Quadruple inversion recovery for quantitative contrast-enhanced black blood imaging
First Claim
1. A method for suppressing a signal from flowing blood in a signal used for magnetic resonance imaging (MRI) of a site in a subject, comprising the steps of:
- (a) generating a preparative sequence of radiofrequency (RF) pulses before executing a data acquisition sequence to image the site, a total number of the said RF pulses being an even number at least equal to four;
(b) applying said RF pulses to the subject prior to executing the data acquisition sequence to image the site, so that the said RF pulses are grouped into a plurality of double inversion procedures, each double inversion procedure including a non-selective RF pulse targeted to the subject and a slice-selective RF pulse that is targeted to a target selected from the group consisting of a slice, a group of slices, and a three-dimensional slab at the site, wherein one of the non-selective RF pulse and the slice-selective RF pulse immediately follows the other of the non-selective RF pulse and the slice-selective RF pulse;
(c) waiting a predefined time period after each of the double inversion procedures; and
(d) after the predefined time period following a last of the double inversion procedures, executing the data acquisition sequence for acquiring a signal that is processed to produce and display an image of the site thereby enabling a clear visual evaluation of anatomic structures and pathologic tissues of interest for diagnostic purposes of the site, because said signal from the flowing blood is substantially suppressed in the signal used to produce the image of the site.
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Accused Products
Abstract
A contrast enhancement (CE) agent is infused into blood flowing through a site that is to be imaged with magnetic resonance imaging (MRI). Two double inversion procedures are carried out, forming a quadruple inversion recovery (QIR) pulse sequence. Each double inversion procedure comprises a non-selective and slice-selective inversion RF pulse. The first double inversion procedure is followed by a first predefined inversion delay period, TI1, and the second procedure by a second predefined inversion delay period, TI2. A black-blood image can thus be produced in which blood appears consistently black and tissues surrounding the blood, such as a vessel wall, heart, atherosclerotic plaque, or thrombus, are clearly visible. Unlike the prior art black-blood imaging technique, the QIR method does not require a precise knowledge of the T1 of the blood carrying the CE agent in order to suppress the signal and artifacts caused by the blood flowing through the site.
15 Citations
38 Claims
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1. A method for suppressing a signal from flowing blood in a signal used for magnetic resonance imaging (MRI) of a site in a subject, comprising the steps of:
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(a) generating a preparative sequence of radiofrequency (RF) pulses before executing a data acquisition sequence to image the site, a total number of the said RF pulses being an even number at least equal to four; (b) applying said RF pulses to the subject prior to executing the data acquisition sequence to image the site, so that the said RF pulses are grouped into a plurality of double inversion procedures, each double inversion procedure including a non-selective RF pulse targeted to the subject and a slice-selective RF pulse that is targeted to a target selected from the group consisting of a slice, a group of slices, and a three-dimensional slab at the site, wherein one of the non-selective RF pulse and the slice-selective RF pulse immediately follows the other of the non-selective RF pulse and the slice-selective RF pulse; (c) waiting a predefined time period after each of the double inversion procedures; and (d) after the predefined time period following a last of the double inversion procedures, executing the data acquisition sequence for acquiring a signal that is processed to produce and display an image of the site thereby enabling a clear visual evaluation of anatomic structures and pathologic tissues of interest for diagnostic purposes of the site, because said signal from the flowing blood is substantially suppressed in the signal used to produce the image of the site. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for suppressing the signal from flowing fluid in magnetic resonance imaging (MRI) after infusion of a contrast agent, comprising the steps of:
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(a) prior to executing a data acquisition sequence to acquire an image, carrying out a first double inversion procedure that includes applying in rapid succession and in either order a non-selective inversion RF pulse and a slice-selective inversion RF pulse, said slice-selective inversion RF pulse being targeted at a target selected from the group consisting of a slice, a group of slices, and a three-dimensional slab; (b) waiting a first predefined inversion delay period after application of the first double inversion procedure; (c) after the first predefined inversion delay period is complete and prior to executing the data acquisition sequence to acquire the image, carrying out a second double inversion procedure that includes again applying in rapid succession and in either order a non-selective inversion RF pulse and a slice-selective inversion RF pulse targeted at the target; (d) waiting a second predefined inversion delay period after application of the second double inversion procedure; and (e) after the second predefined inversion delay period is complete, executing the data acquisition sequence, which comprises a sequence of RF and magnetic field gradient pulses for acquiring a signal that is processed to produce and display the image in which the signal from flowing fluid appears suppressed and in which a tissue surrounding the fluid is consistently visible to aid in diagnosing and evaluating pathologic tissues of interest. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for contrast-enhanced black-blood magnetic resonance imaging (MRI) of a site so that tissue surrounding blood is clearly visible and the blood is consistently black in an image of the site, comprising the steps of:
