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 .
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 .
Claim Status
Claims 1-15 are currently pending in the application filed 10/08/2024
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 10/08/2024 and 09/05/2025 have been considered by the Examiner.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 1 and its dependents is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
The term “as many times as necessary” in claim 1 is a relative term which renders the claim indefinite. The term “as many times as necessary” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. Specifically, the number of repetitions of the basic sequence is rendered indefinite because the claim does not specify how many times the basic sequence must be repeated, nor does it provide a clear standard for determining when sufficient repetitions have been performed. The phrase "as many times as necessary" is subjective and leaves it unclear what quantity of repetitions falls within or outside the scope of the claim.
Claim Rejections - 35 USC § 103
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 6–8, 10-15 are rejected under 35 U.S.C. 103 as being unpatentable by Liu et al., “A low-cost and shielding-free ultra-low-field brain MRI scanner,” Nature Communications 12:7238 (2021) (“Liu”).
Regarding claim 1, (Liu) teaches:
A method for imaging a body using an MRI device,
(Liu, [page 2]; “we report the development and initial clinical demonstration of a permanent magnet-based, low-cost, low-power, and shielding-free brain ULF MRI scanner.”).
Examiner Note: ULF MRI scanner equates to the claimed MRI device.
the method implementing a basic sequence of a repetition time TR that comprises:
(Liu, [page 4, Fig. 2b caption]; “Within each time of repetition (TR), data are acquired simultaneously by both MRI receive coil and EMI sensing coils.”).
generating at least one echo signal over an echo time range PE (Liu, [page 12, Methods]; "3D fast spin echo (FSE; TR/TE = 1500/202 ms, FA = 90/180°, echo train length ETL = 21).") by subjecting the body positioned in an examination volume of the MRI device to a sequence of RF pulses produced by (Liu, [page 12, Methods]; "Separate transmit and receive coils were employed. The RF transmit coil had a solenoid structure.") an RF coil and to magnetic field gradients produced by gradient coils; (Liu, [page 11, Methods]; "The target field method based on the equivalent magnetic dipole approach was utilized to design the Gx, Gy, and Gz gradient coils.")
Examiner Note: The applicant's specification at [0097] describes the claimed echo signals as "spin echo signals SiE" that "occur at specific times, known as echo times TE" and are "spread over the PE echo time range." Liu's FSE sequence operates with FA = 90/180 degrees, meaning a 90 degree excitation pulse is applied to the body followed by 180 degree rephasing pulses that produce spin echo signals. Liu's ETL of 21 means 21 spin echoes are generated per TR, each at a specific echo time and read out over a time window that reads on the claimed "echo time range PE." Liu's "RF transmit coil" produces the RF pulses and Liu's "Gx, Gy, and Gz gradient coils" produce the magnetic field gradients used to spatially encode the body. A person of ordinary skill in MRI would have recognized Liu's FSE spin echoes as the claimed "at least one echo signal" generated by subjecting the body to RF pulses and gradient fields.
performing an echo measurement (Liu, [page 12, Methods]; the conventional MRI signal acquisition.") of the at least one echo signal (Liu, [page 12, Methods]; "3D fast spin echo ") by the RF coil (Liu, [page 12, Methods]; "the main MRI receive coil"); and
(Liu, [page 12, Methods]; "the main MRI receive coil and EMI sensing coils were used to simultaneously sample data within two windows, one was for the conventional MRI signal acquisition.")
(Liu, [page 4, Fig. 2b caption]; "Within each time of repetition (TR), data are acquired simultaneously by both MRI receive coil and EMI sensing coils across within two windows—the conventional MRI signal acquisition window and the EMI signal characterization window.")
Examiner Note: Under the broadest reasonable interpretation, the applicant's specification at paragraph [0096] defines echo measurement as the RF coil collecting the echo signal through activation of an analog-to-digital converter. Liu's "main MRI receive coil" reads on the claimed "RF coil," and Liu's sampling of data during the "conventional MRI signal acquisition" window reads on the claimed "performing an echo measurement of the at least one echo signal." The MRI receive coil detects the spin echo signals generated by the FSE sequence during this acquisition window, which is the echo measurement.
performing a background measurement (Liu, [page 12, Methods]; " EMI characterization data"), by the RF coil (Liu, [page 12, Methods]; "the main MRI receive coil");, over a background time range PF (Liu, [page 4, Fig. 2b caption]; "the conventional MRI signal acquisition window and the EMI signal characterization window.") distinct from the echo range PE and representative of a background signal;
(Liu, [page 4, Fig. 2b caption]; "Within each time of repetition (TR), data are acquired simultaneously by both MRI receive coil and EMI sensing coils across within two windows—the conventional MRI signal acquisition window and the EMI signal characterization window. Note that MRI signal is zero within EMI signal characterization window.")
