Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on September 28, 2023, is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on July 31, 2026, has been entered.
Specification
The specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification.
Response to Amendment
The Amendment filed July 31, 2026, has been received and made of record. Claims 1-21 remain pending in the application. Claims 1, 9, 15, & 20 are amended. Applicant’s amendments to the Claims have overcome each and every objection and 35 U.S.C. § 112(b) rejections previously set forth in the Final Office Action mailed April 2, 2026, hereafter referred to as the Final Office Action.
Response to Arguments
Applicant's arguments filed July 31, 2026, see pp. 6-8 of Applicant’s remarks, with respect to the rejections of independent claims 1, 9, & 15 (independent claims 9 & 15 have been similarly amended), under U.S.C. § 102(a)(1), in view of Schulte et al. (US 2013/0134972 A1), have been fully considered but they are not persuasive. In light of the amendments and upon further consideration, a new ground of rejection is made in view of Schulte, in view of Vaughn et al. (US 2008/0129298 A1), in view of Grissom (US 2015/02534031 A1), and further in view of Frydman et al. (US 2010/0001727 A1).
In response to the Applicant’s argument regarding Schulte’s failure to teach the simultaneous application of “a frequency-modulated, frequency-selective RF excitation pulse” for spatial encoding are noted but unpersuasive. The Examiner respectfully disagrees, and the rejection has been updated under U.S.C. § 103, where Grissom is cited to teach the use of a frequency-modulated RF waveform to comprise an excitation pulse specifically for RF-based spatial encoding, eliminating the need for conventional gradients. Furthermore, Frydman was cited for teaching the application of phase and amplitude-modulated RF pulses simultaneously with the encoding fields to correct for field distortions. Please see updated rejections below.
In response to the Applicant’s argument that a POSITA would not understand that surface coils produce spatially inhomogeneous fields compared to volume coils is respectfully disagreed with. Documentary evidence of this well-known physical property is provided by prior art reference Vaughn et al. Vaughn distinguishes homogenous volume coils such as the “birdcage…is a highly homogeneous coil circuit,” ([0304]) from surface coils. Vaughn teaches that “small loop coils…couple to only superficial fields of view (FOV) of limited range”, ([0285]) and notes that their field penetration flattens and broadens at distances beyond the coil’s diameter. Vaughn further illustrates that “Transmit and receive B1 fields exhibit similar twisted amplitude pattern, but with opposite direction. Note that for each coil element there is a spatial shift between the highest spots obtained...” ([0114]). Therefore, the prior art of record provides evidence that surface coils are spatially inhomogeneous, and applying an off-resonance RF pulse through such a coil meets the claimed limitation.
Therefore, the Applicant’s arguments are unconvincing and the rejections of amended independent claims 1, 9, & 15, and dependent claims 2-8, 10-14, & 16-21, which depend from and incorporate the limitations of amended independent claims 1, 9, & 15, are respectively maintained. Rejections based on the newly cited prior art references follow below.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-6, 9-18, & 20 are rejected under 35 U.S.C. 103 as being unpatentable over Schulte et al. (US 2013/0134972 A1, Pub. Date May 30, 2013, hereinafter, Schulte), in view of Vaughn et al. (US 2008/0129298 A1, Pub. Date Jun. 5, 2008, hereinafter, Vaughn), in view of Grissom et al. (US 2015/0253403 A1, Pub. Date Sep. 10, 2015, hereinafter, Grissom), and further in view of Frydman et al. (US 2010/0001727 A1, Pub. Date Jan. 7, 2010, hereinafter, Frydman).
Regarding independent claim 1, Schulte, teaches:
A method for using a nuclear magnetic resonance (NMR) system (Fig. 1; [Abstract], [0001]-[0002], & [0006]), the method including steps comprising (Fig. 1; [Abstract], [0001]-[0002], & [0006]: details a method of operating an NMR/MRI system): acquiring NMR data from the subject that is spatially encoded (Figs. 2 & 3; [0006], [0035]-[0036], [0038], [0043], & [0052]: RF pulse receiver, step 306, discloses acquiring the spatially encoded NMR data); and
reconstructing the NMR data to produce a report of internal materials forming the subject (Figs. 2 & 3; [0006], [0035]-[0036], [0038], [0040], [0053]-[0054], & [0060]: step 308, reconstructing the encoded signal to produce a B1 field map fulfills producing a report of internal materials/properties).
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Schulte, is silent in regard to:
applying an off-resonance radio frequency (RF) pulse using a radio-frequency coil that is spatially inhomogeneous to induce a B1-dependent resonant frequency shift in spins in a subject;
However, Vaughn, further teaches:
The Examiner is combining Schulte in view of Vaughn by implementing the teaching of the off-resonance RF pulse to induce the B1-dependent shift of Schulte (Fig. 4; [0004], [0021], [0035], [0048], & [0057]).
applying an off-resonance radio frequency (RF) pulse using a radio-frequency coil that is spatially inhomogeneous to induce a B1-dependent resonant frequency shift in spins in a subject ([0282], [0285], & [0288]: while Schulte teaches the off-resonance RF pulse to induce the B1-dependent shift, Vaughn provides the teaching and motivation to use spatially inhomogeneous radio-frequency coils (e.g., surface coils or arrays) for these pulses at high fields);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to combine Schulte and Vaughn, adapting Schulte’s off-resonance B1-mapping sequence to be transmitted via Vaughn’s inhomogeneous surface coils or arrays. Schulte discloses applying an off-resonance RF pulse to induce a B1-dependent resonance shift but lacks details on utilizing a spatially inhomogeneous radio-frequency coil. Vaughn teaches applying RF pulses utilizing a radio-frequency coil, noting that inhomogeneous coils fail to generate uniform B1 fields at high field strengths. The problem being solved is the need to maximize local signal-to-noise ratio (SNR) and limit RF power losses (SAR) when imaging targeted superficial regions of interest. Incorporating Vaughn’s spatially inhomogeneous coils into Schulte’s MRI system is a substitution of one known coil element for another to yield the predictable variation of improved local imaging efficiency without exceeding safety guidelines (KSR).
