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Biomedical subjects

Shyh-Jye Chen

Publications and source records attributed to Shyh-Jye Chen.

At least 19 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

Magnetic resonance imaging of seminal vesicle cyst associated with ipsilateral urinary anomalies.

BACKGROUND: Seminal vesicle cysts rarely cause symptoms. Data on long-term follow-up from childhood to adulthood are lacking. The study analyzed the magnetic resonance imaging (MRI) and follow-up results of this condition. METHODS: From 1991 to 1996, seminal vesicle cyst was diagnosed in 13 boys (mean age, 12 years; range, 7-15 years), six of whom had long-term follow-up data. The clinical symptoms and MRI findings at diagnosis and at follow-up were analyzed. RESULTS: The seminal vesicle cyst was on the right side in six patients and on the left in seven. The size varied, ranging from 1.0 x 1.3 x 1.4 to 4.4 x 3.1 x 3.6 cm. All showed high signal intensity on T2-weighted images but variable signal intensity on T1-weighted images. Associated urinary tract anomalies included renal anomalies (dysplasia in 2 patients, agenesis in 11), ectopic ureteral orifice (11), hydroureter (6), and vertebral anomalies (2). One of the six patients with follow-up had repeated urinary tract infection and underwent surgical resection of the cyst 8 years after the diagnosis. The other five had no symptoms during the follow-up period. Three of the six patients had repeat MRI after a median of 11 years, which showed slight cyst enlargement and increased T1-weighted signal intensity. CONCLUSION: Most seminal vesicle cysts were asymptomatic and did not change during long-term follow-up. MRI is a powerful tool for detecting seminal vesicle cysts and in delineating associated congenital anomalies of the urogenital tract.

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

Clinical implication of hiatal hernia in patients with right isomerism.

OBJECTIVE: Despite a reported association between hiatal hernia in patients with heterotaxy syndrome, the clinical significance has remained unclear. Based on large patient cohorts, this study specifically aimed at defining the implication of hiatal hernia in patients with right isomerism. METHODS: From 1994 to 2002, 143 patients were identified as having right isomerism. Among them, 119 received ultrafast computed tomography (CT) to determine the presence of hiatal hernia as well as any cardiovascular anomalies. RESULTS: Hiatal hernia was found in 17 patients (seven females and 10 males, 14.3%). The upper gastrointestinal (GI) series in six patients confirmed the diagnosis of hiatal hernia in all and revealed severe gastro-oesophageal reflux in four. The most common symptom of hiatal hernia was vomiting (47%), followed by recurrent bronchiolitis or pneumonia (41.2%) and upper gastrointestinal bleeding (11.8%). Three patients with hiatal hernia underwent fundoplication for medically refractory vomiting. Seven patients were found to have midgut malrotation (5.9%), and four of these had both hiatal hernia and malrotation. Pulmonary atresia was closely associated with the presence of hiatal hernia (p=0.02). One patient with hiatal hernia died suddenly at 6 mo. However, overall mortality was similar between those patients with hiatal hernia and those without. CONCLUSIONS: The incidence of hiatal hernia was considerably high in patients with right isomerism, especially in those with pulmonary atresia, and it is this that may have led to vomiting and recurrent airway infections. While an association between sudden death and hiatal hernia may well exist, this does require further clarification.

Abnormalities, Multiple↗
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

Finding the mitral annular lines from 2-D + 1-D precordial echocardiogram using graph-search technique.

The apical four-chamber view echocardiogram collected by a transthoracic transducer can be used to evaluate the left ventricle volume. In the diastole, the left ventricle and left atrium become one chamber. In this case, the left ventricle and left atrium need to be separated using a "mitral annular line" so the volume of the left ventricle can be estimated. In this paper, a nearly automatic method for identifying the mitral annular lines from two-dimensional (2-D) + one-dimensional (1-D) precordial four-chamber view echocardiogram is presented. This method employs the optical flow technique and graph-search approach. The mitral annular line sequence is found by finding the shortest path in a weighted directed graph. The vertices in the graph are candidates for the mitral annular lines. The weights on the directed edges are determined using the optical flow technique. The proposed method requires only a physician to provide a point that is always in the left ventricular chamber. Experimental results show that the average error for the left ventricle volume obtained based on the computed mitral annular lines is 3%.

