DETAILED ACTION
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 Objections
Claims 4, 11, 12, and 14-16 are objected to because of the following informalities:
Claim 4 includes a misspelling and should be read as “further comprising performing Magnetic Resonance Imaging reconstruction based on signals obtained from the applied motion encoding gradients.” (see, e.g., [0031] of Applicant’s disclosure).
Claim 12 appears to be missing an article and should be read as “wherein the method is repeated as a k-space point acquisition step for each k-space point of a k-space.”
Claim 11 includes an antecedent basis issue and should be read as “ further comprising applying a no motion encoding gradient during a reference scan.”
Claim 14 appears to be written in independent form, yet also refers back to another independent claim (claim 1). In one interpretation, claim 14 can be construed as an independent computer-readable medium claim. In another interpretation, claim 14 can be construed as a dependent claim. In order to prevent any ambiguity, it is suggested to bring the entire subject matter of claim 1 (i.e., the method) into claim 14 to have claim 14 construed as a proper independent claim.
Claim 15 should be read as “…one motion encoding gradient in each of three motion encoding scans and no motion encoding gradient in one reference scan.”
Claim 16 should also be read as “…one motion encoding gradient in each of three motion encoding scans and no motion encoding gradient in one reference scan.”
Appropriate correction is required.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph:
(A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier. Such claim limitations are recited in claim 15 and are:
a signal generator configured to provide a periodical vibration signal to excite mechanical vibrations with a vibration period;
a sampler configured to sample the vibration signal with a sampling period corresponding to a natural number including zero of vibration periods plus a fixed time delay; and
a gradient applicator configured to apply, in each sampling period, one motion encoding gradient each in three motion encoding scans and no motion encoding gradient in one reference scan.
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
NOTE: The corresponding structure in Applicant’s specification for the signal generator, sampler, and gradient applicator includes components tied to the computer system, such as controllers, processors, and processing circuitry. (see, e.g., [0050], [0052], and [0053]).
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
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.
Claims 1, 4, 5, 10, and 12-14 are rejected under 35 U.S.C. 103 as being unpatentable over Hirsch S, Guo J, Reiter R, Papazoglou S, Kroencke T, Braun J, Sack I. MR elastography of the liver and the spleen using a piezoelectric driver, single‐shot wave‐field acquisition, and multifrequency dual parameter reconstruction. Magnetic resonance in medicine. 2014 Jan;71(1):267-77 (hereinafter “HIRSCH”) and U.S. Patent Appl. Publ. No. 2015/0309145 A1 (hereinafter “KLATT”).
With respect to claim 1, HIRSCH teaches a method of performing Magnetic Resonance Elastography (MRE). HIRSCH “proposes several modifications to existing magnetic resonance elastography (MRE) techniques to improve the accuracy of abdominal MRE.” (Abstract). Specifically, HIRSCH introduces “a setup and protocol which incorporates a semidistant driver placed at the end of the patient table, fast 3D EPIbased acquisition of vibration fields at multiple drive frequencies, and a single-step inversion algorithm of multifrequency 3D wave-field data.” (p.267, right column, bottom paragraph). The method comprising:
providing a periodical vibration signal to excite mechanical vibrations with a vibration period. HIRSCH explains that “vibrations in the low frequency range below 100 hz…is exploited in [MRE].” (p.267, right column, top paragraph). Specifically, HIRSCH describes using a piezoelectric driver fixed to the end of the patient’s table. (p.269, left column, Wave Generator). “The vibrations were transferred from the tip of the lever to the patient by a carbon fiber rod connected at its distal end to a rubber mat. The transducer mat was moderately pressed onto the body surface in the position just below the right costal arch using Velcro strips attached to the patient table.” (Id). Figure 2 shows a “[s]equence timing diagram for acquisition of wave fields (three Cartesian motion components) in 10 slices at eight time points (Δt1…8) during a vibration period 1/f.” (p.270, Figure 2 caption).
sampling the vibration signal with a sampling period corresponding to a natural number including zero of vibration periods plus a fixed delay, wherein a product of the
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fixed delay and a sampling number is equal to the vibration period, the sampling number being a natural number greater than two. Figure 2 shows the timing diagram for HIRSCH. The sampling period in HIRSCH is, for a particular vibration frequency, one wave dynamic or time step at a particular Δt. This sampling period corresponds to a natural number of vibration periods plus a fixed delay Δt. (see, e.g., “vibration” along vertical axis in Figure 2) Notably, a product of the fixed delay Δt and a sampling number (i.e., 1/8f times 8 samples) is equal to the vibration period (1/f). The sampling number (8) is a natural number greater than two.