Schulte, in combination with Vaughn, are silent in regard to:
simultaneously with the off-resonance RF pulse, applying a frequency-modulated, frequency selective RF excitation pulse to spatially encode the spins in the subject;
However, Frydman, further teaches:
The Examiner is combining Schulte and Vaughn in view of Grissom that provides the frequency-modulated, frequency-selective excitation pulse specifically for RF spatial encoding ([0003]-[0004] & [0060]).
simultaneously with the off-resonance RF pulse, applying a frequency-modulated, frequency selective RF excitation pulse to spatially encode the spins in the subject ([Abstract], [0008], & [0014]: Grissom provides the frequency-modulated, frequency-selective excitation pulse for RF spatial encoding while Frydman teaches applying the modulated excitation pulse “in unison” (simultaneously) with the encoding fields);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to combine the simultaneous excitation and encoding timing of Frydman with the frequency-modulated RF spatial encoding of Grissom into the high-field inhomogeneous MRI system of Schulte and Vaughn. The combination of Schulte and Vaughn discloses applying an off-resonance RF pulse using a spatially inhomogeneous coil to induce a B1-dependent shift, but lacks applying a frequency-modulated, frequency-selective RF excitation pulse simultaneously with the off-resonance pulse to spatially encode the spins. Grissom teaches designing an RF frequency modulation waveform to comprise a frequency-selective excitation pulse configured to provide encoding based on RF gradient fields instead of conventional B0 gradients, which solves the problem of high scanner cost, bulk, acoustic noise, and peripheral nerve stimulation. Frydman further teaches applying a phase and amplitude-modulated radio frequency excitation pulse in unison (simultaneously) with the encoding fields to immediately correct for spatial field distortions at the exact time of spatially-selective RF irradiation. This combination represents the use of known techniques to improve similar devices, yielding the predictable variation of obtaining high-definition MRI spectra without spatial distortion, and maximizing patient comfort in inhomogeneous magnetic environments (KSR).
Regarding dependent claim 2, Schulte, teaches:
The method of claim 1 (Fig. 1; [Abstract], [0001]-[0002], & [0006]), wherein the report includes at least one of an image of the subject ([Abstract], [0002], [0006]-[0007], [0023], [0038]-[0039], [0052], [0055], & [0060]), a map of the subject (Fig. 3; [0002], [0004], [0006], [0023], [0038]-[0039], & [0052]: 308), or a quantitative measure of function ([0060]: calculation of permittivity or conductivity is a quantitative measure of the electrical function of the internal tissues) or the report of the internal materials of the subject ([0002], [0038], [0052], [0058], & [0060]: method uses NMR of atoms of certain elements to generate MRI images, the map is used for image reconstruction for visualization of the body (internal materials)).
Regarding dependent claim 3, Schulte, teaches:
The method of claim 1 (Fig. 1; [Abstract], [0001]-[0002], & [0006]), wherein the off-resonance RF pulse produces a Bloch-Siegert shift ([0021], [0035], & [0052]: identifies that the off resonance RF pulse delivered to the spins operates via the spins, generating a Bloch-Siegert shift to alter the resonance frequency and encode the phase).
Regarding dependent claim 4, Schulte, teaches:
The method of claim 1 (Figs. 1 & 2; [Abstract] & [0001]-[0002]),
The Examiner is combining Schulte in view of Grissom that validates that the exact same RF coil, which Vaugh establishes as the spatially inhomogeneous surface coil, is utilized to apply both the spatial encoding off-resonance pulse and the frequency-modulated excitation pulse ([0003] & [0044]).
wherein the off-resonance RF pulse ([0027]-[0028], [0033]-[0035], & [0052]: pulse transmitter 204 and Rf coil assembly 56) and the frequency-modulated, frequency-selective RF excitation pulse (Fig. 3; [0027]-[0030], & [0035]) are both applied using the RF coil (Figs. 1, 2, & 3; [0027]-[0037]: discloses utilizing the RF coil to transmit both the selective excitation pulses and the off-resonance pulses).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to configure the inhomogeneous surface coil systems of Schulte and Vaughn to transmit both the necessary pulses through a single RF coil which represents a substitution of known multi-purpose RF coil architectures. While the combination of Schulte and Vaughn discloses utilizing a spatially inhomogeneous RF coil, Grissom further provides applying both the off-resonance RF pulse and the frequency-modulated RF excitation pulse using the same RF coil. Grisson specifically teaches that “RF coils in such a system could be used for both spatial encoding, excitation and reception” within a single scan ([0044]). The benefit gained by consolidating both the frequency-modulated excitation and the off-resonance spatial encoding functions into the exact same RF coil is the elimination of conventional B0 gradient coils, which reduces scanner cost, hardware bulk, and acoustic noise. This combination yields the predictable variation of a streamlined MRI hardware architecture that executes complex spatial encoding without requiring additional specialize gradient hardware (KSR).
Regarding dependent claim 5, Schulte, teaches:
The method of claim 1 (Figs. 2 & 3; [Abstract], [0001]-[0002], [0006], [0028]-[0032] & [0043]),
Schulte, is silent in regard to:
wherein the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse are applied simultaneously.
However, Frydman, further teaches:
The Examiner is combining Schulte and Grissom in view of Frydman, applying the teachings of Frydman to the Schulte/Grissom system dictates that the frequency-modulated excitation pulse is delivered at the exact same time as the off-resonance spatial encoding pulse (Grissom: [0003]-[0004] & [0060]).
wherein the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse are applied simultaneously ([Abstract], [0008], & [0014]: teaches the timing relationship of applying the modulated excitation pulse “in unison” (synonymous with simultaneously) with the encoding fields).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to adapt the pulse sequence timing to feature the simultaneous delivery which represents the use of a known technique to improve similar devices. The combination of Schulte, Vaughn, and Grissom provides an off-resonance RF pulse and a frequency-modulated RF excitation pulse, but lacks applying these two simultaneously. Frydman teaches applying a phase and amplitude-modulated radiofrequency (RF) excitation pulse in unison (simultaneously) with the encoding magnetic fields. The problem being solved by this simultaneous application is the correction of spatial field distortions at the exact time of spatially-selective RF irradiation, ensuring that the spin’s phases and amplitudes remain independent of magnetic inhomogeneities. This yields the predictable variation of obtaining high-definition MRI spectra without spatial distortion in inhomogeneous environments (KSR).
