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Normal and Abnormal Appearance of Nose and Paranasal Sinuses After Microendoscopic Surgery, Open Surg., and RT
265
a
b
de
c
fg
Fig. 11.8a-g. Previous sphenoidotomy
for chronic sphenoid mucocele, complicated with osteomyelitis, developed
after transsphenoidal resection of hypophyseal adenoma. a-d On coronal CT,
diffuse, irregular sclerosis of pterygoid
processes (black arrows in a), lateral
walls (black arrows in d), fl oor (arrow-
heads in d) and roof are shown. A large
defect of the sinus fl oor is fi lled by soft
tissue (arrows in c), which extends into
the posterior aspect of the sinus (aster-
isk on c) to reach a focal interruption
of the thickened sinus roof (long white
arrows in d). e On coronal TSE T2 im-
age, the thickened walls of the sphenoid
sinus are clearly shown (arrowheads).
The soft tissue (arrows) within the sphenoid sinuses show heterogeneous signal
(asterisk). f-g On axial CT and TSE T2
a synechia is seen closing the posterior
recess of sphenoid sinus (thick white
arrows). The sphenoid sinus extends
posteriorly into the clivus with a nonsmooth appearance of the cortical rim
(black arrows on f, arrowheads on g).
Hyperintensity within blocked posterior recess is shown (g). Partial resec-
tion of the posterior nasal septum was
performed (thin white arrow)
266
R. Maroldi et al.
Fig. 11.9. Previous bilateral intraoral antrostomy
(Caldwell Luc’s procedure) for nasal polyposis. Marked
reactive enlargement of posterolateral maxillary sinus
walls with thick spongiotic bone. Sinus cavity is quite
small and fi lls by soft tissue. Retraction of the anterior
walls is appreciated (arrows)
c
a
d
Fig. 11.10a-d Frontal mucocele complicating microendoscopic sinus surgery
(right uncinectomy and ethmoidotomy). a-b On coronal CT, a mucosal thick-
ening (asterisk) occupies the space between middle turbinate and lateral nasal wall to continue on adjacent maxillary sinus roof (synechia). The medial
orbital wall and the roof are reabsorbed (arrowheads). Soft tissue density
occupies the frontal sinus. Uncinectomy (white arrows). c On sagittal plane
the frontal recess is occupied by soft tissue (synechia, white arrows). Bone
thickening of the walls of a residual cell close to frontal ostium is present (ar-
rowheads). Focal erosion of the anterior wall of the frontal sinus is indicated
(black arrows). d The large frontal mucocele causes remodelling and reabsorp-
b
tion of the sinus wall (arrows) and lateral displacement of the globe.
Normal and Abnormal Appearance of Nose and Paranasal Sinuses After Microendoscopic Surgery, Open Surg., and RT
267
Fig. 11.11. Limited recurrent polyposis. Polypoid-lining soft
tissue thickening in the large nasal cavities, more evident on
the left side (thin white arrows). On both sides the residual
vertical lamella of the middle turbinate is detected (thick white
arrows). A synechia between the left one and septum is probably present. Chronic infl ammatory bone reaction in the right
maxillary sinus fl oor is shown (black arrows)
In case of widespread recurrence, the entire ethmoid is occupied by polyps which, extending into the
nasal cavity, compress and distort the middle turbinate or other residual bony landmarks. Truncation
of the middle turbinate may be observed on CT
examination (Liang et al. 1996) (Fig. 11.12, 11.13).
This form of recurrent polyposis usually requires aggressive surgery, such as total ethmoidectomy, which
consists in the removal of all bony lamellae and mucosa of the ethmoid, resulting in nasalization of the
sinuses (Jankowski et al. 1997).
The third pattern refers to the recurrence of polyposis combined with iatrogenic lesions, as the development of synechiae causing stenosis. The most
serious and common complication is the stenosis of
the frontal recess, which may eventually result in a
frontal or fronto-ethmoidal mucocele. More rarely,
stenosis of the sphenoid sinus occurs.
