pulmorary embolism imaging what’s new

1. PE
IMAGING:
WHAT’S
NEW
?
G
Ferretti
CHU
Grenoble
-­‐
France
HANOI,
NOV
2015

2. 1992
–
2014
PE
diagnosis
has
been
revolutionized
by
Spiral
CT
scan
ú Non
invasive
technique
ú Quick
to
acquired
ú High
reproducibility
ú High
accuracy
for
diagnosing
PE
and
differential
diagnosis
ú Availability
24/365
ú Low
cost
vs
VQ
scintigraphy
or
P
angiography
Remy-­‐Jardin
M.
Radiology
2007;245:315-­‐29.

3. Recent
technical
inovations
§ Slice
thickness
decreased
from
5
to
<1
mm
§ Speed
of
acquisition
decreased
from
30
sec
to
1-­‐2
sec:
dyspneic
patients
§ contrast
media
administration
decreased
from
de
120
ml
to
50
ml
§ 100
Kv
is
optimal
for
image
contrast
§ RX
dose
can
be
optimized
Ghaye
B,
Radiology.
2011;219:629-­‐36.
94%
of
5th
order
P
arteries
and
74%
d
of
6th
order
P
arteries
are
visualized
MDCT: Se 83 to 100%, Sp: 89 to 97%

4. Increased use of CT has enabled earlier recognition of PE
Wittram C. J Thorac Imaging 2004;19(3):164 –70.
But, controversy exists
1. Do all identified patients with PE had clinically significant lesions
requiring anticoagulation?
Should isolated sub segmental PE be treated?
2. Does CT show to much clinically significant incidental finding
(24%) and too frequent alternative diagnosis (33%)
3. Was CT adopted too quickly to diagnose PE without considering
the risks and benefits?

6. Diagnostic
Strategy

11. D
dimers
§ Level
of
positivity
should
be
adapted
to
the
age
in
patients
>
50
yo
§ In
case
of
low
or
intermediate
probability,
the
level
of
positivity
=
age
X
10
(microg/ml)
§ Such
age-­‐level
increases
the
number
of
PE
that
are
eliminated
in
patients
>
75yo
from
6%
using
the
conventional
level
to
30%
using
the
new
level
(based
on
800
patients
study)
Righini
JAMA
2014;311,1117-­‐24

12. Possible
role
of
ECG-­‐gated
CT
scanner
§ Does
it
help
to
see
the
pulmonary
arteries?
ú Decreases
motion
artifacts
in
the
lung
in
contact
with
the
heart
(lingula,
LLL).
ú Increases
the
dose
delivered
to
the
patient
as
well
as
the
time
of
acquisition
ú Only
1%
of
segmental
arteries
are
impacted
Ghaye
B
Ragiology
1997

13. Possible
role
of
ECG-­‐gated
CT
scanner
§ Functional
evaluation
of
the
heart?
ú In
particular
the
right
heart
function
§ However,
analysis
of
the
cavities
of
the
heart
on
axial
CT
seems
to
do
as
well
as
ECG
gated
CT
Abel
E.
Acta
Radiol.
2012
1;53:720-­‐7.
Kamel
EM,
J
Comput
Assist
Tomogr.
2008;32:438-­‐43.

15. Possible
role
of
ECG-­‐gated
CT
scanner
§ triple
rule-­‐out
in
case
of
atypical
chest
pain
in
order
to
eliminate
the
“big
three”
ú PE
ú Myocardial
infarction
ú Aortic
dissection
§ This
technique
is
still
controversial
Branch
KR,
PLoS
One.
2013
16;
8:e61121.

16. Radiation
Dose
and
CT
for
PE
§ Risk
are
individual
and
collective
ú Due
to
the
increased
used
of
CT
for
suspicion
of
PE
ú While
the
rate
of
positive
CT
is
declining
from
25%
in
2000
to
4-­‐6%
nowadays.
§ In
2010,
a
monocentric
study
showed
that
ú 90%
of
2003
CT
were
negative
 93.6%
in
patients
referred
from
the
ER
 86.5%
for
hospitalized
patients
Mamlouk
MD,
Radiology.
2010;256:625-­‐32