Regarding dependent claim 6, Schulte, teaches:
The method of claim 1 (Fig. 3; [Abstract], [0001]-[0002], [0006], & [0043]), further comprising interleaving the off-resonance RF pulse, and the frequency-modulated, frequency-selective RF excitation pulse ([0029]-[0030] & [0034]-[0035]: establishes that the “selection of the linear projection” utilizes the selective excitation pulse, while the “RF pulse sequence” utilizes the off-resonance pulse, teaches that these two distinct pulses can be applied in an “interspersed” (i.e., interleaved manner rather than in discrete successive steps).
Regarding independent claim 9, Schulte, teaches:
A magnetic resonance imaging (MRI) system comprising (Fig. 1; [Abstract], [0001]-[0002], [0006], [0018], [0025], [0027], [0033], & [0038]: magnet assembly 52, polarizing magnet 54): a magnet system configured to generate a polarizing magnetic field about a portion of a subject positioned in the MRI system (Fig. 1; [Abstract], [0001]-[0002], [0006], [0018], [0025], [0027], & [0038]: magnet assembly 52, polarizing magnet 54, teaches a magnet assembly containing a polarizing magnet to generate the main B0 field);
a radio frequency (RF) system configured to deliver RF pulses to the subject, and acquire therefrom magnetic resonance image (MRI) data (Figs. 1 & 2; [0002], [0007], [0027]-[0029], [0035]-[0037]: RF coil 56, transceiver module 58, RF amplifier 60, preamplifier 64, RF pulse transmitter 204, RF signal receiver 206, discloses an RF system configured to deliver RF excitation pulses and acquire the resulting MRI signal data);
at least one processor configured to ([0007]-[0008] & [0025]-[0026]):
control the RF system to acquire the MRI data from the subject that is spatially encoded (Figs. 2 & 3; [0006], [0035]-[0036], [0038], [0043], & [0052]: RF pulse receiver, step 306); and
reconstruct the MRI data to produce a report of internal materials forming the subject (Figs. 2 & 3; [0006], [0035]-[0036], [0038], [0040], [0053]-[0054], & [0060]: step 308).
Schulte, is silent in regard to:
control the RF system to apply an off-resonance RF pulse using an RF coil of the RF system that is spatially inhomogeneous to induce a B1-dependent resonant frequency shift in spins in the subject;
However, Vaughn, further teaches:
The Examiner is combining Schulte in view of Vaughn, implementing Schulte’s processor controlling the off-resonance RF pulse to induce the B1-shift (Fig. 4; [0004], [0021], [0035], [0048], & [0057]).
control the RF system to apply an off-resonance RF pulse using an RF coil of the RF system that is spatially inhomogeneous to induce a B1-dependent resonant frequency shift in spins in the subject ([0282], [0285], & [0288]: while Schulte teaches the processor controlling the off-resonance RF pulse to induce the B1 shift, Vaughn provides the teaching to implement these pulses using spatially inhomogeneous radio-frequency coils (e.g., surface coils or arrays));
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to modify the MRI system of Schulte to utilize the spatially inhomogeneous surface coils of Vaughn to deliver the off-resonance pulses. Schulte discloses an MRI system comprising processors configure to apply off-resonance RF pulses to induce a B1-dependent resonance shift but lacks details on utilizing a spatially inhomogeneous radio-frequency coil to deliver these pulses. Vaughn teaches an MRI system utilizing spatially inhomogeneous radio-frequency coils, such as surface coils, because homogeneous coils cannot generate uniform B1 fields at high magnetic field strengths. The motivation for this modification is to maximize local signal-to-noise ratio (SNR) and limit specific absorption rate (SAR) losses when imaging targeted superficial anatomical regions of interest. This combination represents a substitution of one known coil element for another to yield the predictable variation of improved local imaging efficiency without exceeding safety guidelines (KSR).
Schulte, in combination with Vaughn, are silent in regard to:
control the RF system to apply, simultaneously with the off-resonance RF pulse, a frequency-modulated, frequency-selective RF excitation pulse to spatially encode the spins in the subject;
However, Frydman, further teaches:
The Examiner is combining Schulte and Vaughn in view of Grissom that provides the processor logic for a frequency-modulated, frequency-selective excitation pulse specifically for RF spatial encoding ([0003]-[0004] & [0060]).
control the RF system to apply, simultaneously with the off-resonance RF pulse, a frequency-modulated, frequency-selective RF excitation pulse to spatially encode the spins in the subject ([Abstract], [0008], & [0014]: Grissom provides the processor logic for a frequency-modulated, frequency-selective excitation pulse specifically for RF spatial encoding. Frydman teaches configuring the processor to apply this modulated excitation pulse “in unison” (simultaneously) with the encoding fields);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to modify the processor instructions of the combined Schulte and Vaughn MRI system to include the simultaneous frequency-modulated spatial encoding RF excitation pulses taught by Grissom and Frydman, representing the application of known techniques to improve similar devices. The combination of Schulte and Vaughn discloses an MRI system controlling off-resonance RF pulses via inhomogeneous coils, but lacks applying a frequency-modulated, frequency-selective RF excitation pulse to spatially encode the spins simultaneously with the off-resonance pulse. Grissom teaches configuring a processor to apply an RF frequency modulation waveform comprising a frequency-selective excitation pulse to provide spatial encoding via RF gradient fields instead of conventional B0 gradients, which solves the problem of high scanner cost, bulk, acoustic noise, and peripheral nerve stimulation. Frydman further teaches applying a phase and amplitude-modulated radio frequency excitation pulse in unison (simultaneously) with encoding magnetic fields to immediately correct for spatial field distortions at the exact time of spatially-selective RF irradiation. The motivation to combine to incorporate Grissom’s RF-based spatial encoding is to eliminate conventional B0 gradients, significantly reducing scanner cost, hardware bulk, acoustic noise, and peripheral nerve stimulation, whereas the motivation to simultaneously apply this excitation with the off-resonance pulse is to immediately correct spatial distortions at the exact time of irradiation, ensuring the spins’ phases remain independent of magnetic inhomogeneities. This combination represents the use of known techniques to improve similar devices, yielding the predictable variation of a high-field MRI system capable of executing spatial encoding without relying on conventional gradient hardware, while obtaining high-definition MRI spectra without spatial distortion, and maximizing patient comfort in inhomogeneous magnetic environments (KSR).