However, HIRSCH does not teach applying three motion encoding gradients in each sampling period for magnetic resonance acquisition. Nonetheless, HIRSCH does teach applying three motion encoding gradients consecutively for each vibration frequency. (see, e.g., p.269, left column, top: “A 2D single-shot spin-echo EPI sequence with a trapezoidal flow-compensated motion encoding gradient (MEG) consecutively applied along all three axes of the scanner coordinate system was used for rapid motion field acquisition.”; see also Figure 2 in which the “explanation” column includes “3 orthogonal encoding directions.”)
In the same field of endeavor, KLATT states in its Summary section that “[e]xample embodiments are disclosed herein for applying MEG in an arrangement capable of encoding three spatial components of a mono-frequency tissue vibration simultaneously.” ([0010]). “Simultaneous application of three spatial components of the MEG…enables all displacement components to be acquired faster than in conventional MRE, and allows the displacements in the different spatial dimensions to be derived from the same temporally-resolved MR phase images.”
It would have been obvious to one having ordinary skill in the art at the time of filing to modify HIRSCH’s system to apply three motion encoding gradients in each sampling period. More specifically, one having ordinary skill would have been motivated to modify HIRSCH’s consecutive three-axis MEG acquisition by using the simultaneous three-axis MEG technique taught in KLATT to enable acquisition of the different spatial dimensions, to reduce acquisition time, and improve temporal/spatial co-registration. There would have been a reasonable expectation of success as KLATT teaches the technique can be used for acquiring MRE data.
With respect to claim 4, HIRSCH teaches the method further comprising performing Magnetic Resonance Imaging reconstruction based on signals obtained from the applied motion encoding gradients. At least one purpose of HIRSCH is to introduce an improved reconstruction method. (see p.272, Discussion, right column). Figure 6 of HIRSCH includes images (or parameter maps) to illustrate an “[f]low of information for the MRE parameter reconstruction in the liver of a healthy volunteer,.” (Caption of Figure 6).
With respect to claim 5 (depending from claim 4), HIRSCH teaches the method further comprising using a result from the reconstruction to evaluate stiffness and/or viscosity of an object being examined by the MRE. “Spatial maps of magnitude and phase of the complex shear modulus were acquired within 6–8 min.” (Abstract, Results). According to HIRSCH, the improved techniques provide “abdominal images of viscoelasticity in a short time with spatial resolution comparable to conventional MR images and improved quality without being compromised by ascites.” (Abstract, Conclusion). “It is a stimulating result of this study that we could resolve hepatic and splenic stiffness from the same scan in all subjects including those with ascites.” (p.274, left column).
With respect to claim 10, HIRSCH teaches wherein the three motion encoding gradients represent gradients in three orthogonal space directions. “…where the indices 1, 2, and 3 refer to the imaging gradient directions of read-out, phase-encoding, and slice selection.” (p.270, left column, bottom). The “explanation” column in Figure 2 describes the read-out, phase-encoding, and slice selection as “3 orthogonal encoding directions.” (p.270, Figure 2).
With respect to claim 12, HIRSCH and KLATT teach wherein the method is repeated as k-space point acquisition step for each k-space point of a k-space. HIRSCH uses MRI image data with matrix size, EPI readout, and image reconstruction, which necessarily requires acquisition of k-space data. This is further supported by KLATT, which teaches that the KLATT method “allows for simultaneously acquired 3D displacement data and storage of such data in the same k-space.” (Abstract; see also [0005]: “MR signal data detected from an object are typically described in mathematical terms as “k-space” data (k-space is the Fourier inverse of image or actual space). An image in actual space is produced by a Fourier transform of the k-space data. MR signal data are acquired by traversing k-space over the course of applying to the object the various RF pulses and magnetic field gradients.”). “Example embodiments SLIM-MRE disclosed herein provide a method and system to collect and analyze 3D displacement data that are simultaneously acquired and stored in the same k-space.” ([0011]).
