The precision and ease of use of the C-arm becomes even more important for advanced interventional imaging techniques such as parallax-free X-ray image stitching. Today’s standard mobile C-arms have been modeled with only five degrees of freedom (DOF), which definitely restricts buy MG-132 their motions in 3-D Cartesian space. In this paper, we present a method to model both the mobile C-arm and patient’s table as an integrated kinematic chain having six DOF without
constraining table position. The closed-form solutions for the inverse kinematics problem are derived in order to obtain the required values for all C-arm joint and table movements to position the fluoroscope at a desired pose. The modeling method and the closed-form solutions can be applied to general isocentric or nonisocentric mobile C-arms. By achieving this Quisinostat manufacturer we develop an efficient and intuitive inverse kinematics-based method for parallax-free panoramic X-ray imaging. In addition, we implement a 6-DOF C-arm system from a low-cost mobile fluoroscope to optimally acquire X-ray images based solely on the computation of the required movement for each joint by solving the inverse kinematics on a continuous basis. Through simulation experimentation,
we demonstrate that the 6-DOF C-arm model has a larger working space than the 5-DOF model. C-arm repositioning experiments show the practicality and accuracy of our 6-DOF C-arm system. selleck inhibitor We also evaluate the novel parallax-free X-ray stitching method on phantom and dry bones. Using five trials, results show that parallax-free panoramas generated
by our method are of high visual quality and within clinical tolerances for accurate evaluation of long bone geometry (i.e., image and metric measurement errors are less than 1% compared to ground-truth).”
“OBJECTIVES: To estimate trends in infant mortality rates and cesarean delivery rates for extremely preterm infants born in the United States.
METHODS: This national population-based study used public data from the Centers for Disease Control and Prevention to investigate extremely preterm infants born alive between 22 0/7 and 27 6/7 weeks of gestational age from 1999 to 2005.
RESULTS: There were 177,552 extremely preterm infant births (fewer than 1% of all births) from 1999 to 2005. The number of annual extremely preterm births increased by 7% compared with a 4.5% increase for births at all gestations. During the study years, the extremely preterm infant mortality rate (percentage of infants who died in the first year) remained steady (range 33-34%; P=.22), whereas the cesarean delivery rate increased from 43% to 54% (P<.001). The infant mortality rate after cesarean delivery increased from 24% to 26% (P=.012). At each gestational age, the annual cesarean delivery rate increased over time (P<.