Regarding dependent claim 10, Schulte, teaches:
The system of claim 9 (Fig. 1; [Abstract], [0001]-[0002], & [0006]), wherein the report includes at least one of an image of the subject ([Abstract], [0002], [0006]-[0007], [0023], [0038]-[0039], [0052], [0055], & [0060]), a map of the subject (Fig. 3; [0002], [0004], [0006], [0023], [0038]-[0039], & [0052]: 308), or a quantitative measure of function ([0060]: calculation of permittivity or conductivity is a quantitative measure of the electrical function of the internal tissues) or the report of the internal materials of the subject ([0002], [0038], [0052], [0058], & [0060]: method uses NMR of atoms of certain elements to generate MRI images, the map is used for image reconstruction for visualization of the body (internal materials)).
Regarding dependent claim 11, Schulte, teaches:
The system of claim 9 (Fig. 1; [Abstract], [0001]-[0002], & [0006]), wherein the off-resonance RF pulse produces a Bloch-Siegert shift ([0021], [0035], & [0052]).
Regarding dependent claim 12, Schulte, teaches:
The system of claim 9 (Fig. 1; [Abstract], [0001]-[0002], & [0006]),
The Examiner is combining Schulte in view of Grissom that validates that the exact same RF coil, which Vaugh establishes as the spatially inhomogeneous surface coil, is configured by the system to apply both the spatial encoding off-resonance pulse and the frequency-modulated excitation pulse ([0003] & [0044]).
wherein the off-resonance RF pulse ([0027]-[0028], [0033]-[0035], & [0052]: pulse transmitter 204 and Rf coil assembly 56) and the frequency-modulated, frequency-selective RF excitation pulse (Fig. 3; [0027]-[0030], & [0035]) are both applied using the RF coil (Figs. 1, 2, & 3; [0027]-[0037]: discloses utilizing the RF coil to transmit both the selective excitation pulses and the off-resonance pulses).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to configure the MRI system of Schulte and Vaughn to apply both the excitation and off-resonance pulses using the same RF coil as taught by Grissom. The combination of Schulte and Vaughn discloses an MRI system with processors controlling off-resonance pulses via inhomogeneous RF coils but does not detail the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse are both applied using the same RF coil. Grisson specifically teaches applying both the frequency-modulated excitation pulse and the spatial encoding pulse using the same RF coil, noting that “RF coils in such a system could be used for both spatial encoding, excitation and reception” within a single scan ([0044]). The benefit gained by configuring the system to consolidate the transmission of both the excitation and off-resonance spatial encoding pulses into a single RF coil is the elimination of conventional B0 gradient coils, which reduces scanner cost, hardware bulk, and acoustic noise. This modification represents a substitution of known multi-purpose RF coil architectures to yield the predictable variation of a streamlined MRI hardware architecture that executes complex spatial encoding without requiring additional specialize gradient hardware (KSR).
Regarding dependent claim 13, Schulte, teaches:
The system of claim 9 (Fig. 1; [Abstract], [0001]-[0002], & [0006]), wherein the at least one processor ([0007]-[0008] & [0025]-[0026]) is further programmed (Fig. 3; [0025]-[0026], & [0041]) to
Schulte, is silent in regard to:
simultaneously apply the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse.
However, Frydman, further teaches:
The Examiner is combining Schulte in view of Frydman, applying Schultes processors used to execute the instructions for the MRI pulse sequence ([0025]-[0026]) and applying the teachings of Frydman to the Schulte/Grissom system which dictates that the frequency-modulated excitation pulse is delivered at the exact same time as the off-resonance spatial encoding pulse ([0003]-[0004] & [0060]).
simultaneously apply the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse ([Abstract], [0008], & [0014]: provides the specific instruction executed by the processor, applying the modulated excitation pulse “in unison” (simultaneously) with the encoding fields, integrating this logic into the Schulte/Grissom system dictates that the processor is programmed to deliver the frequency-modulated excitation pulse at the exact same time as the off-resonance spatial encoding pulse).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to modify the processor instructions of the combined Schulte, Vaughn, and Grissom MRI system to simultaneously apply these pulses as taught by Frydman represents the use of a known technique to improve similar devices. The combination of Schulte, Vaughn, and Grissom provides an MRI system having a processor, configured to apply an off-resonance RF pulse and a frequency-modulated RF excitation pulse, but lacks the specific instruction wherein at least one processor is further programmed to simultaneously apply the off-resonance pulse and the frequency-modulated, frequency-selective RF excitation pulse. Frydman teaches configuring an MRI system’s control means to apply a phase and amplitude-modulated radiofrequency (RF) excitation pulse in unison (simultaneously) with the magnetic field gradient and encoding magnetic pulses to provide spins with a homogeneous excitation profile. The benefit gained by programming the processor to ensure this simultaneous application is the correction of spatial field distortions at the exact time of spatially-selective RF irradiation, ensuring that the spin’s phases and amplitudes remain independent of magnetic inhomogeneities. Modifying the processor instructions of the combined Schulte, Vaughn, and Grissom MRI system to simultaneously apply these pulses as taught by Frydman represents the use of a known technique to improve similar devices. This combination yields the predictable variation of obtaining high-definition MRI spectra without spatial distortion in inhomogeneous magnetic environments (KSR).
