Electricity: measuring and testing – Particle precession resonance – Using a nuclear resonance spectrometer system
Reexamination Certificate
1999-12-27
2002-03-26
Arana, Louis (Department: 2862)
Electricity: measuring and testing
Particle precession resonance
Using a nuclear resonance spectrometer system
C324S314000
Reexamination Certificate
active
06362620
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of medical diagnostic systems, such as imaging systems. More particularly, the invention relates to a system and technique for interactive image contrast prescription control.
When a substance such as human tissue is subjected to an uniform magnetic field (polarizing field Bo), the individual magnetic moments of the spins in the tissue attempt to align with this polarizing field, but process about it in random order at their characteristic Larmor frequency. If the substance, or tissue, is subjected to a magnetic field (excitation field B
1
) which is the x-y plane and which is near the Larmor frequency, the net aligned moment, M
z
, may be rotated, or “tipped”, into the x-y plane to produce a net transverse magnetic moment M. A signal is emitted by the excited spins after the excitation signal B
1
is terminated and this signal may be received and processed to form an image.
When utilizing these signals to produce images, magnetic field gradients (G
x
, G
y
and G
z
) are employed. Typically, the region to be imaged is scanned by a sequence of measurement cycles in which these gradients vary according to the particular localization method being used. The resulting set of received NMR signals (also referred to as MR signals) are digitized and processed to reconstruct the image using one of many well known reconstruction techniques.
When viewing an MR image of a structure of interest, such as an anatomical section, the MR imaging system operator may desire to view an MR image in which one or more types of tissue comprising the anatomical section is contrasted with respect to the remaining types of tissue of the anatomical section. Moreover, the operator may desire to modify the image contrast of an MR image acquisition in progress or to prescribe the image contrast prior to an MR image acquisition.
Currently, various image contrast mechanisms such as chemical saturation and spatial saturation are used in MR imaging to generate images of varying contrast. For example, chemical saturation is used to suppress the relatively large magnetization signal from fatty tissue. Each image contrast mechanism is made possible by a corresponding magnetization preparation applied to the anatomical section prior to the MR scan. Briefly, magnetization preparation involves preparing the spin state in the bore such that the anatomical section to be imaged is in a certain magnetized state immediately before the regular image scanning commences. Thus, to acquire an MR image with image contrast, the MR imaging system executes an MR imaging pulse sequence comprised of at least two sets of waveform segments—at least one set of image contrast waveform segment and a set of (regular) imaging waveform segment.
In conventional MR imaging systems, the MR imaging pulse sequence responsible for a specific image contrast mechanism is typically constructed and stored in the MR imaging system prior to scanning. In particular, the MR imaging pulse sequence is comprised of the specific image contrast waveform segment permanently linked to the imaging waveform segment, thus one waveform set. When an operator desires this specific image contrast mechanism, this all-inclusive pulse sequence is evoked and executed in its entirety, The drawback of this type of pulse sequence architecture is that the operator must wait until the image acquisition in progress is completed before new desired image contrast mechanism(s) can be applied. Furthermore, even if the amplitudes of the image contrast waveform segment of the MR imaging pulse sequence can be set to zero while the image acquisition is in progress, essentially prescribing a new image contrast mechanism during acquisition, there is no reduction in acquisition time because the zero amplitude image contrast waveform segment portion must still be executed along with the rest of the MR imaging pulse sequence.
Solutions to the problems described above have not heretofore included significant remote capabilities. In particular, communication networks, such as, the Internet or private networks, have not been used to provide remote services to such medical diagnostic systems. The advantages of remote services, such as, remote monitoring, remote system control, immediate file access from remote locations, remote file storage and archiving, remote resource pooling, remote recording, remote diagnostics, and remote high speed computations have not heretofore been employed to solve the problems discussed above.
Thus, there is a need for a medical diagnostic system which provides for the advantages of remote services and addresses the problems discussed above. In particular, there is a need for interactive image contrast control including remote control via a network. Further, there is a need for manipulation of MR imaging systems remotely via a network.
SUMMARY OF THE INVENTION
One embodiment of the invention relates to an interactive magnetic resonance (MR) imaging system. The system includes a MR imaging device, a network coupling the MR imaging device and a remote facility, an operator interface coupled to the MR imaging device and the network, a memory coupled to the MR imaging device, and a sequence controller coupled to the memory. The MR imaging device is configured to acquire and reconstruct MR data in real-time of a current imaging section and display a MR image in real-time of the current imaging section. The network provides remote services to the MR imaging device. The operator interface permits an operator to select from a plurality of image contrast mechanisms. The memory stores a plurality of image contrast waveform segments and at least one imaging waveform segment. Each of the plurality of image contrast waveform segments and the at least one imaging waveform segment is distinctly addressable such that each waveform segment can be independently accessed from the memory. The sequence controller dynamically links the selected image contrast waveform segments and one imaging waveform segment, causing the MR imaging device to acquire a new image with the selected waveform segment mechanisms.
Another embodiment of the invention relates to a method for interactively and remotely controlling the image contrast of a real-time magnetic resonance (MR) image produced in a MR system. The method includes a) establishing a communication connection over a network between the MR system and a remote facility; b) storing a plurality of image contrast waveform segments in a waveform memory of the MR system; c) storing at least one imaging waveform segment in the waveform memory of the MR system; d) selecting from the plurality of image contrast waveform segments stored in the waveform memory; e) selecting from the at least one imaging waveform segment stored in the waveform memory; f) constructing a MR imaging pulse sequence in real-time by a sequence controller dynamically linking the selected image contrast waveform segment to the selected imaging waveform segment stored in the waveform memory at run-time; g) acquiring MR data using the dynamically linked MR imaging pulse sequence in real-time; h) reconstructing the MR data acquired in real-time; and i) displaying the newly acquired MR image as the current image.
Another embodiment of the invention relates to an interactive magnetic resonance (MR) imaging system. The system includes a) means for establishing a communication connection over a network between the MR system and a remote facility; b) means for storing a plurality of image contrast waveform segments in a waveform memory of the MR system; c) means for storing at least one imaging waveform segment in the waveform memory of the MR system; d) means for selecting from the plurality of image contrast waveform segments stored in the waveform memory; e) means for selecting from the at least one imaging waveform segment stored in the waveform memory; f) means for constructing a MR imaging pulse sequence in real-time by a sequence controller dynamically linking the selected image contrast waveform seg
Debbins Josef P.
Francis Roshy J.
Ploetz Lawrence E.
Prorok Richard J.
Arana Louis
Della Penna Michael A.
Foley & Lardner
GE Medical Systems Global Technology Company LLC
Vogel Peter J.
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