(Liu, [page 12, Methods]; "the main MRI receive coil and EMI sensing coils were used to simultaneously sample data within two windows, one was for the conventional MRI signal acquisition, the other was chosen for acquiring the EMI characterization data in absence of any MRI signals (i.e., EMI signals only).")
Examiner Note: The applicant's specification at [0100] defines the background time range PF as a time range that does "not overlap" with the echo time range PE, enabling the RF coil to measure "only the environmental signal, devoid of any spin echo likely to originate from the body." Liu discloses two windows within each TR: the "conventional MRI signal acquisition window" (reads on echo time range PE) and the "EMI signal characterization window" (reads on background time range PF). Liu states "MRI signal is zero within EMI signal characterization window" and that EMI characterization data is acquired "in absence of any MRI signals (i.e., EMI signals only)," confirming the two windows are temporally separate and do not overlap. The EMI-only data collected during the characterization window reads on data "representative of a background signal." A person of ordinary skill in MRI would have recognized Liu's two non-overlapping acquisition windows as the claimed distinct echo range PE and background time range PF.
a) repeating the basic sequence as many times as necessary to form, in Fourier space, a Fourier image of the body from the echo signals and a Fourier image of the background from the background measurements; and
(Liu, [page 12, Methods]; "All image reconstruction procedures above were based on Fourier transform of fully sampled data.")
(Liu, [page 12, Methods]; "the main MRI receive coil and EMI sensing coils were used to simultaneously sample data within two windows, one was for the conventional MRI signal acquisition, the other was chosen for acquiring the EMI characterization data in absence of any MRI signals.")
(Liu, [page 4, Fig. 2d caption]; "This procedure is repeated for all individual FE lines.")
Examiner Note: Liu's "k-space" filled by "Fourier transform of fully sampled data" is related to the claimed "Fourier space." Each "FE line" (frequency encoding line) equates to one Fourier-encoded line in k-space. The procedure "repeated for all individual FE lines" equates to the claimed "repeating the basic sequence as many times as necessary." Within each TR, the receive coil samples two datasets (background measurements): MRI signal acquisition data fills k-space as the Fourier image of the body, and EMI characterization data (acquired "in absence of any MRI signals") fills a separate k-space dataset as the Fourier image of the background.
b) a step for processing either the Fourier image of the body and the Fourier image of the background, or the echo signals and the background signals,
(Liu, [page 4]; "This predicted EMI signal component was subsequently subtracted or removed from the MRI receive coil signals, creating EMI-free k-space data prior to image reconstruction.")
Examiner Note: Liu processes the echo signals (MRI receive coil signals) and the background signals (predicted EMI component) by subtracting the EMI from the echo data in k-space. This follows the second claimed alternative: processing "the echo signals and the background signals."
so as to obtain an image of the body in real space,
(Liu, [page 12, Methods]; "All image reconstruction procedures above were based on Fourier transform of fully sampled data. All images were reconstructed to 1 × 1 × 5 mm3 display resolution by applying zero padding in k-space.")
Examiner Note: Liu's "Fourier transform" based "image reconstruction" converts the EMI-free k-space data into spatial images at "1 x 1 x 5 mm3 display resolution." The reconstructed spatial image equates to the claimed "image of the body in real space."
wherein a signature of the background signal(s) is reduced or even eliminated.
(Liu, [page 4]; "the procedure provided a nearly complete removal of EMI noise in the images, with final image noise levels as low as those obtained using the RF shielding cage (within 5% range).")
Examiner Note: Liu's "nearly complete removal of EMI noise" with noise levels "within 5% range" of a shielded system equates to the claimed "signature of the background signal(s) is reduced or even eliminated."
Examiner Note: Liu's processing follows the second claimed alternative of processing "the echo signals and the background signals." Liu predicts the EMI component from the background data and subtracts it from the MRI receive coil signals, "creating EMI-free k-space data prior to image reconstruction." Liu then reconstructs images based on "Fourier transform of fully sampled data" at "1 x 1 x 5 mm3 display resolution," which reads on the claimed "obtain an image of the body in real space." Liu achieves "nearly complete removal of EMI noise in the images, with final image noise levels as low as those obtained using the RF shielding cage (within 5% range)," which reads on the claimed background signal signature being "reduced or even eliminated." A person of ordinary skill would have understood that Liu's EMI subtraction in k-space followed by Fourier transform reconstruction produces a real-space body image with the background noise signature substantially eliminated.