With respect to claim 13 (depending from claim 12), HIRSCH and KLATT teach wherein the k-space point acquisition steps are synchronized with the vibration signal. HIRSCH’s trigger delay scheme and MEG-start-time scheme necessarily teach synchronizing the k-space point acquisition steps with the vibration signal.
With respect to claim 14, HIRSCH does not explicitly teach a non-transitory computer-readable storage medium with an executable program stored thereon, that when executed, instructs a processor to perform the method of claim 1.
However, in the same field of endeavor, KLATT teaches one or more processors and memory storing instructions that, when executed by the one or more processors, cause the MRE device to perform the programmed steps and also teaches a non-transitory computer-readable storage medium with an executable program stored thereon, that when executed, instructs a processor to perform the programmed steps. (see, e.g., [0018] and [0051]).
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH system to include one or more processors and memory storing instructions that, when executed by the one or more processors, cause the MRE device to perform the programmed steps. One would have been motivated to add the hardware and software to control the HIRSCH system so that one could perform the MRE protocol on different patients. There would have been a reasonable expectation of success as KLATT teaches that computer systems can be used to implement MRE protocols.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Hirsch S, Guo J, Reiter R, Papazoglou S, Kroencke T, Braun J, Sack I. MR elastography of the liver and the spleen using a piezoelectric driver, single‐shot wave‐field acquisition, and multifrequency dual parameter reconstruction. Magnetic resonance in medicine. 2014 Jan;71(1):267-77 (hereinafter “HIRSCH”) and U.S. Patent Appl. Publ. No. 2015/0309145 A1 (hereinafter “KLATT”) as applied to claim 1 above, and further in view of U.S. Patent Appl. Publ. No. 2018/0106879 A1 (hereinafter “JOHNSON”).
With respect to claim 2, neither HIRSCH nor KLATT teach wherein the motion encoding gradients are part of a three-dimensional (3D) slab-selective Magnetic Resonance Imaging sequence.
In the same field of endeavor, JOHNSON teaches “an acquisition scheme for generating magnetic resonance elastography displacement data with whole-sample coverage, high spatial resolution, and adequate SNR in a short scan time.” (Abstract). Moreover, the method and system can “acquire in-plane and through-plane k-space shots over a volume of a sample divided into a plurality of slabs that each include a plurality of non-adjacent slices to obtain three dimensional multiband, multishot data….” (Abstract). JOHNSON’s method enables obtaining high-resolution MRE image data that can be generated in “clinically-acceptable scan times.” ([0050]).
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH system to use three-dimensional (3D) slab-selective Magnetic Resonance Imaging sequence. One would have been motivated to use JOHNSON’s sequence to obtain high-resolution MRE image data in clinically-acceptable scan times. There would have been a reasonable expectation of success as JOHSON teaches that 3D slab-selective Magnetic Resonance Imaging sequence can be used.
Claims 3, 6-9, and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Hirsch S, Guo J, Reiter R, Papazoglou S, Kroencke T, Braun J, Sack I. MR elastography of the liver and the spleen using a piezoelectric driver, single‐shot wave‐field acquisition, and multifrequency dual parameter reconstruction. Magnetic resonance in medicine. 2014 Jan;71(1):267-77 (hereinafter “HIRSCH”) and U.S. Patent Appl. Publ. No. 2015/0309145 A1 (hereinafter “KLATT”) as applied to claim 1 above, and further in view of U.S. Patent Appl. Publ. No. 2022/0317219 A1 (hereinafter “DARWISH”).
With respect to claim 3, HIRSCH does not explicitly teach wherein the motion encoding gradients are applied at different phases of the vibration signal and a corresponding phase correction is applied to each motion encoding by the respective one of the motion encoding gradients.
In the same field of endeavor, DARWISH generally relates to “a method and system for performing three-dimensional, 3D, magnetic resonance elastography, MRE.” (Abstract). DARWISH teaches that “[t]ypically, 3D GRE-MRE sequences require four breath-holds: three acquisitions are executed with motion encoding in three orthogonal directions (Phase, Readout, Slice), and a reference acquisition without motion encoding that enables the background phase error to be acquired.” More specifically, the reference acquisition can be used to account for unwanted background noise caused by other sources.
