Download “Black Blood” MR Angiography

Robert
Jonathan
Jeffrey
R. Edelman,
Kleefield,
B. Mendel,
MD
MD
MD
#{149}
Heinrich
#{149}
Craig
#{149}
Dennis
Extracranial
with
“Black
Carotid
Blood”
The authors
evaluated
the accuracy
of “black
blood”
magnetic
resonance
(MR) angiography
for depicting
disease
involving
al carotid
the
arteries.
Two-
extracrani-
and
three-
dimensional
flow-compensated
gradient-echo
sequences
were
ployed
to create
“bright
blood”
ages. A thin-section
quence
with
flow
lowed
the creation
images.
made
images
mumjection
angiograms
bright
with
emim-
spin-echo
sepresaturation
alof black
blood
Projection
from
and
were
black
application
blood
of a maxi-
or minimum-intensity
algorithm,
pro-
tients,
both
carotid
arteries
with both bright
methods;
in pawere
sensitive
in 13 of 33 arteries,
mostly
in
severe
disease;
this problem
was not
encountered
with black
blood
angiography.
The authors
conclude
that
bright
blood
angiography
is a sensi-
tive method
for screening
carotid
disease;
when
a significant
abnormality
is found,
black blood
angiography
should
be performed
for
more precise
delineation
of the lesion.
Index
terms:
Carotid
arteries,
MR studies,
172.i214
#{149}
Carotid
arteries,
stenosis
or occlusion,
172.721
#{149}
Magnetic
resonance
(MR),
image processing,
172.1214
#{149}
Magnetic
resonance
(MR), pulse sequences,
172.1214
Radiology
I From
1990;
the
the
disease
cause
carotid
arteries
of stroke.
Several
affecting
is a major
imaging
mo-
dalities
have
been
used
for diagnosing carotid
artery
disease.
Conventional
angiography
is considered
the
standard
of reference
but is invasive.
#{149}
its accuracy
of the carotid
SUBJECTS
AND
for
bifur-
METHODS
performed
imaging
at 1.5 T
system
(Mag-
vasive
method
for screening
suspected carotid
disease
but has a limited
field
of view
(FOV),
is degraded
by
calcified
plaque,
and may not enable
the distinction
of severe
stenoses
netom
SP; Siemens
un, NJ).
A Helmholtz
Medical
coil,
Systems,
Isewhich
con-
was the
studied.
transmitter.
Thirty
subjects
These
included
13 healthy
were
vol-
from
unteers
(mean
23-48
sonography
is a good
nonin-
occlusions.
techniques
creating
have
magnetic
(MR) angiograms
in a projectional
that deformat
studies,
“bright
blood”
imag-
ing methods
have
been
used
(ie,
flowing
protons
are made
to appear
more
intense
than
surrounding
tissues).
However,
there
are substantial
technical
problems
with
bright
blood
methods.
These
problems
include
the
exaggeration
recirculation
of stenoses
due
and turbulence
the stenosis.
In addition,
stenoses
may cause
low
ties
and therefore
We report
an
for evaluating
very
severe
flow
veloci-
poor
alternative
the
to flow
distal
to
flow
carotid
contrast.
approach
arteries
with
conventional
years)
without
tery
disease.
conventional
for sequence
17 patients
angiog-
B.W.,
RB.,
J.K.,
J.B.M.,
D.J.A.)
and
age,
35 years;
any
history
years)
were
went
selective
did
58 years;
who
rial
inch
respectively).
digital
image
within
with-
the
Committee
(9X
in all cases
Studies
were
guidelines
on
and
or intraarte-
angiography
with
a 1,024
1,024
matrix)
was performed
in at least
two projections.
hospital
range,
under-
(14 patients)
(three
patients
Cut-film
subtraction
intensifier
performed
ar-
undergo
angiography
in 1 day of the MR study
within
2, 6, and
17 days
each,
not
and
was used
In addition,
studied
carotid
range,
of carotid
group
angiography
development.
(mean
age,
24-77
Clinical
of the
Investiga-
tions.
