Biomedical subjects

Chung-Ming Chen

Publications and source records attributed to Chung-Ming Chen.

25 records · Page 2Linked to original sources

PubMed2003

Breast lesions on sonograms: computer-aided diagnosis with nearly setting-independent features and artificial neural networks.

PURPOSE: To develop a computer-aided diagnosis (CAD) algorithm with setting-independent features and artificial neural networks to differentiate benign from malignant breast lesions. MATERIALS AND METHODS: Two sets of breast sonograms were evaluated. The first set contained 160 lesions and was stored directly on the magnetic optic disks from the ultrasonographic (US) system. Four different boundaries were delineated by four persons for each lesion in the first set. The second set comprised 111 lesions that were extracted from the hard-copy images. Seven morphologic features were used, five of which were newly developed. A multilayer feed-forward neural network was used as the classifier. Reliability, extendability, and robustness of the proposed CAD algorithm were evaluated. Results with the proposed algorithm were compared with those with two previous CAD algorithms. All performance comparisons were based on paired-samples t tests. RESULTS: The area under the receiver operating characteristic curve (A(z)) was 0.952 +/- 0.014 for the first set, 0.982 +/- 0.004 for the first set as the training set and the second set as the prediction set, 0.954 +/- 0.016 for the second set as the training set and the first set as the prediction set, and 0.950 +/- 0.005 for all 271 lesions. At the 5% significance level, the performance of the proposed CAD algorithm was shown to be extendible from one set of US images to the other set and robust for both small and large sample sizes. Moreover, the proposed CAD algorithm was shown to outperform the two previous CAD algorithms in terms of the A(z) value. CONCLUSION: The proposed CAD algorithm could effectively and reliably differentiate benign and malignant lesions. The proposed morphologic features were nearly setting independent and could tolerate reasonable variation in boundary delineation.

Adolescent↗

PubMed2002

Methylprednisolone does not enhance the surfactant effects on oxygenation and histology in paraquat-induced rat lung injury.

OBJECTIVE: To investigate whether exogenous surfactant would improve gas exchange and lung histology and methylprednisolone pretreatment would enhance the surfactant effect in a rat model of paraquat-induced lung injury. SETTING: University research facility. SUBJECTS: Thirty-three adult male Sprague-Dawley rats. INTERVENTIONS: All rats received intraperitoneal paraquat injection (35 mg/kg) and were assigned randomly to one of four groups: the control group received no further treatment; the methylprednisolone group received a concomitant intraperitoneal methylprednisolone injection (30 mg/kg); the surfactant group received intratracheal Survanta (100 mg/kg) at the start of ventilation; and the methylprednisolone + surfactant group received both methylprednisolone and surfactant treatments. MEASUREMENTS AND MAIN RESULTS: Three days after paraquat injection, every rat was ventilated for 90 min, a static pressure-volume curve and bronchoalveolar lavage were performed and postmortem histology was examined. Treatment with surfactant and methylprednisolone + surfactant improved oxygenation relative to the control group and produced significantly higher lung volumes than the control and methylprednisolone groups. Treatment with surfactant resulted in a significant decrease in total cell and neutrophil counts relative to the control group. Surfactant with methylprednisolone pretreatment significantly decreased total cell, macrophage and neutrophil counts when compared with the surfactant group. The histological appearance of the lungs was better in the two surfactant-treated groups. CONCLUSION: Intratracheal instillation of surfactant improves gas exchange, ameliorates lung inflammation and results in less lung damage in paraquat-induced rat lung injury. Surfactant with methylprednisolone pretreatment decreases inflammatory cell infiltration, but cannot further improve oxygenation and lung histology.

Animals↗

PubMed2002

Cell-based dual snake model: a new approach to extracting highly winding boundaries in the ultrasound images.

Two common deficiencies of most conventional deformable models are the need to place the initial contour very close to the desired boundary and the incapability of capturing a highly winding boundary for sonographic boundary extraction. To remedy these two deficiencies, a new deformable model (namely, the cell-based dual snake model) is proposed in this paper. The basic idea is to apply the dual snake model in the cell-based deformation manner. While the dual snake model provides an effective mechanism allowing a distant initial contour, the cell-based deformation makes it possible to catch the winding characteristics of the desired boundary. The performance of the proposed cell-based dual snake model has been evaluated on synthetic images with simulated speckles and on the clinical ultrasound (US) images. The experimental results show that the mean distances from the derived to the desired boundary points are 0.9 +/- 0.42 pixels and 1.29 +/- 0.39 pixels for the synthetic and the clinical US images, respectively.

Algorithms↗

PubMed2002

Calculation of simplified single-root surface area from simulated X-ray projection.