According to DARWISH, while known techniques use one breath-hold for each of the four acquisitions for a total of four breath-holds, DARWISH specifically teaches acquiring all four scans in a single breath-hold. “Advantageously, the present techniques enable the four scans that are typically required to be performed during MRE, and during four breath-holds, to be combined into a single measurement that can be performed during a single breath-hold.” The benefit is improved quality and precision because it is not necessary to align image data from separate breath-holds. (see, e.g., [0007]).
Furthermore, DARWISH teaches that one known imaging sequence requires “the acquisition of multiple temporal offsets between vibration and MRE acquisition in order to capture the wave displacement at different wave phases.” ([0007]). DARWISH then teaches “[i]n order to perform MRE using three-dimensional wave fields, the MRI acquisition needs to be synchronised with the temporal component of the wave propagation. The [DARWISH] sequence incorporates time delays within imaging shots in order to synchronise slice and vibrational wave phase acquisition with the mechanical vibration. This allows the interleaved acquisition of multiple slices, wave phases and motion encodings in a single concatenated measurement. This allows the interleaved acquisition of multiple slices, wave phases and motion encodings in a single concatenated measurement.” ([0015]). DARWISH also teaches “[i]n order to generate the quantitative images, decoding may be applied to each signal received by each coil of the MRI apparatus during image acquisition, prior to signal combination. Decoding is needed to remove any phase error in the signals. The decoding operation is the opposite or inverse of the encoding scheme.” ([0022]).
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH-KLATT system to include applying the motion encoding gradients at different phases of the vibration signal and applying a corresponding phase correction to each motion encoding by the respective one of the motion encoding gradients. As taught in DARWISH, one would have been motivated to acquire image data using the temporal offsets in order to capture different wave phases and one would have been motivated to obtain a no motion encoding acquisition (i.e., reference acquisition) for background phase error. There would have been a reasonable expectation of success as DARWISH teaches that three motion-encoding acquisitions and a reference acquisition can be acquired.
With respect to claim 6, HIRSCH does not explicitly teach wherein the natural number of vibration periods within one sampling period is equal to one, two, or three.
In the same field of endeavor, DARWISH teaches an “Intenso” imaging sequence, “which enables the four scans to be combined into a single measurement that can be performed during a single breath-hold.” In one example, DARWISH teaches that imaging was performed at “60 Hz actuation frequency” with “four wave-phase offsets and four Hadamard motion encoding combinations….” ([0037]). In this example, the vibration period is 16.67 ms (i.e., 1/60 s) and one set of four acquisitions at 9.38 ms provides a total of 37.52 ms, which is 2.25 vibration periods (i.e., 2 vibration periods plus 1/4 vibration period for fixed delay).
The benefits to this timing sequence is that it “incorporates time delays within imaging shots in order to synchronise slice and vibrational wave phase acquisition with the mechanical vibration. This allows the interleaved acquisition of multiple slices, wave phases and motion encodings in a single concatenated measurement.” ([0015]).
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH-KLATT system such that the natural number of vibration periods within one sampling period is equal to one, two, or three. As taught in DARWISH, one would have been motivated to use the Intenso timing sequence that acquires image data at a 60 Hz actuation frequency because the timing sequence “incorporates time delays within imaging shots in order to synchronise slice and vibrational wave phase acquisition with the mechanical vibration” thereby allowing “the interleaved acquisition of multiple slices, wave phases and motion encodings in a single concatenated measurement.” ([0015]). There would have been a reasonable expectation of success as DARWISH teaches that three motion-encoding acquisitions and a reference acquisition can be acquired.
With respect to claim 7, HIRSCH does not explicitly teach wherein the fixed delay corresponds to one third, one quarter, or one fifth of the vibration period.
As explained above with respect to claim 6, the Intenso timing sequence at 60 Hz actuation frequency has a fixed delay of one quarter the vibration period.
