University of Virginia Patent Foundation v. General Electric Co. (755 F. Supp. 2d 709, 2010)

Memorandum Opinion

NORMAN K. MOON, District Judge.

In this action, Plaintiff alleges that Defendant infringed and continues to infringe its patent, which discloses a technique for three-dimensional magnetic resonance imaging (“MRI”) of the human body. Two matters are presented for the Court’s decision. First, Plaintiff and Defendant submitted a Joint Claim Construction and Prehearing Statement (docket no. 99), setting forth the constructions of claim terms and phrases in the patent on which they agree, and proposing constructions of the terms and phrases on which they disagree. After full briefing, the Court held a claim construction hearing. The Court’s construction of the disputed terms is explained herein.

Second, Defendant moved for partial summary judgment seeking an order that Defendant is not liable for any activities infringing the patent that occurred prior to the issuance of the reexamination certificate for the patent (docket no. 100). After full briefing, the Court heard arguments on Defendant’s motion. For the following reasons, the Court will grant Defendant’s motion for partial summary judgment.

I. Background

Plaintiff University of Virginia Patent Foundation (“Patent Foundation”), a not-for-profit Virginia corporation, is the assignee of United States Patent No. 5,245,282 (“'282 Patent”) for an invention entitled “Three-Dimensional Magnetic Resonance Imaging.” (Complaint ¶¶ 1, 8.) The Patent Foundation brought an action for infringement of the '282 Patent against Defendant General Electric Company d/b/a G.E. Healthcare (“GE”), a New York corporation, on May 20, 2008 (docket no. I). The Patent Foundation alleged that GE infringed the '282 Patent by “practicing the methods of the '282 Patent and by making, using, selling, offering for sale, and/or importing in or into the United States, without authority, MRI scanners that practice the methods of the '282 Patent.” (Complaint ¶ 11.)

MRI is a medical diagnostic imaging process that can produce high-contrast images of the interior soft-tissue structures of the human body without the use of ionizing radiation, which can potentially be harmful to human organs. The subject in an MRI examination is placed in a very strong static magnetic field, and the information necessary to create the images is generated using a series of magnetic field gradient pulses and radiofrequency (or “RF”) pulses. The precise manner in which the gradient pulses and radiofrequency pulses are applied to the body is generally referred to as a pulse sequence. Pulse sequences are usually repeated many times during a scan in order to obtain enough information about a region of interest in the body to construct an image of it.

MRI imaging techniques take advantage of the fact that nuclei of some atoms, including hydrogen atoms, have “spin” and act like tiny bar magnets. When exposed to an external magnetic field, they align with it in much the same manner as a compass needle aligns with the earth’s magnetic field. At this stage, the nuclei are in their steady state and said to be aligned with the external magnetic field, which is represented by a vector projecting into the z-plane. If aligned nuclei are excited by applied pulses of electromagnetic energy of the resonant frequency, however, they jump to a higher energy state and their axes move out of alignment with the external magnetic field. The magnetization of tissues while their nuclei are being excited is usually represented by their projections into a three-dimensional plane. Their projections have two components: one in the direction of the external magnetic field (i.e., the extension into the vertical z-plane), called the longitudinal component, and the other perpendicular to the external magnetic field (i.e., the extension into the horizontal (x, y)-plane), called the transverse component.

Excited nuclei in a sample generate a resonance signal that can be detected. Tissues can be distinguished based upon characteristics of the resonance signal, especially the manner in which the resonance signal fades over time, or “relaxes.” In the process called “relaxation,” when the applied high frequency energy is removed, the nuclei release their absorbed energy and realign with the external magnetic field, while the signal decays. Tl, or “spin-lattice relaxation time,” and T2, or “spin-spin relaxation time,” are values arbitrarily selected to measure the time it takes the nuclei to return to their original alignment in the external magnetic field, before they were disturbed. The spin-lattice relaxation process concerns the restoration of the longitudinal component of the magnetization (i.e., the extension of the excited nuclei into the vertical z-plane) to its initial value. It is measured by the time constant Tl, which is the time required for the longitudinal component of the magnetization to return to sixty-three percent of its original magnitude following an excitation pulse. Strictly speaking, the longitudinal component approaches but never fully reaches its steady-state value; it would require an infinite amount of time to fully reach equilibrium. The spin-spin relaxation process concerns the decay of the transverse component of the magnetization (i.e., the extension of the excited nuclei into the horizontal (x, y)-plane) toward its steady-state value of zero at equilibrium. It is measured by the time constant T2, which is the time required for the transverse component of the magnetization to return to thirty-seven percent of its thermal equilibrium value of zero. Transverse relaxation occurs more quickly than longitudinal relaxation, so Tl will always be greater than T2.

Different tissues recover at different rates, so the amount of time represented by Tl and T2 varies according to the type of tissue being excited by the electromagnetic pulse. In other words, the amount of time it takes for the longitudinal component of excited Tissue A to return to sixty-three percent of its original magnitude may be different than the amount of time it would take in Tissue B. Differences between recovery rates of tissues are used to distinguish between types of tissues in an MRI scan; these differences in magnetization of the tissues at the time their resonance signal is measured create “contrast.” For example, at the time at which the magnetization of the tissues is measured, the difference in the amount of relaxation that has occurred in a healthy tissue and in a tissue with a tumor can be used to distinguish the two tissues. To create an image, the measured magnetization properties of the tissue are used to determine the brightness of the pixels of that region.

The '282 Patent describes an invention of “a rapid process for producing three-dimensional magnetic resonance imaging” through a pulse sequence which is referred to as 8D MP-RAGE. '282 Patent, col. 1, 11. 8-9; id. col. 4, 11. 23-26. Claim 1, its only independent claim, provides:

In a method for producing a set of magnetic resonance three-dimensional image data, a preparation-aequisition-recovery pulse sequence cycle comprising the steps of:

a — a magnetization preparation period in which a series of at least one of RF pulses, gradient field pulses, and time delays are applied to encode the desired contrast properties in the form of longitudinal magnetization,

b — a data acquisition period, said data acquisition period including at least two repetitions of a gradient echo sequence to acquire data for a fraction of k-space,

c — a magnetization recovery period which allows TI and T2 relaxation before the start of the next sequence cycle, and

d — repeating steps a, b and c until a predetermined k-space volume is sampled.

The patent application was granted by the United States Patent and Trademark Office (“PTO”) in 1993 with no objections because “[n]o prior art has been found to meet the limitations of claims 1-44 calling for a method of producing three dimensional image data.” PTO, Notice of Allow-ability and Reasons for Allowance, at 2 (Aug. 6,1992).

