Feature stabilized digital x-ray coronary angiograms improve human visual detection in JPEG compressed images.

We evaluate the effect on human visual detection of a display method that stabilizes the motion of the feature of interest in sequential JPEG compressed x-ray coronary angiogram images. At all levels of image compression the feature stabilized display significantly improved performance with respect to the standard display where the artery is moving. In addition, for both the moving artery and stabilized display, human performance with images compressed at 15:1 was not significantly different from performance with the uncompressed images.

Laboratory study of predation by Solenopsis invicta (Hymenoptera: Formicidae) on eggs of Aedes albopictus (Diptera: Culicidae).

The red imported fire ant, Solenopsis invicta Buren, punctured and fed on the Asian Tiger mosquito, Aedes albopictus (Skuse), eggs in the laboratory. The presence and actions of the ants, especially the minima workers, reduced the hatching of egg populations.

Fecundity, fertility, and developmental stage survivorship of Eretmapodites quinquevittatus.

This laboratory study analyzed fecundity, fertility (percentage hatched), and developmental stage survivorship of Eretmapodites quinquevittatus. Fecundity for females averaged 190.4 eggs, whereas paired (one male/female pair) females averaged 100.5 eggs. Fertility for autogenous eggs from paired females was 84.4%, which was significantly greater than percentage hatched of anautogenous eggs (67.3%). Percentage hatched of autogenous eggs from experimental groups (25 males/25 females) was 87.8%, whereas percentage hatched of anautogenous eggs was 74.5%. Developmental stage survivorship was significantly different for every stage of development of progeny from autogenous eggs, except the egg stage, when comparing experimental groups with pairs. Developmental stage survivorship of progeny from anautogenous eggs was significantly different only at the egg stage and 1st instar when comparing experimental groups and pairs.

Creation of radiofrequency lesions in a porcine model: correlation with sonography, CT, and histopathology.

OBJECTIVE: We studied the correlation between sonographic and CT appearances of radiofrequency thermal lesions created in porcine liver and histopathologic findings to evaluate the accuracy of these techniques in revealing the extent of tissue necrosis. MATERIALS AND METHODS: We used sonographic guidance and a 2.0-cm-diameter, eight-prong retractable radiofrequency electrode to view 12 hepatic lesions that were created in five pigs. Biphasic helical CT was performed 12-48 hr after ablation. The animals were sacrificed immediately after CT, and their livers were histopathologically examined. The maximum lesion size in the long and short axes as measured on CT and sonography was then correlated with the histopathologically determined lesion size. RESULTS: On sonography, lesions changed rapidly within 5 min after the termination of ablation. An early echogenic cloud became peripherally hypoechoic with a variable thin echogenic rim. Early (0-2 min after ablation) sonograms led to an underestimation of true lesion sizes on histopathology (r = 0.3-0.49; p < 0.05). Delayed (2-5 min after ablation) sonograms also led to an underestimation of true lesion size (r = 0.5-0.62; p < 0.05); however, lesions were larger and better demarcated. Biphasic contrast-enhanced helical CT revealed avascular lesions surrounded by hyperemic rims that closely correlated with true pathologic lesions size (r = 0.93-0.95; p < 0. 05). Lesions with hyperemic rims that were measured on CT led to overestimations of true lesion size. CONCLUSION: Sonography led to underestimations of the true size of ablated lesions within the first 5 min after creation; however, delayed images provided better results. The avascular lesion measured on contrast-enhanced helical CT closely correlated with the size of ablated tissue; therefore, contrast-enhanced CT is preferred for serially monitoring the effect of radiofrequency ablation.