110 / 232
strongly
support
the
responsibility
of
frontal
sinusitis
in
most
cases:
the mean age of our patients
(11 years
for SE and 10 years
for EE),
which was
similar
to
those previously
reported
in
the
literature
[3,4,14]
,
corresponds
to
the
age
of
development
of
the
frontal
sinus
82%
of
empyema
(8
SE
and
6
EE) were
at
least
partly
located
in
the polar part of
the
frontal
lobe and not
in
its basal part,
i.e.
they
faced
the
frontal
and
not
the
ethmoid
sinus.
Two
cases
clearly
originated
from
the
ethmoidal
sinus
since
these
patients
did
not
have
any
frontal
sinus.
In
one
case,
the
EE
originated
from
a Pott’s puffy
tumor
and not directly
from
a
sinus
cavity
(
Fig.
2
).
With regards
to
imaging
techniques,
in
the present work as well
as
in other publications
[15]
, CT
scans were more often prescribed
than MRI
(76.5% versus 41% of cases). This
is mostly due
to
the
fact
that
they
are
easier
to
obtain
in
an
emergency
setting
and
also
easier
to
perform
on
children.
However,
CT
scans
may
fail
in
revealing
intracranial complications
[16,17]
. The American College
of
Radiology
considers
that
MRI
with
contrast
and
contrast-
enhanced
CT
are
complementary
examinations when
evaluating
potential complications of
sinusitis
[18]
. CT
scans are
less effective
in
detecting
empyema
and
in
distinguishing
SE
from
EE
as
compared
to
MRI,
but
its
specificity
for
the
diagnosis
of
thrombophlebitis
is
higher
and
it
better
shows
absent
sinuses
and bony
erosions of
sinus walls or
cranial vault. Concerning MRI,
gadolinium-enhanced
T1-weighted
sequences
are
particularly
useful
in
distinguishing
EE
from
SE,
since
in
these
sequences,
the
dura
mater
clearly
appears
as
a
thick
enhanced
layer.
The
distinction
is usually quite obvious
in
extended
forms
(
Fig. 4
), but
can be more difficult
at
the
beginning
of
the
evolution
(
Fig. 1
):
SE
inner
contours
are
rather
irregular,
following
the
form
of
underlying
cerebral
gyri.
They
often
have
a multilocular
appear-
ance, are
frequently
spread way beyond
the
infected
sinus and are
often
partly
localized
in
the
interhemispheric
fissure.
Concerning microbiological data, a striking
trend noted was
the
frequent
involvement
of
Streptococcus
anginosus.
Indeed,
this
group
of
streptococci
has
long
been
recognized
to
cause
invasive
pyogenic
infections
in
various
tissues
[19]
.
In
pediatric
studies
of
intracranial
complications
of
rhinosinusitis,
S.
anginosus
was
not
only
the most
frequently
involved bacterium, but
it also
increased
Fig. 2.
CT and MR
imaging of
empyema not
in
contact with
the
infected
sinus
.
(A)
In
this patient, only
the
right
frontal
sinus was
infected
(black arrow) even
though
the SE was
located on
the opposite
side
(*).
(B1–B3) SE with no visible
continuity with
the
frontal or ethmoid
sinuses.
(C1–C2) Left
frontal
sinusitis and
right
frontal EE originated
from
Pott’s
puffy
tumor.
A.
Garin
et
al.
/
International
Journal
of
Pediatric Otorhinolaryngology
79
(2015)
1752–1760
88