Regarding dependent claim 14, Schulte, teaches:
The system of claim 9 (Fig. 1; [Abstract], [0001]-[0002], & [0006]), wherein the at least one processor ([0007]-[0008] & [0025]-[0026]) is further programmed to simultaneously apply the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse ([0025]-[0026], [0029]-[0030], & [0034]-[0035]: discloses an MRI system with processors configured to control the pulse sequences, establishes that the “selection of the linear projection” utilizes the selective excitation pulse, while the “RF pulse sequence” utilizes the off-resonance pulse, and teaches programming the system to apply these two distinct pulses in an “interspersed” (i.e., interleaved) manner rather than in discrete successive steps).
Regarding independent claim 15, Schulte, teaches:
A method for generating images or maps of a subject using a nuclear magnetic resonance (NMR) system (Fig. 1; [Abstract], [0001]-[0002], & [0006]), the method including steps comprising (Fig. 1; [Abstract], [0001]-[0004], & [0006]):
acquiring NMR data from the subject that is spatially encoded ([0036]: discloses acquiring the spatially encoded NMR data); and
reconstructing the NMR data to produce the images or maps of the subject (Figs. 2 & 3; [0006], [0035]-[0036], [0038], [0040], [0053]-[0053], & [0060]: step 308).
Schulte, is silent in regard to:
applying an off-resonance radio frequency (RF) pulse using a radio-frequency coil that is spatially inhomogeneous to induce a B1-dependent resonant frequency shift in spins in a subject;
However, Vaughn, further teaches:
The Examiner is combining Schulte in view of Vaughn by implementing the teaching of the off-resonance RF pulse to induce the B1-dependent shift of Schulte (Fig. 4; [0004], [0021], [0035], [0048], & [0057]).
applying an off-resonance radio frequency (RF) pulse using a radio-frequency coil that is spatially inhomogeneous to induce a B1-dependent resonant frequency shift in spins in a subject ([0282], [0285], & [0288]: while Schulte teaches the off-resonance RF pulse to induce the B1-dependent shift, Vaughn provides the teaching and motivation to use spatially inhomogeneous radio-frequency coils (e.g., surface coils or arrays) for these pulses at high fields);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to modify the MRI system of Schulte to utilize the spatially inhomogeneous surface coils taught by Vaughn to deliver the off-resonance pulses. Schulte discloses applying an off-resonance RF pulse to induce a B1-dependent resonant frequency shift but lacks details on utilizing a spatially inhomogeneous radio-frequency coil. Vaughn teaches applying an MRI system utilizing spatially inhomogeneous radio-frequency coils, such as surface coils, because homogenous coils cannot generate uniform B1 fields at high magnetic field strengths. The motivation for this modification is to maximize local signal-to-noise ratio (SNR) and limit specific absorption rate (SAR) losses when imaging targeted superficial anatomical regions of interest. This combination represents a substitution of one known coil element for another to yield the predictable variation of improved local imaging efficiency without exceeding safety guidelines (KSR).
Schulte, in combination with Vaughn, are silent in regard to:
simultaneously with the off-resonance RF pulse, applying a frequency selective RF excitation pulse that is frequency modulated to correspond to a B1 of interest to spatially encode the spins in the subject;
However, Frydman, further teaches:
The Examiner is combining Schulte and Vaughn in view of Grissom that provides the excitation pulse that is frequency modulated to correspond to a specific B1 magnitude of interest for RF spatial encoding ([0003]-[0004] & [0060]).
simultaneously with the off-resonance RF pulse, applying a frequency selective RF excitation pulse that is frequency modulated to correspond to a B1 of interest to spatially encode the spins in the subject ([Abstract], [0008], & [0014]: Grissom provides the excitation pulse that is frequency modulated to correspond to a specific B1 magnitude of interest for spatial encoding while Frydman teaches applying this modulated excitation pulse “in unison” (simultaneously) with the encoding fields);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to modify the pulse sequence of the combined Schulte and Vaughn MRI system to include the simultaneous, frequency-modulated B1-selective spatial encoding RF excitation pulses taught by Grissom and Frydman, representing the application of known techniques to improve similar devices. The combination of Schulte and Vaughn discloses inducing a B1-dependent shift via inhomogeneous coils but lacks simultaneously applying a frequency-selective RF excitation pulse that is frequency modulated to correspond to a B1 of interest to spatially encode the spins in the subject. Grissom teaches applying an RF frequency modulation waveform that comprises a frequency-selective, [B1+]-selective excitation pulse configured to provide encoding based on RF gradient fields. Frydman further teaches applying a phase and amplitude-modulated radio frequency excitation pulse in unison (simultaneously) with the encoding magnetic fields to provide spins with a homogeneous excitation profile. The motivation to incorporate Grissom’s B1-selective RF spatial encoding is to eliminate conventional B0 gradients to reduce scanner cost, hardware bulk, and acoustic noise, while simultaneously applying this excitation as taught by Frydman provides the benefit of correcting spatial field distortions at the exact time of spatially-selective RF irradiation. This combination yields the predictable variation of a high-field MRI system capable of executing spatial encoding without relying on conventional gradient hardware, while obtaining high-definition maps without spatial distortion, and maximizing patient comfort in inhomogeneous magnetic environments (KSR).