BACKGROUND: The prognosis of a tooth affected by periodontitis might depend on the amount of bone remaining around the root surface. The surface area of a single tooth root relates to a simulated x-ray projection. METHODS: The aim of the study was to determine root surface area from radiographs. Two methods were used. In the first, cross-sections of a single-tooth root were simulated using ellipses with different eccentricities. Projection data from 90 directions at 1 degrees intervals were obtained, which were then used to estimate circumferences that were then compared with the known circumference. In the second model, circumference was estimated from projection data derived from the projection of an ellipse with the central ray parallel to the long axis. The estimated circumference was compared with possible circumferences resulting from this projection data. RESULTS: In the first model, all estimated circumferences are less than the true circumferences. The largest error in each case decreased rapidly as the eccentricity of the simulated ellipse decreased. Less than 6% of the largest errors were found when the eccentricity is 0.83. In the second model, the estimation should be within less than 2% of error when the asymmetry factor is less than 0.6. CONCLUSIONS: The circumference of an elliptical object can be approximated from the projection data of this ellipse. Therefore, the surface area of a single tooth root may be estimated with clinically useful accuracy from the projection data.

Algorithms↗

PubMedDate not supplied

Changing position does not improve the efficacy of conventional phototherapy.

The aim of this study was to compare the efficacy of position-changing phototherapy with conventional fixed-position phototherapy. Clinically well, term infants with nonhemolytic hyperbilirubinemia were enrolled in the study. After entry into the study, infants were randomly assigned to receive single-direction phototherapy with or without changing from a supine to a prone position or vice versa every 2 h. Phototherapy was initiated when the serum bilirubin concentration was greater than 15 mg/dl and was discontinued when the bilirubin level had declined below 10 mg/dl. Total serum bilirubin concentrations were measured just prior to initiation of phototherapy and at 12-h intervals until phototherapy was discontinued. The rate of bilirubin decline expressed by the first and secondary 24-h declines and overall bilirubin concentration decrease per hour were comparable between the two groups. The rebound in bilirubin levels after cessation of phototherapy was negligible, and none of the infants needed re-phototherapy. We conclude that changing an infant's position at 2-h intervals does not improve the efficacy of conventional single-direction phototherapy.

Breast Feeding↗

PubMedDate not supplied

Maternal nicotine effects on lung collagen gene expression in newborn rats.

We evaluated the effects of maternal nicotine treatment on collagen gene expression in newborn rat lungs. Timed pregnant Sprague-Dawley rats were injected subcutaneously with nicotine tartrate (2 mg/kg/day) from day 3 to day 21 of gestation. A control group was injected with an equal volume of 0.9% NaCl. On days 1, 7, 14, and 21 after birth, rat pups were randomly selected from each group and lungs were removed for measurement of collagen gene expression and collagen contents by reverse transcription-polymerase chain reaction and histology, respectively. Body weights of nicotine-treated dams were lower than those of control dams from gestational days 5 to 21, and the values reached statistical significance on gestational days 17, 20, and 21. The body weight, lung weight, and lung/body weight ratio were comparable between control and nicotine-exposed rats. Lung collagen I and III mRNA expressions and collagen-staining pattern in alveolar septa were similar between control and nicotine-exposed rats during the study period. We conclude that maternal exposure to nicotine (2 mg/kg/Day) during pregnancy does not influence collagen gene expression or collagen contents in postnatal rat lungs.

Animals↗

PubMedDate not supplied

Maternal acupuncture effects on surfactant and antioxidant enzymes in preterm rat lungs.

The objectives of this study are to evaluate the effects of maternal acupuncture treatment on lung maturation in preterm rats. Two stainless-steel needles were inserted into the Tsu-San-Li locus in the right hind leg of timed pregnant Sprague-Dawley rats for 30 min. One-day acupuncture-group mothers received electroacupuncture on day 18 of gestation. Two-day acupuncture-group mothers received electroacupuncture on days 17 and 18 of gestation. Control-group mothers received acupuncture at a site not contained in the Atlas of Human Acupuncture Points on day 18 of pregnancy. On day 19 of gestation, pups in all dams were delivered by cesarean section. Maternal 2-day acupuncture treatment significantly increased total phospholipids in fetal lung tissue when compared with control and 1-day acupuncture-treated groups. Two-day acupuncture-treated fetuses had higher saturated phosphatidylcholine level in lung tissue although the difference did not reach statistical significance. Two-day acupuncture-treated fetuses had significantly lower superoxide dismutase, catalase, and glutathione peroxidase activities than did the control and 1-day acupuncture-treated fetuses. We conclude that maternal acupuncture treatment affects surfactant and antioxidant enzyme development in contrasting ways and may have both beneficial and potentially harmful effects on different aspects of lung development.

Animals↗