriate for the size of a nodule.

Acrylic Resins↗
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

VX2 carcinoma in rabbits after radiofrequency ablation: comparison of MR contrast agents for help in differentiating benign periablational enhancement from residual tumor.

PURPOSE: To prospectively compare the accuracy of a blood pool agent, SH L 643A, with that of gadopentetate dimeglumine in differentiating benign periablational enhancement from residual tumor in VX2 carcinomas in rabbits after radiofrequency (RF) ablation. MATERIALS AND METHODS: Experiment was approved by the animal care committee. Sequential MR images were obtained before and with SH L 643A (17 000 Da, 0.05 mmol/kg) and, after a 24-hour interval, gadopentetate dimeglumine (546 Da, 0.1 mmol/kg) in 12 rabbits with VX2 carcinoma in the back muscle prior to (n = 12) and early (n = 12), 1 week (n = 8), and 4 weeks (n = 4) after RF ablation. RF ablation was performed with output of 90 W but at less than 300 seconds to ensure incomplete tumor ablation. The pathologic specimens were sectioned in the same plane as MR imaging, and the enhancement ratios (ie, the ratios of postcontrast to precontrast signal intensity) and the microvessel densities of residual tumor and benign periablational enhancement were assessed. RESULTS: With SH L 643A, the peak enhancement ratios of residual tumor (1.64 +/- 0.31 [standard deviation]) were significantly higher than those of benign periablational enhancement (0.97 +/- 0.16) (P < .001). With gadopentetate dimeglumine, the peak enhancement ratios of residual tumor (1.82 +/- 0.33) were not different from those of benign periablational enhancement (1.71 +/- 0.36). In benign periablational enhancement, enhancement ratios with injection of SH L 643A were lower than those with injection of gadopentetate dimeglumine for all time points up to 30 minutes (P < .05). The microvessel density was 25.72 +/- 5.43 vessels per field of view for residual tumor and 10.37 +/- 2.88 vessels per field of view for benign periablational enhancement (P < .001). CONCLUSION: Blood pool contrast agent SH L 643A permits more accurate differentiation of benign periablational enhancement from residual tumor compared with the extracellular agent gadopentetate dimeglumine.

Animals↗
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

The potential contribution of a computer-aided detection system for lung nodule detection in multidetector row computed tomography.

RATIONALE AND OBJECTIVES: We sought to evaluate the potential benefits of a computer-aided detection (CAD) system for detecting lung nodules in multidetector row CT (MDCT) scans. METHODS: A CAD system was developed for detecting lung nodules on MDCT scans and was applied to the data obtained from 15 patients. Two chest radiologists in consensus established the reference standard. The nodules were categorized according to their size and their relationship to the surrounding structures (nodule type). The differences in the sensitivities between an experienced chest radiologist and a CAD system without user interaction were evaluated using a chi2 analysis. The differences in the sensitivities also were compared in terms of the nodule size and the nodule type. RESULTS: A total of 309 nodules were identified as the reference standard. The sensitivity of a CAD system (81%) was not significantly different from that of a radiologist (85%; P > 0.05). The sensitivities of the CAD system for detecting nodules < or = 5 mm in diameter as well as detecting isolated nodules were higher than those of a radiologist (83% vs. 75%, P > 0.05; 93% vs. 76%, P < 0.001). The sensitivities of a radiologist for detecting nodules >5 mm and the nodules attached to other structures were higher than those of a CAD system (98% vs. 79%, P < 0.001; 91% vs. 71%, P < 0.001). There were 28.8 false-positive results of CAD per CT study. CONCLUSION: The CAD system developed in this study performed the nodule detection task in different ways to that of a radiologist in terms of the nodule size and the nodule type, which suggests that the CAD system can play a complementary role to a radiologist in detecting nodules from large CT data sets.

Adult↗
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↗
PubMed2003

Recurrent bronchobiliary fistula: unsuccessful management with repeated insertion of metallic biliary stent.

This case of a recurrent bronchobiliary fistula was first managed temporarily with repeated metallic biliary stent placement, and finally required surgery. A 65-year-old man, who had undergone a hepatic resection for metastatic colon carcinoma, with a bronchobiliary fistula was treated with metallic biliary stent placement for a stenosis in the common bile duct. During 16 months of follow-up, the biliptysis recurred twice by a recurrent stricture of the common bile duct, which was managed by placement of a second and third stent in a coaxial manner. Three months after placement of the third stent, jaundice developed and the patient finally underwent a Roux-en-Y choledochojejunostomy.

Aged↗
PubMed2002

CT of tuberculosis and nontuberculous mycobacterial infections.

Radiologic manifestations of pulmonary tuberculosis (TB) can vary according to several host factors, including prior exposure to TB, age, and underlying immune status. Although chest radiography is the mainstay in the evaluation of pulmonary TB, CT generally is required to detect fine lesions overlooked on chest radiographs, to define equivocal lesions, or to evaluate complications. High-resolution CT is useful in understanding the pathologic process of the disease and in determining disease activity in selected cases. This article describes the characteristic CT findings of various forms of pulmonary TB and nontuberculous mycobacterial infection according to immune status of the patients, and assesses the role of CT in the diagnosis and management of pulmonary TB.

AIDS-Related Opportunistic Infections↗
PubMed2002

Tuberculosis in patients with myelodysplastic syndromes.

AIM: The purpose of our study was to describe radiological manifestations of tuberculosis in patients with myelodysplastic syndromes. MATERIALS AND METHODS: Chest radiographs and CTs of 12 patients with tuberculosis among 195 consecutive patients with myelodysplastic syndrome, proved by bone marrow biopsy, were reviewed. Six of the 12 patients presented with tuberculosis and were subsequently found to have myelodysplastic syndrome. RESULTS: Chest radiographs and CTs revealed pulmonary tuberculosis in all 12 patients and extrapulmonary tuberculous involvement in six (50%). Initial chest radiographic findings of pulmonary tuberculosis included a primary pattern (n = 6), a post-primary pattern (n = 3), a miliary pattern (n = 1), atypical infiltrates (n = 1) and normal radiograph (n = 1). Tuberculosis involved extrathoracic lymph nodes (n = 5), liver (n = 2), spleen (n = 2), kidney (n = 2), bowel (n = 2), pericardium (n = 2) peritoneum (n = 1) and rib (n = 1). CONCLUSION: Tuberculosis is a relatively common cause of infection in patients with myelodysplastic syndromes. The radiological appearance of pulmonary tuberculosis in myelodysplastic syndromes is often a primary pattern, and there is frequently extrapulmonary involvement.

Adult↗