In May 2008, the Patent Foundation brought the present action against GE for past and continuing infringement of the '282 Patent. Subsequently, GE filed a request with the PTO for ex parte reexamination of the '282 Patent, arguing that the body of published art anticipates and renders obvious claims 1-13, 15-19, 22, 26-39, 41, 42, and 44 of the '282 Patent. Request for Ex Parte Reexamination (Mar. 13, 2009). The PTO granted the request, finding that the request had raised eight substantial new questions of patentability based upon certain prior art. PTO, Order Granting Reexamination of U.S. Patent 5,245,282 (May 6, 2009).

Upon reexamination, the PTO rejected all of the claims in question. PTO, Reexamination of U.S. Patent 5,245,282 (Oct. 1, 2009). Pursuant to 35 U.S.C. § 102(b), the PTO rejected Claims 1-12, 18, 19, 22, 26, 27, 29, 30, 37, 39, 41, and 42 in the '282 Patent as being anticipated by United States Patent No. 4,707,658 by Frahm, et al. (“'658 Patent”), and rejected Claim 1 as being anticipated by United States Patent No. 4,724,301 by Van der Meulen et al. (“'301 Patent”). Furthermore, pursuant to 35 U.S.C. § 103(a), the PTO rejected Claims 1, 4,13,15-17, 26-28, 31-36, and 44 as being unpatentable because such claims were rendered obvious in light of certain prior publications. After the claims were rejected, the Court granted a stay of the present action. (Order Adopting Stipulation to Stay Case (Nov. 9, 2009) (docket no. 90).)

In response to the PTO’s action, the Patent Foundation filed an Amendment under 37 C.F.R. § 1.111 and § 1.550 canceling dependent Claim 4 of the patent, which had recited “[t]he method of claim 1, wherein said magnetization recovery period has a time of zero.” The Patent Foundation explained that it canceled the claim “because it does not properly depend from claim 1 because a ‘magnetization recovery period [that] has a time of zero’ does not ‘allow[s] [sic] TI and T2 relaxation before the start of the next sequence cycle,’ as required by the magnetization recovery period of claim 1. Stated simply, a finite period of time must occur for TI and T2 relaxation to occur, and thus a magnetization recovery period that has a time of zero is inconsistent with claim 1____” PL’s Amendment Under 37 C.F.R. § 1.111 and § 1.550 and Written Statement of Examiner Interview Under 37 CFR § 1.560(b), at 12-13 (Nov. 30, 2009) [hereinafter “PL’s Amendment”] (alterations in original).

Based on the Patent Foundation’s amendment, the PTO withdrew all of its objections to the claims except for those pertaining to Claim 4, which was canceled, and issued the reexamination certificate on May 4, 2010. In its statement of reasons for patentability, the PTO declared that “the claimed ‘magnetization recovery period’ is interpreted to correspond to a finite period of time (i.e., greater than zero) that allows substantially complete TI and T2 relaxation to occur — i.e., relaxation to thermal equilibrium of both the longitudinal component and the transverse component — as opposed to partial or substantially incomplete relaxation.” PTO, Notice of Intent to Issue Ex Parte Reexamination Certificate and Statement of Reasons for Patentability and/or Confirmation, at 3 (Jan. 28, 2010) [hereinafter “Statement of Reasons for Patentability”]. The Patent Foundation submitted comments on the PTO’s statement of reasons in order to clarify that it was the Patent Foundation’s position that the magnetization recovery period in Claim 1 need only allow “partial TI and T2 relaxation to occur.” PL’s Comments on Statement of Reasons for Patentability and/or Confirmation, at 2 (Mar. 1, 2010).

After the reexamination proceedings concluded, the stay of the present suit was lifted, and the parties requested that a claim construction hearing be held to resolve the meaning of disputed terms in the claims of the '282 Patent and filed a Joint Claim Construction and Prehearing Statement with the Court (docket no. 99). GE moved for partial summary judgment, requesting a finding of no liability for any infringement that occurred prior to the issuance of the reexamination certificate. The claim construction issues and GE’s motion were both fully briefed and heard before this Court.

II. Claim Construction

A. Applicable Law

Patent claim construction is a “question of law, to be determined by the court.” Markman v. Westview Instruments, Inc., 517 U.S. 370, 384, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996); Markman v. Westview Instruments, Inc., 52 F.3d 967, 997 (Fed.Cir.1995). The patentee may exercise the right to exclude granted by its patent, and “the claims of a patent define the invention to which the patentee is entitled the right to exclude.” Phillips v. AWH Corp., 415 F.3d 1303, 1312 (Fed.Cir.2005) (en banc). The patentee must “define precisely what his invention is,” because it would be “unjust to the public, as well as an evasion of the law, to construe [the patent] in a manner different from the plain import of its terms.” Id. (quoting White v. Dunbar, 119 U.S. 47, 52, 7 S.Ct. 72, 30 L.Ed. 303 (1886)). A court need only construe, however, claims “that are in controversy, and only to the extent necessary to resolve the controversy.” Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc., 200 F.3d 795, 803 (Fed.Cir.1999).

The Court begins its claim construction analysis with the words of the claim. Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed.Cir.1996). The words of a claim are given their ordinary and customary meaning, which “is the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention,” i.e., as of the effective filing date of the patent application. Nystrom v. TREX Co., Inc., 424 F.3d 1136, 1142 (Fed.Cir.2005) (citing Phillips, 415 F.3d at 1313). A person of ordinary skill in the art is not deemed to read the disputed claim term in isolation, but instead “views the claim term in light of the entire intrinsic record,” id., i.e., “in the context of the entire patent, including the specification.” Conoco, Inc. v. Energy & Envtl. Int’l, L.C., 460 F.3d 1349, 1357 (Fed.Cir.2006) (quoting Phillips, 415 F.3d at 1313).

To ascertain the meaning of claims, the Court must first consider the intrinsic record, which consists of three sources: the claims, the specification, and the prosecution history. Markman, 52 F.3d at 979. The first and most important step in the Court’s inquiry is to examine the words used in the claims themselves, both asserted and unasserted claims. Vitronics, 90 F.3d at 1582; accord Phillips, 415 F.3d at 1314 (“[T]he claims themselves provide substantial guidance as to the meaning of the particular claim terms.”); Digital Biometrics, Inc. v. Identix, Inc., 149 F.3d 1335, 1344 (Fed.Cir.1998) (“The actual words of the claim are the controlling focus.”). Because claim terms are often used “consistently throughout the patent, the usage of a term in one claim can often illuminate the meaning of the same term in other claims.” Phillips, 415 F.3d at 1314.

