<s>
Ultrasonography	B-Application
in	O
suspected	O
deep	O
vein	O
thrombosis	O
focuses	O
primarily	O
on	O
the	O
femoral	O
vein	O
and	O
the	O
popliteal	O
vein	O
,	O
because	O
thrombi	O
in	O
these	O
veins	O
are	O
associated	O
with	O
the	O
greatest	O
risk	O
of	O
harmful	O
pulmonary	O
embolism	O
.	O
</s>
<s>
Lower	O
limbs	O
venous	O
ultrasonography	B-Application
is	O
also	O
indicated	O
in	O
cases	O
of	O
suspected	O
pulmonary	O
embolism	O
where	O
a	O
CT	B-Algorithm
pulmonary	I-Algorithm
angiogram	I-Algorithm
is	O
negative	O
but	O
a	O
high	O
clinical	O
suspicion	O
of	O
pulmonary	O
embolism	O
remains	O
.	O
</s>
<s>
Serial	O
follow-up	O
the	O
ultrasound	O
exam	O
is	O
not	O
necessary	O
after	O
an	O
initially	O
complete	O
,	O
normal	O
study	O
in	O
individuals	O
with	O
DVT	O
symptoms	O
who	O
have	O
suspected	O
pulmonary	O
embolism	O
and	O
nondiagnostic	O
ventilation/perfusion	B-Algorithm
scans	I-Algorithm
.	O
</s>
<s>
Unlike	O
arterial	O
ultrasonography	B-Application
,	O
venous	O
ultrasonography	B-Application
is	O
carried	O
out	O
with	O
the	O
probe	O
in	O
a	O
transversal	O
position	O
,	O
(	O
perpendicular	O
to	O
the	O
vein	O
axis	O
)	O
,	O
displaying	O
cross-sections	O
of	O
the	O
veins	O
.	O
</s>
<s>
There	O
is	O
a	O
simplified	O
technique	O
called	O
"	O
compression	O
ultrasonography	B-Application
"	O
which	O
can	O
be	O
used	O
for	O
quick	O
DVT	O
diagnosis	O
,	O
mainly	O
for	O
the	O
common	O
femoral	O
vein	O
and	O
the	O
popliteal	O
vein	O
.	O
</s>
<s>
Compression	O
ultrasonography	B-Application
has	O
both	O
high	O
sensitivity	O
and	O
specificity	O
for	O
detecting	O
DVT	O
in	O
symptomatic	O
patients	O
.	O
</s>
<s>
Doppler	B-Algorithm
ultrasonography	I-Algorithm
of	O
venous	O
blood	O
flow	O
that	O
correlates	O
with	O
respiration	O
can	O
be	O
diagnostic	O
of	O
the	O
absence	O
of	O
deep	O
vein	O
thrombosis	O
.	O
</s>