Apart from recurrent severe mucosal and polypoid thickening and possible middle turbinate truncation, dense sclerotic new bone formation appears as
a typical feature of patients who have undergone repeated microendoscopic sinus surgery for nasal polyposis. Bony changes may be widespread or focal. On
CT, a proper bone window is necessary to correctly
assess abnormalities (Fig. 11.10, 11.12). Since several
fi ndings suggesting chronic osteomyelitis have been
a
b
Fig. 11.12a,b. Widespread recurrent polyposis in both eth-
moids with partial resorption of right middle turbinate, which
(a) appears “truncated” (short arrows). Mild lateral bowing of
both medial orbital walls is a typical fi nding secondary to
chronic pressure of the growing polyps (thick arrows). b CT
cannot distinguish polyps from thickened mucosa. Bilateral
soft tissue thickening without polypoid appearance occupies
the frontal sinus ostia; on right side it is associated with both
thickening of bone (roof of the sinus, black arrows) and focal
erosions (fl oor of the sinus white arrow)
demonstrated by histopathologic studies in patients
with recurrent nasal polyposis, the hypothesis of
recurrent sinusitis sustained by bone infection has
been advanced, but not confi rmed (Kennedy et al.
1998).
268
Fig. 11.13. Widespread recurrent polyposis associated with left
maxillary sinus mucocele (asterisk) arising within a concameration. On TSE T2 coronal image, the polyps show various
signal intensity, probably refl ecting different degrees of edema.
The hypointensity of the bony laminae of the middle turbinate
permits their identifi cation (white arrows). Thickening of the
hypointense medial orbital wall suggests reactive bone (ar-
rowheads)
11.3.2
Expansile and Benign Lesions
The most common expansile non-infl ammatory lesions and non-malignant neoplasms treated by microendoscopic sinus surgery include inverted papilloma and juvenile angiofi broma. In both lesions, a
large cavity usually results after surgical resection,
facilitating the survey of the mucosal surface. On the
other hand, the two lesions differ in the patterns of
relapsing or persistent disease. Since inverted papilloma develops from mucosa, recurrences tend to
be recognized early by endoscopic examination.
Therefore, imaging is indicated only to detail the
extent towards not assessable areas, either because
extramucosal (anterior cranial fossa, orbit), blocked
(by the tumor or by post surgical synechiae) (Petit
et al. 2000), or located in less easily accessible areas as
the frontal sinus. Conversely, juvenile angiofi broma is
a submucosal lesion, which relapse (i.e., the growth
of residual disease) is often subclinical, and, as a consequence, detected earlier by follow up imaging than
by clinical examination. Less frequently, relapse is
suspected because of the onset of new symptoms or
the presence of indirect signs, such as submucosal
R. Maroldi et al.
bulging. Not only is imaging required to identify the
submucosal growth of a residual lesion into diploic
bone, or intracranially, or into the masticator space,
but it is also essential either to detail the extent of
disease or to monitor its progression (Nicolai et
al. 2003).
Furthermore, MR is the imaging technique recommended in the follow up of both inverted papilloma
and juvenile angiofi broma, although with different
roles: to integrate a diagnosis already obtained by endoscopy in the inverted papilloma; to be the mainstay
follow up tool, in case of juvenile angiofi broma. In
addition, MR is preferable because it avoids patient’s
irradiation, particularly in case of juvenile angiofi broma. Nevertheless, in those patients who undergo
CT, post treatment changes are quite similar to those
observed in the group of patients treated for rhinosinusitis without nasal polyposis. Major differences are
given more extended resections, which is frequently
required by expansile and benign lesions.
Detailed analysis of imaging fi ndings suggestive
of recurrent inverted papilloma or persisting juvenile angiofi broma are reported in chapter 8, in section 8.3.6 and 8.4.6, respectively.
Apart from the peculiar features of these two lesions, the interpretation of follow up MR studies requires the knowledge of the normal appearance of
sinonasal structures after endonasal surgery so that
post-operative changes can be distinguished from
recurrences.
As after microendoscopic sinus surgery for infl ammatory lesions, a variable number of bony structures
appears partially or totally resected. Differently from
CT, only high resolution MR images may identify the
hypointense signal indicating the bony wall, which is
more easily detected on condition that mucosa, mucus, or fat separate the wall from air (see chapter 4)
(Maroldi et al. 1999).
Unlike CT, the reactive changes of mucosa are
more easily distinguished from fi brosis on MR. A key
point is the presence of signals consistent with fl uid
within the thickened, infl amed mucosa. As a general
rule, the abnormal mucosa appears hyperintense on
T2 sequences, hypointense on plain T1, and shows a
thin and regular rim enhancement on post contrast
T1 images (Fig. 11.14). The signal pattern of retained
secretions within the sinusal cavity is also important.
It is related to the composition of the entrapped fl uid.