Bright
Blood
Angiography
In all subjects,
bright
blood
angiograms
were obtained
before
black blood
angio.
grams.
Earlier
studies
sagittal
employed
a single-
three-dimensional
gradient-echo
tients).
Imaging
(GRE) sequence
variables
were
tion
of 40 msec,
time
(TR)
of 8 msec
(TR/TE
15#{176},
and
one
70/8,
25#{176}
flip
thickness,
256
two
X 192
patient
40/8),
excitation
angle,
for a two-slab
slab thickness,
tion
H.P.M.,
of the neck, was used
and the body coil
This
or two-slab
with
“black
blood’
angiography.
With
black
blood
angiography,
flowing protons
are made
to appear
hypointense,
to reduce
artifacts
created
by abnormal
flow
patterns.
In this
study,
black
blood
angiography
was
compared
forms
to the shape
for signal
detection,
In
(R.R.E.,
MD
raphy
to determine
depicting
disease
cation.
tion,
of Radiology
Bajakian,
All studies
were
with
a whole-body
Ouplex
177:45-50
Departments
#{149}
Richard
MD
Arteries:
Evaluation
MR Angiography’
THEROSCLEROTIC
these
for detecting
carotid
disease.
However, bright
blood
angiography
exaggerated
the severity
of carotid
lesions
MD
Wallner,
Skillman,
similar
to that of conventional
angiograms.
MR angiography
has been
used
with
some
success
in the evaluation
of carotid
artery
disease
(1-8).
In
and conwas per-
methods
#{149}
Bernd
J.
MS
resonance
pict vessels
These
methods
were used in 13
healthy
volunteers
and 17 patients,
and a prospective
blinded
compari-
formed.
Normal
were well shown
and black blood
MD
#{149}
John
Recently,
several
been
described
for
respectively.
son of MR angiography
ventional
angiography
P. Mattle,
Kent, MD
J. Atkinson,
first-order
studies,
echo
time
(TE)
flip
angle
of
for a single
slab
and
one excitation
acquisition,
32 partitions,
matrix,
(six paa repeti-
with a 40-mm
1.25-mm
secflow
and
or
compensa-
a 23-cm
FOV.
a three-dimension-
Surgery
(C.K., J.J.S.),
Beth Israel
Hospital
and Harvard
Medical
School,
330 Brookline
Ave. Boston,
MA
02115;
Department
of Radiology,
New England
Deaconess
Hospital,
Boston
(H.P.M.);
and Siemens
Medical
Systems,
Iselin,
NJ (D.J.A.).
Received
March
15, 1990; revision
requested
April
19; revision
received
May 30; accepted
May 31. Address
reprint
requests
to R.R.E.
c) RSNA,
1990
Abbreviations:
FOV
field of view,
GRE
gradient
echo,
RF = radio
frequency,
SE
spin
echo, TE = echo time, TR
repetition
time.
45
al sequence
with an axial excitation
and
coronal
readout
was tested.
This technique
excites
through
only
the
a limited
neck,
axial
without
volume
affecting
the
great vessels within
the chest. As a result,
flow contrast
is improved.
Imaging
vanables were 40/9, 20#{176}
flip angle, one excitation,
10-cm axial excitation
volume,
double
presaturation
slabs positioned
to
eliminate
wraparound
artifact
from the
anterior
and posterior
neck and to reduce
jugular
venous
signal,
first-order
flow
compensation,
256
X 192
matrix,
23-cm
FOV, 64 partitions
yielding
a 1.5-mm section thickness,
and an 8.2-minute
imaging time for both carotid
arteries.
In 11
patients,
sequential
multisection
two-dimensional
acquisitions
were performed.
A series
of sagittal
multisection
two-dimensional
flow-compensated
GRE images
were
obtained,
with
three
sections
per ac-
quisition.
Imaging
variables
were: 72/10,
350
flip angle,
two excitations,
3-mm section thickness
with a 6-mm intersection
gap, and a 256 X 256 acquisition
matrix
with a 23-cm FOV. Two patients
under-
a.
went
Figure
bright
both
two-
blood
and three-dimensional
angiography.
nies
Bright
blood
images
were
cessed
with a maximum-intensity
tion algorithm.
