Paranasal Sinuses Imaging

7/23/2019 Paranasal Sinuses Imaging

http://slidepdf.com/reader/full/paranasal-sinuses-imaging 1/28

Paranasal Sinuses Imaging

Prof. J. Stelmark



PARANASAL SINUSES

The large, air-filled a!ities of the "aranasal sinuses are sometimes alled the

aessor# nasal sinuses $eause the# are lined %ith muous mem$rane, %hihis ontinuous %ith the nasal a!it#. These sinuses are di!ided into four grou"s,

aording to the $ones that ontain them&

'.(a)illar# *+ (a)illar# *faial $ones

+. rontal *usuall# + rontal *ranial $ones

. Ethmoid *man# Ethmoid *ranial $ones

/. S"henoid *ranial $one



0nl# the ma)illar# sinuses are "art of the faial $one struture. The frontal,

ethmoid, and s"henoid sinuses are ontained %ithin their res"eti!e ranial

$ones.

The "aranasal sinuses $egin to de!elo" in the fetus, $ut onl# the ma)illar#

sinuses e)hi$it a definite a!it# at $irth. The frontal and s"henoid sinuses

$egin to $e !isi$le on radiogra"hs at age 1 or 2. The ethmoid sinuses de!elo"

last. All the "aranasal sinuses generall# are full# de!elo"ed $# the late

teenage #ears.





(a)illar# Sinuses

The large ma)illar# sinuses are "aired strutures, one of %hih is loated %ithin

the $od# of eah ma)illar# $one. An older term for ma)illar# sinus is antrum, an

a$$re!iation for Antrum of 3ighmore.

Eah ma)illar# sinus is sha"ed some%hat like a "#ramid on a frontal !ie%.

Laterall#, the# a""ear more u$i. The a!erage total !ertial dimension is

$et%een and / m, and the other dimensions are $et%een +.4 and m.



rontal Sinuses

The frontal sinuses are loated $et%een the inner and outer ta$les of the skull,

"osterior to the gla$ella5 the# rarel# $eome aerated $efore age 1. The ma)illar#

sinuses are al%a#s "aired and are usuall# fairl# s#mmetri in si6e and sha"e5 the

frontal sinuses are rarel# s#mmetri. The frontal sinuses usuall# are se"arated $# ase"tum, %hih de!iates from one side to the other or ma# $e a$sent entirel#,

resulting in a single a!it#.



Ethmoid Sinuses

The ethmoid sinuses are ontained %ithin the lateral masses or la$#rinths of the

ethmoid $one. These air ells are grou"ed into anterior, middle, and "osterior

olletions, $ut the# all interommuniate.

7hen !ie%ed from the side, the anterior ethmoid sinuses a""ear to fill the or$its.

This ours $eause "ortions of the ethmoid sinuses are ontained in the lateral

masses of the ethmoid $one, %hih hel"s to form the medial %all of eah or$it.



S"henoid Sinuses

The s"henoid sinuses lie in the $od# of the s"henoid $one diretl# $elo% the sella

turia. The $od# of the s"henoid that ontains these sinuses is u$i and

fre8uentl# is di!ided $# a thin se"tum to form t%o a!ities. This se"tum ma# $e

inom"lete or a$sent entirel#, ho%e!er, resulting in onl# one a!it#.



PARANASAL SINUSES

Tehnial ators

A medium k9 range of 2: to ;: is ommonl# used to "ro!ide suffiient ontrast ofthe air-filled "aranasal sinuses. 0"timum densit# as ontrolled $# the mAs is

es"eiall# im"ortant for sinus radiogra"h# to !isuali6e "atholog# %ithin the sinus

a!ities. A small foal s"ot should $e used for ma)imum detail.

As %ith ranial and faial $one imaging, gonadal shielding is not useful in reduing

gonadal e)"osure, $ut shields o!er the "el!i area ma# $e used for "atientreassurane. <lose ollimation and elimination of unneessar# re"eats are the $est

measures for reduing radiation dose in sinus and tem"oral $one radiogra"h#.



LATERAL P0SITI0N=RI>3T 0R LET LATERAL& SINUSES

Pathology Demonstrated

Inflammator# onditions and sinus "ol#"s or #sts.

(o!ing or stationar# grid

? 14 to 24 k9 range

? Small foal s"ot

Tehnial ators



Part Position

? Plae lateral as"et of head against ta$le@u"right uk# surfae, %ith side of

interest losest to IR.

? AdBust head into a true lateral "osition, mo!ing $od# in an o$li8ue diretion as

needed for "atientCs omfort *midsagittal "lane "arallel to IR.