The next source to be considered is the specification. The specification is required to provide a written description of the invention in “full, clear, concise, and exact terms,” 35 U.S.C. § 112, and the patentee may satisfy this requirement by using “such descriptive means as words, structures, figures, diagrams, formulas, etc., that set forth the claimed invention.” Regents of the Univ. of Cal. v. Eli Lilly & Co., 119 F.3d 1559, 1566 (Fed.Cir.1997). On questions of claim construction, “[usually, [the specification] is dispositive; it is the single best guide to the meaning of a disputed term.” Phillips, 415 F.3d at 1315 (citing Vitronics, 90 F.3d at 1582). Where the specification “reveal[s] a special definition given to a claim term by the patentee that differs from the meaning it would otherwise possess,” it is “the inventor’s lexicography” that governs. Id. at 1316. Similarly, where the specification “reveal[s] an intentional disclaimer, or disavowal, of claim scope by the inventor,” again, “the inventor’s intention, as expressed in the specification, is regarded as dispositive.” Id.

The Federal Circuit has cited as a “well-established” principle that a “court may not import limitations from the written description into the claims.” Laitram Corp. v. NEC Corp., 163 F.3d 1342, 1347 (Fed.Cir.1998). The disclosure of a particular embodiment of the claimed invention in the specification does not function to narrow the patent claims. See id. at 1347-48. It is also the case, however, that a proposed claim interpretation that would exclude a preferred embodiment would rarely, if ever, be correct. See SanDisk Corp. v. Memorex Prods., Inc., 415 F.3d 1278, 1285 (Fed.Cir.2005) (quoting Vitronics, 90 F.3d at 1583). “It is therefore entirely appropriate for a court, when conducting claim construction, to rely heavily on the written description for guidance as to the meaning of the claims.” Phillips, 415 F.3d at 1317.

Next, the patent’s prosecution history, as part of the “intrinsic record,” should be considered by the Court when construing a claim. See Markman, 52 F.3d at 980. The prosecution history consists of the complete record of proceedings before the PTO, including reexamination proceedings. Phillips, 415 F.3d at 1317; CIAS, Inc. v. Alliance Gaming Corp., 504 F.3d 1356, 1362-63 (Fed.Cir.2007); CVI/Beta Ventures, Inc. v. Tura LP, 112 F.3d 1146, 1155-56 (Fed.Cir.1997). Prior art cited in the patent examination or reexamination is also part of the prosecution history. Phillips, 415 F.3d at 1317. The patent prosecution history “often lacks the clarity of the specification and thus is less useful for claim construction purposes,” id., however, it is still “often of critical significance in determining the meaning of the claims.” Vitronics, 90 F.3d at 1582.

The purpose of consulting the prosecution history is to determine “how the inventor understood the invention and whether the inventor limited the invention in the course of prosecution, making the claim scope narrower than it otherwise would be.” Phillips, 415 F.3d at 1317 (citing Vitronics, 90 F.3d at 1582-83). The Court consults the prosecution history in order to “exclude any interpretation that was disclaimed during prosecution.” Chimie v. PPG Indus., Inc., 402 F.3d 1371, 1384 (Fed.Cir.2005). District courts therefore have broad power to look at the prosecution history to determine “the true meaning of language used in the patent claims,” since this history may demonstrate the patentee’s understanding and use of the relevant terms at the time of the application. See Markman, 52 F.3d at 980. Importantly, however, the prosecution history may not be used to “enlarge, diminish, or vary the limitations in the claims.” Id. Moreover, a patentee may not construe a claim term one way during prosecution in order to obtain allowance of the patent and then in a different way during litigation in order to obtain a finding of infringement. See Chimie, 402 F.3d at 1384; Omega Eng’g, Inc. v. Raytek Corp., 334 F.3d 1314, 1323-26 (Fed.Cir.2003); Southwall Techs., Inc. v. Cardinal IG Co., 54 F.3d 1570, 1576 (Fed.Cir.1995). In order for the patentee to disclaim an interpretation, the alleged disavowing statements in the prosecution history must be “clear and unmistakable.” Omega Eng’g, 334 F.3d at 1325-26 (“[W]e ... have consistently rejected prosecution statements too vague or ambiguous to qualify as a disavowal of claim scope.... ”).

Generally, the Court will be able to resolve any ambiguity in a disputed claim term by considering the intrinsic record, in which case, “it is improper to rely upon extrinsic evidence.” Vitronics, 90 F.3d at 1583. Expert testimony, dictionaries, treatises, and other types of extrinsic evidence, while considered to be “less reliable than the patent and its prosecution history in determining how to read claim terms,” Phillips, 415 F.3d at 1318, are still “an available resource” and are “often useful” to claim construction, Vanguard Prods. Corp. v. Parker Hannifin Corp., 234 F.3d 1370, 1372 (Fed.Cir.2000). In any event, trial courts may always consult extrinsic evidence in aid of understanding the general technology involved in the patent claims at issue, but not to vary or contradict the patent claims. See Phillips, 415 F.3d at 1319-24; Vitronics, 90 F.3d at 1584 n. 6. Ultimately, “[t]he construction that stays true to the claim language and most naturally aligns with the patent’s description of the invention will be, in the end, the correct construction.” Phillips, 415 F.3d at 1316.

B. Construction of “magnetization recovery period”

Claim 1, limitation (c) reads, “a magnetization recovery period which allows T1 and T2 relaxation before the start of the next sequence cycle”, (emphasis added) The parties dispute the meaning of the term “magnetization recovery period,” and disagree over whether the reexamination proceedings changed its meaning. The resolution of this term’s meaning is both important to the Court’s construction of Claim 1 and crucial to the Court’s decision on GE’s motion for partial summary judgment, which is discussed in Section III. below. First, I will determine the meaning of the “magnetization recovery period” limitation in Claim 1 as of the filing date of the application for the patent in suit and prior to reexamination. Then I will address the parties’ arguments in the claim construction briefing and hearing over whether the meaning of the term was altered by the reexamination proceedings. I reserve for Section III. discussion of the scope of the change in the meaning of the term.