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH-KLATT system such that the fixed delay corresponds to one quarter the vibration period. As taught in DARWISH, one would have been motivated to use the Intenso timing sequence that acquires image data at a 60 Hz actuation frequency because the timing sequence “incorporates time delays within imaging shots in order to synchronise slice and vibrational wave phase acquisition with the mechanical vibration” thereby allowing “the interleaved acquisition of multiple slices, wave phases and motion encodings in a single concatenated measurement.” ([0015]). There would have been a reasonable expectation of success as DARWISH teaches that three motion-encoding acquisitions and a reference acquisition can be acquired.
With respect to claim 8, HIRSCH does not explicitly teach wherein the sampling period comprises four time slots, three of the four time slots for the three motion encoding gradients, respectively, and a remaining one of the four time slots for a reference scan.
In the same field of endeavor, DARWISH generally relates to “a method and system for performing three-dimensional, 3D, magnetic resonance elastography, MRE.” (Abstract). DARWISH teaches that “[t]ypically, 3D GRE-MRE sequences require four breath-holds: three acquisitions are executed with motion encoding in three orthogonal directions (Phase, Readout, Slice), and a reference acquisition without motion encoding that enables the background phase error to be acquired.” More specifically, the reference acquisition can be used to account for unwanted background noise caused by other sources.
Furthermore, according to DARWISH, while known techniques use one breath-hold for each of the four acquisitions for a total of four breath-holds, DARWISH specifically teaches acquiring all four scans in a single breath-hold. “Advantageously, the present techniques enable the four scans that are typically required to be performed during MRE, and during four breath-holds, to be combined into a single measurement that can be performed during a single breath-hold.” The benefit is improved quality and precision because it is not necessary to align image data from separate breath-holds. (see, e.g., [0007]).
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH-KLATT system to include obtaining the reference acquisition, in addition to the three motion-encoding gradients, within one sampling period. For four acquisitions to occur during the sampling period, each of the acquisitions would necessarily have its own time slot within the sampling period. One would have been motivated to acquire image data with the three motion-encoding gradient acquisitions and image data with a no motion encoding acquisition to enable acquiring the background phase error as taught in DARWISH. There would have been a reasonable expectation of success as DARWISH teaches that three motion-encoding acquisitions and a reference acquisition can be acquired.
With respect to claim 9 (depending from claim 8), HIRSCH does not explicitly teach wherein the four time slots are a same size.
As discussed above, DARWISH teaches that “[t]ypically, 3D GRE-MRE sequences require four breath-holds: three acquisitions are executed with motion encoding in three orthogonal directions (Phase, Readout, Slice), and a reference acquisition without motion encoding that enables the background phase error to be acquired.” While known techniques use one breath-hold for each of the four acquisitions for a total of four breath-holds, DARWISH specifically teaches acquiring all four scans in a single breath-hold. “Advantageously, the present techniques enable the four scans that are typically required to be performed during MRE, and during four breath-holds, to be combined into a single measurement that can be performed during a single breath-hold.” The benefit is improved quality and precision because it is not necessary to align image data from separate breath-holds. (see, e.g., [0007]).
One having ordinary skill in the art would then select four equal time slots within the sampling period. DARWISH teaches using constant delays to synchronize the multi-slice GRE sequence with mechanical vibration. ([0017]). DARWISH also teaches that the time delays are constructed so the eddy-current steady state is not perturbed. ([0015]). Equal-sized slots support these goals as unequal time slots would complicate the phase relationship to the vibration and could introduce different eddy-current/background phase conditions.
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH-KLATT system to include equal-sized time slots for the four acquisitions within one sampling period. One would have been motivated to use equal-sized time slots as the readouts would be uniform and the image data easier to process compared to unequally-sized time slots. There would have been a reasonable expectation of success as DARWISH teaches that three motion-encoding acquisitions and a reference acquisition can be acquired within a single sampling period and one having ordinary skill in the art could make the time slots equal.
With respect to claim 11, HIRSCH does not explicitly teach wherein no motion encoding gradient is applied during a reference scan.
In the same field of endeavor, DARWISH teaches that “[t]ypically, 3D GRE-MRE sequences require four breath-holds: three acquisitions are executed with motion encoding in three orthogonal directions (Phase, Readout, Slice), and a reference acquisition without motion encoding that enables the background phase error to be acquired.” More specifically, the reference acquisition can be used to account for unwanted background noise caused by other sources.