Regarding dependent claim 16, Schulte, teaches:
The method of claim 15 (Figs. 1 & 2; [Abstract], [0001]-[0004], & [0006]),
The Examiner is combining Schulte in view of Grissom that validates that the exact same RF coil, which Vaugh establishes as the spatially inhomogeneous surface coil, is utilized to apply both the spatial encoding off-resonance pulse and the frequency-modulated excitation pulse ([0003] & [0044]).
wherein the off-resonance RF pulse ([0027]-[0028], [0034]-[0035], & [0052]: pulse transmitter 204 and Rf coil assembly 56) and the frequency-modulated, frequency-selective RF excitation pulse (Fig. 3; [0027]-[0030] & [0035]) are both applied using the RF coil (Figs. 1, 2, & 3; [0027]-[0037]: discloses utilizing the RF coil to transmit both the selective excitation pulses and the off-resonance pulses).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to execute the method of Schulte and Vaughn by applying both the excitation and off-resonance pulses using the same RF coil as taught by Grissom. The combination of Schulte and Vaughn discloses applying off-resonance pulses via inhomogeneous RF coils but does not detail the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse are both applied using the exact same RF coil. Grisson specifically teaches applying both the frequency-modulated excitation pulse and the spatial encoding pulse using the same RF coil, noting that “RF coils in such a system could be used for both spatial encoding, excitation and reception” within a single scan ([0044]). The benefit gained by consolidating the transmission of both the excitation and off-resonance spatial encoding pulses into a single RF coil is the complete elimination of conventional B0 gradient coils, which reduces scanner cost, hardware bulk, and acoustic noise. This modification represents a substitution of known multi-purpose RF coil architectures to yield the predictable variation of a streamlined MRI method that executes complex spatial encoding without requiring additional specialized gradient hardware (KSR).
Regarding dependent claim 17, Schulte, teaches:
The method of claim 15 (Figs. 1 & 2; [Abstract], [0001]-[0004], [0006]),
Schulte, is silent in regard to:
wherein the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse are applied simultaneously.
However, Frydman, further teaches:
The Examiner is combining Schulte and Grissom in view of Frydman, applying the teachings of Frydman to the Schulte/Grissom system dictates that the frequency-modulated excitation pulse is delivered at the exact same time as the off-resonance spatial encoding pulse (Grissom: [0003]-[0004] & [0060]).
wherein the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse are applied simultaneously ([Abstract], [0008], & [0014]: teaches the timing relationship of applying the modulated excitation pulse “in unison” (synonymous with simultaneously) with the encoding fields).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention was made to modify the pulse sequence timing of the combined Schulte, Vaughn, and Grisom method to simultaneously apply the frequency-modulated excitation pulse and the off-resonance spatial encoding pulse as taught by Frydman which represents the use of a known technique to improve similar methods. The combination of Schulte, Vaughn, and Grissom provides an MRI method of applying an off-resonance RF pulse and a frequency-modulated RF excitation pulse, but lacks applying the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse simultaneously. Frydman teaches a method of applying a phase and amplitude-modulated radiofrequency (RF) excitation pulse in unison (simultaneously) with the encoding magnetic fields to provide spins with a homogeneous excitation profile. The problem being solved by this simultaneous application is the correction of spatial field distortions at the exact time of spatially-selective RF irradiation, ensuring that the spin’s phases and signal amplitudes remain independent of magnetic inhomogeneities. This combination yields the predictable variation of obtaining high-definition MRI maps and images without spatial distortion in inhomogeneous magnetic environments (KSR).
Regarding dependent claim 18, Schulte, teaches:
The method of claim 15 (Figs. 1 & 2; [Abstract],[0001]-[0004], & [0006]), further comprising interleaving the off-resonance RF pulse, and the frequency-modulated, frequency-selective RF excitation pulse ([0029]-[0030] & [0034]-[0035]: establishes that the method utilizes a selective excitation pulse to perform the “selection of the linear projection” while the “RF pulse sequence” utilizes the off-resonance pulse, teaches that these two distinct pulses can be applied in an “interspersed” (i.e., interleaved) manner rather than in discrete successive steps).
Regarding dependent claim 20, Schulte, teaches:
The method of claim 15 (Figs. 1 & 2; [Abstract] & [0001]-[0004]), wherein the off-resonance RF pulse ([0004], [0021], [0035], & [0052])
Schulte, is silent in regard to:
indicates a flip angle other than 90 or 180 degrees to produce a range of inhomogeneous values of a B1 field within a selected region of the subject.
However, Vaughan, further teaches:
indicates a flip angle other than 90 or 180 degrees (Fig. A13 & B5; [0173], [0225], [0353]-[0354], [0356], [0413], [0421]-[0422], [0434], [0523], [0550]-[0551], & [0582]) to produce a range of inhomogeneous values of a B1 field within a selected region of the subject ([0031], [0039], [0065], [0096], [0111], [0151], [0155], [0159], [0163], [0167], [0191], [0213], [0255], [0264], [0282], [0313], [0320], [0324], [0330], [0343], [0369], [0409], [0433], & [0518]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate a flip angle other than 90 or 180 degrees to produce a range of inhomogeneous values of a B1 field within a selected region of the subject, of Vaughn to Schulte, in order to attain, and improve SB1 mapping accuracy and efficiency, by combining the teachings of Schulte and Vaughan, adopting a non-90° or non-180° flip angle for the off-resonance RF pulse of Schulte’s method, the modification would optimize signal conditions (e.g., in a non-linear optimization routine for B1 magnitude/phase control mentioned by Vaughan) to more effectively map the inhomogeneous range of B1 values within the selected region (linear projection), overcoming known problems of B1 inhomogeneity in high-field MRI, yielding expected predictable results (KSR).
Claims 7 & 21 are rejected under 35 U.S.C. 103 as being unpatentable over Schulte, in view of Vaughn, in view of Grissom, in view of Frydman, and further in view of Zhang et al. (US 2015/0226821 A1, Pub. Date Aug. 13, 2015, hereinafter, Zhang).
Regarding dependent claim 7, Schulte, teaches:
The method of claim 1 (Fig. 1; [Abstract], [0001]-[0002], [0006], & [0035]),
Schulte, is silent in regard to:
wherein the frequency-modulated, frequency selective RF excitation pulse is a frequency modulation waveform that is transformed into an amplitude modulation waveform using a variable-rate selective excitation (VERSE) to control distortions due to limited amplifier bandwidth.