On MR, an inverse correlation is observed between
protein concentration and T2 signal, resulting in signal hypointensity in case of “old” dehydrated mucus,
which has a high protein concentration. On plain
T1 sequence, signal rises to a maximal hyperintensity
Normal and Abnormal Appearance of Nose and Paranasal Sinuses After Microendoscopic Surgery, Open Surg., and RT
Fig. 11.14a-c. Follow up of juvenile angiofi broma 4 months after resection of
a large lesion via microendoscopic surgery. a Coronal TSE T2. A wide nasoethmoid cavity results after surgery. Persistent post treatment changes are
characterized by relevant and asymmetric thickening of mucosa, especially
in the right maxillary sinus cavity (arrows). Bright edematous mucosa fi lls
the spared posterior ethmoid cells (asterisks). The edematous mucosa in
the sphenoid fl oor (single asterisk), and in the residual right maxillary sinus
cavity (double asterisks) has bright signal on TSE T2 (b), internal non-enhancing core and peripheral enhancing rim of variable thickness on post
contrast T1 (c). The thick lining of right choana (1) is fl atter, hypointense on
TSE T2, and slightly enhances on T1, indicating non-mature scar. Conversely,
the residual turbinate abutting the left nasal wall (2) shows the typical bright
enhancement. On TSE T2 a clear separation of scar from masticator space
is traced by a hypointense linear signal (long arrows on b and c). While
the residual posterolateral maxillary sinus wall is clearly detected on TSE
T2, both the sinusal wall and the hypointense linear signal enhance on T1,
indicating, respectively, infl ammation and persistent vascularization. This
immature scar tissue replaces fat within the masticator space (3) and sur-
rounds (S) a distorted medial pterygoid muscle (white arrowheads on b,
black arrowheads on c). Focal enhancement within residual posterolateral
maxillary sinus wall can suggest granuloma (black arrow)
a
269
b
at about 40% protein concentration, and then progressively decreases to hypointensity (Som et al. 1989).
If the lesion previously extended beyond the bony
boundaries of the sinonasal tract, the scar tissue replacing tumor at the involved site or developed at the
edge with adjacent structures - orbit, pterygopalatine fossa, masticator space – over the time usually
undergoes changes in thickness and signal pattern,.
Progressive reduction in tissue thickness is observed,
often combined with the tendency to assume a less
convex and fl atter shape (retraction). After months,
and mostly within one year, scar tissue appears more
or less hypointense on both T1 and T2 and should not
enhance on MR after contrast agent administration
(Fig. 11.15) (Gong et al. 1991).
c
Likewise open surgery, radical excision of the benign lesion has to be achieved by the microendoscopic
approach to fulfi l the principles of oncologic surgery.
This requires a careful dissection of lesions along
the subperiosteal plane, on condition that no sign of
bony resorption is present. Resection of the underlying bone is needed whenever cross sectional imaging
suggests bony thinning or resorption. Subtotal drilling of thick bones, especially the pterygoid process, is
frequently associated with development of sclerosis,
which appears as a diffuse, heterogeneous hypointensity on both T2 and plain T1 sequences. Similarly to
the signal behavior of fi brotic tissue, absence of enhancement should rule out intraosseous recurrences.
Fat saturation sequences improve MR sensitivity.
270
Fig. 11.15a,b, Follow up of juvenile angiofi broma one year after microendoscopic surgery. Resection of left middle turbinate,
sphenoid sinus fl oor is noted. a On pre-contrast T1 image, thickening of the mucosa along the lateral wall of the sphenoid sinus
and the choana (arrowheads) is seen. The resected left pterygoid process has been replaced by hypointense signal (white arrows),
which on post-contrast T1 image (b) does not show any signifi cant enhancement (black arrows), appearing clearly hypointense
when compared with the adjacent enhancing mucosa (arrowheads)
R. Maroldi et al.
ba
11.4
Imaging After Treatment of
Malignant Neoplasms
In the follow up of malignant neoplasms of the sinonasal tract, the main purpose of imaging consists in detecting early and late complications due
to treatment, and persisting or relapsing lesions. If
time is taken as the keynote, clinical problems are
ordered into three different periods: an immediate
post-operative phase (hours to day/s); an intermediate phase (weeks to few months); a late phase (months
to years).
