ACIST Medical Systems, Inc.

Patent Trials and Appeals Board

May 12, 2021

2020004944 (P.T.A.B. May. 12, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
13/902,224 05/24/2013 Robert F. Wilson 58534.57.2 6266
12827 7590 05/12/2021
Fredrikson & Byron, P.A.
Intellectual Property Group, ACIST Patents
200 South Sixth Street, Suite 4000
Minneapolis, MN 55402
EXAMINER
MOHAMMED, SHAHDEEP
ART UNIT PAPER NUMBER
3793
NOTIFICATION DATE DELIVERY MODE
05/12/2021 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
ip@fredlaw.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte ROBERT F. WILSON, EDWARD R. MILLER,
SIDNEY DONALD NYSTROM, and KENDALL R. WATERS

Appeal 2020-004944
Application 13/902,224
Technology Center 3700
____________

Before MICHAEL L. HOELTER, MICHAEL J. FITZPATRICK, and
JEREMY M. PLENZLER, Administrative Patent Judges.

FITZPATRICK, Administrative Patent Judge.

DECISION ON APPEAL
Appellant, ACIST Medical Systems, Inc.,1 appeals under 35 U.S.C.
§ 134(a) from the Examiner’s final decision rejecting claims 1–7, 10–12,
14–18, 35–41, 44–46, 48, 49, and 52. Appeal Br. 6. We have jurisdiction
under 35 U.S.C. § 6(b).
We reverse.

1 “Appellant” refers to the applicant as defined in 37 C.F.R. § 1.42.
Appellant identifies itself as the sole real party in interest. Appeal Br. 3.
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STATEMENT OF THE CASE
The Specification
Appellant’s “disclosure generally relates to systems and methods that
may be used to measure fluid flow through a [blood] vessel using imaging
techniques.” Spec. ¶5.
In one example, an injector system of a measurement system may
deliver a bolus of a flushing agent into a vessel of a patient and
the bolus may be observed using, for example, an ultrasound
transducer. Data collected from the ultrasound transducer may
be used to determine a travel distance of the bolus within the
vessel and/or an elapsed time during which the bolus traveled the
distance.
Id. The Specification explains that the flushing agent bolus can be
distinguished from blood via intravascular ultrasound (IVUS) by observing
changes in speckle densities:
The speckle density may be used to detect a position of the
quantity of fluid within the vessel to determine a start time and/or
an end time. Speckle is an image artifact that commonly appears
as specks in ultrasound images that are caused when structure in
an object is on a scale too small to be resolved by an imaging
system. A density of speckle (e.g., the density of specks in the
ultrasound image) is directly correlated to the concentration of
unresolvable structure in an object. Blood may be a cause of
speckle in an ultrasound image as the content of blood (e.g., red
blood cells, white blood cells, platelets) is too small to be
resolved by an ultrasound transducer. Generally, speckle is
considered an undesirable image artifact as it can mask small but
potentially diagnostically significant imaging features. To avoid
speckle caused by blood, many imaging systems (e.g., IVUS,
OCT) can be configured to use a flushing agent (e.g., saline,
contrast, Ringer’s solution, dextran, lactate solution) to clear
blood out of an area of interest within a vessel before imaging
the vessel.
Id. ¶36.
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The Claims
The first page of the Final Action erroneously indicates that only
claims 1, 4–7, 10–12, 14, 35, 38–41, 44–46, and 48 are pending and rejected.
Final Act. 1. However, the Final Action proceeds to additionally reject
pending claims 2, 3, 15–18, 36, 37, 49, and 52. Final Act. 6–18. Appellant
agrees that claims 2, 3, 15–18, 36, 37, 49, and 52 are pending (see Appeal
Br. 13–18) and rejected (see id. at 7–12). Thus, in total, claims 1–7, 10–12,
14–18, 35–41, 44–46, 48, 49, and 52 are rejected.
Claim 1 is illustrative of the claims on appeal and reproduced below.
1. A system comprising:
a catheter assembly including an intravascular measuring
device comprising an intravascular ultrasound imaging probe
having a measurement module configured to emit and receive
energy and generate ultrasound measurement data, the catheter
assembly configured to introduce a quantity of fluid into a
vessel of a patient; and
a measurement engine in communication with the
intravascular measuring device comprising at least one
processor, the measurement engine configured to:
receive the ultrasound measurement data from the
intravascular measuring device;
generate, using the at least one processor, a speckle
density value based on the ultrasound measurement data,
the speckle density value corresponding to a
concentration of structure in the vessel that is too small to
be resolved by the intravascular ultrasound imaging
probe, wherein when the quantity of fluid is introduced
into the vessel the speckle density value is relatively high
compared to the speckle density value when the
intravascular ultrasound imaging probe is surrounded by
the quantity of fluid;
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determine a fluid flow travel start time associated
with an introduction of the quantity of fluid into a
predetermined portion of the vessel;
determine a fluid flow travel end time as being
when the speckle density crosses a first predetermined
speckle density threshold using the at least one processor;
calculate, using the at least one processor, an
elapsed fluid flow travel time based on the fluid flow
travel start time and the fluid flow travel end time; and
calculate, using the at least one processor, a flow
rate of the quantity of fluid through the vessel based on
the elapsed fluid flow travel time and a travel distance of
the quantity of fluid during the elapsed fluid flow travel
time.
Appeal Br. 13.
The Examiner’s Rejections
The following rejections, all under 35 U.S.C. § 103, are before us:
(1) claims 1, 2, 6, 7, 10–12, 14–16, 35, 36, 40, 41, 44–46, and 48 as
unpatentable over Kemp,2 Knight,3 and Kassab4 (Final Act. 6);
(2) claims 2–5 and 36–39 as unpatentable over Kemp, Knight,
Kassab, and Roschak5 (id. at 10);
(3) claims 17 and 52 as unpatentable over Kemp, Knight, Kassab,
and Frinking6 (id. at 11);
(4) claim 18 as unpatentable over Kemp, Knight, Kassab, and
Schutt7 (id. at 12);