While Liu does teach acquiring both echo data and background (EMI) data through the same MRI receive coil in two separate time windows within each TR, and teaches removing the background noise to reconstruct real-space images, Liu does not explicitly teach using the receive coil's own background measurements to form a separate background dataset in Fourier space and directly processing it against the body dataset to remove the background signature. Instead, Liu uses the background data along with ten auxiliary EMI sensing coils to train a CNN that predicts and removes the noise. However, it would have been obvious to have done so. The reason is Liu's receive coil already collects background-only data ("EMI signals only") during the EMI characterization window for every frequency encoding line across all TRs (Liu, [page 12, Methods]; "the main MRI receive coil and EMI sensing coils were used to simultaneously sample data within two windows, one was for the conventional MRI signal acquisition, the other was chosen for acquiring the EMI characterization data in absence of any MRI signals (i.e., EMI signals only)"), so the receive coil already has all the data needed to build a background Fourier image on its own. A person of ordinary skill would have recognized that these two paired datasets from the same coil (echo and background) could be directly processed together using known techniques to remove the background, as a simpler alternative to Liu's CNN approach. Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date to form both a body and background Fourier image from the RF coil's measurements and process them to obtain a clean real-space image, because Liu's dual-window acquisition already provides the paired data and directly processing it achieves the same noise removal result without the added complexity of auxiliary sensing coils and CNN training.
Regarding claim 6, (Liu) teaches:
wherein the generating of the at least one echo signal comprises implementing an initial electromagnetic pulse
(Liu, [page 12, Methods]; "3D fast spin echo (FSE; TR/TE = 1500/202 ms, FA = 90/180°, echo train length ETL = 21).")
Examiner Note: In Liu's FSE sequence, the first pulse applied is the 90 degree excitation pulse. This 90 degree pulse = the claimed "initial electromagnetic pulse." It is "initial" because it comes first, before the 180 degree rephasing pulses.
orthogonal to a permanent magnetic field B0
(Liu, [page 3]; "The system was based on a compact two-pole 0.055 T permanent samarium-cobalt (SmCo) magnet.")
Examiner Note: Liu's "0.055 T permanent samarium-cobalt (SmCo) magnet" = the claimed "permanent magnetic field B0." A 90 degree flip angle means the RF pulse tips the magnetization into a plane perpendicular to B0. By definition in MRI, a 90 degree pulse is orthogonal to B0.
imposed on the body located in the examination volume of the MRI device
(Liu, [page 3]; "The system was based on a compact two-pole 0.055 T permanent samarium-cobalt (SmCo) magnet with front opening of 29 cm height and 70 cm width for patient chest and shoulder access.")
Examiner Note: Liu's magnet imposes 0.055 T on the patient positioned in the scanner opening. The scanner opening = the claimed "examination volume."
during the repetition of the basic sequence.
(Liu, [page 4, Fig. 2b caption]; "Within each time of repetition (TR), data are acquired simultaneously by both MRI receive coil and EMI sensing coils.")
Examiner Note: The 90 degree excitation pulse occurs at the start of each TR. Each TR = one repetition of the claimed "basic sequence."
Examiner Note: The applicant's specification at [0071] describes the magnet as "a permanent magnet" and [0076] gives example field amplitudes "less than 0.1 Tesla." Liu's "0.055 T permanent samarium-cobalt (SmCo) magnet" reads on the claimed "permanent magnetic field B0 imposed on the body." Liu's FSE sequence uses FA = 90/180 degrees, where the 90 degree excitation pulse is applied first. In MRI, a 90 degree flip angle means the RF pulse tips the magnetization into a plane perpendicular to B0, which reads on the claimed "initial electromagnetic pulse, orthogonal to a permanent magnetic field B0." This pulse occurs at the start of each TR, reading on "during the repetition of the basic sequence." A person of ordinary skill in MRI would have recognized that Liu's 90 degree excitation pulse is inherently orthogonal to the permanent B0 field by definition of the flip angle.