1. Construction of “magnetization recovery period” as of Filing Date of Patent Application

The parties dispute whether, from the time the application was filed and prior to reexamination, the “magnetization recovery period” limitation, properly construed, was broad enough to encompass a process wherein duration of the period was zero, i.e., where no magnetization recovery period was provided.

GE contends that prior to the reexamination, limitation (c) encompassed a magnetization recovery period of zero duration. (Def.’s Mem. in Support of Mot. Partial Summ. J. 8.) GE points to several portions of the specification, Figure 5, and Claim 4 for support. First, it is stated in the “Summary of the Invention” section of the specification that “[a] magnetization recovery period is provided which allows TI and T2 relaxation before the start of the next sequence cycle. The magnetization recoven'y period can have a time of zero.” '282 Patent, col. 2, 11. 20-26 (emphasis added). Second, it is stated in the “Description of the Preferred Embodiments” section of the specification that “[t]he two limiting cases for the magnetization recovery period are zero duration and a duration which is relatively long compared to the Tls of interest.” '282 Patent, col. 15, 11. 18-20 (emphasis added). Third, Example III describes and Figure 5 illustrates a preferred embodiment of the invention having a magnetization recovery period of “none.” '282 Patent, col. 18, 11. 5-13. Fourth, dependent Claim 4 recites “[t]he method of claim 1, wherein said magnetization recovery period has a time of zero.” As GE correctly concludes, because dependent Claim 4 covers the specific case where the recovery period has time zero, its independent Claim 1 must cover that specific case as well. (Def.’s Mem. Supp. Mot. Partial Summ. J. 8-9 (citing EMI Group N. Am., Inc. v. Cypress Semiconductor Corp., 68 F.Supp.2d 421, 430 (D.Del.1999), aff’d in relevant part, 268 F.3d 1342 (Fed.Cir.2001)).)

The Patent Foundation argues that Claim 1 cannot encompass the possibility of a duration of time zero because Claim 1 plainly states that the magnetization recovery period allows for TI and T2 relaxation, and no such relaxation would occur if the recovery period had a time period of zero. (PL’s Resp. Br. Opp’n Mot. Partial Summ. J. 3-4,12-13.)

After consideration of the parties’ contentions and in accordance with the principles of claim construction, I hold that from the time the application for the patent was filed and until the issuance of the reexamination certificate, the “magnetization reeovery period” in Claim 1 encompassed within its scope a time period of zero. In reaching this conclusion, I ascribe to the claim’s term the meaning that would have been accorded it by a person of ordinary skill in the art, who would have read the claim in light of the entire intrinsic record, including the specification. See Nystrom, 424 F.3d at 1142; Conoco, 460 F.3d at 1357 (quoting Phillips, 415 F.3d at 1313).

Here, the person of ordinary skill in the art would see that the patentee expressly and unambiguously states in two places in the patent specification that one possible time period for the magnetization recovery period is zero duration. See 282 Patent, col. 2, 11. 20-26; id. col. 15, 11. 18-20. In addition, the person of ordinary skill in the art would review the embodiments the patentee labeled as “preferred,” one of which (Example III) has no magnetization recovery period. See id., col. 18, 11. 5-14. The Patent Foundation’s proposed claim interpretation would exclude that “preferred” embodiment; such an interpretation is rarely, if ever, the right one. See SanDisk Corp., 415 F.3d at 1285. The specification “is the single best guide to the meaning of a disputed term,” and here it makes abundantly clear that a magnetization recovery period of zero duration is within the intended scope of Claim 1. See Phillips, 415 F.3d at 1315 (“Usually, [the specification] is dispositive.... ”).

Dependent Claim 4, in specifically reciting “[t]he method of claim 1, wherein said magnetization recovery period has a time of zero,” supports this conclusion. In light of the requirement that an independent claim be broad enough to encompass a limitation added by a claim dependent therefrom, dependent Claim 4 necessarily implies that Claim 1 is sufficiently broad in scope to include a period of time zero.

In consideration of this overwhelming evidence, I hold that prior to the reexamination, a person of ordinary skill in the art would have understood the term “magnetization recovery period” in Claim 1 to include the case of a time of zero duration. The Patent Foundation’s argument that limitation (c) must allow for TI and T2 relaxation to occur and that no such relaxation would occur if the magnetization recovery period had a time period of zero would only be persuasive if limitation (c) were read in isolation, i.e., without giving due consideration to the specification and to Claim 4. But such a reading of the claim terminology in isolation would be contrary to Federal Circuit precedent. See, e.g., Conoco, 460 F.3d at 1357; Phillips, 415 F.3d at 1313.

2. Construction of “magnetization recovery period” After Reexamination

I turn now to determine the meaning of the “magnetization recovery period” limitation as of the close of the reexamination proceedings. The Patent Foundation proposes construing the term as “a distinct period following data acquisition which allows TI and T2 relaxation and provides for additional control over the image contrast.” GE offers the definition “a distinct time period, greater than 150 [milliseconds], for recovery of magnetization in the tissues of interest.” For the reasons stated below, the Court adopts the following construction of “magnetization recovery period”: “a distinct period following data acquisition which allows T1 and T2 relaxation and provides for additional control over the image contrast.”

Both parties proposed adding the term “distinct” to describe the duration of time of the recovery period, although “distinct” is not used in the patent’s glossary definition for “magnetization recovery period.” The addition of “distinct” is intended to clarify that the recovery period must have a positive value and cannot be of duration zero. The parties appear to agree that as of the Patent Foundation’s filing of the amendment canceling Claim 4 and the accompanying remarks, the magnetization recovery period cannot be a time of zero, though they disagree about the reasons for that construction. The Patent Foundation argues that the term always precluded a value of zero, whereas GE argues that the original patent included the option of a value of zero but the Patent Foundation disclaimed that option during the reexamination proceedings. Indeed, the Patent Foundation’s Amendment expressly stated to the PTO that the magnetization recovery period “precludes an embodiment wherein the magnetization recovery period is zero or none.” Pl.’s Amendment at 14. Having already decided that the magnetization recovery period included the possibility of a value of zero prior to the issuance of the reexamination certificate, I concur with GE that the statements made by the Patent Foundation in the reexamination proceedings disclaimed the possibility of time zero. Accordingly, I interpret the meaning of “magnetization recovery period” following reexamination to include the limitation that the period be “distinct.”

