ROC study of the effect of stereoscopic imaging on assessment of breast lesions

An observer performance study was conducted to evaluate the usefulness of assessing breast lesion characteristics with stereomammography. Stereoscopic image pairs of 158 breast biopsy tissue specimens were acquired with a GE Senographe 2000D full field digital mammography system using a 1.8x magnification geometry. A phantom-shift method equivalent to a stereo shift angle of +/- 3 degrees relative to a central axis perpendicular to the detector was used. For each specimen, two pairs of stereo images were taken at approximately orthogonal orientations. The specimens contained either a mass, microcalcifications, both, or normal tissue. Based on pathological analysis, 39.9% of the specimens were found to contain malignancy. The digital specimen radiographs were displayed on a high resolution MegaScan CRT monitor driven by a DOME stereo display board using in-house developed software. Five MQSA radiologists participated as observers. Each observer read the 316 specimen stereo image pairs in a randomized order. For each case, the observer first read the monoscopic image and entered his/her confidence ratings on the presence of microcalcifications and/or masses, margin status, BI-RADS assessment, and the likelihood of malignancy. The corresponding stereoscopic images were then displayed on the same monitor and were viewed through stereoscopic LCD glasses. The observer was free to change the ratings in every category after stereoscopic reading. The ratings of the observers were analyzed by ROC methodology. For the 5 MQSA radiologists, the average Az value for estimation of the likelihood of malignancy of the lesions improved from 0.70 for monoscopic reading to 0.72 (p=0.04) after stereoscopic reading, and the average Az value for the presence of microcalcifications improved from 0.95 to 0.96 (p=0.02). The Az value for the presence of masses improved from 0.80 to 0.82 after stereoscopic reading, but the difference fell short of statistical significance (p=0.08). The visual assessment of margin clearance was found to have very low correlation with microscopic analysis with or without stereoscopic reading. This study demonstrates the potential of using stereomammography to improve the detection and characterization of mammographic lesions.     

Selenium supplementation at low doses contributes to the antioxidant status in Trichinella spiralis-infected rats

Selenium (Se) supplementation may prevent the formation of free radicals and lipid peroxidation processes in trichinellosis. The oxidative-antioxidant status of male Wistar rats infected or uninfected with Trichinella spiralis (Nematoda) and supplemented or unsupplemented with Sel-plex (Alltech) was tested through blood biomarkers. Sel-plex was applied to restore antioxidant defense system. The oxidative marker was malondialdehyde (MDA) concentration. The antioxidant markers were superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and concentrations of Se and vitamin E. The animals were allocated into four groups. The experiment covered 8 weeks post infection. A mathematical model was proposed for the time course of host body weight. The model solutions were in good agreement with the experimental data. The relative rates of body weight gain were determined as growth kinetic parameters. The supplementation of the rats with dietary Se improved their antioxidant status. Increases by 10% in SOD activity, 6% in GPx activity, 13% in vitamin E concentration, 17% in plasma Se concentration, and 19% in liver Se concentration, respectively, and a decrease by 18% in serum MDA concentration were recorded in the infected and supplemented towards infected and unsupplemented rats. The reduction of muscle larvae after Sel-plex application was 63%. The mortality in infected and uninfected animals did not differ significantly. No statistically significant differences were established between the growth of the control and infected rats. At week 8, the body weight gain in the supplemented rats (both uninfected and infected) was 30% higher, compared to that in unsupplemented ones. Diet with Se could be beneficial in the treatment of diseases correlated with considerable oxidative stress, particularly parasitoses.