摘要:
A medical apparatus (1100) comprising a magnetic resonance imaging system and an interventional device (300) comprising a shaft (302, 1014, 1120). The medical apparatus further comprises a toroidal magnetic resonance fiducial marker (306, 600, 800, 900, 1000, 1122) attached to the shaft. The shaft passes through a center point (610, 810, 908, 1006) of the fiducial marker. The medical apparatus further comprises machine executable instructions (1150, 1152, 1154, 1156, 1158) for execution by a processor. The instructions cause the processor to acquire (100, 200) magnetic resonance data, to reconstruct (102, 202) a magnetic resonance image (1142), and to receive (104, 204) the selection of a target volume (1118, 1144, 1168). The instructions further cause the processor to repeatedly: acquire (106, 206) magnetic resonance location data (1146) from the fiducial marker and render (108, 212) a view (1148, 1162) indicating the position of the shaft relative to the target zone.
摘要:
Using only projection data in one temporal gating window around a certain target phase point may lead to motion artifacts such as blurred images. By using projection data corresponding to three temporal gating windows, which are slightly shifted with respect to each other but at least partially overlap, motion within the gating window may be estimated and, according to an exemplary embodiment of the present invention, this estimation may be used for improving the image quality. Advantageously, only the projection data inside the at least partially overlapping gating windows are used for reconstruction and motion compensation.
摘要:
The invention relates to a method and a system for the reconstruction of an object function (f(x)) based on projections acquired during the motion of a radiation source on a helical trajectory (17). The method is particularly suited for an n-PI+ acquisition which by definition completely comprises an n-PI and additionally some overscan data from the (n+2)-PI window. According to the method, two sets (∑≤m, ∑>m) of filtered projections are generated from the measuring values and separately back- projected to yield two absorption functions. The first absorption function (flf(x)) is based on contributions of Radon-planes with at most m intersections with the source trajectory (17), while the second absorption function (fhf(x)) is based on Radon-planes with more than m intersections with the source trajectory (17). The two absorption functions are added to yield the final absorption function (f(x)) of an object in the examination zone. In an approximative version of the method, the sets (∑≤m, ∑>m) of filtered projections are first added and then back-projected.
摘要:
Using only projection data in one temporal gating window around a certain target phase point may lead to motion artifacts such as blurred images. By using projection data corresponding to three temporal gating windows, which are slightly shifted with respect to each other but at least partially overlap, motion within the gating window may be estimated and, according to an exemplary embodiment of the present invention, this estimation may be used for improving the image quality. Advantageously, only the projection data inside the at least partially overlapping gating windows are used for reconstruction and motion compensation.
摘要:
Magnetic resonance examination system comprises displaceable carrier for supporting an object to be examined. The carrier can be moved over a two dimensional area. The magnetic resonance examination system is configured to acquire sets of magnetic resonance signals from the object for various positions of the carrier in the two dimensional area.
摘要:
The invention relates to an MR method for examining a cyclically changing object where a first and a second sequence act on the object during a cycle. When very many cycles are required so as to complete the second MR data set, a two-dimensional image can be reconstructed from the MR data of the first sequence so as to utilize such a two-dimensional image for monitoring purposes or as a navigator image.
摘要:
The invention relates to a method of automatically acquiring magnetic resonance (MR) image data (500; 504) of an object located on a support (140), the support (140) being adapted to be moved to an image acquisition region of an MRI apparatus, the method comprising: specifying an area of interest (510) to be detected by the MRI apparatus, automatically moving of the support (140) in the direction towards the image acquisition region, automatically acquiring of first MR image data (500; 504) with a first resolution for identification of the area of interest (510) in the acquired image data (500; 504), automatically acquiring of second MR image data of the identified area of interest (510) with a second resolution, wherein the first resolution is lower than the second resolution.
摘要:
A computer tomography apparatus (100) for examination of an object of interest (107) comprising an electromagnetic radiation source (104) adapted to emit electromagnetic radiation to an object of interest (107), a detecting device (108) adapted to detect electromagnetic radiation generated by the electromagnetic radiation source (104) and passed through the object of interest (107), and a motion generation device (101, 119) adapted to move the electromagnetic radiation source (104) and the detecting device (108) with respect to the object of interest (107) along a first trajectory and along a second trajectory which differs from the first trajectory, wherein the second trajectory is selected in such a manner that electromagnetic radiation detected during performing the second trajectory provides data which complete mathematically incomplete data detected during performing the first trajectory to thereby allow a reconstruction of structural information concerning the object of interest (107).
摘要:
A computed tomography method and apparatus are provided wherein a radiation source moves circularly relative to an examination zone about an axis of rotation (14). The radiation source produces a cone beam of x-rays and the focal point of this cone beam is switched between at least two positions (23a, 23b) sapced apart from each other and arranged on a line parallel to the axis of rotation to enlarge the reconstructable examination zone parallel to the axis of rotation. Preferably, the image of the examination zone is reconstructed using an iterative reconstruction method, in particular an algebraic reconstruction method or a maximum likelihood method.