The Patent Foundation proposes that the phrase “and provides for additional control over the image contrast” be added to the construction. Although this phrase is not found in the patent’s glossary definition of magnetization recovery period, a variation of it is stated at least twice in the specification. See '282 Patent, col. 4, 11. 21-23 (“Additional control over the image contrast is provided by varying the duration of the magnetization recovery period.”); id., col. 15,11. 10-18 (“The recovery period provides an additional degree of freedom for controlling the image contrast by providing additional time for TI and T2 relaxation before the start of the next sequence cycle. The duration of the recovery period is determined by the desired contrast properties of the image, the T1 relaxation properties of the tissues, and the state of the longitudinal magnetization at the end of the gradient-echo acquisition.”). GE contends that the proffered phrase is merely one description of the preferred embodiment and was not designed to define the claim term. GE adds that there is no justification for defining the term in this way, that the language is redundant because allowing TI and T2 relaxation is itself the method for controlling the image contrast, and that the language is vague.

I find it appropriate to include the phrase “and provides for additional control over the image contrast” in the construction of “magnetization recovery period.” On questions of claim construction, the specification “is the single best guide to the meaning of a disputed term.” Phillips, 415 F.3d at 1315 (citing Vitronics, 90 F.3d at 1582). Here, the patentee provided in two separate places in the specification an explicit statement of the relationship between the duration of the magnetization recovery period and the resulting image contrast. An ordinary person skilled in the art, after reviewing the statements in the specification that explicitly discuss image contrast, would recognize that the magnetization recovery period plays a key role in enabling control of image contrast. The magnetization recovery period’s function in affecting image contrast appears to be the principal, if not sole, benefit of having a recovery step in the imaging process. Nothing in the claims or the patent’s glossary definition contradicts or undermines this view.

I decline to adopt GE’s proposed construction, which would require the magnetization recovery period to last for at least 150 milliseconds. A 150 millisecond period is not described anywhere in the patent. GE argues that in the reexamination proceedings, the Patent Foundation disclaimed a magnetization recovery period of less than 150 milliseconds in order to distinguish its patent claims from prior art U.S. Patent No. 4,707,658. (Def.’s Opening Claim Constr. Br. 16-17.) In support, GE cites to sections of the amendment and comments that the Patent Foundation submitted to the PTO in the reexamination proceedings, and to the Patent Examiner’s Statement of Reasons for Patentability.

It is only the Patent Examiner’s statement that suggests that a magnetization recovery period of less than 150 milliseconds would be anticipated by the '658 Patent. See Statement of Reasons for Patentability at 6 (“[F]or cases in which T1 and T2 are smaller than 150 ms, unintentional Tl and T2 relaxation occurs, and [the '659 Patent] would inherently anticipate the claimed magnetization recovery period.”). But to disclaim an interpretation, the Patent Foundation’s disavowing statements must be “clear and unmistakable,” see Omega Eng’g, 334 F.3d at 1325-26, and here the Patent Foundation never disavowed a magnetization recovery period of less than 150 milliseconds. A unilateral statement by a patent examiner without a disavowal of claim scope by the patentee is not sufficient to constitute a disclaimer. Salazar v. Procter & Gamble Co., 414 F.3d 1342, 1344-48 (Fed.Cir.2005) (holding that a unilateral statement by a patent examiner in stating his reasons for allowance did not disavow claim scope because “the applicant has disavowed nothing”) (emphasis added); cf. Phillips, 415 F.3d at 1317 (describing the purpose of consulting prosecution history as a means to determine “how the inventor understood the invention and whether the inventor limited the invention in the course of prosecution”) (emphasis added).

C. Construction of “Tl and T2 Relaxation”

The next term to construe is “Tl and T2 relaxation,” which is found in Claim 1, limitation (c), reciting “a magnetization recovery period which allows Tl and T2 relaxation before the start of the next sequence cycle”, (emphasis added) The Patent Foundation proposes that “Tl relaxation” be defined as “the process by which the longitudinal component of the magnetization vector relaxes to its thermal equilibrium value aligned with the main magnetic field” and “T2 relaxation” be defined as “the process by which the transverse component of the magnetization vector relaxes to its thermal equilibrium value of zero.” In contrast, GE proposes that “Tl relaxation” be defined as “the amount of longitudinal relaxation that takes place in longitudinal relaxation time Tl; each tissue has a characteristic time constant Tl,” and “T2 relaxation” be defined as “the amount of transverse relaxation that takes place in transverse relaxation time T2; each tissue has a characteristic time constant T2.”

Neither “Tl relaxation” nor “T2 relaxation” is defined in the patent, however, “Tl” is defined in the patent’s glossary as “[t]he spin-lattice or longitudinal relaxation time. See longitudinal relaxation.” '282 Patent, col. 21,11. 42-43. Similarly, “T2” is defined in the glossary as “[t]he spin-spin or transverse relaxation time. See transverse relaxation.” '282 Patent, col. 21, 11. 47-48. In turn, “longitudinal relaxation,” which is referenced in the definition of “Tl,” is defined in the glossary as “[t]he process by which the longitudinal component of the magnetization vector relaxes to its thermal equilibrium value aligned with the main magnetic field. The relaxation takes place with a characteristic time constant Tl.” '282 Patent, col. 19, 11. 60-64. “Transverse relaxation,” which is referenced in the definition of “T2,” is defined in the glossary as “[t]he process by which the transverse component of the magnetization vector relaxes to its thermal equilibrium value of zero. The relaxation takes place with a characteristic time constant T2.” '282 Patent, col. 21, 11. 62-65.

The Patent Foundation’s proposed constructions are exactly the same as the first sentences of the definitions for longitudinal relaxation and transverse relaxation. The second sentences, which describe the characteristic time constant, are excluded from the Patent Foundation’s construction. This reflects, argues the Patent Foundation, that Tl and T2 relaxation would be understood by a person with ordinary skill in the art in question reviewing the '282 patent as processes rather than fixed amounts of time because the other limitations of Claim 1 refer to processes. In contrast, GE argues that Tl and T2 relaxation are the fixed amounts of relaxation that occur within the time it takes a particular tissue to relax within time constant Tl or T2. Under this construction, the amount of Tl or T2 relaxation will depend on the type of tissue being imaged because each tissue has a particular Tl time and T2 time associated with it. GE reaches its construction by taking Tl and T2, which the glossary defines as an amount of time, and pairing that understanding of Tl and T2 with relaxation, which is a process as shown by the glossary definitions of longitudinal relaxation and transverse relaxation. When placed together, the phrase Tl relaxation (or T2 relaxation) “is understood to be the amount of that process that occurs in Tl.” (Def.’s Opening Claim Constr. Br. 22.) GE’s construction would place a clear time constraint on the duration of the magnetization recovery period.

