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Wen-Jeng Lee

Publications and source records attributed to Wen-Jeng Lee.

10 recordsLinked to original sources
PubMed2006

Coronary artery anatomy in children with congenital heart disease by computed tomography.

AIMS: To evaluate electron beam computed tomography (EBCT) for recognition of coronary artery patterns in children with congenital heart diseases. METHODS: Institutional review board approval was obtained; informed consents were not required. A total of 226 children diagnosed with Tetralogy of Fallot (n=122), double outlet right ventricle (n=52), transposition of the great arteries (n=34), and congenitally corrected transposition (n=18) who had undergone cardiac EBCT at our institution between 1995 and 2002 were identified. Iodinated contrast medium was injected with arterial phase acquisition. The two radiologists and one pediatric cardiologist that interpreted the EBCT images and cardiac angiograms, respectively, were blinded to each other's results. Surgical and cardiac angiogram findings were compared to the EBCT results. Descriptive statistics were used to compare efficacy. RESULTS: Numerous aberrant patterns were clearly identified on the EBCT images. Pattern IX occurred in most patients with Tetralogy of Fallot or double outlet right ventricle. Patterns I and 0 are the most common coronary artery types in transposition of the great arteries and congenitally corrected transposition, respectively. Overall diagnostic accuracy for all disease groups was 82.7%. The diagnostic accuracy of the coronary arterial anatomy by EBCT increased with older age, and was more than 90% in individuals aged over 3 months. CONCLUSION: EBCT is effective for identification of the coronary anatomy of children with specific congenital heart diseases, except for neonates and small infants less than 3 months of age.

Adolescent↗
PubMed2006

A study of grid artifacts formation and elimination in computed radiographic images.

Computed radiography (CR) has many advantages such as filmless operations, efficiency, and convenience. Furthermore, it is easier to integrate with the picture archiving and communication systems. Another important advantage is that CR images generally have a wider dynamic range than conventional screen film. Unfortunately, grid artifacts and moiré pattern artifacts may be present in CR images. These artifacts become a more serious problem when viewing CR images on a computer monitor when a clinic grade monitor is not available. Images produced using a grid with higher frequency or a Potter--Bucky grid (i.e., a moving grid, Bucky for short) can reduce occurrence but cannot guarantee elimination of these artifacts [CR & PACS (2000); Detrick F (2001), pp 7-8]. In this paper, the formation of the artifacts is studied. We show that the grid artifacts occur in a narrow band of frequency in the frequency domain. The frequency can be determined, accurately located, and thus removed from the frequency domain. When comparing the results obtained from the proposed method against the results obtained using previous computer methods, we show that our method can achieve better image quality.

Artifacts↗
PubMed2006

Three-dimensional reconstruction and modeling of middle ear biomechanics by high-resolution computed tomography and finite element analysis.

OBJECTIVE: To present a systematic and practical approach that uses high-resolution computed tomography to derive models of the middle ear for finite element analysis. STUDY DESIGN: This prospective study included 31 subjects with normal hearing and no previous otologic disorders. Temporal bone images obtained from 15 right ears and 16 left ears were used for evaluation and reconstruction. METHODS: High-resolution computed tomography of temporal bone was performed using simultaneous acquisition of 16 sections with a collimated slice thickness of 0.625 mm. All images were transferred to an Amira visualization system for three-dimensional reconstruction. The created three-dimensional model was translated into two commercial modeling packages, Patran and ANSYS, for finite element analysis. RESULT: The characteristic dimensions of the model were measured and compared with previously published histologic section data. This result confirms that the geometric model created by the proposed method is accurate except that the tympanic membrane is thicker than when measured by the histologic section method. No obvious difference in the geometrical dimension between right and left ossicles was found (P > .05). The three-dimensional model created by finite element method and predicted umbo and stapes displacements are close to the bounds of the experimental curves of Nishihara's, Huber's, Gan's, and Sun's data across the frequency range of 100 to 8000 Hz. CONCLUSION: The model includes a description of the geometry of the middle ear components and dynamic equations of vibration. The proposed method is quick, practical, low-cost, and, most importantly, noninvasive as compared with histologic section methods.

Adolescent↗
PubMed2005

Establishing a Web-based DICOM teaching file authoring tool using open-source public software.

Online teaching files are an important source of educational and referential materials in the radiology community. The commonly used Digital Imaging and Communications in Medicine (DICOM) file format of the radiology community is not natively supported by common Web browsers. The ability of the Web server to convert and parse DICOM is important when the DICOM-converting tools are not available. In this paper, we describe our approach to develop a Web-based teaching file authoring tool. Our server is built using Apache Web server running on FreeBSD operating system. The dynamic page content is produced by Hypertext Preprocessor (PHP). Digital Imaging and Communications in Medicine images are converted by ImageMagick into Joint Photographic Experts Group (JPEG) format. Digital Imaging and Communications in Medicine attributes are parsed by dicom3tools and stored in PostgreSQL database. Using free software available from the Internet, we build a Web service that allows radiologists to create their own online teaching file cases with a common Web browser.

