Analysis of elastographic and B-mode features at sonoelastography for breast tumor classification.

The purpose of this study was to evaluate the accuracy of neural network analysis of elastographic features at sonoelastography for the classification of biopsy-proved benign and malignant breast tumors. Sonoelastography of 181 solid breast masses (113 benign and 68 malignant tumors) was performed for 181 patients (mean age, 47 years; range, 24-75 years). After the manual segmentation of the tumors, five elastographic features (strain difference, strain ratio, mean, median and mode) and six B-mode features (orientation, undulation, angularity, average gradient, gradient variance and intensity variance) were computed. A neural network was used to classify tumors by the use of these features. The Student's t test and receiver operating characteristic (ROC) curve analysis were used for statistical analysis. Area under ROC curve (Az) values of the three elastographic features- mean (0.87), median (0.86) and mode (0.83)-were significantly higher than the Az values for the six B-mode features (0.54-0.69) (p < 0.01). Accuracy, sensitivity, specificity and Az of the neural network for the classification of solid breast tumors were 86.2% (156/181), 83.8% (57/68), 87.6% (99/113) and 0.84 for the elastographic features, respectively, and 82.3% (149/181), 70.6% (48/68), 89.4% (101/113) and 0.78 for the B-mode features, respectively, and 90.6% (164/181), 95.6% (65/68), 87.6% (99/113) and 0.92 for the combination of the elastographic and B-mode features, respectively. We conclude that sonoelastographic images and neural network analysis of features has the potential to increase the accuracy of the use of ultrasound for the classification of benign and malignant breast tumors.

[A case of Paenibacillus polymyxa bacteremia in a patient with cerebral infarction].

We report a case of Paenibacillus polymyxa bacteremia in a patient with cerebral infarction. The patient was a 93-year-old female who was admitted to our hospital. On the 4 day after admitted, she had a fever 38.2 degrees C. The result of the blood culture showed a gram positive spore bacillus in the blood culture bottle. As a result of performing 16SrDNA sequence analysis (500bp), it was a close relationship most by 99.26% P. polymlxa of coincidence was found. With a result using api 20E and api 50CH, this bacillus turned out to be P. polymyxa. The patient had a habit of weeding around her house daily. So we had to take her habit into consideration. We thought she could to get her hands injured. We assumed probably her habit might put her into high risk state of infection of this bacillus. We have supposed this bacillus might be infected with her through her blood.

Evaluation of antibacterial efficacy of drugs for urinary tract infections by genotyping based on pulsed-field gel electrophoresis (PFGE).

We attempted to determine whether the same bacterium isolated from patients with urinary tract infections (UTI) before and after treatment with antimicrobial agents was of the same strain ("persisted") or of a different strain ("changed"). Furthermore, to verify the effectiveness of antimicrobial agents for UTI, we investigated whether bacterial strains could be classified as persisted or changed based on their electrophoretic patterns in pulsed-field gel electrophoresis (PFGE). We examined eight species of bacteria ( Enterococcus avium, Staphylococcus epidermidis, Pseudomonas fluorescens, Serratia marcescens, Citrobacter freundii, Enterobacter cloacae, Enterobacter aerogenes, and Escherichia coli), consisting of 41 strains (19 pairs isolated before and after treatment with antimicrobial agents) isolated from patients with complicated UTI. It was concluded that all bacteria were unchanged, based on the clinical effect on bacteriuria. The chromosomal DNA of these bacteria was digested with restriction enzymes and classified based on their electrophoretic pattern in PFGE. A comparison of the patterns of the fragments revealed that 14 pairs were indistinguishable before and after treatment, 3 pairs were closely related, 1 pair was possibly related, and 1 pair was different. These results demonstrated that 18 pairs of isolates (indistinguishable, closely related, and possibly related) were highly likely to be continued infections by the same strain, and that 1 pair (different) had been replaced by another strain. Based on these results, we believe that bacterium genotyping by PFGE is a more effective method for evaluating the antibacterial efficacy of antimicrobial agents.