I conclude that the Patent Foundation’s proposed constructions reflect the terms’ ordinary and customary meaning and are best supported by the intrinsic evidence. Although the patent glossary defines Tl and T2 as fixed amounts of time, and longitudinal relaxation and transverse relaxation as processes of relaxation, it never defines Tl relaxation or T2 relaxation. To best approximate the meaning of those terms, GE combines the definition of Tl and part of the definition of longitudinal relaxation, and the definition of T2 and part of the definition of transverse relaxation. This method, though somewhat logical, does not produce an accurate interpretation of the terms at issue. In fact, GE’s construction would prove quite unworkable in practice. An MRI scan involves at least two tissues, and sometimes more. The hydrogen atoms in each tissue take a different amount of time to relax, and so the atoms in the tissues have different Tl and T2 values associated with them. Because GE’s proposed construction does not specify to which tissue type its construction is applicable, it would be unclear in any given scan which tissue’s atom’s Tl or T2 values should be used to determine the length of the magnetization recovery period.

GE’s construction would also render the reference in Claim 1 to T2 relaxation superfluous because Tl relaxation is always a greater value than T2 relaxation. Accordingly, a magnetization recovery period would always have to last long enough to allow Tl relaxation, but never more since T2 relaxation would have already occurred. Moreover, an ordinary person skilled in the art would think it highly unlikely that the patentee intended to limit the claimed invention to the precise values of Tl and T2 for a given tissue being imaged without describing that limitation and the reason for it in any detail in any part of the patent. Such a major restriction on the scope of the patent claims appears unlikely to have been intended to be included in the terms Tl relaxation and T2 relaxation, which are commonly understood by experts in the field to be interchangeable with the processes of longitudinal relaxation and transverse relaxation.

The construction proposed by the Patent Foundation is supported by the intrinsic evidence. First, it draws from the definitions provided in the patent’s glossary of longitudinal relaxation and transverse relaxation, which are referenced in the definitions of Tl and T2. Second, it provides a basis of interpretation of the claimed magnetization recovery period stage that is compatible with the clear import of the previous two stages and the process of the claimed invention. It appropriately characterizes the recovery period as a process. Claim 1 sets forth a “cycle” for producing image data that is divided into four “steps,” with each step representing a process or “period.” '282 Patent, col. 22, 11. 7-25. The “magnetization preparation period” referred to in step (a) and the “data acquisition period” referred to in step (b) clearly, by their terms, describe a process or series of events that occur at each of those steps. Likewise, the “magnetization recovery period” in step (c) refers to the process of Tl and T2 relaxation, not the amount of time for a specific amount of such relaxation to occur.

Although the intrinsic evidence by itself adequately supports the constructions of Tl relaxation and T2 relaxation adopted by the Court, the extrinsic evidence is consistent with this meaning. The parties provided expert testimony that, on the whole, indicated that Tl relaxation and longitudinal relaxation are viewed by persons of ordinary skill in the art as different ways to describe the same process of relaxation. 0See Haacke Dep. 106:6-20, June 22, 2010 (Pl.’s expert) (testifying that Tl relaxation and longitudinal relaxation are always used synonymously); Gore Dep. 62:6-15, June 14, 2010 (Def.’s expert) (testifying that outside this particular patent, “many people” of ordinary skill in the art would use the terms Tl relaxation and longitudinal relaxation “interchangeably”); contra Gore Decl. ¶¶ 66-67, June 24, 2010.) As demonstrated in oral argument, GE’s own online medical encyclopedia defines T2 relaxation as “one of two principle contrast determining processes of the NMR phenomenon (the other being spin-lattice, longitudinal or Tl relaxation), also known under the names of transverse relaxation and spin-spin relaxation.” (emphasis added). GE’s encyclopedia defines Tl relaxation as the “process by which the longitudinal magnetization Mz attains its equilibrium value MzO” and under “longitudinal relaxation” it says “see T1 relaxation.” (emphasis added) Thus, the weight of the extrinsic evidence aligns with the meaning of the terms adopted by the Court.

D. Construction of “repeating steps a, b and c” and of “wherein said time period employed for magnetization recovery is also employed for magnetization preparation”

Claim 1, limitation (d) states “repeating steps a, b and c until a predetermined k-space volume is sampled.” '282 Patent, col. 22, 11. 24-25. Dependent Claim 44 adds the following limitation: “The method of claim 1, wherein said time period employed for magnetization recovery is also employed for magnetization preparation.” '282 Patent, col. 24, 11. 49-51. At the center of the parties’ dispute over these phrases is a disagreement about whether each step in Claim 1 of the patent must be distinct from both the prior step and the successive step, or whether overlap is permitted between step (c) and the following step (a).

The Patent Foundation proposes interpreting the term “repeating steps, a, b and c” as meaning “repeating steps a, b, and c, in that order, until a predetermined k-space volume is sampled.” The Patent Foundation’s position is that each of the steps need not be distinct from one another, but only need be sequential, which does not preclude overlapping. It points to dependent Claim 44, which includes an embodiment of the sequence wherein the time period employed for magnetization recovery in step (c) can also be used for magnetization preparation in step (a) of the following sequence. The Patent Foundation argues that this potential secondary use of the magnetization recovery period was highlighted as one of five “[a]dvantages of the 3D MP RAGE technique” when compared to prior three-dimensional imaging techniques. '282 Patent, col. 15, 11. 60-65. In fact, this portion of the specification states that “[t]he dead times in the magnetization preparation and/or recovery periods can be used for secondary magnetization preparations such as spatial or chemical presaturation.” '282 Patent, col. 16, 11. 12-15. Finally, the Patent Foundation calls the Court’s attention to Figure 1 of the patent, in which “secondary preparations” is listed as an aspect of the magnetization recovery period. '282 Patent, Figure 1, page 2.

In contrast, GE proposes construing step (d) to mean “repeating distinct steps a, b and c, in that order until a predetermined k-space volume is sampled.” GE argues that “distinct” is an appropriate interpretation because language in the specification provides that the magnetization preparation period must be distinct from the data acquisition period, and the Patent Foundation itself described the magnetization recovery period as distinct in the reexamination proceedings. Following from the conclusion that the steps must be distinct, GE takes the position that Claim 44 is indefinite because it contradicts the requirement that the steps be distinct, precluding a person of ordinary skill in the art from determining the scope of the claim. (Def.’s Opp’n Claim Constr. Br. 24 (citing Competitive Techs. v. Fujitsu Ltd., 286 F.Supp.2d 1161, 1175 (N.D.Cal.2003))).