Computer Communication Networks↗
PubMed2005

Anomalous brachiocephalic vein: CT, embryology, and clinical implications.

OBJECTIVE: CT patterns of anomalous brachiocephalic veins are presented with reconsideration of the structure's embryogenesis. CONCLUSION: With advancements in central line procedures and corrective cardiac surgery, and the widespread use of noninvasive imaging techniques, the clinical importance of identification of the anomalous brachiocephalic vein is shown.

Adolescent↗
PubMed2004

Measurement of tracheal size in children with congenital heart disease by computed tomography.

BACKGROUND: To establish a reference of tracheal size in children with congenital heart disease to allow detection of airway stenosis. METHODS: We conducted a retrospective study using existing data from children referred for computed tomography (CT) scanning. From January 1999 to February 2001, 540 consecutive children with congenital heart disease who received electron beam CT scanning at our hospital were considered eligible for inclusion in the study. After exclusion criteria were considered, 99 children (50 girls and 49 boys; aged 4 days to 16 years 10 months) were enrolled in the study. Tracheal width was measured at three levels on CT images. The relationship between tracheal width and the patient's height, weight, age, and sex were analyzed by multiple regression and formula transformation. RESULTS: Height was the most effective parameter for predicting the transverse diameter of the intrathoracic trachea, and tracheal size could be predicted based on height using the established equations. In addition, tracheal width increased from the thoracic inlet to the carina. Reference curves based on the subject's height were created for convenient use. CONCLUSIONS: Tracheal stenosis in children with congenital heart disease may be diagnosed by comparing the size of the trachea of the individual to the 95% confidence interval of predicted values based on the patient's height.

Adolescent↗
PubMed2004

Computed tomography diagnosis of post-obstructive atelectasis by an endobronchial lipoma.

Endobronchial lipoma is a rare benign tumor in the bronchial tree. We report a case of endobronchial lipoma in a 73-year-old man with hemoptysis. Chest radiograph revealed atelectasis of the right upper lung. Bronchoscopy revealed a well-defined endobronchial lesion in the right upper lobe bronchus with near total occlusion, but a biopsy was not performed. An endobronchial tumor was identified on CT scan with demonstration of fat within the tumor. Endobronchial lipoma was diagnosed and a sleeve lobectomy of the right upper lobe bronchus was performed. The pathological diagnosis was submucosal lipoma. The patient's symptoms improved during follow-up of more than 1 year. CT scan can be used to diagnose endobronchial lipoma and can help in the development of a management plan.

Aged↗
PubMed2003

Usefulness of three-dimensional electron beam computed tomography for evaluating tracheobronchial anomalies in children with congenital heart disease.

This study was undertaken to delineate tracheobronchial anomalies associated with congenital heart disease. From June 1995 to December 2000, 1,245 children with congenital heart disease underwent cardiac electron beam computed tomography with 3-dimensional reconstruction on an independent workstation. Tracheobronchial anomalies are strongly associated with congenital heart disease and accompanying tracheal stenosis is not uncommon. With 3-dimensional reconstruction, electron beam computed tomography provided excellent anatomic definition of the central tracheobronchial abnormalities.

Abnormalities, Multiple↗
PubMed2002

Adrenal gland volume after spinal cord injury.

OBJECTIVE: Spinal cord injury in adult men may result in hypothalamic-pituitary-adrenal axis dysfunction. Atrophy of adrenal glands was speculated in these patients. This study was undertaken to clarify the functional-anatomic correlation between adrenal volume and body surface area in subjects with spinal cord injury with impaired adrenal reserve. DESIGN: Twenty male subjects with chronic spinal cord injury with impaired adrenal reserve were identified by adrenocorticotropic hormone stimulation test from a group of 42 subjects. All subjects with spinal cord injury and healthy volunteers underwent computed tomographic imaging with contiguous 3-mm section over adrenal glands for volumetric measurements. Ten pairs of subjects with spinal cord injury and controls with matched height and weight were included in the statistical analysis. RESULTS: Significantly increased relative adrenal volumes were noted among subjects with chronic spinal cord injury and impaired adrenal reserve as compared with the body weight-matched and height-matched control group. CONCLUSIONS: Increased relative adrenal volumes were found after chronic spinal cord injury. Hyperplasia of the zona glomerulosa may be the cause of increased relative adrenal volume after chronic spinal cord injury.

Adrenal Glands↗