2 US 2012/0022360 A1, published Jan. 26, 2012 (“Kemp”).
3 US 2009/0234231 A1, published Sept. 17, 2009 (“Knight”).
4 US 2011/0196255 A1, published Aug. 11, 2011 (“Kassab”).
5 US 2009/0131765 Al, published May 21, 2009 (“Roschak”).
6 US 2009/0304593 A1, published Dec. 10, 2009 (“Frinking”).
7 US 2002/0065467 A1, published May 30, 2002 (“Schutt”).
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(5) claims 1, 2, 6, 7, 10–12, 14–16, 35, 36, 40, 41, 44–46, and 48 as
unpatentable over Kemp, Knight, and Tolkowsky (id. at 13);
(6) claims 2–5 and 36–39 as unpatentable over Kemp, Knight,
Tolkowsky, and Roschak (id. at 16–17);
(7) claims 17 and 52 as unpatentable over Kemp, Knight,
Tolkowsky, and Frinking (id. at 18); and
(8) claim 18 as unpatentable over Kemp, Knight, Tolkowsky, and
Schutt (id.).
DISCUSSION
Rejection 1
Appellant identifies two purported errors in the rejection of
independent claims 1 and 35 (the only independent claims on appeal):
“First, the Final Office Action’s rationale for combining teaching from
Knight with Kemp’s system is unsound. Second, even if such teaching from
Knight were combined with Kemp’s system (and teaching from Kassab), the
combined system would lack a key element required by each of claims 1 and
35.” Appeal Br. 7–8; see also id. at 9–11 (identifying the purportedly
lacking key element as the “first predetermined speckle density threshold”
recited in claims 1 and 35). For reasons explained below, we agree with
Appellant regarding the former and do not address the latter.
The Examiner found that Kemp discloses a method for intravascular
imaging and flushing that includes much of the subject matter of claims 1
and 35. Final Act. 6–8. However, the Examiner conceded that Kemp does
not explicitly teach the last two “calculat[ing]” steps of claims 1 and 35. Id.
at 8. The Examiner found that Knight discloses an “imaging catheter with
integrated contrast agent injector,” in which the fluid flow travel and end
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times are used to calculate an elapsed time for fluid flow (i.e., the first
calculating step). Id.8
Based on these findings, the Examiner determined:
Therefore, it would have been obvious to one of ordinary
skill in the art, before the filling of the effective day of the
claimed invention, to have utilized calculating the fluid flow
travel and end time, and calculating an elapsed time from the
fluid low travel and end time in the invention of Kemp, as taught
by Knight, to be able to know the exact timing when the flushing
fluid has arrived in the predetermined portion of the vessel for
more accurate start timing of the imaging.
Id.; see also Ans. 6 (“[P]roviding [Kemp] with the additional information
such as the fluid flow start and end time would provide accuracy of start
timing of the image by knowing precisely when the fluid flow arrives at the
region of interest by the IVUS probe.”).
Appellant argues that the Examiner’s rationale is deficient. Appellant
points out—correctly—that “Kemp determines the exact timing of when the
flushing fluid has arrived at the location of interest based on the
backscattering signal change and then begins image data collection that
instant.” Appeal Br. 8; Kemp ¶¶77–78, Fig. 6A. Appellant adds:
As soon as that backscattering signal change is received, Kemp
begins image data collection. The backscattering signal change
triggers image data collection without regard for any time
measurement. The amount of time from when the flushing fluid
is first introduced into the vessel to when the flushing fluid
causes the backscattering signal change would have had no effect
on the accuracy of when Kemp begins image data collection.
This is because information relating to flushing fluid flow
preceding its arrival at the imaging unit, as in Knight, is