The words of the claim are “generally given [the] ordinary and customary meaning” that the terms would have “to a person of ordinary skill in the art in question.” Phillips, 415 F.3d at 1312-13. With that guiding principle in mind, the Court observes that on its face, Claim 1, step (d) does not require that steps (a), (b), or (c) be distinct. The language of step (c) does not exclude the possibility that magnetization preparation could be conducted during magnetization recovery. The passages from the specification cited by GE that use the term “distinct” merely indicate that step (a) and step (b) are separate; no comparable language in the specification supports the proposition that step (c) is distinct from the step (a) in the following sequence cycle. Rather, the specification explicitly contemplates the possibility of some overlap between the magnetization recovery period and the subsequent magnetization preparation period, stating in two places the possibility of conducting secondary magnetization preparations during the recovery period. See 282 Patent, Figure 1, page 2; id. col. 16, 11. 12-15.

It is also important to note that when construing one claim term, “[o]ther claims of the patent in question, both asserted and unasserted, can also be valuable sources of enlightenment as to the meaning of a claim term.” Phillips, 415 F.3d at 1314. The fact that Claim 44 provides for magnetization recovery to occur at the same time as magnetization preparation activities strongly suggests that step (c) allows overlap with the subsequent step (a). The Patent Foundation’s proposed constructions of Claim 1, limitation (d) and Claim 44 are consistent with, and mutually support, each other. In contrast, GE’s interpretation of Claim 1, limitation (d) would, according to GE, create a contradiction between Claim 1 and Claim 44, and require the Court to find Claim 44 invalid for indefiniteness. Courts are especially reluctant to invalidate a claim where a narrowing definition is available. See Datamize, LLC. v. Plumtree Software, Inc., 417 F.3d 1342, 1347-48 (Fed.Cir.2005).

The Court must also consider whether the prosecution history sheds light on the meaning of the claims, or whether the patentee disclaimed the possibility of overlap between the steps. The Patent Foundation used the adjective “distinct” to describe step (c) several times in its comments accompanying the amendment during the reexamination proceedings. See, e.g., Pl.’s Amendment at 30 (“step (c) provides a distinct magnetization recovery period which allows TI and T2 relaxation to occur before the start of the next preparation-acquisition-recovery pulse sequence cycle, and which occurs outside of the repetitions of the gradient-echo pulse sequence”) (emphasis added). GE claims that the Patent Foundation’s statements were made to maintain the validity of the patent in light of prior art. But these statements do not disavow, in a “clear and unmistakable” manner, the possibility that secondary preparations can be conducted during the recovery period, see Omega Eng’g, 334 F.3d at 1325-26, or otherwise indicate that the patentee intended the terminology to preclude overlap. In several instances, “distinct” is explicitly used by the Patent Foundation to merely distinguish the magnetization recovery period from the data acquisition period, which does not address the issue of whether the recovery period must be separate from the next preparation period. See PL’s Amendment at 30, 34, 42. The statements that do address the relationship between step (c) and step (a) were made in the context of distinguishing prior art that contained relaxation time intervals during or between radiofrequency pulses. In essence, those statements were made in the context of arguing that the magnetization recovery period is actually a third step, rather than an interval of relaxation within step (a) or step (b). Those statements did not address, nor did the prior art raise, whether the TI and T2 relaxation in step (c) was distinct from any type of magnetization preparation activity, such as the chemical or spatial presaturation activities described in the specification. Thus, those statements are also irrelevant to determining whether the possibility of overlap between the steps was disclaimed. Notably, the relevant parts of the specification and Claim 44 were not addressed in the reexamination proceedings. Therefore, I conclude that the evidence is not clear and unmistakable that the Patent Foundation disclaimed the option of having some overlap between step (e) and step (a).

I adopt the construction of Claim 1, limitation (d) proposed by the Patent Foundation, “repeating steps a, b and c, in that order, until a predetermined k-space volume is sampled,” which is best supported by the intrinsic evidence, as I describe above. Having found that step (c) and the subsequent step (a) need not be distinct, there is no logical contradiction between Claim 1 and Claim 44 that could render Claim 44 indefinite. Claim 44 merely encompasses an embodiment in which magnetization preparation is conducted during the magnetization recovery period, which is consistent with the descriptions in the specification of secondary preparation activities occurring during recovery. '282 Patent, Figure 1, page 2; id. col. 16, 11. 12-15. The Federal Circuit has set a high bar for finding a claim term indefinite, which is not met here because the claim terms are amenable to the constructions adopted herein. See Praxair, Inc. v. ATMI, Inc., 543 F.3d 1306, 1319 (Fed.Cir.2008) (“A claim will be found indefinite only if it is insolubly ambiguous and no narrowing construction can properly be adopted.”); Datamize, 417 F.3d at 1347-48 (“By finding claims indefinite only if reasonable efforts at claim construction prove futile, we accord respect to the statutory presumption of validity and we protect the inventive contribution of patentees, even when the drafting of their patents has been less than ideal. In this way we also follow the requirement that clear and convincing evidence be shown to invalidate a patent.”).

E. Construction of “gradient echo sequence”

Claim 1, limitation (b) of the '282 Patent recites “a data acquisition period, said data acquisition period including at least two repetitions of a gradient echo sequence to acquire data for a fraction of k-space”. (emphasis added) The parties dispute the meaning of the term “gradient echo sequence.” Although the patent does not define “gradient echo sequence,” it defines “gradient echo” as follows:

A refocusing of phase coherence among spin isochromats at different positions along the magnetic field gradient resulting from (1) balanced negative and positive gradient pulses, or (2) balanced gradient pulses of the same sign on opposite sides of an RF pulse. A gradient echo does not refocus phase shifts due to static field inhomogeneities, susceptibility differences or chemical shift.

'282 Patent, col. 19,11. 25-33.

The Patent Foundation proposes defining the term as “a pulse sequence that includes just one RF pulse before reading out a line or multiple lines of data.” The Patent Foundation’s proposed construction is drawn from an identical definition of “gradient echo” provided in a textbook on the subject. See E. Mark Haacke et al. Magnetic Resonance Imaging: Physical Principles and Sequence Design 821 (1999). The Patent Foundation argues that the patent’s glossary definition of “gradient echo” should not be used to define “gradient echo sequence” because a gradient echo is a phenomenon that can be produced by a spin echo sequence as well as by a gradient echo sequence. According to this argument, the definition of “gradient echo” would not accurately capture the defining characteristics of a gradient echo sequence.