Regarding claim 7, (Liu) teaches:
wherein the initial electromagnetic pulse is followed by at least one electromagnetic rephasing pulse
(Liu, [page 12, Methods]; "3D fast spin echo (FSE; TR/TE = 1500/202 ms, FA = 90/180°, echo train length ETL = 21).")
Examiner Note: In Liu's FSE, the initial 90 degree pulse is followed by 180 degree pulses. Each 180 degree pulse refocuses the magnetization to produce a spin echo. Liu's 180 degree pulses = the claimed "electromagnetic rephasing pulse." ETL = 21 means 21 rephasing pulses per TR.
and concomitant with the selection of a slice by way of one of the gradient coils comprising a slice plane selection coil,
(Liu, [page 12, Methods]; "DWI scan protocol was implemented with a 2D spin-echo EPI using a pair of diffusion gradients. The parameters were TR/TE = 2800/102 ms, acquisition matrix = 64 × 64, FOV = 250 × 250 mm2, acquisition slice thickness/slice gap = 10/0 mm.")
(Liu, [page 11, Methods]; "The target field method based on the equivalent magnetic dipole approach was utilized to design the Gx, Gy, and Gz gradient coils.")
Examiner Note: Liu's 2D DWI acquires images with a defined "acquisition slice thickness/slice gap = 10/0 mm." A 2D acquisition with specific slice thickness requires one of the three gradient coils (Gx, Gy, or Gz) to select the imaging slice. That gradient coil = the claimed "slice plane selection coil."
while the measurement of the at least one echo signal implements phase and frequency encoding by two of the gradient coils comprising a phase gradient coil and a frequency gradient coil.
(Liu, [page 12, Methods]; "DWI scan protocol was implemented with a 2D spin-echo EPI...acquisition matrix = 64 × 64, FOV = 250 × 250 mm2.")
Examiner Note: Liu's "acquisition matrix = 64 x 64" requires two-dimensional spatial encoding: one gradient coil performs phase encoding (one matrix dimension) and another performs frequency encoding during readout (other matrix dimension). These two gradient coils = the claimed "phase gradient coil" and "frequency gradient coil."
Regarding claim 8, (Liu) teaches:
wherein the basic sequence is a spin echo sequence comprising a single measurement of an echo signal, wherein the background measurement is performed after the measurement of the echo signal.
(Liu, [page 12, Methods]; “DWI scan protocol was implemented with a 2D spin-echo EPI.”).
Examiner Note: Liu’s “spin-echo EPI” = the claimed “spin echo sequence.” Fig. 2b shows the EMI characterization window (background measurement) occurs AFTER the MRI signal acquisition window (echo measurement) within each TR.
Regarding claim 10, (Liu) teaches:
wherein the basic sequence is a fast spin echo sequence comprising repeating a sub-sequence within the sequence, the sub-sequence comprising the electromagnetic rephasing pulse and the measurement of an echo signal.
(Liu, [page 12, Methods]; “3D fast spin echo (FSE; TR/TE = 1500/202 ms, FA = 90/180°, echo train length ETL = 21).”).
Examiner Note: Liu’s FSE with ETL = 21 = 21 repeated sub-sequences, each comprising a 180° rephasing pulse and one echo measurement.
Regarding claim 11, (Liu) teaches:
wherein the basic sequence is a 3D fast spin echo sequence comprising repeating N basic sub-sequences within the sequence, each basic sub-sequence comprising the electromagnetic rephasing pulse and the measurement of an echo signal.
(Liu, [page 12, Methods]; “3D fast spin echo (FSE; TR/TE = 1500/202 ms, FA = 90/180°, echo train length ETL = 21, acquisition matrix = 128x126x32).”).
Examiner Note: Liu’s “3D fast spin echo” with ETL = 21 = the claimed “3D fast spin echo sequence comprising repeating N basic sub-sequences” where N = 21.
Regarding claim 12, (Liu) teaches:
wherein the basic sequence comprises a single background measurement.
(Liu, [page 4, Fig. 2b caption]; “the conventional MRI signal acquisition window and the EMI signal characterization window.”).
Examiner Note: Fig. 2b shows ONE EMI signal characterization window per TR = the claimed “single background measurement.”
Regarding claim 13, (Liu) teaches:
wherein the basic sequence comprises N background measurements, each background measurement being performed within its own basic sub-sequence.
(Liu, [page 3]; “EMI signal can change dynamically during scanning due to surrounding EMI sources of various nature and behaviors.”).