? Align IPL "er"endiular to IR *ensures no tilt.

? AdBust hin to align I0(L "er"endiular to front edge of IR.



<entral Ra#

? Align a hori6ontal <R "er"endiular to the IR.

? <enter <R to a "oint mid%a# $et%een outer anthus and EA(.

? <enter IR to <R.

? (inimum SID is /: inhes *':: m.



Res"iration

Sus"end res"iration during e)"osure.

Notes& To !isuali6e air-fluid le!els, an eret "osition %ith a hori6ontal $eam is

re8uired. luid %ithin the "aranasal sinus a!ities is thik and gelatin-like, ausing it

to ling to the a!it# %alls. To !isuali6e this fluid, allo% a short time *at least 4

minutes for the fluid to settle after a "atientCs "osition has $een hanged *i.e., from

reum$ent to eret.

If "atient is una$le to $e "laed in the u"right "osition, the image ma# $e o$tained

%ith the use of a hori6ontal $eam.



Strutures Sho%n& ? All four "aranasal sinus grou"s

are sho%n.



PA PR0JE<TI0N& SINUSES <ald%ell (ethod

Patholog# Demonstrated

Inflammator# onditions and sinus "ol#"s@#sts are sho%n.



Part Position

? Plae "atientCs nose and forehead against u"right uk# or ta$le %ith nek

e)tended to ele!ate the 0(L '4 from hori6ontal. A radioluent su""ort $et%een

forehead and u"right uk# or ta$le ma# $e used to maintain this "osition. <Rremains hori6ontal. *alternate method if uk# an $e tilted '4.

? Align (SP "er"endiular to midline of grid or u"right uk# surfae.

? <enter IR to <R and to nasion, ensuring no rotation.



<entral Ra#

? Align <R hori6ontal, "arallel %ith the floor.

? <enter <R to e)it at nasion.




Strutures Sho%n& ? rontal sinuses "roBeted a$o!e the

frontonasal suture. ? Anterior ethmoid air ells !isuali6ed lateral to

eah nasal $one, diretl# $elo% the frontal sinuses.



PARIET0A<ANT3IAL PR0JE<TI0N& SINUSES 7aters (ethod


Inflammator# onditions and sinus "ol#"s are sho%n.



Part Position

? E)tend nek, "laing hin and nose against ta$le@u"right uk# surfae.

? AdBust head until ((L is "er"endiular to IR5 0(L %ill form a 2 angle %ith the"lane of the IR.

? Position the (SP "er"endiular to the midline of grid or ta$le@u"right uk#

surfae.

? Ensure that no rotation or tilt e)ists.

? <enter IR to <R and to aanthion.



<entral Ra#

? Align a hori6ontal <R "er"endiular to the IR entered to e)it at the aanthion.




Strutures Sho%n& ? (a)illar# sinuses %ith the inferior as"et !isuali6ed free

from su"erim"osing al!eolar "roesses and "etrous ridges, the inferior or$ital

rim, and an o$li8ue !ie% of the frontal sinuses



SU(ENT09ERTEF *S(9 PR0JE<TI0N& SINUSES


Inflammator# onditions *sinusitis, seondar# osteom#elitis and sinus "ol#"s are

sho%n.



Part Position

? Raise hin, h#"ere)tend nek if "ossi$le until I0(L is "arallel to ta$le@u"right

uk# surfae.

? 3ead rests on !erte) of skull.

? Align (SP "er"endiular to midline of the grid or ta$le@u"right uk# surfae5

ensure no rotation or tilt.



<entral Ra#

? <R direted "er"endiular to I0(L

? <R entered mid%a# $et%een angles of mandi$le, at a le!el 'G to + inhes*/ to 4 m inferior to mandi$ular s#m"h#sis

? <R entered to IR

? (inimum SID of /: inhes *':: m



Strutures Sho%n& ? S"henoid sinuses, ethmoid sinuses,

nasal fossae, and ma)illar# sinuses.



PARIET0A<ANT3IAL TRANS0RAL PR0JE<TI0N& SINUSES

0"en (outh 7aters (ethod



Strutures Sho%n& ? (a)illar# sinuses %ith the inferior as"et !isuali6ed, free from

su"erim"osing al!eolar "roesses and "etrous ridges, the inferior or$ital rim, an

o$li8ue !ie% of the frontal sinuses, and the s"henoid sinuses !isuali6ed through

the o"en mouth.

Paranasal Sinuses Imaging

Documents