17. PE
and
radiation
dose
?
§ Great
question:
appropriate
pre
CT
selection
of
the
patients
that
should
be
send
to
CT???
ú Lot
of
papers
and
algorithm…
few
clinical
applications
§ Optimization
of
CT
dose
delivered
to
patients
ú 100
kV
instead
of
120
kV
in
thin
to
normal
BMI
patients
 Dose
reduction:
40%
to
20%
 Increases
quality
of
angiogram
ú iterative
reconstruction
:
dose
reduction
30
to50%
Kubo
T,
AJR
Am
J
Roentgenol.
2008;190:335-­‐43.
Pontana
F,
Radiology.
2013;267:609-­‐18

19. PE
signs
were
described
in
1992,
but
have
no
wrinkle
in
2015
§ Filling
defect
within
an
opacified
PA:
low
density
matérieal
surrounded
by
contrast
media
§ Complete
occlusion
of
the
PA
is
often
associated
with
an
enlargement
of
the
artery
Remy-­‐Jardin
M,
Radiology.
1992;185:
381-­‐7.

20. Causes
of
false
+
and
-­‐
False
positive
False
negative
§ Hilar
or
bronchopulmonary
lymph
nodes
§ Partial
opacification
of
pulmonary
veins
or
arteries
§ Partial
volume
effect
§ Use
of
high
spatial
frequency
reconstruction
algorithm
§ Inadequate
opacification
of
the
PA
§ Sub
segmental
PE
§ Motion
artifacts
§ Partial
volume
effect
§ Low
signal
to
noise
Quality
of
CT
should
be
verified
for
every
patient,
if
inadequate,
re
scan
the
patient

21. Indirect
signs
of
PE
§ Pulmonary
infarction,
pleural
effusion
§ GGO
surrounded
by
pulmonary
consolidation
§ Angio
CT
remains
necessary
to
detect
PE
Coche
EE,
Radiology.
1998;207:753-­‐8.
Revel
MP,
Radiology.
2007;244:875-­‐82.

25. pneumonia
infarction
Chest
pain
with
pulmonary
consolidation
Pneumonia
vs.
Infarction

26. Sub
segmental
PE
§ No
treatment
is
a
good
option
if:
ú Respiratory
function
is
preserved
ú No
deep
venous
thrombosis
ú The
clinical
condition
that
is
a
high
risk
for
thrombosis
is
canceled
ú No
history
of
central
venous
catheter
ú Follow
up
by
US
of
the
legs
possible
ú The
patients
should
be
informed
and
agree

27. Spiral
of
severity
in
PE

28. Clinical
severity
score:
PESI

29. Severity
of
PE:
dysfunction
of
RV
or
embolic
burden?
§ presence
of
RVD
on
echocardiography
is
associated
with
an
increased
risk
for
in-­‐hospital
mortality
(risk
ratio,
2.5;
95%
CI,
1.2-­‐5.5).
§ Correlation
between
clot
burden
and
early
mortality
is
still
debated
§ The
importance
of
preexisting
alteration
of
RV
function
has
certainly
an
important
role
to
explain
the
discordance
§ Research:
estimation
of
the
pulmonary
perfusion
alteration
studied
with
double
energy
CT
scan
in
patients
with
PE
Moroni
AL,
Eur
J
Radiol
2011;79:452–8.
Apfaltrer
P,
Eur
J
Radiol.
2012;81:3592-­‐7.
Remy-­‐Jardin
M,
Radiol
Clin
North
Am.
2014;52:183-­‐93.

30. Severity
of
PE:
dysfunction
of
RV
or
embolic
burden?
§ Axial
CT
allows
to
systematically
assess
signs
related
to
RVD
ú Enlargement
of
the
right
ventricle
as
compared
to
the
left
ventricle
ú RV/LV
ration
>
1
ú Ventricular
septal
bowing
ú reflux
in
the
IVC
Kamel
EM,
J
Comput
Assist
Tomogr.
2008;32:438-­‐43.
Kumamaru
KK.
Int
J
Cardiovasc
Imaging.
2012;28
:965-­‐73.