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(a) infusing a contrast enhancement agent into the blood so that the blood carrying a portion of the contrast enhancement agent is flowing through the site to be imaged; (b) prior to executing an image acquisition sequence, carrying out a first double inversion procedure; (c) waiting a first predefined inversion delay period after carrying out the first double inversion procedure; (d) after the first predefined inversion delay period is complete and prior to executing the image acquisition sequence, carrying out a second double inversion procedure, each of the first and the second double inversion procedures including the steps of applying in rapid succession and in either order a non-selective inversion RF pulse and a slice-selective inversion RF pulse, said slice-selective inversion RF pulse being targeted to a target selected from the group consisting of a slice, a group of slices, and a three-dimensional slab at the site; (e) waiting a second predefined inversion delay period after carrying out the second double inversion procedure; and (f) after the second predefined inversion delay period is complete, executing the image acquisition sequence for acquiring a signal for processing to produce and display the image, in which flowing blood is consistently black, thereby enabling a clear visualization of pathological tissues of interest at the site. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. A controller for generating a pulse sequence for inversion-recovery magnetic resonance imaging of a site, comprising:
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(a) a memory in which a plurality of machine executable instructions are stored; and (b) a processor that is coupled to the memory and executes the machine executable instructions, causing the pulse sequence to be generated, said pulse sequence being characterized by including; (i) a first double inversion pulse pair generated to comprise and to be applied in rapid succession and in either order prior to execution of an acquisition sequence to image the site, a slice-selective inversion radiofrequency (RF) pulse, and a non-selective inversion RF pulse; (ii) a first delay period that begins after application of the first double inversion pulse pair; (iii) a second double inversion pulse pair generated to comprise and to be applied in rapid succession and in either order prior to execution of the acquisition sequence to image the site, a slice-selective inversion RF pulse, and a non-selective inversion RF pulse; (iv) a second delay period that begins after application of the second double inversion pulse pair; and (v) the acquisition sequence comprising RF pulses and magnetic field gradient pulses generated for spatial encoding and readout of a signal for producing an image of the site. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A system for carrying out quadruple inversion-recovery preparative pulse sequence, followed by data acquisition, comprising:
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(a) an MRI apparatus adapted for producing an image of a site; and (b) a computer coupled to the MRI apparatus to control it, said computer including; (i) a memory in which machine instructions are stored; and (ii) a processor coupled to the memory, said processor executing the machine instructions to control the MRI apparatus to carry out a sequence of operations, including; (1) prior to executing a data acquisition procedure to image the site, initiating a preparative sequence by generating and applying in rapid succession a pair of radiofrequency (RF) inversion pulses, one RF inversion pulse being selective and the other being non-selective; (2) waiting for a first predefined delay period after application of the pair of RF inversion pulses; (3) after the first predefined delay period is complete and prior to executing the data acquisition procedure to image the site, again generating and applying in rapid succession the pair of RF inversion pulses, one of which is selective and the other of which is non-selective; (4) waiting for a second predefined delay period after application of the pair of RF inversion pulses; and (5) after the second predefined delay period is complete, generating the data acquisition pulse sequence in order to acquire a magnetic resonance signal for use in producing the image of the site. - View Dependent Claims (32, 33, 34, 35, 36)
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37. A memory medium on which machine readable instructions are stored, which when executed by a computing device that is coupled to MRI apparatus, cause the MRI apparatus to carry out a plurality of functions, including:
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(a) prior to executing a data acquisition sequence, generating a preparative sequence of radiofrequency (RF) pulses, a total number of the said RF pulses being an even number at least equal to four; (b) applying said RF pulses to a subject prior to executing the data acquisition sequence in such a manner so that the said RF pulses are grouped into a plurality of double inversion procedures, each double inversion procedure including a non-selective RF pulse targeted to the subject and a slice-selective RF pulse that is targeted to a target selected from the group consisting of a slice, a group of slices, and a three-dimensional slab at the site, wherein one of the non-selective RF pulse and the slice-selective RF pulse immediately follows the other of the non-selective RF pulse and the slice-selective RF pulse; (c) delaying for a predefined time period after each of the said double inversion procedures; and (d) after delaying the predefined time period following a last of the said double inversion procedures, applying the data acquisition sequence comprising the step of acquiring a signal that is processed to produce and display an image of the site, thereby enabling a clear visual evaluation of anatomic structures and pathologic tissues of interest for diagnostic purposes of the site, because said signal from the flowing blood is substantially suppressed in the signal used to produce the image of the site.
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38. A memory medium on which machine readable instructions are stored, which when executed by a computing device that is coupled to MRI apparatus, cause the MRI apparatus to carry out a plurality of functions to be executed prior to execution of a signal acquisition sequence to image a site, including:
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(a) prior to execution of the signal acquisition sequence to image the site, carrying out a first double inversion procedure of the site; (b) waiting a first predefined inversion delay period; and (c) prior to execution of the signal acquisition sequence to image the site, carrying out a second double inversion procedure of the site, each of the first and the second double inversion procedures including the steps of applying in rapid succession and in either order a non-selective inversion RF pulse and a slice-selective inversion RF pulse, said slice-selective inversion RF pulse being targeted at a target selected from the group consisting of a slice, a group of slices, and a three- dimensional slab at the site.
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Specification