A series
ages were generated
individual
images,
for evaluation.
Black
Blood
Several
postpro-
of projection
of
MR
imthe
open
angiograms
sequential
of healthy
multisection
two excitations,
the skull.
The
atlas
loop.
(b)
gonithm.
Long
projec-
and, along
with
were photographed
b.
1.
curved
subjects.
two-dimensional
(a) Bright
bright
blood
blood
angiogram
images
created
(72/
10,
3-mm
sections).
The left carotid
artery
is seen
from
its origin
left vertebral
artery
is also seen
from
its origin
at the subclavian
Black
blood
angiogram
postprocessed
with
a minimum-intensity
straight
arrow
internal
carotid
artery,
short
arrow
external
arrow
=
jugular
vein,
solid
curved
arrow
=
vertebral
artery.
from
35#{176}
flip
a se-
angle,
to the base of
artery
to the
projection
alcarotid
artery,
Angiography
methods
were
studied
in
healthy
subjects,
to create black blood
images of the carotid
bifurcation.
The requirements
for these sequences
were that
(a) they produce
a uniform
signal-intensity void
within
the
carotid
artery,
(b) good
contrast
be maintained
between
the yessel and surrounding
fat and muscle,
(c) susceptibility
and chemical
shift antifacts be minimal
so as not to interfere
with plaque
visualization,
and (d) imaging times be sufficiently
short that gross
patient
motion
is unlikely
to occur during
the study.
The two- and three-dimensional GRE
sequences
we
tested
with
flow
presaturation
(9,10) failed to satisfy
requirements
and therefore
are not
scnibed
in detail
here.
The most effective
method
tested
two-dimensional
with
flow
spin-echo
presaturation
(SE)
and thin
these
detations,
was
sequence
sections.
The use of a thin section
exacerbates
signal loss from washout,
which
occurs
as
flowing
protons
move out of the section
during
the time interval
TE/2 between
the 90#{176}
and 180#{176}
radio-frequency
(RF)
pulses.
Initial
sequence
comparisons
included
variations
in section
thickness
(1.2-2.0
mm), intersection
gap (0%-40%
of section
thickness),
and sampling
times
(7.7 vs 12.8 msec).
The resulting
images
were judged
according
to the four criteria
listed
previously.
On the basis of these initial
sequence
comparisons,
imaging
variables
considered
to represent
the “optimal”
black blood
technique
were a doubleecho SE sequence
(1,600/20,
45), two exci-
46
#{149}
Radiology
a
7.68-msec
sampling
192 acquisition
matrix,
msec
timized
with
use
profiles,
RF
pulses
section
thickness
sagittal
with
acquisition
no
time,
23-cm
256
FOV,
X
6-
of computer-op1.8-mm
section
intersection
with
two
gap,
groups
slab
tion,
Flow
was
presaturation
employed
applied
just
presaturation
and
of
2 mT/rn,
and
of 8-mT/m
tion.
The
encompassing
with
a constant
amplitude
total
spoiler
and
tion
algorithm
of
5-msec
implemented
on
(Digital
A series
ages
were
is
projec-
the
most
hypenin-
a user-defined
viewing
into
the projection
im-
of black
blood
generated
with
projection
viewing
of -30#{176}to +30#{176}
and were
along
with the individual
imangles
photographed
images
for
evaluation.
dura-
imaging
time
of a study
both
carotid
bifurcations
II computer
than
pixel
along
is extracted
age.
technique
that
has been
previously
except
that
the most
hy-
rather
tense,
angle
This
maximum-intensity
gradient
was 10.2 minutes.
The black blood images
were
cessed
with a minimum-intensity
MicroVAX
Mass).
to the
pointense,
of the carotid
a 5-cm
axial
caudad
to the bifurcaselection
gradient
Maynard,
tion
algorithm
described
(1 i),
sections
acquired
simultaneously
and
each group
centered
over a carotid
bifurcation.
arteries
ics,
similar
Data
Analysis
The
studies
postproprojec-
were
graded
mild
stenosis
the
tery
the
host
Electron-
(less
sagittal
of the
carotid
as follows:
of
the
than
50%
plane),
internal
bifurcation
1
normal,
2
carotid
an-
diameter
reduction
3
moderate
stenosis
October
in
1990
Figure
2.
blood
Comparison
of bright
angiography.