11.4.1
Clinical Issues in the Immediate Postoperative
and Intermediate Phases
Clinical problems arising in the immediate post-operative and in the intermediate phase are usually largely
dependent on the type of surgery performed. In general, limited resections are less prone to cause relevant
complications. Conversely, extended procedures with
wide tissue resection and complex reconstruction, as
anterior craniofacial resection, give more frequently
rise to severe complications. Similarly to what occurs
after microendoscopic surgery, only a minority of
early complications requires imaging studies. Among
the most frequent ones are those which involve the
brain or the orbit: brain edema or hemorrhage, de-
hiscences of the duraplasty of the restored anterior
cranial fossa fl oor, tension pneumocephalus, thrombophlebitis, meningitis, exophthalmos (Richtsmeier
et al. 1992; Catalano et al. 1994).
CT is the technique of choice, as the examination
time is reduced, permitting to study even poorly cooperative patients. Only in case a brain stem lesion
is suspected, or the detailed extent of an intracranial
venous thrombosis is required, is MR indicated.
11.4.2
Clinical Issues in the Late Phase
The most common clinical problems arising months
to years from surgery, radiation therapy, or chemotherapy include late infl ammatory complications,
more often mucoceles caused by synechiae limiting
or blocking sinus drainage, and persistent or recurrent malignant neoplasm.
In the late phase, the onset or the worsening of
symptoms or signs is particularly relevant. More specifi cally, it is important to know how symptoms developed and which progression curve over the time they
had. In fact, for a similar symptom or sign, different
lesions can be inferred according to these issues. A
trismus, which develops during radiation treatment,
and gets progressively worse for months after the end
of RT, is probably caused by radiation damage to masticator space structures, and needs an imaging study
to rule out osteonecrosis of the mandible. Conversely,
Normal and Abnormal Appearance of Nose and Paranasal Sinuses After Microendoscopic Surgery, Open Surg., and RT
271
the onset of progressive trismus some months after
treatment suggests recurrent disease.
Furthermore, the presence of a subcutaneous or
submucosal (endoscopic fi nding) mass, the onset of
pain (headache, neuralgia), or neurologic/ophthalmologic signs are clear indications for an anticipated
follow up imaging study.
When designing a strategy for following up patients
treated for malignant sinonasal tract neoplasms, two
critical issues should be thoroughly considered.
Apart from rare histotypes, the rate of nodal metas-
tases is very low. On the other hand, the probability
of systemic metastases is not negligible, with lung,
liver and bone accounting for the most frequently
involved sites. The biological aggressiveness of
the different tumors is usually expressed by the
course of the disease: undifferentiated carcinoma
and squamous cell carcinoma are very aggres-
sive, with early metastasization, whereas adenoid
cystic carcinoma has a much slower progression,
but it eventually spreads locally along nerves, and
very often gives metastases to the lung.
Submucosal recurrence is frequently undetected
at clinical examination or endoscopy. When symp-
toms develop or a submucosal mass is suspected,
the recurrent tumor is usually rather advanced.
nal features (CT density or MR intensity) between
the recurrent tumor and adjacent tissues. Clearly,
MR is preferred to CT because contrast resolution is
defi nitely superior, and – in this critical setting – any
strategy capable of maximizing signal differences
between recurrent lesion and surrounding tissue
should be pursued. Given the fact that the differences
in shape or signal are less relevant than in the preoperative MR, a second strategy is to record the new
anatomy resulting from treatment to be used as baseline. Careful matching of baseline data with current
imaging and clinical fi ndings is certainly a key point
in minimizing the chance of missing early relapsing
lesions.
An interval of 3 to 4 months from surgery or radiotherapy is recommended in order to minimize the
infl uence of post treatment infl ammatory changes on
the baseline study.
Timing of further follow up studies depends on
post treatment outcome and tumor type. As a general
rule, MR are scheduled every 4 months for the fi rst
two years, than twice a year until the fi fth year after
treatment. Adenoid cystic carcinoma and olfactory
neuroblastoma usually requires a more prolonged
follow up (Bely et al. 1997; Lell et al. 2000).
Therefore, the critical goal of cross sectional imaging consists in detecting sub-clinical recurrences,
and differentiate relapsing disease from late complications. Clinical assessment and cross sectional
imaging play complementary roles (Lell et al. 2000;
Loevner et al. 2002).