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH-KLATT system to include obtaining the reference acquisition, in addition to the three motion-encoding gradients, within one sampling period. One would have been motivated to acquire data without motion encoding to enable acquiring the background phase error as taught in DARWISH. There would have been a reasonable expectation of success as DARWISH teaches that three motion-encoding acquisitions and a reference acquisition can be acquired.
Claims 15 and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Hirsch S, Guo J, Reiter R, Papazoglou S, Kroencke T, Braun J, Sack I. MR elastography of the liver and the spleen using a piezoelectric driver, single‐shot wave‐field acquisition, and multifrequency dual parameter reconstruction. Magnetic resonance in medicine. 2014 Jan;71(1):267-77 (hereinafter “HIRSCH”) and U.S. Patent Appl. Publ. No. 2015/0309145 A1 (hereinafter “KLATT”), and U.S. Patent Appl. Publ. No. 2022/ 0317219 A1 (hereinafter “DARWISH”).
With respect to claim 15, HIRSCH teaches a Magnetic Resonance Elastography (MRE) device. HIRSCH “proposes several modifications to existing magnetic resonance elastography (MRE) techniques to improve the accuracy of abdominal MRE.” (Abstract). Specifically, HIRSCH introduces “a setup and protocol which incorporates a semidistant driver placed at the end of the patient table, fast 3D EPIbased acquisition of vibration fields at multiple drive frequencies, and a single-step inversion algorithm of multifrequency 3D wave-field data.” (p.267, right column, bottom paragraph). The MRE device comprising:
a signal generator configured to provide a periodical vibration signal to excite mechanical vibrations with a vibration period. HIRSCH explains that “vibrations in the low frequency range below 100 hz…is exploited in [MRE].” (p.267, right column, top paragraph). Specifically, HIRSCH describes using a piezoelectric driver fixed to the end of the patient’s table. (p.269, left column, Wave Generator). “The vibrations were transferred from the tip of the lever to the patient by a carbon fiber rod connected at its distal end to a rubber mat. The transducer mat was moderately pressed onto the body surface in the position just below the right costal arch using Velcro strips attached to the patient table.” (Id). Figure 2 shows a “[s]equence timing diagram for acquisition of wave fields (three Cartesian motion components) in 10 slices at eight time points (Δt1…8) during a vibration period 1/f.” (p.270, Figure 2 caption).
a sampler configured to sample the vibration signal with a sampling period corresponding to a natural number including zero of vibration periods plus a fixed time delay, wherein a product of the fixed time delay and a sampling number is equal to the vibration period, the sampling number being a natural number greater than two. Figure 2 shows the timing diagram for HIRSCH. The sampling period in HIRSCH is, for a particular vibration frequency, one wave dynamic or time step at a particular Δt. This sampling period corresponds to a natural number of vibration periods plus a fixed delay Δt. (see, e.g., “vibration” along vertical axis in Figure 2) Notably, a product of the fixed delay Δt and a sampling number (i.e., 1/8f times 8 samples) is equal to the vibration period (1/f). The sampling number (8) is a natural number greater than two.
HIRSCH does not teach the MRE device includes a gradient applicator configured to apply, in each sampling period, one motion encoding gradient each in three motion encoding scans and no motion encoding gradient in one reference scan. Nonetheless, HIRSCH does teach applying three motion encoding gradients consecutively for each vibration frequency. (see, e.g., p.269, left column, top: “A 2D single-shot spin-echo EPI sequence with a trapezoidal flow-compensated motion encoding gradient (MEG) consecutively applied along all three axes of the scanner coordinate system was used for rapid motion field acquisition.”; see also Figure 2 in which the “explanation” column includes “3 orthogonal encoding directions.”)
In the same field of endeavor, KLATT states in its Summary section that “[e]xample embodiments are disclosed herein for applying MEG in an arrangement capable of encoding three spatial components of a mono-frequency tissue vibration simultaneously.” ([0010]). “Simultaneous application of three spatial components of the MEG…enables all displacement components to be acquired faster than in conventional MRE, and allows the displacements in the different spatial dimensions to be derived from the same temporally-resolved MR phase images.”