Examiner Note: Liu teaches one background measurement per TR but does not teach N measurements (one per sub-sequence). However, Liu acknowledges that EMI changes dynamically. It would have been obvious to perform a background measurement within each of the N FSE sub-sequences to capture EMI closer in time to each echo, yielding more accurate noise estimates.
Regarding claim 14, (Liu) teaches:
An MRI device
(Liu, [page 3]; "The system was based on a compact two-pole 0.055 T permanent samarium-cobalt (SmCo) magnet.")
(Liu, [page 11, Methods]; "The target field method based on the equivalent magnetic dipole approach was utilized to design the Gx, Gy, and Gz gradient coils.")
(Liu, [page 12, Methods]; "Separate transmit and receive coils were employed. The RF transmit coil had a solenoid structure.")
Examiner Note: Liu's complete scanner system comprises a permanent magnet, gradient coils, and RF coils. The applicant's specification at [0070]- [0081] describes the claimed MRI device as comprising these same components: a magnet ([0071]), gradient coils ([0077]), and an RF coil ([0080]). Liu's scanner equates to the claimed "MRI device."
provided with a unit on which a computer program is loaded, the MRI device being configured to implement the method according to claim 1.
(Liu, [page 12, Methods]; "Gradient and RF subsystems and data acquisition were controlled by a PC-based multi-channel NMR spectrometer console (EVO Spectrometer with Powerscan™ v6.3 software).")
Examiner Note: Liu's "PC-based multi-channel NMR spectrometer console" equates to the claimed "unit." Liu's "Powerscan v6.3 software" equates to the claimed "computer program" loaded on the unit.
Regarding claim 15, (Liu) teaches:
wherein the single background measurement is performed after the basic sub-sequences.
(Liu, [page 4, Fig. 2b]; see figure showing EMI signal characterization window positioned after MRI signal acquisition window within each TR).
Examiner Note: Fig. 2b shows the EMI characterization window (background measurement) occurs after the MRI signal acquisition window (which contains the echo sub-sequences).
Claims 2-3 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Liu further in view of Ertürk et al., “Denoising MRI Using Spectral Subtraction”).
Regarding claim 2, Liu fails to teach:
step b1) comprising mathematical processing of the background and body Fourier images to subtract the background signal from the body Fourier image to form a processed Fourier image in Fourier space,
step b2) comprising a transformation of the processed Fourier image to obtain an image of the body in real space.
Ertürk teaches:
step b1) comprising mathematical processing of the background and body Fourier images to subtract the background signal from the body Fourier image to form a processed Fourier image in Fourier space,
(Ertürk, [page 3, Section II, Eq. 3]; “we can subtract the root-mean-square noise power, |N(f)|2, from the PSD of the acquired signal to get an estimate of |Sr(f)|2.”).
Examiner Note: Ertürk’s spectral subtraction of noise power from the signal in Fourier space = the claimed “mathematical processing to subtract the background signal from the body Fourier image in Fourier space.”
step b2) comprising a transformation of the processed Fourier image to obtain an image of the body in real space.
(Ertürk, [page 3, Section II]; “a conventional 2-D FT image reconstruction yields the denoised MRI.”).
Examiner Note: Ertürk’s “2-D FT image reconstruction” = the claimed “transformation of the processed Fourier image to obtain an image in real space.”
Before the time of filing, it would have been obvious to one of ordinary skill in the art to combine Liu and Ertürk. Liu acquires both echo and background data in k-space but uses a CNN for noise removal. Ertürk adds the explicit spectral subtraction framework in Fourier space followed by 2D Fourier transform reconstruction (Ertürk, Abstract; “a new denoising method based on spectral subtraction of the measured noise power”).
Regarding claim 3, the combination of Liu and Ertürk together teaches:
wherein the mathematical processing step b1) comprises at least one of the following methods: spectral subtraction method, anisotropic diffusion filtering, or non-local means.
(Ertürk, [page 1, Abstract]; “a new denoising method based on spectral subtraction of the measured noise power from each signal acquisition is presented.”).
Examiner Note: Ertürk’s “spectral subtraction” is expressly one of the three methods listed in the claim.
Regarding claim 9, Liu teaches:
wherein the background measurement is performed with phase
(Liu, [page 4, Fig. 2c caption]; “for each frequency encoding (FE) line.”).
Liu fails to teach:
frequency coding identical to a phase and frequency coding implemented during the echo signal measurement.
Ertuk teaches:
frequency coding identical to a phase and frequency coding implemented during the echo signal measurement.