11.4.3
Imaging Strategies in the Follow-up
In general, the interpretation of post treatment CT
or MR studies of the sinonasal tract can result quite
challenging due to the changes induced by treatment
(surgery, RT, chemotherapy). These consist of:
changes in the anatomy due to surgical resection
and reconstruction;
presence of reactive mucosal changes, more pro-
nounced than in rhinosinusitis because subperi-
osteal dissection is extensively required and irra-
diation effect is added;
changes in density and signal intensity of tissues
caused by the different treatments;
Overall, the compound of these elements greatly
reduces the differences both in morphology and sig-
11.4.4
CT and MR Imaging Findings
One of the most critical factors affecting the effects of
imaging studies on clinical decision during the follow
up is the cooperation between the radiologist and the
otorhinolaryngologist, the maxillo-facial surgeon, or
the radiotherapist, which permits to access critical information. We consider indispensable conditions for
interpreting CT or MR the following information:
tumor type and extent prior to treatment;
type of treatment. If surgery: type of approach,
extent of resection, materials used for reconstruction. If radiation treatment: irradiation portals,
boost areas, overall dose;
areas at higher risk for persistent/recurrent dis-
ease, as intraoperatively assessed;
post treatment course, complications;
present symptoms and signs.
11.4.4.1
Normal Postoperative Imaging Changes
Surgical resection, reconstruction, and infl ammatory
tissue reaction account for three main categories of
post-operative imaging changes.
272
R. Maroldi et al.
Changes secondary to resection can be predicted
based on the surgical report. However, the extent
of each resection may vary, according to the actual
spread of tumor. Acknowledge of variations from
standard procedures helps to make a proper interpretation. For example, knowing that an ethmoido-maxillectomy required removal of the lamina papyracea
because remodeled or invaded by tumor is important, as this variation accounts for a partial “collapse”
into the nasal cavity of the orbital content (Som et al.
1986a,b).
After orbital sparing surgical procedures entailing removal of a variable extent of orbital wall(s),
enophthalmos or hypophthalmos can occur. Imaging
may precise the status of the orbital walls (Imola and
Schramm 2002) (Fig. 11.16).
In extended resections and reconstructions, as in
anterior craniofacial resection, one of the most important elements to be evaluated is the modality of
restoring the separation of the inner cranium from
the naso-ethmoidal cavity. In analyzing CT or MR
follow up examinations, the assessment of these reconstructed interfaces is usually quite complex. The
radiologist should know which materials have been
used (dura mater, pericranium fl ap, in some cases
bone or bone pâté), because duraplasty presents as a
multiple-layer “sandwich” of signals (Schuster et al.
1994; Maroldi et al. 1997).
This meningo-galeal complex results from the
need to remove a possibly invaded dura, along with
the bony part of the anterior cranial fossa fl oor, and
to restore the separation of cranium from nasal cavity. During anterior craniofacial resection, a small
rectangle of dura (including the invaded area) is usually resected and replaced by autologous fascia lata
or lyophilized dura. To obtain a better sealing and a
more robust structure, a pedicled pericranium fl ap is
used to reinforce the duraplasty and to offer a nicely
vascularized barrier, which eventually divides the sinonasal tract from the cranium (Osguthorpe and
Pat e l 1995).
During the immediate post-operative phase, it is
normal to observe a mild extradural air-fl uid collection and a smaller intradural air collection on CT.
Infrequently, a tension pneumocephalus may develop (Fig. 11.3) (Wanamaker et al. 1995). Particular
attention has to be given to even minimal frontal
lobe lesions, though small contusions or mild edema
may be considered expected fi ndings (Som et al.
1986b), but more extensive lesion may occur, yet
sometimes asymptomatic since anosmia is a rule
(Fig. 11.17). Months after surgery, the appearance
of the meningo-galeal complex is characterized by
a quite regular “plaque”, 3-5 mm in thickness, which
shows signifi cant enhancement both on CT and on
MR. Enhancement has been reported to be related to
chronic infl ammatory reaction and to increased vascularization of the dura.