It would have been obvious to one having ordinary skill in the art at the time of filing to modify HIRSCH’s system to apply three motion encoding gradients in each sampling period. More specifically, one having ordinary skill would have been motivated to modify HIRSCH’s consecutive three-axis MEG acquisition by using the simultaneous three-axis MEG technique taught in KLATT to enable acquisition of the different spatial dimensions, to reduce acquisition time, and improve temporal/spatial co-registration. There would have been a reasonable expectation of success as KLATT teaches the technique can be used for acquiring MRE data.
However, neither HIRSCH nor KLATT teaches that the gradient applicator is configured to apply, in each sampling period, no motion encoding gradient in one reference scan.
In the same field of endeavor, DARWISH generally relates to “a method and system for performing three-dimensional, 3D, magnetic resonance elastography, MRE.” (Abstract). DARWISH teaches that “[t]ypically, 3D GRE-MRE sequences require four breath-holds: three acquisitions are executed with motion encoding in three orthogonal directions (Phase, Readout, Slice), and a reference acquisition without motion encoding that enables the background phase error to be acquired.” More specifically, the reference acquisition can be used to account for unwanted background noise caused by other sources.
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH-KLATT system to include obtaining the reference acquisition, in addition to the three motion-encoding gradients, within one sampling period. One would have been motivated to acquire data without motion encoding to enable acquiring the background phase error as taught in DARWISH. There would have been a reasonable expectation of success as DARWISH teaches that three motion-encoding acquisitions and a reference acquisition can be acquired.
To the extent that HIRSCH does not teach the corresponding structure described in Applicant’s disclosure for performing the claimed function, and equivalents thereof, for a signal generator, a sampler, or a gradient applicator, Examiner notes that each of these is described in Applicant’s specification as a controller, data processor, processing circuitry, and/or a function of the computer system in general. (see, e.g., [0050]: “The at least one computer 10 may be configured to carry out a computer-implemented method for controlling the MRE-system according to a specific timing scheme” and [0053]). Likewise, KLATT teaches one or more processors and memory storing instructions that, when executed by the one or more processors, cause the MRE device to perform the programmed steps and also teaches a non-transitory computer-readable storage medium with an executable program stored thereon, that when executed, instructs a processor to perform the programmed steps. (see, e.g., [0018] and [0051]).
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH system to include one or more processors and memory storing instructions that, when executed by the one or more processors, cause the MRE device to perform the programmed steps. One would have been motivated to add the hardware and software to control the HIRSCH system so that one could perform the MRE protocol on different patients. There would have been a reasonable expectation of success as KLATT teaches that computer systems can be used to implement MRE protocols.
With respect to claim 16, HIRSCH teaches a Magnetic Resonance Elastography (MRE) device. HIRSCH “proposes several modifications to existing magnetic resonance elastography (MRE) techniques to improve the accuracy of abdominal MRE.” (Abstract). Specifically, HIRSCH introduces “a setup and protocol which incorporates a semidistant driver placed at the end of the patient table, fast 3D EPIbased acquisition of vibration fields at multiple drive frequencies, and a single-step inversion algorithm of multifrequency 3D wave-field data.” (p.267, right column, bottom paragraph). The MRE device is configured to:
provide a periodical vibration signal to excite mechanical vibrations with a vibration period. HIRSCH explains that “vibrations in the low frequency range below 100 hz…is exploited in [MRE].” (p.267, right column, top paragraph). Specifically, HIRSCH describes using a piezoelectric driver fixed to the end of the patient’s table. (p.269, left column, Wave Generator). “The vibrations were transferred from the tip of the lever to the patient by a carbon fiber rod connected at its distal end to a rubber mat. The transducer mat was moderately pressed onto the body surface in the position just below the right costal arch using Velcro strips attached to the patient table.” (Id). Figure 2 shows a “[s]equence timing diagram for acquisition of wave fields (three Cartesian motion components) in 10 slices at eight time points (Δt1…8) during a vibration period 1/f.” (p.270, Figure 2 caption).
sample the vibration signal with a sampling period corresponding to a natural number including zero of vibration periods plus a fixed time delay, wherein a product of the fixed time delay and a sampling number is equal to the vibration period, the sampling number being a natural number greater than two. Figure 2 shows the timing diagram for HIRSCH. The sampling period in HIRSCH is, for a particular vibration frequency, one wave dynamic or time step at a particular Δt. This sampling period corresponds to a natural number of vibration periods plus a fixed delay Δt. (see, e.g., “vibration” along vertical axis in Figure 2) Notably, a product of the fixed delay Δt and a sampling number (i.e., 1/8f times 8 samples) is equal to the vibration period (1/f). The sampling number (8) is a natural number greater than two.