Algorithms↗
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↗
PubMed2003

Sequential diagnosis of coronary arterial anatomy in congenitally corrected transposition of the great arteries.

BACKGROUND: The objective of this study was to analyze coronary arteries (CA) in congenitally corrected transposition (CCT) and to determine the influence of aortopulmonary rotation on its pattern systematically. Precise CA anatomy is surgically needed in the current era of double switch for CCT. METHODS: We collected data on 62 patients who had CCT with situs solitus or inversus between 1981 and 1999. Coronary artery anatomy was analyzed as it related to apical position, atrial situs, ventricular looping, and aortopulmonary rotation. Five main types with similar variants of epicardial configuration at the base of the heart were categorized into five central patterns (patterns X, O, I, II, and IV). RESULTS: The right CA coursed to the left in CCT with situs solitus, and to the right in CCT with situs inversus; and to the more posterior atrioventricular groove in both without apicocaval ipsilaterality. However, in CCT with more apicocaval ipsilaterality, the left circumflex might shift posterior to the right CA. With the same aortopulmonary rotation, the two groups had similar central patterns, and eta-square analysis showed that the evolution from patterns X, O, I, II, toward IV (n = 1, 36, 15, 9 to 1) was dependent on clockwise aortopulmonary rotation (p < 0.00000). CONCLUSIONS: Peripheral CA pattern in the atrioventricular groove was dictated by apicocaval ipsilaterality anteroposteriorly and ventricular looping dextrosinistrally, irrespective of atrial situs. The central CA pattern near the aortic sinus depended on aortopulmonary rotation due to "marriage of convenience" between them, and thus was predictable from arterial relations irrespective of its disease category.

Adolescent↗
PubMed2003

Electron beam computed tomography appearance of endocardial fibroelastosis EBCT appearance of endocardial fibroelastosis.

Recent reports of endocardial fibroelastosis (EFE) have not reported the disease to be correctly diagnosed during the patients' life spans. Our purpose in this communication is to provide some feasible approaches toward correct diagnosis at the primitive stage and possible correlations to the prognosis. We analyzed five cases of EFE from 1997 to 2001. Four had pathology proven EFE. Data were sampled from the clinical symptoms, eletrocardiography, echocardiography, electron beam computed tomography (EBCT), management, and prognosis. A case of anomalous left coronary artery originating from main pulmonary artery diagnosed EFE correctly before death by utilizing an EBCT. The second case was double outlet of the right ventricle with severe calcification and fibrosis shown on EBCT studies, while the third case had severe calcification over both apices. Both patients required heart transplantation. The fourth case, with a decreasing ejection fraction, was idiopathic hypertropic subaortic stenosis with mild calcification and fibrosis on the EBCT images. The last stationary case had severe aortic stenosis with trivial fibrotic change and calcification. We propose that EBCT may accurately help to diagnose EFE before pathology confirmation. The magnitude of calcification and fibrotic thickness in the myocardium of the EBCT imaging may predict the outcome of EFE.

Adult↗
PubMed2002

Horseshoe lung with pseudo-ring-sling complex.

We report on a 1-month-old boy who presented with a "horseshoe" lung, complete "O" rings of the trachea, and an unusual course of the left pulmonary artery mimicking a left pulmonary artery sling. Computed tomography, cardiac catheterization, and bronchoscopy were performed to confirm the rare coexistence of these anomalies. To our knowledge, such a combination of anomalies has not been reported in the English-language literature.

Abnormalities, Multiple↗