(a)
gram
shows
a severe
stenosis
the left internal
carotid
artery.
blood
angiogram
created
tial two-dimensional
sion at the origin
Black
blood
black
angio-
at the origin
(b) Bright
with
the
approach
of the internal
tery but shows
a finding
of a second
stenosis
more
(c)
and
Conventional
sequen-
shows
a lecarotid
ar-
falsely
distally
angiogram
of
suggestive
(arrow).
more
correctly
depicts
a solitary
stenosis
(arrow).
(d) Conventional
angiogram
in the same
patient
shows
a mild
stenosis
of the right
internal
carotid
artery.
(e) Bright
blood
angiogram
accurately
depicts
the mild
stenosis
(arrow).
(f) Black blood
angiogram
also correctly
depicts the stenosis
(arrow).
a.
b.
C.
giograms
the
ses.
in these
length
In one
proximal
cases
exaggerated
and severity
of the stenosevere
stenosis
of the
internal
carotid
artery
(Fig
2b), findings
at bright
blood
angiography
suggested
a second
stenosis
more
distal;
this was not shown
at
black blood
or conventional
angiography
(Fig 2a, 2c). Generally,
there
was close correspondence
between
the
appearance
black
d.
of the internal
carotid
diameter
reduction
in
4 = severe
stenosis
of
artery (more than 75%
artery (50%-75%
the sagittal plane),
the
internal
diameter
carotid
reduction
in the sagittal
plane),
and 5 = occlusion
of
the internal
carotid
artery.
Two authors
(R.R.E.,
H.P.M.)
prospectively
interpreted
the MR studies
without
knowing
the results
of conventional
angiography.
Both the bright
and black
blood
studies
were available
for this in-
terpretation;
the projection
angiograms
and the individual
sections
were exammed. Two other
authors
(J.K., J.B.M.)
reviewed
the conventional
angiograms
without
knowing
the results
of MR angiography.
In each case, the interpretation
was made
by consensus
servers.
of the two ob-
In one case,
ancy
had been found
ventional
angiogram
rotid occlusion)
(which
showed
giography
was
after a major discrepbetween
the con(which
showed
a caand the MR angiograms
a severe
stenosis),
MR an-
repeated.
RESULTS
For black blood
imaging,
quences
were ineffective
flow
voids,
despite
uration.
Lengthening
crease
flow-related
ed in a loss of vessel
sel-muscle
contrast.
SE sequences
proved
Volume
177
#{149}
Number
the
GRE sefor creating
use of presatthe TE to indephasing
resultdetail
and yesTwo-dimensional
effective
for
1
creating
The
black
flow
blood
void
images
was
(Fig
maximized
1).
with
the use of very
thin
sections
and no
intersection
gap.
Because
we desired
to maintain
imaging
times
of 10 mmutes or less and images
became
noisier as the section
thickness
was reduced,
a section
thickness
of 1.8 mm
was
found
to represent
promise
between
volume
averaging
a good
minimizing
and
compartial
an adequate
signal-to-noise
ratio.
The sequence
with
a shorter
sampling
time
was
preferred
because
chemical
shift
artifact in images
obtained
with
the lower-bandwidth
sequence
could
be
falsely
interpreted
as plaque.
The results
of the clinical
study
are
summarized
found
was
in the
Table.
at conventional
detected
with
All
disease
angiography
MR angiography.
In 20 arteries,
the bright
blood
and
black
blood
angiograms
helped
correctly
grade
and provide
similar
portrayals
of normal
carotid
bifurcations
and of mild
to moderate
stenoses
(Figs
1, 2). Bright
blood
angiograms
helped
detect
all stenoses
of the internal
carotid
artery.