(Ertürk, [page 5, Section III.C]; “The receiver bandwidth and gain are identical for each set of experiments.”).
Examiner Note: Liu’s background data is organized per “frequency encoding (FE) line,” implying frequency encoding is applied during background measurement. Ertürk teaches maintaining identical receiver conditions for noise measurement. It would have been obvious to apply identical phase and frequency encoding during the background window to ensure accurate noise characterization.
Before the time of filing, it would have been obvious to one of ordinary skill in the art to combine Liu and Ertürk. Liu acquires background data by the receive coil during a distinct window within each TR but does not explicitly disclose that identical phase and frequency encoding gradients are applied during that background window. Ertürk adds that noise measurement must be performed under identical conditions as the signal measurement to produce an accurate noise estimate (Ertürk, [page 5, Section III.C]; "The average noise power in the MRI experiments is accurately determined from data acquired during the preparation phase of the scanner with both RF power and gradients turned off. The receiver bandwidth and gain are identical for each set of experiments.").
Claims 4 and 5 are rejected under 35 U.S.C. 103 as being unpatentable over Liu further in view of Campbell-Washburn et al., “Using the Robust Principal Component Analysis Algorithm to Remove RF Spike Artifacts from MR Images,”.
Regarding claim 4, Liu fails to teach:
step b3) comprising a transformation of the Fourier image of the body and the Fourier image of the background into an image of the intermediate body and an image of the background in real space, and step b4) comprising processing to subtract the background contribution to obtain an image of the body in real space.
Campbell – Washburn teaches:
step b3) comprising a transformation of the Fourier image of the body and the Fourier image of the background into an image of the intermediate body and an image of the background in real space, and step b4) comprising processing to subtract the background contribution to obtain an image of the body in real space.
((Campbell-Washburn, [page 2, Methods]; "RPCA aims to decompose a measured matrix (M) into a low-rank matrix (L) and a sparse matrix (S), by solving the optimization problem: minL,S||L|| + λ||S||1 subject to M = L+S.")*
(Campbell-Washburn, [page 2, Methods]; "In the case of RF spike noise, M represents the measured data, S represents the high intensity RF spikes, and L represents the recovered artifact-free k-space data.")
Examiner Note: Campbell-Washburn teaches RPCA decomposition under the constraint M = L + S, where M is "the measured data," S is "the high intensity RF spikes," and L is "the recovered artifact-free k-space data." Rearranging, L = M minus S, meaning the clean body data is obtained by subtracting the noise/background component from the measured data. This reads on the claimed "processing to subtract the contribution of the background signal in the intermediate body image." Campbell-Washburn then applies an "Inverse Fourier Transform" to L "to create the despiked corrected images," which reads on the claimed "to obtain an image of the body in real space." A person of ordinary skill would have understood that RPCA's separation of measured data into signal and noise components, followed by inverse Fourier transform of the signal component, constitutes subtraction of the background contribution and reconstruction of a corrected real-space image.
Before the time of filing, it would have been obvious to one of ordinary skill in the art to combine Liu and Campbell-Washburn. Liu subtracts noise in k-space but does not teach transforming both datasets to real space and subtracting there. Campbell-Washburn adds the inverse Fourier transform step to obtain corrected real-space images (Campbell-Washburn, [page 2, Methods]; "The low-rank matrix, L, was then Inverse Fourier Transformed to create the despiked corrected images.").
Regarding claim 5, the combination of Liu and Campbell-Washburn teaches:
wherein step b4) comprises processing by principal component analysis.
(Campbell-Washburn, [page 1, Abstract]; “we present an application of the Robust Principal Component Analysis (RPCA) algorithm to remove spike noise from k-space.”).
Examiner Note: Campbell-Washburn’s “Robust Principal Component Analysis (RPCA)” = the claimed “principal component analysis.”
Before the time of filing, it would have been obvious to one of ordinary skill in the art to combine Liu and Campbell-Washburn. Liu uses a CNN to separate noise from MRI signal but does not teach principal component analysis. Campbell-Washburn adds RPCA, a form of principal component analysis, that decomposes MRI data into clean signal and noise components (Campbell-Washburn, [page 1, Abstract]; "we present an application of the Robust Principal Component Analysis (RPCA) algorithm to remove spike noise from k-space.").
Conclusion
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/SHIVANGI SARKAR/Examiner, Art Unit 2666
/VINCENT RUDOLPH/Supervisory Patent Examiner, Art Unit 2671
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