The HACEK group of fastidious gram-negative organisms is a recognized but unusual cause of infective endocarditis, responsible for approximately 3% of cases. We report our experience with 45 cases of endocarditis caused by HACEK organisms. In Olmsted County, Minnesota, the incidence of HACEK endocarditis was 0.14 per 100,000 person-years. In patients with native valves, 33 cases occurred, and in patients with prosthetic valves, 12 cases occurred. The most common presenting symptoms were fever, splenomegaly, new or changing murmur, and microvascular phenomena. Symptoms were present in the majority of patients anywhere from two weeks to six months prior to diagnosis. Blood cultures became positive in a mean 3.375 days, and therapy with a beta-lactam alone or as part of a combination was given for anywhere between three and six weeks. Within the first month of diagnosis, surgery was performed for 13 regurgitant valves in 11 patients (24%). Echocardiography was an insensitive predictor of subsequent major arterial embolization (odds ratio, 1.33; 95% confidence interval, 0.31-5.67). The overall survival in our cohort of patients was 87%. These results confirm previous reports that HACEK endocarditis portends a favorable prognosis.

In this article the authors evaluate a recently proposed variable dose ͑VD͒-digital breast tomosynthesis ͑DBT͒ acquisition technique in terms of the detection accuracy for breast masses and microcalcification ͑MC͒ clusters. With this technique, approximately half of the total dose is used for one center projection and the remaining dose is split among the other tomosynthesis projection views. This acquisition method would yield both a projection view and a reconstruction view. One of the aims of this study was to evaluate whether the center projection alone of the VD acquisition can provide equal or superior MC detection in comparison to the 3D images from uniform dose ͑UD͒-DBT. Another aim was to compare the mass-detection capabilities of 3D reconstructions from VD-DBT and UD-DBT. In a localization receiver operating characteristic ͑LROC͒ observer study of MC detection, the authors compared the center projection of a VD acquisition scheme ͑at 2 mGy dose͒ with detector pixel size of 100 m with the UD-DBT reconstruction ͑at 4 mGy dose͒ obtained with a voxel size of 100 m. MCs with sizes of 150 and 180 m were used in the study, with each cluster consisting of seven MCs distributed randomly within a small volume. Reconstructed images in UD-DBT were obtained from a projection set that had a total of 4 mGy dose. The current study shows that for MC detection, using the center projection alone of VD acquisition scheme performs worse with area under the LROC curve ͑A L ͒ of 0.76 than when using the 3D reconstructed image using the UD acquisition scheme ͑A L = 0.84͒. A 2D ANOVA found a statistically significant difference ͑p = 0.038͒ at a significance level of 0.05. In the current study, although a reconstructed image was also available using the VD acquisition scheme, it was not used to assist the MC detection task which was done using the center projection alone. In the case of evaluation of detection accuracy of masses, the reconstruction with VD-DBT ͑A L = 0.71͒ was compared to that obtained from the UD-DBT ͑A L = 0.78͒. The authors found no statistically significant difference between the two ͑p-value= 0.22͒, although all the observers performed better for UD-DBT.

Exercise echocardiography provides incremental prognostic information in patients > or = 65 years of age. The best model included clinical, exercise testing and exercise echocardiographic variables.

We examined the application of an iterative penalized maximum likelihood (PML) reconstruction method for improved detectability of microcalcifications (MCs) in digital breast tomosynthesis (DBT). Localized receiver operating characteristic (LROC) psychophysical studies with human observers and 2D image slices were conducted to evaluate the performance of this reconstruction method and to compare its performance against the commonly used Feldkamp FBP algorithm. DBT projections were generated using rigorous computer simulations that included accurate modeling of the noise and detector blur. Acquisition dose levels of 0.7, 1.0 and 1.5 mGy in a 5-cm-thick compressed breast were tested. The defined task was to localize and detect MC clusters consisting of seven MCs. The individual MC diameter was 150 μm. Compressed-breast phantoms derived from CT images of actual mastectomy specimens provided realistic background structures for the detection task. Four observers each read 98 test images for each combination of reconstruction method and acquisition dose. All observers performed better with the PML images than with the FBP images. With the acquisition dose of 0.7 mGy, the average areas under the LROC curve (AL) for the PML and FBP algorithms were 0.69 and 0.43, respectively. For the 1.0-mGy dose, the values of AL were 0.93 (PML) and 0.7 (FBP), while the 1.5-mGy dose resulted in areas of 1.0 and 0.9 respectively for the PML and FBP algorithms. A 2D analysis of variance applied to the individual observer areas showed statistically significant differences (at a significance level of 0.05) between the reconstruction strategies at all three dose levels. There were no significant differences in observer performance for any of the dose levels.