However,
in 13
arteries,
only
grams
usually
correctly
in severe
(Figs
2-4).
sions
and
grams.
In two patients,
giograms
failed
signal
intensity
f.
e.
of the
blood
the
black
blood
angio-
depicted
the disease,
stenoses
or occluThe bright
blood
an-
carotid
artery
occlusion,
conventional
stenosis
on
conventional
the
angio-
bright
blood
anto demonstrate
high
within
the internal
and
falsely
whereas
black
angiograms
strated
a severe
images
of another
stenosis.
cluded
internal
suggested
blood
and
demon-
Bright
patient
carotid
blood
with
an
oc-
artery
showed
mildly
high
signal
intensity
within
the vessel
that
could
be incorrectly
interpreted
as slow
flow.
Black
blood
images
showed
uniform
intermediate
signal
intensity
within
the
vessel,
a finding
consistent
with
thrombus.
In one patient
in whom
both
bright
blood
and black
blood
angiography
showed
severe
bilateral
stenoses of the proximal
internal
carotid
conventional
angiography,
performed
4 days
later,
showed
a severe
stenosis
of the right
internal
carotid
artery
and an occlusion
of the
left internal
carotid
artery
(Fig 4). Because
of the discrepancy,
a repeat
MR
angiogram
was obtained
2 days
later.
Both
bright
and black
blood
angiog-
artery,
raphy
showed
again
a severe
stenosis
of the right
internal
carotid
artery
but an occlusion
of the left internal
carotid
artery.
Black
blood
images
showed
thrombus
with
a peripheral
rim
of
sity
filling
ternal
high
moderately
carotid
the
signal
lumen
of
artery
(Fig
the
intenleft
in-
4e).
Radiology
#{149}
47
DISCUSSION
able
Bright
tool
blood
angiography
for the depiction
is a valuof vascular
anatomy
and function.
The technique
has proved
advantageous
for
the evaluation
of disease
involving
the intracranial
vessels,
such as arteriovenous
malformations
(12,13),
eurysms
(14), and venous
disorders
(15). Recent
work
has suggested
ana po-
tential
role for MR angiography
in
the assessment
of carotid
bifurcation
disease
(16,17).
However,
the anatomic
bright
depiction
blood
cise,
of vascular
angiography
especially
due
in severe
to signal
lence,
loss
recirculation,
raphy
flow
or (in the
study,
trast
An
case
bright
blood
between
the
perivascular
that
for
f.
de-
but
of
was
con-
vessel
by
e.
angiog-
approach
creates
blood
tissue
c.
of
in all cases
the degree
alternative
developed
b.
slow
to be sensitive
picting
carotid
disease
frequently
exaggerated
disease.
therefore
a.
turbu-
acquisitions)
proved
at
stenoses,
from
three-dimensional
flow.
In our
lesions
is impre-
and
rendering
flowing
blood
as a signal-intensity
void. We designated
this technique
as black
blood
blood
angiography.
angiography
in that
the
flow
signal
produced
does
not
In our
study,
nique
ages
for producing
combined
flow
with
an SE sequence
sections.
For
the section,
ity that will
the
flow
the
tech-
black
blood
presaturation
im-
and
very
thin
perpendicular
maximum
result
ensure
to
flow
in an
thickness)/(TE/2).
a section
thickness
TE of 20 msec, the
will
the
is
flow
best
intensity
on an
by the ratio
alone
by
degrade
Also,
good
flow
contrast
even
at relatively
low
velocities.
signal
termined
an advantage
loss
turbulence
images.
preserved
Black
has
veloc-
observable
is de-
Vmax
(section
For instance,
with
of 1.8 mm and a
washout
effect
flow
velocity
to 8 cm/sec,
18
the
most
pected
to occur
an impractically
al sections
compass
fore,
a sagittal
be
carotid
#{149}
Radiology
needed
artery.
orientation
ployed
(19).
Because
of the
48
is ex-
for an axial section,
large number
of
would
the
washout
very
thin
its
origin.
(c)
stenosis
of
Black
(arrow)
the
blood
at
right
the
carotid
angiogram
shows
origin
of
the
artery
shows
occlusion
external
carotid
severe
stenosis
of the
internal
artery.