31. Severity
of
PE:
dysfunction
of
RV
or
embolic
burden?
§ The
RV/LV
ratio
is
correlated
to
ú Hemodynamic
severity
of
PE
ú Intra
hospital
morbidity
and
mortality
of
PE
ú Mortality
prédiction
at
3
months:
226
patients
with
and
initial
stable
clinical
condition:
RV/LV>1
is
a
predictif
sign
of
mortality
when
the
clot
burden
is
<
40%
§ a
prospective
study
including
848
patients
with
clinical
stable
PE
showed
that
the
size
of
RV
(RV/LV>0,9on
CT
did
not
correlate
to
prognostic
at
30
days
Jiménez
D,
Thorax.
2014;69:109-­‐15.
Contractor
S,
J
Comput
Assist
Tomogr.
2002;26:587-­‐91
Collomb
D,
Eur
Radiol
2003;
13:1508
–1514
Ghaye
B,
Radiology.
2006;239:884-­‐91.

33. CAD
for
PE
detection?
§ CAD
par
rapport
à
la
lecture
classique
197
patients
(159
sans
embolie
et
38
avec)
par
6
lecteurs
d’expérience
variable.
§ La
référence
était
établie
par
2
lecteurs
indépendants
(35).
ú la
sensibilité
de
détection
des
EP
variait
 Sans
CAD,
de
68%
à
100%
 avec
CAD
de
76%
à
100%
(p<0,001),
 sans
perte
de
spécificité
 lecteur
dépendante
(p<0,001).
 réduction
significative
de
la
durée
de
lecture
(24-­‐208
sec
sans
CAD
versus
17-­‐196
sec
avec
CAD)
 accroissement
significatif
de
la
confiance
diagnostique

§ Une
autre
étude
soulignait
que
le
CAD
améliorait
la
sensibilité
de
détection
des
EP
des
lecteurs
inexpérimentés
au
prix
d’une
augmentation
importante
des
faux
positifs
Wittenberg
R.
J
Thorac
Imaging.
2013;28:315-­‐21
Blackmon
KN,
Eur
Radiol.
2011;21:1214-­‐23.

34. Double
energy
CT
§ A
dream:
ú Morphology
of
the
arteries
ú Function
of
the
parenchyma
/
perfusion
§ However
perfusion
defects
are
not
specific
for
PE
and
may
be
related
to
small
airway
disease
Lu GM, Zhao Y, Zhang LJ, Schoepf UJ. Dual-energy CT of the lung. AJR Am J Roentgenol. 2012;199(5 Suppl):S40-53.
Lu GM, Zhao Y, Zhang LJ, Schoepf UJ. Dual-energy CT of the lung. AJR Am J Roentgenol. 2012;199(5 Suppl):S40-53.
Lu GM, AJR. 2012;199(5 Suppl):S40-53.
Kang
MJ,
Radiographics.
2010;30:685-­‐98

35. PE
and
pregnancy
§ Radiation
dose
ú Angio
CT:
3
to
10
mSv
ú (natural
radiation:
3
mSv/year
)
§ Mammary
dose
:
ú 50-­‐90
mGy
(2
breasts)
ú (mammography
2
incidences
:
3
mGy)
§ Higher
risk
of
breast
cancer
?
Sadigh
G
AJR
2011;
196:497-­‐515

38. PE
and
pregnancy
In
pregnant
women
with
suspected
PE
§ R1.
we
suggest
that
D-­‐dimer
not
be
used
to
exclude
PE
(weak
recommendation).
§ R2.
in
presence
of
signs
and
symptoms
of
DVT,
we
suggest
performing
bilateral
CUS
of
lower
extremities
followed
by
anticoagulation
treatment,
if
positive
and
further
testing,
if
negative
(weak
recommendation,
very-­‐low-­‐
quality
evidence).
§ R3.
if
no
signs
and
symptoms
of
DVT,
we
suggest
performing
studies
of
the
pulmonary
vasculature
rather
than
CUS
of
the
lower
extremities

39. PE
and
pregnancy
In
pregnant
women
with
suspected
PE
§ R4.
we
recommend
a
CXR
as
the
first
radiation-­‐
associated
procedure
in
the
imaging
work-­‐up
(strong
recommendation,
low-­‐quality
evidence).
§ R5.
if
CXR
is
normal
,
we
recommend
lung
scintigraphy
as
the
next
imaging
test
rather
than
CTPA
(strong
recommendation,
low
quality
evidence)
§ R5.
if
V/
Q
scan
is
nondiagnostic
,
we
suggest
further
diagnostic
testing
rather
than
clinical
management
alone
.
we
recommend
CTPA
rather
than
DSA
(strong
recommendation,
very-­‐low-­‐quality
evidence).
§ R6.
If
CXR
is
abnormal
,
we
suggest
CTPA
as
the
next
imaging
test
rather
than
lung
scintigraphy
(weak
recommendation,
very-­‐low-­‐quality
evidence)