HIRSCH does not teach the MRE device includes one or more processors and memory storing instructions that, when executed by the one or more processors, cause the MRE device to perform the steps described above.
However, in the same field of endeavor, KLATT teaches one or more processors and memory storing instructions that, when executed by the one or more processors, cause the MRE device to perform the programmed steps. (see, e.g., [0018]).
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH system to include one or more processors and memory storing instructions that, when executed by the one or more processors, cause the MRE device to perform the programmed steps. One would have been motivated to add the hardware and software to control the HIRSCH system so that one could perform the MRE protocol on different patients. There would have been a reasonable expectation of success as KLATT teaches that computer systems can be used to implement MRE protocols.
HIRSCH also does not teach that the device is configured to apply, in each sampling period, one motion encoding gradient each in three motion encoding scans and no motion encoding gradient in one reference scan. Nonetheless, HIRSCH does teach applying three motion encoding gradients consecutively for each vibration frequency. (see, e.g., p.269, left column, top: “A 2D single-shot spin-echo EPI sequence with a trapezoidal flow-compensated motion encoding gradient (MEG) consecutively applied along all three axes of the scanner coordinate system was used for rapid motion field acquisition.”; see also Figure 2 in which the “explanation” column includes “3 orthogonal encoding directions.”)
In the same field of endeavor, KLATT states in its Summary section that “[e]xample embodiments are disclosed herein for applying MEG in an arrangement capable of encoding three spatial components of a mono-frequency tissue vibration simultaneously.” ([0010]). “Simultaneous application of three spatial components of the MEG…enables all displacement components to be acquired faster than in conventional MRE, and allows the displacements in the different spatial dimensions to be derived from the same temporally-resolved MR phase images.”
It would have been obvious to one having ordinary skill in the art at the time of filing to modify HIRSCH’s system to apply three motion encoding gradients in each sampling period. More specifically, one having ordinary skill would have been motivated to modify HIRSCH’s consecutive three-axis MEG acquisition by using the simultaneous three-axis MEG technique taught in KLATT to enable acquisition of the different spatial dimensions, to reduce acquisition time, and improve temporal/spatial co-registration. There would have been a reasonable expectation of success as KLATT teaches the technique can be used for acquiring MRE data.
However, neither HIRSCH nor KLATT teaches applying, in each sampling period, no motion encoding gradient in one reference scan.
In the same field of endeavor, DARWISH teaches that “[t]ypically, 3D GRE-MRE sequences require four breath-holds: three acquisitions are executed with motion encoding in three orthogonal directions (Phase, Readout, Slice), and a reference acquisition without motion encoding that enables the background phase error to be acquired.” More specifically, the reference acquisition can be used to account for unwanted background noise caused by other sources.
It would have been obvious to one having ordinary skill in the art at the time of filing to modify the HIRSCH-KLATT system to include obtaining the reference acquisition, in addition to the three motion-encoding gradients, within one sampling period. One would have been motivated to acquire data without motion encoding to enable acquiring the background phase error as taught in DARWISH. There would have been a reasonable expectation of success as DARWISH teaches that three motion-encoding acquisitions and a reference acquisition can be acquired.
Prior Art Made of Record
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US-20120289814-A1 teaches a MRE method including application of mechanical oscillations with an oscillation period to an object to generate mechanical waves in the object.
US-20120289814-A1 teaches a sequence to acquire MRE data using a single-shot, echo-planar imaging readout, avoiding to need for off-line image processing.
Conclusion
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/JASON P GROSS/ Examiner, Art Unit 3797
/SERKAN AKAR/ Primary Examiner, Art Unit 3797
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