(d)
(approximately
carotid
Digital
artery
subtraction
75%
reduction
in
diameter)
at the origin
of the internal
carotid
artery
and occlusion
of the external
carotid
artery.
(e) Sequential
two-dimensional
bright
blood
angiogram
shows
reconstitution
of flow
signal
intensity
within
the internal
carotid
artery
(arrow),
consistent
with
turbulent
flow
distal
to a stenosis.
The stenosis,
however,
is poorly
depicted.
(f) Black
blood
angiogram
shows
a severe
stenosis
at the origin
of the internal
carotid
artery
and occlusion
of the external carotid
artery.
The stenosis
appears
slightly
less severe
in the individual
black
blood
im(not
shown).
exaggerate
the
Both
extent
the
maximum-
of vascular
and
minimum-intensity
projection
algorithms
tend
to
disease.
sections,
flowing
protons
are still
likely
to wash
out of the section
between
the 900
and i800
RF pulses.
Signal
loss due to flow
turbulence
generally
enhances,
rather
than
degrades,
the quality
of black
blood
images,
which
is particularly
relevant
in
axi-
to en-
Therewas
at
the
al-
though
the signal-to-noise
ratio is
suboptimal
in the second-echo
images. In comparison,
the mean
flow
velocity
measured
in the internal
carotid artery
with Ooppler
sonography is 36.3 cm/sec
± 8.6 cm/sec
(18).
Although
seen
and
ages
void if the velocity
is greater
than
cm/sec.
The availability
of a second
echo (TE = 45 msec) reduces
the
minimum
Studies
in a patient
with
an occlusion
of the left internal
carotid
artery
and moderate
stenosis
of the right
internal
carotid
artery.
(a) Conventional
angiogram
of the left Carotid
artery
shows
occlusion
of the internal
carotid
artery
and stenosis
(arrow)
at the origin
of the external
carotid
artery.
(b) Sequential
two-dimensional
bright
blood
angiogram
demonstrates
occlusion
of the internal
carotid
artery,
but the external
carotid
artery
is poorly
3.
angiogram
SE image
a complete
d.
Figure
em-
(1.8 mm)
the
These
black
better
in
evaluation
of
severe
stenoses.
factors
may explain
why
the
blood
techniques
performed
than
bright
blood
techniques
depicting
severely
Several
drawbacks
blood
technique
are
stenotic
vessels.
of the black
also evident.
the
cannot
be applied
the carotid
artery
that
pass
through
bone
(eg, the petrous
portion),
because
of the absence
of
signal
adjacent
to the artery.
Second,
First,
to
portions
method
of
the useful
field
of view
is limited;
the
bright
blood
images
were
much
better for studying
the common
carotid
artery.
Third,
in some
projections,
overlap
of the
carotid
ular vein
could
limit
problem
is prevented
the individual
black
well
as the projection
and
jug-
evaluation.
by inspecting
blood
images
angiograms;
artery
This
October
as
1990
a.
b.
C.
Figure
4.
Studies
of a patient
with
duplex
of a severe
stenosis
artery.
(a) Sequen-
sonographic
evidence
the left internal
carotid
tial
two-dimensional
bright
blood
of
angio-
gram
origin
depicts
severe
stenosis
(arrow)
at the
of the internal
carotid
artery.
(b) Black blood
angiogram
also shows
the
severe stenosis
(arrow),
which
appears
shorter
than
in a. (c) Conventional
angiogram
obtained
occlusion
4 days
later
left
internal
of the
(d) Repeat
bright
blood
shows
interval
carotid
artery.
angiogram,
obtained
2 days
after
the conventional
angiogram,
shows
the occlusion.
(e) Single
section
from
repeat
black
blood
acquisition
also shows
the occlusion
and high
signal
intensity
(arrow) around
the acute
thrombus.
slow flow in the case of critically
stenosed
vessels.
Compared
with threedimensional
methods,
the advantages
of sequential
two-dimensional
methods
d.
