摘要:
A temperature monitoring system employs a temperature detection means incorporated into an invasive device intended to be placed within a body during a magnetic resonance procedure. The temperature monitoring system is used to monitor temperature rises in tissue arising from the creation of electric fields within the tissue. These electric fields are created by the application of RF pulses during the course of a magnetic resonance procedure which induce electrical current in the invasive device. It the detected temperature rise exceeds a selected threshold, the temperature monitoring system can cause the magnetic resonance imaging system to either reduce RF power or terminate the procedure. An optical coupling may be used between the imaging or tracking RF coil and the MR receiver to eliminate heating induced by the application of RF pulses during the procedure.
摘要:
A tracking system monitors the position of a device within a subject and superimposes a graphic symbol on a diagnostic image of the subject. Registration of the tracked location with the diagnostic image is maintained in the presence of subject motion by monitoring subject motion and adjusting the display to compensate for subject motion. Motion monitoring can be performed with ultrasonic, optical or mechanical methods. The display can be adjusted by modifying the displayed location of the device or it can be adjusted by translating, rotating or distorting the diagnostic image.
摘要:
An optical coupling is incorporated into an invasive device used in magnetic resonance (MR) imaging. The coupling is incorporated into the invasive device between an imaging or tracking RF coil, and the MR receiver. The optical coupling has a first transducer circuit coupled to the RF which converts between optical and electrical signals. An optical fiber is coupled to the first transducer circuit and extends out of the invasive device to medical imaging equipment. Near this equipment, a second transducer circuit converts optical signals to electrical, and electrical signals to optical, just opposite that of the first transducer circuit. The present invention thereby replaces long lead wires which can cause heating during MR imaging, and may distort an MR image.
摘要:
A tracking system monitors the position of a device within a subject and superimposes a graphic symbol on a diagnostic image of the subject. Registration of the tracked location with the diagnostic image is maintained in the presence of subject motion by monitoring subject motion and adjusting the display to compensate for subject motion. Motion monitoring can be performed with ultrasonic, optical or mechanical methods. The display can be adjusted by modifying the displayed location of the device or it can be adjusted by translating, rotating or distorting the diagnostic image.
摘要:
A magnetic resonance (MR) active invasive device system employs a small, high-field polarizing magnet, and a large low-field magnetic resonance (MR) imaging magnet for the purpose of generating MR images of blood perfusion in tissue. A subject is positioned in a large low-field MR imaging magnet. A catheter is inserted into the patient at or near the root of a vessel supplying blood to a portion of tissue to be imaged. A fluid, intended to be used as a contrast agent is first passed through the small high-field polarizing magnet, causing a high degree of net longitudinal magnetization to be produced in the fluid. The fluid is then introduced into the subject through the catheter. Radiofrequency (RF) pulses and magnetic field is gradients are then applied to the patient as in conventional MR imaging. Since the fluid has a larger longitudinal magnetization, before the MR imaging sequence, the fluid produces a much larger MR response signal than other tissue. Images acquired during periods of time in which the fluid is flowing and not flowing are mathematically combined to give an MR image whose pixel intensity is related to the degree of tissue perfusion.
摘要:
An imaging and interventional system and methods are provided. The system comprises an imaging device for acquiring volumetric image data for an anatomical region of interest, a catheter for acquiring electrophysiological (EP) measurements of the anatomical region of interest, the catheter having at least one tracking coil for detecting signals indicative of a position of the catheter, and, a processor coupled to the catheter for receiving the EP measurements and signals indicative of the position of the catheter. The position of the catheter and EP measurements are combined and superimposed on a resultant image. The method comprises acquiring volumetric image data for an anatomical region of interest, acquiring position data for a catheter inserted in the region of interest, obtaining electrophysiological (EP) measurements for the region of interest and combining the image data, position data and EP measurements into a resultant image for use in the interventional procedure.
摘要:
An invasive probe for mapping the walls of a lumen employs a real-time tracking means and a wall distance measurement means. As the probe is advanced within the lumen, the real-time tracking means provides three-dimensional coordinates of the probe's position and orientation. Concurrent with probe localization, the distance between the probe and the lumen walls is measured. Both the probe position and the wall distance measurement are sent to a data acquisition system which in turn provides a graphic or numeric display to the operator. Probe tracking can be performed with radio-frequency, magnetic resonance, ultrasonic techniques or the like. If desired, lumen wall distance measurements can be performed with magnetic resonance or ultrasound methods. Lumen wall distance measurements can also be performed with mechanical devices such as balloons and/or expanding structures.
摘要:
Secondary data set information is incorporated into a primary data set (such as a digital image) retaining a desired dynamic range and retaining the original primary set data quality. The secondary data set information is ‘smuggled’ into the least significant bits of the primary data set to result in an enhanced data set. If desired, the primary data word can be shifted toward the most significant bit. The enhanced data set may be viewed as if it were the original primary data set with existing playback devices, however it now includes additional ‘smuggled’ information which may be played back in coordination with the primary data set information. One example is flow-direction information ‘smuggled’ into an angiographic image. The least significant bits of the enhanced data words may be used to select the color map and color code the images. A user-adjustable intensity threshold can also be employed to select between color maps. Information stored in this fashion results in a substantial savings in disk storage requirements. Also, since the information of the primary and secondary data sets are merged into a single word, they will remain together throughout many different types of processing, such as maximum intensity projection in volumetric imaging.
摘要:
An invasive probe for determining the morphological characteristics of walls of a lumen employs a real-time tracking means and an optical spectral measurement means. As the probe is advanced within the lumen, the real-time tracking means provides three-dimensional coordinates of the probe's position and orientation. Concurrent with probe localization, measurement of the spectral properties of the lumen wall are made by detecting the reflectance and/or absorption of light at the lumen wall. Both the probe position and the spectral measurement are sent to a data acquisition system which in turn provides an graphic or numeric display to the operator. Probe tracking can be performed with radio-frequency, magnetic resonance, ultrasonic techniques or the like. If desired, spectral measurements can be made in the visible, ultra-violet or infra-red spectral bands to provide optimized detection of chemical species of interest.
摘要:
An interactive three-dimensional (3D) pointing device for selecting points within a subject employs a tracking device which determines the position of the operator, a semi-transparent screen positioned by the operator and the subject and provides this information to a model workstation. The model workstation superimposes computer graphic images of internal structures of the subject on a the semi-transparent screen through which the operator is viewing the subject. The superimposed image is derived from image data either previously generated and stored or obtained with an imaging system. The images of the internal structures are registered with the operator's view of the external structures of the operator. The operator interactively views internal and external structures and the relation between them simultaneously, while moving the screen to select 3D target points at an image depth within the subject. Optionally other input devices may be used to identify current `target points` as selected points. The 3D points are then provided to an output device which utilizes them. Another embodiment employs stereoscopic viewing methods to provide 3D representations of the internal images superimposed on external structures to allow the operator to employ parallax to select 3D points.