41. PE
and
pregnancy
§ Pregnancy
modifies
hemodynamic
parameters,
therefore
it
is
recommended
to
increase:
ú the
rate
of
CM
Injection
(6
cc/sec)
ú the
concentration
of
CM
(350mg/ml)
ú the
volume
if
injected
CM
(90cc
vs
70cc)
ú during
an
apnea
but
not
deep
Hartmann
IJ,
Eur
J
Radiol.
2010;74:40-­‐9.

42. MR
and
PE
§ Many
drawbacks
of
MRI
ú Length
of
imaging
ú difficulty
to
take
care
of
an
emergency
in
MR
ú limited
spatial
resolution
ú Limited
sensitivity
ú limited
availability
ú complex
technique
imposing
trained
and
experimented
technicians
and
radiologists
ú higher
cost
than
CT

43. MRI
ú Steady-­‐state-­‐free-­‐precession
ú Contrast
enhanced
angio
MR
ú Parenchymal
perfusion
§ Compared
with
contrast-­‐enhanced
angiographic
sequences,
unenhanced
sequences
demonstrate
lower
sensitivity,
except
for
proximal
PE,
but
high
specificity
and
agreement.
§ The
negative
predictive
value
of
perfusion
sequences
was
insufficient
to
safely
rule
out
PE.
Revel
MP,
Eur
Radiol.
2013;23:2374-­‐82
Hosch
W,
Emerg
Radiol.
2014;21:151-­‐8.
Kluge
A,
AJR
Am
J
Roentgenol
2006;
187:
W7–W14

44. MRI
§ Expert
centers
results
ú Sensitivity
:
71-­‐100%
ú specificity
:
92
à
100%
§ PIOPED
III
 Sensitivity
:
78
à
90%
 specificity
:
99%
à
100%
 NPV
97%
at
3
months
in
case
of
technically
optimal
MRI
 BUT
MRI
were
technically
optimal
in
48
to
89
%
of
cases
(mean
75%)
Biederer
J,
Insights
Imaging
2012;
3:
373–86.
Pleszewski
B,
Clin
Imaging
2006;
30:166–172
Stein
PD,
(PIOPED
III).
Ann
Intern
Med
2010;
152:
434–43,

45. MRI
in
clincal
practice
§ Reserved
to
ú Expert
centers
ú Patients
intolerance
to
iodine
CM,
young
patients,
pregnancy
Ersoy
H,
AJR
Am
J
Roentgenol
2007;188:1246–54.
Kalb
B,
Radiology.
2012;263:271-­‐8.

46. Diagnosis
of
pulmonary
embolism
in
patients
with
cancer
§ A
negative
D-­‐dimer
test
has
the
same
diagnostic
value
as
in
non-­‐cancer
patients.
§ On
the
other
hand,
D-­‐dimer
levels
are
non-­‐specifically
increased
in
many
patients
with
cancer
§ In
one
study,
raising
the
D-­‐dimer
cut-­‐off
level
to
700
mg/
L,
or
using
age-­‐dependent
cut-­‐off
levels,
increased
the
proportion
of
cancer
patients
in
whom
PE
could
be
ruled
out
from
8.4
to
13%
and
12%,
respectively;
the
corresponding
false-­‐negative
rates
appeared
acceptable.
Douma
RA,
Thromb
Haemost
2010;104(4):831–836.
Dentali
F,.
Thromb
Res
2010;125(6):518–522.

47. Take
home
messages
§ PE
without
or
with
hypotension:
CTA
§ D
dimer
related
to
the
age
if
patient
>
50ans
§ Favor
exploration
with
100kVp
§ Severity:
RV
larger
than
left
ventricle
§ PE
and
pregnancy
ú CXR
first
 If
unremarkable:
VQ
scan
 If
abnormal
:
CTA
first