C.
multiplanar
reconstructions
be helpful.
When
in the
either.
projection
Vessel
prevented
presaturating
tense
with
images.
plaques
is more
is the possibility
plaque
could
blood
seen
flowing
in our
blood
study
intensity
from
flowing
within
the vessel
lumen.
A limitation
of our study
-
1’7’7
#{149}
images
by
vein. Finalthat densebe isoin-
Nonetheless,
termediate
signal
readily
distinguished
er-signal-intensity
blood
imaging,
quential
sagittal
also
to ex-
angiograms
overlap
in bright
blood
the jugular
ly, there
ly calcified
easily
is taken
dude
the most
lateral
sections
taming
the jugular
vein
from
processing,
overlap
is seldom
lem
conposta prob-
was
bright
the
mal
has
can
care
I
that
the methods
employed
for
blood
imaging
evolved
over
course
of the study,
and an optibright
blood
imaging
sequence
not yet been
devised.
For bright
because
imaging
and it was sensitive
times
and
ately
rotid
specific
disease.
most
advantage
compared
all
dimensional
showed
and were
the lowblood
in-
for depicting
The major
with
sequential
imaging
were
moder-
axial
(17)
is
seap-
catwo-
a shorter
might
However,
be better
axial
for
acquisitions
detecting
very
better
flow
contrast
in the setting
[20]) and
motion
for
sections.
Three-dimensional
the dual
advantages
and smaller
voxels
of low
less sensitivthe individ-
ual
ner
sections),
from
Masaryk
loss
sults
with
so
sequences
of shorter
(due
to the
there
is
less
have
TEs
thinsignal
flow-related
et al (16)
dephasing.
obtained
good
a sagittal
three-dimension-
al sequence
in
study
time,
since
much
fewer
sections
are required.
The sagittal
orientation
uniformly
provided
good
flow
contrast
when
thin
sections
were
ob-
tamed.
design
the
proach
short
in black
the
we preferred
two-dimensional
are
(particularly
flow
velocities
ity to patient
by
imaging
their
a 30-cm-diameter,
ceive-mode,
re-
patients
transmit-re-
linearly
polarized
head
coil. Since
inflowing
spins
beyond
the limit
of the head
coil are not affected
by the RF pulses,
flow
contrast
is generally
adequate.
ence
with
rotid
bifurcation
disappointing,
the
Our
linear
head
imaging
because
experi-
coil for cahas been
the bifurcaD.%A;,.i,%,._
AG
tion is not consistently
within
the imaging
coil
in large
short
fore,
coil
patients
necks.
id artery
or those
Also,
the
is poorly
we used
with
positioned
volume
of the
common
the
body
coil
carot-
receiver
and
coronal
read-out.
However,
the
resulting
coronal
ages were
suboptimal
ing carotid
stenoses;
tended
to be degraded
We currently
the
sequential
sagittal
A final
point
is that
created
projection
tracranial
Therefore,
im-
supplement
vidual
images
most precise
angiograms
an overall
particularly
projection
noses
bright
blood
angiography
depiction
and
plaque
Bright
Wedeen
RA,
Edelman
imaging
of pulsatile
magnetic
resonance.
Science
RR,
flow
Dumoulin
CL,
phy.
6.
7.
E.
Magn
Souza
SP,
Walker
Time-resolved
Reson
Med
14.
9.
17.
DG,
18.
Yo-
JM.
by
lective
inversion
recovery.
Magn
Reson
Med 1988; 7:472-484.
Edelman
RR, Atkinson
DJ, Silver
MS.
FRODO
pulses:
a new method
for elimiof motion,
Radiology
flow,
1988;
and
se-
with
selective
venography.
19.
clinical
Dumoulin
with
and
in progress.
6:275-286,
Macovski
A, Pauly
of MR angiography
and
gy 1989; 171:801-806.
Keller
PJ, Drayer
BP,
ography
flow
im-
MR
arteri-
Radiology
1989;
experience.
Fram
CL, Souza
EK,
SP.
two-dimensional
Williams
MR angiacquisi-
three-dimensional
Radiology
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display:
1989;
work
173:527-532.
