摘要:
A MR method determines nuclear magnetic resonance distribution in an examination area and the position of at least one microcoil which is located in the examination area in or on an examination object. In the presence of a homogeneous stationary magnetic field acting on the examination area, sequences are carried out in which at least one high-frequency pulse acting on the examination area is generated, and after the high-frequency pulse an MR signal induced in the microcoil is detected under the influence of a gradient magnetic field that acts on the examination area. Then the position of the microcoil in the gradient direction defined by the gradient field is derived from the detected MR signal. The aforementioned sequences are repeated for another gradient direction, and MR signals are detected by a further receiving coil arrangement to determine the nuclear distribution. Without additional measuring sequences, a position is detected in a manner that the sequences are continuously repeated while the gradient direction is varied, and that the position of the microcoil and the nuclear magnetic distribution are derived from MR signals detected simultaneously by the microcoil and the receiving coil arrangement.
摘要:
System and method for enabling intra-operative selection of an image registration transformation for use in displaying a first image dataset and a second image dataset in correspondence with one another. Image dataset acquisition devices (12, 14) obtain the first and second image datasets. A similarity function indicative of a likelihood that the first and second image datasets are in correspondence with one another is computed by a processor (16) and then a ranking of each of a plurality of local maxima of the similarity function is determined. Registration transformations derived from a plurality of the local maxima are displayed on a display (18), and using a user-interface (22), a physician can select each registration transformation to ascertain visually whether it is the clinically-optimal registration transformation for subsequent use.
摘要:
A method and system for navigation of a medical instrument, including: introducing at least three reference device(s) disposed to at least three reference locations; employing an imaging and guidance system to acquire a plurality of image projections corresponding to a desired anatomy including the reference devices, the plurality of image projections being sufficient to permit generating a three-dimensional modeling or reconstruction images corresponding to the reference devices. The method also includes measuring a position of the reference devices; formulating a transformation matrix based on comparing positions of the reference devices computed from the modeling or reconstruction images with the measured positions of the reference devices; and superimposing an image of a medical instrument in at least one of the plurality of image projections based on the transformation matrix and a position of the medical instrument.
摘要:
Iso-centering a volume of interest (VOI) (170) within a patient (168) to undergo examination on a rotational X-ray apparatus (100) is achieved by taking two differently-angled pictures (S210) and updating positional settings (172) for the patient's table (112) responsive to respectively displayed centering of the VOI (152). Alternatively, the operator identifies respective VOI centers (S410, S450) for each of the two displayed pictures, and corresponding table movement is automatically calculated (S420).
摘要:
The invention relates to an imaging system and a method for generating high-quality X-ray projections (24) of a patient (1). The system comprises a rotational X-ray device (10), for example a cone-beam CT-gantry (12), and an associated data processing unit (20). During a medical intervention, low-dose raw projections (22) of the patient (1) are continuously generated from different directions. A volume of interest (23) is then reconstructed from said projections (22), from which high-quality virtual projections (24) can be calculated for a display on a monitor (25). The number and direction of said virtual projections (24) can be arbitrarily chosen by the user.
摘要:
System and method for enabling intra-operative selection of an image registration transformation for use in displaying a first image dataset and a second image dataset in correspondence with one another. Image dataset acquisition devices (12, 14) obtain the first and second image datasets. A similarity function indicative of a likelihood that the first and second image datasets are in correspondence with one another is computed by a processor (16) and then a ranking of each of a plurality of local maxima of the similarity function is determined. Registration transformations derived from a plurality of the local maxima are displayed on a display (18), and using a user-interface (22), a physician can select each registration transformation to ascertain visually whether it is the clinically-optimal registration transformation for subsequent use.
摘要:
Position measurements are often performed using a localization system with a given fixed capture range and accuracy and resolution. Having a fixed capture range often comes at the cost of decreased accuracy and resolution. According to the present invention, at the start, a large capture range is provided where the accuracy and resolution is low. In this large capture area, the target area can be identified and aimed at. With this identification, a smaller capture range is iteratively provided and centered around the region of interest, which leads to an increased accuracy and resolution.
摘要:
An X-ray imaging method comprises forming 2-dimensional X-ray images of an object to be examined, for example the coronary vascular system of a patient, and reconstruction of a 3-dimensional volume thereof. With a relatively long run length of a scan rotation over substantially 180° of at least 15 sec. and preferably about 20 sec. A sufficient number of images is obtained to perform a more accurate volume reconstruction. This reconstruction method may be combined with existing modelling techniques.
摘要:
A method is provided for analysis of a multi-dimensional structure which includes a tubular structure from two-dimensional datasets for respective pre-determined projection directions. A pair of corresponding initial projected centre points of the tubular structure is identified in two respective initial and further two-dimensional datasets. Projected edges of the tubular structure in said initial two-dimensional datasets and in said further two-dimensional dataset near the respective projected centre points are identified. A local size of the tubular strucwur is derived at the three-dimensional spatial position of the centre point of the tubular structure from said projected edges and the predetermined projection directions.
摘要:
The invention relates to an MR method for determining the frequency map in an examination zone as well as to an appropriate sequence in which the nuclear magnetization is read in conjunction with the read gradient of varying direction. Subsequent to an excitation of the nuclear magnetization, a plurality of MR echo signals are acquired. From the sub-images acquired with different echo times on the one hand the frequency map can be derived whereas on the other hand these sub-images can be combined so as to form an MR overall image of higher spatial resolution. The invention also relates to a device for carrying out this method.