8 The Examiner found that a third reference, Kassab, teaches the second
calculating step. The Examiner’s reliance on Kassab is not at issue in this
Decision.
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irrelevant to Kemp. Thus, contrary to the Final Office Action’s
assertion, one of ordinary skill in the art would have had no
motivation to have combined Knight’s measurement techniques
with Kemp’s system because it would have been clear that such
a combination would have provided no benefit.
Id. at 9. Appellant’s argument is factually correct and its conclusion about a
lack of motivation is persuasive. In fact, as discussed below, Kemp may
even teach away from the proposed modification.
Kemp “relates to methods for determining when to initiate an imaging
procedure inside a lumen of a vessel.” Kemp ¶2. Kemp explains that
“blood interferes” with imaging of a blood vessel. Id. ¶4. “Successful
imaging of the inside of the vessel . . . requires temporarily displacing the
blood from the portion of the vessel that will be imaged.” Id. However,
“the blood cannot be displaced for an extended period of time without
resulting in harm to a patient.” Id. Thus, “displacement of the blood must
be coordinated with initiation of the imaging procedure so that the imaging
procedure may be accomplished in an accurate and timely manner without
harming the patient.” Id. Kemp accomplishes its objective by measuring
changes in red blood cell “backscattering,” using this as a trigger for turning
imaging (or image capturing) on and off. Id. ¶77 (“Blood backscattering or
erythrocyte backscattering can be employed to detect the start and the stop
of a flush in the vessel lumen during imaging. The blood backscattering or
hemoglobin reflectivity measurement/signal is at a maximum during periods
before and after the saline flush and drops substantially when the flush bolus
arrives; thus represents a signal change.”). For example, after the flush
bolus is introduced and backscattering is no longer detected, “step 688 starts
the image acquisition and saving of the image frames to a memory device
operably coupled to the imaging system or computer system.” Id. ¶78,
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Fig. 6A; see also Ans. 4–5 (conceding that “Kemp does use the
backscattering signal to start collecting the imaging data”).
The Examiner does not explain how the proposed modification could
improve Kemp. In fact, the Examiner does not even explain how the
proposed modification would operate. As best we can understand, the
proposed modification would require injecting two flushes or boluses into a
patient’s vessel. The first bolus would be used to figure out how long it
takes to arrive at the portion of the vessel to be imaged and how long
thereafter it takes for blood to return to that same vessel portion. Then, the
second bolus would be used for the actual imaging operation, with the
imaging being turned on and off based on the travel times of the first bolus,
as opposed to actual arrival and departure of the second bolus. This
modification would, at best, result in the same imaging outcome as Kemp
unmodified yet would expose the patient to twice the amount of blood
displacement.9 Further, if the second bolus behaves differently than the first
bolus, the imaging obtained from the modification may actually be inferior
to that obtained from Kemp’s disclosed method.
The Examiner’s rationale does not support the conclusion of
obviousness. Accordingly, we reverse this rejection of independent claims 1
and 35. We likewise reverse the rejection of claims 2, 6, 7, 10–12, 14–16,
36, 40, 41, 44–46, and 48, each of which ultimately depends from either

9 For this reason, Kemp may even teach away from the proposed
modification. See Kemp ¶4 (explaining that blood should not be displaced
from a blood vessel portion for an extended period of time). However, as
Appellant does not argue that Kemp teaches away and such a finding is not
necessary for our Decision, we do not make a finding one way or another on
that issue.
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claim 1 or claim 35. See In re Fine, 837 F.2d 1071, 1076 (Fed. Cir. 1988)
(“Dependent claims are nonobvious under section 103 if the independent
claims from which they depend are nonobvious.”).
Rejections 2–8
All of these additional rejections rely on the same proposed
modification of Kemp in view Knight based on the same inadequate
rationale. Final Act. 10–12 (Rejections 2–4), 15 (Rejection 5), 16–18
(Rejections 6–8). Thus, for the same reason we reverse Rejection 1, we
likewise reverse Rejections 2–7.

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SUMMARY
Claim(s)
Rejected
35 U.S.C.
§
Reference(s)/
Basis
Affirmed Reversed
1, 2, 6, 7,
10–12, 14–
16, 35, 36,
40, 41, 44–
46, 48
103 Kemp, Knight,
Kassab
1, 2, 6, 7,
10–12, 14–
16, 35, 36,
40, 41, 44–
46, 48
2–5, 36–39 103 Kemp, Knight,
Kassab, Roschak
2–5, 36–39
17, 52 103 Kemp, Knight,
Kassab, Frinking
17, 52
18 103 Kemp, Knight,
Kassab, Schutt
18
1, 2, 6, 7,
10–12, 14–
16, 35, 36,
40, 41, 44–
46, 48
103 Kemp, Knight,
Tolkowsky
1, 2, 6, 7,
10–12, 14–
16, 35, 36,
40, 41, 44–
46, 48
2–5, 36–39 103 Kemp, Knight,
Tolkowsky,
Roschak
2–5, 36–39
17, 52 103 Kemp, Knight,
Tolkowsky,
Frinking
17, 52
18 103 Kemp, Knight,
Tolkowsky,
Schutt
18
Overall
outcome
1–7, 10–12,
14–18, 35–
41, 44–46,
48, 49, 52

REVERSED