Computer-aided diagnosis in chest radiography for detection of childhood pneumonia.

OBJECTIVES: This article presents a novel approach based on computer-aided diagnostic (CAD) scheme and wavelet transforms to aid pneumonia diagnosis in children, using chest radiograph images. The prototype system, named Pneumo-CAD, was designed to classify images into presence (PP) or absence of pneumonia (PA). MATERIALS AND METHODS: The knowledge database for the Pneumo-CAD comprised chest images confirmed as PP or PA by two radiologists trained to interpret chest radiographs according to the WHO guidelines for the diagnosis of pneumonia in children. The performance of the Pneumo-CAD was evaluated by a subset of images randomly selected from the knowledge database. The retrieval of similar images was made by feature extraction using wavelets transform coefficients of the image. The energy of the wavelet coefficients was used to compose the feature vector in order to support the computational classification of images as PP or PA. Methodology I worked with a rank-weighted 15-nearest-neighbour scheme, while methodology II employed a distance-dependent weighting for image classification. The performance of the prototype system was assessed by the ROC curve. RESULTS: Overall, the Pneumo-CAD using the Haar wavelet presented the best accuracy in discriminating PP from PA for both, methodology I (AUC=0.97) and methodology II (AUC=0.94), reaching sensitivity of 100% and specificity of 80% and 90%, respectively. CONCLUSION: Pneumo-CAD could represent a complementary tool to screen children with clinical suspicion of pneumonia, and so to contribute to gather information on the burden of-pneumonia estimates in order to help guide health policies toward preventive interventions.

Carriage of methicillin-resistant Staphylococcus aureus in children in Brazil.

The extent of methicillin-resistant Staphylococcus aureus (MRSA) carriage in Brazilian infants is largely unknown. We evaluated the presence of MRSA nasopharyngeal (NP) carriage in 686 children younger than 5 years with respiratory tract infection (609) and meningitis (77). S. aureus was isolated in 93 (13.5%) NP specimens of which 7 (1.02%) were identified as MRSA (oxacillin MIC, >256 microg/mL) harboring SCCmec type III. The dendrogram derived from the pulsed-field gel electrophoresis gel images showed that the MRSA strains diverged from the Brazilian endemic hospital-acquired clones from 10.4% to 21.7%. Although the MRSA strains were recovered from children within the first 6 h of their admission to hospital, the presence of SCCmec type III along with the multidrug-resistant profile of the isolates raises the hypotheses that these MRSA strains may have hospital origin and are now spreading into the pediatric community as colonizing pathogens.

Effectiveness of Haemophilus influenzae b conjugate vaccine on childhood pneumonia: a case-control study in Brazil.

BACKGROUND: The conjugate Haemophilus influenzae type b (Hib) vaccine has been highly efficacious in reducing type b H. influenzae meningitis. However, information is limited about its impact on childhood pneumonia after vaccine introduction into the routine programme. This study evaluated the effectiveness of Hib conjugate vaccine in the reduction of community-acquired pneumonia among infants in Central Brazil. METHODS: A matched case-control study was built into an ongoing prospective population-based surveillance of pneumonia, enrolling 1293 participants between May 2000 and August 2001. Cases (n = 431) were children