A detailed evaluation of the overall extent of the
meningo-galeal complex is obtained with sagittal MR
Fig. 11.16a,b. Follow up of ethmoid adenocarcinoma after anterior craniofacial resection. a On coronal TSE T2, bilateral medialization of medial orbital wall is seen. Dehiscence of left medial orbital wall with fat content (arrowheads) is present. A quite
thick duraplasty has a linear hypointense inner signal in its lower aspect (possible autologous bone, short arrows). The duraplasty is invested on nasal surface by a thickened mucosa (long arrows). Post-surgical focal encephalomalacia is seen on right
side (asterisk). b On axial TSE T2, the medial prolapse of left medial orbital wall results more evident (arrowheads). A small
fl uid collection faceting the anterior portion of left lamina papyracea is also present. The lesion has the potential to mucocele
development (arrows)
ba
Normal and Abnormal Appearance of Nose and Paranasal Sinuses After Microendoscopic Surgery, Open Surg., and RT
sequences. By combining sagittal with coronal T2 and
enhanced T1 images, a clear demonstration of the integration of the meningo-galeal complex with the adjacent dura is obtained (Fig. 11.18. 11.19). Moreover,
its relationship with frontal bone, planum sphenoidale, and nasal cavity are detailed. On T2 sequences,
the meningo-galeal complex has a continuous, thick,
and quite regular hypointense signal. On high resolution post contrast T1, multiple layers with slightly
different signals are usually detected. The whole
complex of duraplasty can be disassembled into its
singular components, which show different signal
intensity. Moreover, the identifi cation of the single
components by their specifi c signal on MR sagittal
and coronal planes help to differentiate the meningogaleal complex from recurrent disease.
Fig. 11.17. Follow up of anterior craniofacial resection nine
years after removal of an ethmoid recurrent inverted papilloma with foci of squamous cell carcinoma. The coronal Fat
sat T2 image show two large cavities within the frontal lobes
with fl uid content (black arrows). Both reach the anterior cranial fossa fl oor. Quite regular lining of the nasal surface of the
meningo-galeal complex is seen (white arrows)
After extensive resection of the maxilla or of the
orbit, the resulting large defect is reconstructed by
means of a local or revascularized fl ap (muscular,
myo-cutaneous, or fascio-cutaneous) (Fig. 11.20–
11.23). Frequently, the temporalis muscle is used. The
muscle can be easily recognized by identifying two
273
abc
Fig. 11.18a-d. Follow up of anterior craniofacial resection one year after removal of a
left ethmoid olfactory neuroblastoma. On coronal TSE T2 (a-c), the meningo-galeal
complex is not cut perpendicularly on all images, therefore appearing with apparent different thickness and a more hypointense signal in the most anterior plane
(a), because of the oblique course of the complex at this level (asterisk). For the
same reason the superior limit of the complex has an unsharp appearance (arrows).
Removal of the ethmoid associates with mild medial prolapse of the orbits (double
arrowheads arrow). b-c The meningo-galeal complex has an asymmetric mild thick-
ness, three main layers, which are all demonstrated only on the most perpendicular
plane (b, c). The nasal mucosal lining (thin arrows) is quite hypointense and borders
an intermediate layer with heterogeneous hyperintense signal (asterisk), which is
limited superiorly by the inner layer (thick arrows), which faces the CSF. d On the
contrast sagittal T1 plane, the meningo-galeal complex separable in its different
d
components: nasal mucosa (a); intermediate layers (b and c), dura (d). At the inte-
gration with the posterior wall of the marsupialized frontal sinus (asterisk) the dura
is thicker (arrowheads). Sphenoid sinus (SS), Onodi cell (OnC)
274
R. Maroldi et al.
ba
Fig. 11.19. a Follow up of anterior craniofacial resection and left rhinotomy nine months after removal of an ethmoid adeno-
carcinoma invading the skull base, olfactory fi la, and nasal septum. The sagittal post-contrast T1 image permits to separate the
thicker than usual meningo-galeal complex into separate layers: nasal mucosa (a); more (b) and less mature (c) fi brotic scar;
residual bone ad the periphery of the resection (d); restored dura mater (e). The thickened dura lines the restored anterior
cranial fossa and the posterior aspect of frontal bone (arrowheads). Clear cur resection of the frontal bone cortical rim is seen
(1). Small fl uid collection between dura and facial bone (double asterisks). Mucus retention within the blocked sphenoid sinus
has high signal intensity (asterisk). b Follow up of anterior craniofacial resection and total rhinectomy for squamous cell carcinoma 10 years before, sagittal post-contrast T1 image. The thickness of the meningo-galeal complex is mild; the dural lining
(arrows) is similar for enhancement and thickness to non-involved areas
ba
Fig. 11.20a,b. Follow up CT after radical maxillectomy for adenoid cystic carcinoma of right hard palate three years before. In
the absence of the prosthetic obturator, a large defect results in a single oro-nasal cavity. Smooth surface is seen (white arrows
on a). Resection of the right maxillary and vidian nerve with exploration of the respective canals was performed at surgery.
Dense sclerosis of right pterygoid process is demonstrated by CT around the foramen rotundum (black arrows on b). Soft tissue
fi lls the area previously occupied by the vidian canal (white arrow)
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