Mattle
H, Grolimund
P. Huber
P. Sturzenegger
M, Zurbrugg
HR.
Transcranial
Doppler
sonographic
findings
in middle
cerebral
artery
disease.
Arch Neurol
1988;
45:289-295.
Daniels
DL, Kneeland
JB, Foley WD, et al.
Cardiac-gated
local coil MR imaging
of
the carotid
neck bifurcation.
AJNR
1986;
7: 1036-1037.
20.
21.
Nishimura
Considerations
12:377-382.
KR.
MR
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TJ, Modic
MT. Ross JS, Ruggieri
P. VanDyke
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aneurysms
(abstr).
AJNR
1989; 10:893-894.
Mattle
HP, Edelman
RR, Reis MA, et al.
Cerebral
venography
and flow quantification with MR. Radiology
1989; l73(P):187.
Masaryk
TJ, Modic
MT. Ruggieri
PM, et al.
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(volume)
gradientecho imaging
of the carotid
bifurcation:
with
3:454-462.
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evaluation
preliminary
MR angiogra1988;
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173:831-837.
KD,
Dumoulin
CL, Souza
SP, Walker
MF, Wagle W. Three-dimensional
phase
contrast
angiography.
Magn
Reson
Med 1989;
9:139-149.
Dixon
WT, Du LN, Faul DD, et al. Projection angiograms
of blood
labeled
by adiabatic fast passage.
Magn
Reson
Med 1986;
presaturaflow
aging
in vascular
malformations
using
gradient
recalled
acquisitions.
AJNR
1988;
9:637-642.
Edelman
RR, Wentz
KU, Mattle
H, et al.
Intracerebral
arteriovenous
malforma-
et al.
MF,
Spatial
suppressing
put Assist
Tomogr
1988;
Needell
WM.
Maravilla
tion
5.
RL.
for
facts and improving
depiction
of vascular
anatomy
in MR imaging.
Radiology
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MR angiography
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rephasing.
J Com-
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#{149}
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Meuli
Projective
nation
50
VJ,
JP, Ehman
a method
tions:
16.
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230:946-948.
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CL, Hart HR.
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as
anatomy,
angiography,
black
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more
acof severe
carotid
ste-
morphology.
13.
15.
Ruggieri
PM, Laub GA, Masaryk
TJ, Modic
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pulse-sequence
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Radiology 1989; 171:785-791.
shitome
In conclusion,
bright
blood
angiography
is a good screening
method
and accurately
portrays
normal
bifurcations
and mild stenoses.
Compared
with
blood
curate
12.
U
2.
3.
the
projection
useful
to vascular
the clinician.
arteries.
Edelman
RR, Wentz
KU, Mattle
H, et al.
Projection
arteriography
and venography:
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clinical
results
with MR. Radiology
a
of mdifor
1 1.
of
1.
an-
with the maximumalgorithm
show
is required
guide
for
carotid
1989;
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are nonetheless
or
combination
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We are indebted
to Gerhardt
Laub, PhD, of Siemens
Medical
Systems,
Erlangen,
Federal
Republic
of Germany,
for assistance
in pulse
sequence
development,
and
Mark Haacke,
PhD, of Case Western
Reserve
University.
Cleveland,
for helpful
discussions.
loss of vascular
detail
due to random
noise
propagation
(21). We have
found
this to be true
of the minimum-intensity
projection
algorithm
as well.
when
angio-
Acknowledgments:
axial
two-dimen-
sional
sequence
with
dimensional
sequence;
tion appears
promising.
disease.
Felmlee
tion:
latter
be employed
bright
blood
are suggestive
10.
are
the
these methods
provides
an accurate
depiction
of disease
affecting
the ex-
for interpretalso,
the studies
if the patient
swallowed.
angiography
methods;
should
on the
severe
as transmitter.
excitation
giograms
intensity
gram
There-
tried
a three-dimenwith
use of an
blood
method
findings
the saturation
effects
with three-dimensional
sequences,
we
sional
sequence
black
complementary
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a Helmholtz
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October
1990