However, Zhang, further discloses:
The Examiner is combining Schulte and Grissom in view of Zhang, implementing “the algorithm of the various embodiments directly designs an RF frequency modulation waveform…that is paired with an amplitude and sign modulation waveform” of Grissom ([0060]).
wherein the frequency-modulated, frequency selective RF excitation pulse is a frequency modulation waveform ([Abstract], [0016]-[0018], [0024],[0026], [0034], & [0061]) that is transformed into an amplitude modulation waveform using a variable-rate selective excitation (VERSE) (Figs. 1A & 1B; [0013], [0017], [0026], [0031], [0059], & [0061]-[0062]: figures both illustrated “FM” (frequency modulation) waveforms as part of the pulse sequence, alongside AM (amplitude modulation waveforms and a time-varying gradient G) to control distortions due to limited amplifier bandwidth ([0013], [0017], [0026], [0031], [0059], & [0061]-[0062]: teaches the variable-rate selective excitation (VERSE) technique can be applied to modify the RF pattern with required excitation profile, method is used in conjunction with frequency-swept RF excitation to achieve pulse flexibility and control pulse shapes).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the VERSE transformation taught by Zhang to the paired frequency and amplitude-modulated excitation pulses of the combined prior art, representing the application of a known technique to improve similar devices. The combination of Schulte, Vaughn, Grissom, and Frydman discloses applying a simultaneous frequency-modulated RF excitation pulse but does not detail that the frequency modulation waveform is transformed into an amplitude modulation waveform using a variable-rate selective excitation (VERSE) to control distortions due to limited amplifier bandwidth. Zhang teaches transforming an RF frequency modulation waveform into an amplitude modulation waveform by applying a variable-rate selective excitation (VERSE) implementation to modify the RF pattern to maintain a required profile without distortions. Zhang further teaches that utilizing these gradient-modulated RF pulse transformations solves the problem of reaching peak power limitations of the hardware when a high excitation bandwidth is required. The motivation for this combination is to overcome peak RF amplifier power limitations and support high excitation bandwidths while preventing profile distortions, yielding the predictable variation of efficient, artifact-free spatial encoding at high magnetic field strengths (KSR).
Regarding dependent claim 21, Schulte, teaches:
The method of claim 20 (Figs. 1 & 2; [Abstract], [0001]-[0004], [0006], [0021], [0036], & [0038]),
The Examiner is combining Schulte in view of Zhang, implementing the teaching of transforming the RF pulse to maintain a “flat excitation profile,” meaning the flip angle is kept constant (minimal variation) across the region. By applying a flat excitation profile to a region where the B1 field is mapped via its shifting resonance, the variation of the flip angle is mathematically and physically constrained to be less than the variation of the B1-dependent resonant frequency shift ([0026], [0029], & [0031]).
wherein a variation of the flip angle is less than a variation of the B1-dependent resonant frequency shift in the region ([0021], [0036], & [0038]: relies on the B1-dependent resonant frequency shift varying across the region to accurately map the inhomogeneous B1 field strength at various points).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the combined method to incorporate the flat excitation profile transformations taught by Zhang, representing the application of a known technique to improve similar devices. The combination of Schulte, Vaughn, Grissom, and Frydman discloses applying an off-resonance pulse to induce a spatially varying B1-dependent shift but lacks that the variation of the flip angle is less than the variation of this B1-dependent resonant frequency shift in the region. Zhang teaches transforming the RF excitation pulse modulations (using techniques like VERSE or GOIA) to generate a “flat excitation profile,” which minimizes the variation of the flip angle across the targeted region. The problem being solved by generating the flat excitation profile is the elimination of signal distortions caused by hardware bandwidth limitations and B1 non-uniformities, ensuring consistent transverse magnetization across the targeted anatomy. This combination yields the predictable variation of a uniform flip angle that varies significantly less than the intentionally induced spatially varying B1-dependent Bloch-Siegert shift, allowing accurate mapping of the inhomogeneous magnetic environment without generating unwanted excitation artifacts (KSR).
Claims 8 & 19 are rejected under 35 U.S.C. 103 as being unpatentable over Schulte, in view of Vaughn, in view of Grissom, in view of Frydman, and further in view of Alsop (US 2016/0041246 A1, Pub. Feb. 11, 2016, hereinafter, Alsop).
Regarding dependent claim 8, Schulte, teaches:
The method of claim 1 (Figs. 1 & 3; [Abstract] & [0001]-[0002], [0006], [0025]-[0027][0035]),
Schulte, is silent in regard to:
wherein the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse are superimposed
that is dependent on a frequency modulation of both the off-resonance RF pulse and the frequency-modulated, frequency selective RF excitation pulse.
However, Alsop, further discloses:
wherein the off-resonance RF pulse ([0011] & [0041]: discloses applying saturation pulses which are off-resonance) and the frequency-modulated, frequency-selective RF excitation pulse ([0029]-[0030], [0041]-[0042], & [0045]-[0046]) are superimposed (Fig. 2; [0047]-[0049]: teaches superimposing multiple frequencies into a single RF pulse structure by modulating the RF pulse to produce power at multiple frequency bands simultaneously)
The Examiner is combining Schulte in view Grissom and Alsop, by implementing Alsop’s “amplitude modulation generating a frequency response with components at +ω and - ω” of Grissom ([0060], Alsop and Grissom collectively demonstrate that when the multiple bands are superimposed into a single modulated pulse, the resulting excitation field generated in the subject is dependent on the combined frequency and amplitude modulations of both the off-resonance and excitation components).
that is dependent on a frequency modulation ([0011], [0018]-[0019], [0021]-[0022], [0025], [0029]-[0030], [0039], & [0046]-[0047]) of both the off-resonance RF pulse and the frequency-modulated, frequency selective RF excitation pulse (Fig. 2; [0011], [0030], [0041]-[0042], & [0046]-[0047]: teaches a method to apply multi-frequency saturation using a single, modulated pulse).