In contrast, GE proposes defining the term as “a sequence of pulses for creating and refocusing phase coherence among spin isochromats at different positions along the magnetic field gradient resulting from (1) balanced negative and positive gradient pulses, or (2) balanced gradient pulses of the same sign on opposite sides of an RF pulse.” GE reaches its construction by taking the first sentence of the patent glossary’s definition of “gradient echo” and modifying it to mean a “sequence of pulses ...,” not an echo. GE argues that by defining “gradient echo” in the glossary, the patentee acted as its own lexicographer, and gradient echo sequence should be defined by incorporating the patentee’s own choice of definition.

The Court begins its claim construction inquiry with the intrinsic evidence. On its face, the glossary definition describes a “refocusing of phase coherence” that results from balanced negative and positive gradient pulses or from balanced gradient pulses and a radiofrequency pulse. The glossary definition describes the effect of pulses on phase coherence; it does not describe a sequence of pulses. Thus, it does not appear from the language of the glossary definition alone that the meaning of gradient echo is interchangeable with that of gradient echo sequence. Because the patent’s glossary only defines gradient echo and not gradient echo sequence, and there appears to be a difference between the two, it is not controlling, though it remains relevant in light of the similarity of the terms employed.

Aside from the patent’s glossary, the specification provides other clues that are relevant to how a person of ordinary skill in the art would interpret the claim. The patentee specified that a gradient echo sequence “may be any one of the standard gradient-echo techniques such as FLASH, FFE, GRASS, FAST, or FISP, or some variant of these sequences as described below.” '282 Patent, col. 13,11. 55-59; see also id., col. 8, 11. 17-22 (“The 3D short-TR gradient-echo sequences can be divided into two general categories, those which employ a steady state of only the longitudinal component of the magnetization vector (e.g., FLASH, FFE) and those which employ a steady state of the complete magnetization vector (e.g., GRASS, FAST, FISP).”). Thus, the construction of gradient echo sequence must be broad enough to include “any one of the standard gradient-echo techniques” within its scope. Both parties maintain that their constructions would encompass these standard categories of pulse sequences. Another piece of evidence is found in Figure 2 of the patent, which depicts a FLASH gradient echo sequence as consisting of a single radiofrequency pulse and negative and positive gradient pulses. '282 Patent, Figure 2, page 3; id. col. 3, 11. 45-48. The negative and positive gradient pulses depicted are consistent with the patent’s glossary definition of gradient echo, which states that the echo may result from “balanced negative and positive gradient pulses.”

Because the intrinsic record does not resolve the ambiguity in the meaning of gradient echo sequence, the Court proceeds to examine the extrinsic evidence while recognizing that such evidence is considered less reliable than evidence from the patent itself. See Phillips, 415 F.3d at 1318. Both parties have submitted extrinsic evidence to assist the Court with determining the meaning of the disputed term. The glossary of definitions provided in the Clinical Magnetic Resonance Imaging text is particularly helpful because it places a gradient echo sequence in the context of other pulse sequences and explains the relationship between a gradient echo and a pulse sequence. See Clinical Magnetic Resonance Imaging 1168 (Robert R. E delman & John R. Hesselink eds.) (1990). This source defines “pulse sequence” as a “[s]eries of radiofrequency and gradient pulses used to excite the spins and measure the MR [i.e., magnetic resonance] signal.” Id. Then, under the general heading of pulse sequence, the text provides the definitions for “gradient-echo sequence” and “spin-echo sequence.” Id. It defines a gradient echo sequence as a “[p]ulse sequence having a single radiofrequency (alpha) pulse. The echo is produced by reversal of the magnetic field gradients.” Id. The text also makes clear that a spin echo sequence involves two radiofrequency pulses rather than one and produces both a spin echo and a gradient echo. Id.

The definitions provided in the Clinical Magnetic Resonance Imaging text are consistent, on balance, with the remainder of the extrinsic evidence submitted for this Court’s review. Both that text and the text authored by the Patent Foundation’s expert state that a gradient echo sequence uses a single radiofrequency pulse. See Haacke et al„ supra, at 821 (defining “gradient echo” as “[a] method which uses just one rf pulse before reading out a line or multiple lines of data”). The parties’ experts appear to agree that within a data acquisition period, a gradient echo sequence contains only one radiofrequency pulse, though additional radiofrequency pulses may be used in preparation or ancillary to the data acquisition period. {See Tr. 179:5-10, 180:10-17, 184:8-16; Haacke Dep. 168:19-23.) The patent proposes using a gradient echo sequence only within the data acquisition period. See '282 Patent, col. 22,11. 16-20. The expert testimony also confirms that a gradient echo sequence produces a gradient echo, and a spin echo sequence produces both a spin echo and a gradient echo. {See Gore Dep. 136:19-21; Haacke Dep. 170:2-8.) Further, the Clinical Magnetic Resonance Imaging text’s description of a gradient echo sequence as a type of pulse sequence is supported by other extrinsic evidence. See David D. Stark & William G. Bradley, Jr., Magnetic Resonance Imaging 1464 (1988); Haacke Dep. 168:17-23. Finally, the expert testimony indicates that the phrase “(1) balanced negative and positive gradient pulses” describes the features of a gradient echo sequence. (See Tr. 183:9-14.)

Therefore, the extrinsic evidence demonstrates that a gradient echo sequence is not merely a sequence of pulses that create a gradient echo — such a sequence would also describe a spin echo sequence, which is a different type of sequence under the broader category of pulse sequences. Based on this insight, GE’s proposed construction is not entirely accurate because it fails to distinguish between a gradient echo sequence and a spin echo sequence. The key differences, according to the expert literature and testimony, are that a gradient echo sequence uses only one radiofrequency pulse before reading out a line of data and produces only a gradient echo, whereas the spin echo sequence uses at least two radiofrequency pulses before reading out a line of data and produces both a gradient echo and a spin echo. In order to remain faithful to the language chosen by the patentee in its glossary definition, I adopt the patent’s glossary definition but modify it to show that a gradient echo sequence is a type of pulse sequence, not an echo, and a gradient echo sequence involves only a single radiofrequency pulse, as compared to a spin echo sequence, which involves two.

These changes result in the following construction of gradient echo sequence: “a pulse sequence that includes just a