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It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to superimpose the simultaneous off-resonance and B1-selective excitation RF pulses of Grissom and Frydman into a single frequency-modulated waveform as taught by Alsop. The combination of Schulte, Vaughn, Grissom, and Frydman, teaches simultaneously applying an off-resonance RF pulse and a frequency-modulated RF excitation pulse, but lacks superimposing them to produce a selective B1 excitation dependent on a frequency modulation of both pulses. Alsop teaches that the simultaneous application of power at multiple RF frequencies can be achieved by superimposing them into a single modulated RF pulse, such that the excitation includes multiple frequency bands and generates a frequency response dependent on the combined modulations of both components. The benefit gained by superimposing these distinct RF frequency bands into a single modulated pulse is the ability to efficiently deliver power at both frequencies simultaneously while keeping the overall pulse bandwidth narrow and maintaining the desired power levels. This combination constitutes a substitution of one known RF transmission technique for another to yield the predictable variation of a streamlined consolidated RF pulse that efficiently produces a selective B1 excitation profile without requiring multiple overlapping RF transmission hardware channels (KSR).
Schulte, and Alsop, are silent in regard to:
to produce a selective B1 excitation in the subject
However, Grissom, further discloses:
to produce a selective B1 excitation in the subject ([0003] & [0060]: establishes that combining and modulating these RF waveforms produces a selective B1 excitation profile in the subject)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the frequency-modulated, B1-selective RF excitation pulse taught by Grissom into the inhomogeneous high-field MRI system of Schulte and Vaughn. The base combination of Schulte and Vaughn discloses applying off-resonance pulses via inhomogeneous coils but does not detail producing a selective B1 excitation in the subject that is dependent on a frequency modulation of the RF excitation pulse. Grissom teaches designing an RF frequency modulation waveform to comprise a frequency-selective B1 selective excitation pulse. The benefit gained by utilizing this frequency-modulated, B1-selective excitation is the ability to perform spatial encoding using RF gradients instead of conventional B0 gradients, which reduces the scanner cost, hardware bulk, and patient discomfort from acoustic noise and peripheral nerve stimulation. This combination represents a substitution of known spatial encoding techniques to yield the predictable variation of an efficient MRI architecture capable of spatial encoding without relying on conventional gradient hardware (KSR).
Regarding dependent claim 19, Schulte, teaches:
The method of claim 15 (Figs. 1 & 2; [Abstract], [0001]-[0004], & [0006]),
Schulte, is silent in regard to:
wherein the off-resonance RF pulse and the frequency-modulated, frequency-selective RF excitation pulse are superimposed
that is dependent on a frequency modulation of both the off-resonance RF pulse and the frequency-modulated, frequency selective RF excitation pulse.
However, Alsop, further discloses:
wherein the off-resonance RF pulse ([0011] & [0041]: discloses applying saturation pulses which are off-resonance) and the frequency-modulated, frequency-selective RF excitation pulse ([0029]-[0030], [0041]-[0042], & [0045]-[0046]) are superimposed (Fig. 2; [0047]-[0049]: teaches superimposing multiple frequencies into a single RF pulse structure by modulating the RF pulse to produce power at multiple frequency bands simultaneously)
The Examiner is combining Schulte in view Grissom and Alsop, by implementing Alsop’s “amplitude modulation generating a frequency response with components at +ω and - ω” of Grissom ([0060], Alsop and Grissom collectively demonstrate that when the multiple RF bands are superimposed into a single modulated pulse, the resulting excitation field generated in the subject is dependent on the combined frequency and amplitude modulations of both the off-resonance and excitation components).
that is dependent on a frequency modulation ([0011], [0018]-[0019], [0021]-[0022], [0025], [0029]-[0030], [0039], & [0046]-[0047]) of both the off-resonance RF pulse and the frequency-modulated, frequency selective RF excitation pulse (Fig. 2; [0011], [0030], [0041]-[0042], & [0046]-[0047]: teaches a method to apply multi-frequency saturation using a single, modulated pulse).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to superimpose the simultaneous off-resonance and B1-selective excitation RF pulses of Grissom and Frydman into a single frequency-modulated waveform as taught by Alsop. The combination of Schulte, Vaughn, Grissom, and Frydman, teaches simultaneously applying an off-resonance RF pulse and a frequency-modulated RF excitation pulse, but lacks superimposing them to produce a selective B1 excitation dependent on a frequency modulation of both pulses. Alsop teaches that the simultaneous application of power at multiple RF frequencies can be achieved by superimposing them into a single modulated RF pulse, such that the excitation includes multiple frequency bands and generates a frequency response dependent on the combined modulations of both components. The benefit gained by superimposing these distinct RF frequency bands into a single modulated pulse is the ability to efficiently deliver power at both frequencies simultaneously while keeping the overall pulse bandwidth narrow and maintaining the desired power levels. This combination constitutes a substitution of one known RF transmission technique for another to yield the predictable variation of a streamlined consolidated RF pulse that efficiently produces a selective B1 excitation profile without requiring multiple overlapping RF transmission hardware channels (KSR).
Schulte, and Alsop, are silent in regard to:
to produce a selective B1 excitation in the subject
However, Grissom, further teaches:
to produce a selective B1 excitation in the subject ([0003] & [0060]: establishes that combining and modulating these RF waveforms produces a selective B1 excitation profile in the subject)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the method of applying a frequency-modulated, B1-selective RF excitation pulse taught by Grissom into the inhomogeneous high-field MRI method of Schulte and Vaughn. The base combination of Schulte and Vaughn discloses a method of applying off-resonance pulses via inhomogeneous coils but does not detail applying a frequency selective RF excitation pulse that is frequency modulated to correspond to a B1 of interest to spatially encode the spins in the subject. Grissom teaches a method of designing and applying an RF frequency modulation waveform that is paired with an amplitude modulation waveform to comprise a frequency-selective, [B1+]-selective excitation pulse that is tailored to provide spatial encoding. The benefit gained by utilizing this frequency-modulated, B1-selective excitation method is the ability to perform spatial encoding using RF gradients instead of conventional B0 gradients, which reduces the scanner cost, hardware bulk, and patient discomfort from acoustic noise and peripheral nerve stimulation. This combination represents a substitution of known spatial encoding techniques to yield the predictable variation of an efficient MRI method capable of spatial encoding without relying on conventional gradient hardware (KSR).
Conclusion
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/HUGO NAVARRO/ Examiner, Art Unit 2858 September 15, 2026
/A.A/Primary Examiner, Art Unit 2858
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