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Supratubal recess and sinus tympani: CT
analysis of middle ear hidden areas
Mohammad Waheed El-Anwar
1*
, Diaa Bakry Eldib
2
, Ashraf Elmalt
1
and Alaa Omar Khazbak
1
Abstract
Background: High-resolution computed tomography (HRCT) magnifies the role of preoperative imaging for
detailed middle ear anatomy particularly its hidden area. The purpose of the current study was to assess the sinus
tympani (ST) and supratubal recess (STR) by HRCT, to create CT classification of the STR depth, and to study the
relationship between ST types and the new STR grades.
Results: In HRCT of non-pathological temporal bones of 100 subjects (200 ears), measurements of the STR and ST
were calculated, registered, and analyzed. The depth of the STR was classified into grade 1 with depth less than 3
mm, grade 2 with depth ranged between 3 and 5 mm, and grade 3 with depth more than 5 mm. The mean STR
length, width, and height were 4.17 ± 0.86, 3.55 ± 0.65, and 3.64 ± 0.7 mm, respectively, while the ST mean length
and width of were 2.52 ± 0.5 and 1.82 ± 0.78 mm, respectively, without significant differences between either sexes
or sided. The ST types were found to be type A in 56 ears (28%), type B in 142 ears (71%), and type C in 2 ears
(1%). The STR grading was grade 1 in 12 ears (6%), grade 2 in 160 ears (80%), and grade 3 in 28 ears (14%) without
significant relationship between ST types and STR grading (P= 0.3).
Conclusion: The current study provided reliable and applicable methods of CT assessment of STR and ST that can
help to predict the degree of surgical visibility of the ST and STR during ear surgery.
Keywords: Supratubal recess, Sinus tympani, Computed tomography, Anterior epitympanic space, Cholesteatoma
Background
In the last three decades, endoscope has been increas-
ingly used in endonasal surgery that nowadays is simple
and common [1]. Since the last decade, endoscope was
used in otology firstly as a diagnostic tool then during
middle ear surgery [2–7]. Endoscopy provided an im-
portant and sometimes unexpected detailed middle ear
anatomy particularly for the hidden recesses such as
the sinus tympani (ST) and the supratubal recess
(STR). The STR is also known as the anterior epitym-
panic recess (AER) [8,9].
Maximum exposure of the ST and STR in cholestea-
toma surgery and complete removal of the disease is
mandatory [10]. Endoscopic exploration of such hidden
recesses (ST and STR) provides visualization and magni-
fication that is almost impossible to achieve with micro-
scopic traditional approaches without excess bone
drilling [11]. But endoscopic visualization of STR and ST
could not be achieved in non-operated ears or after
canal wall up mastoidectomy except during surgery. So,
high-resolution computed tomography (HRCT) has a
magnified role for the preoperative more detailed inner
and middle ear anatomical information [1,12] and it is
the main guide for the surgeon to assess such hidden
areas preoperatively and during surgery. However, in
spite their crucial role in residual and recurrent disease,
the ST and STR have received few and scattered atten-
tion in the radiological and otological literature and
when they studied, many details are usually missed.
Recently, Marchioni et al. [13] classified the depth of
the ST into three types (A, B, and C) (Fig. 1) based on
the radiologic findings: type A, small sinus tympani
without medial or posterior extension in relation to the
3rd portion of facial nerve; type B, deep sinus tympani
with medial extension but without posterior extension in
relation to 3rd portion of the facial nerve; and type C,
large and deep sinus tympani with medial and posterior
extension in relation to the 3rd portion of the facial
© The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.
* Correspondence: mwenteg1973@gmail.com;mwenteg@yahoo.com
1
Otorhinolaryngology-Head and Neck Surgery Department, Faculty of
Medicine, Zagazig University, Zagazig, Egypt
Full list of author information is available at the end of the article
Egyptian Journal of Radiolog
y
and Nuclear Medicin
e
El-Anwar et al. Egyptian Journal of Radiology and Nuclear Medicine (2019) 50:49
https://doi.org/10.1186/s43055-019-0056-1
nerve. Marchioni et al. [13] recommended further stud-
ies focused on ST types to prove their concept. More-
over, ST classification was not correlated with STR
pneumatization and no classification of depth of STR
had been developed yet.
The aim of the current study was to find an applicable
way by HRCT imaging to assess the STR and ST in the
way of proper preoperative review of the anatomy of
middle ear. We aimed also to create an applicable CT
classification of the depth of the STR and investigate the
relation between ST types and our new STR grades.
Methods
Subjects
This study was conducted in the Otorhinolaryngology
Department, in collaboration with the Radiodiagnosis
Department. We retrospectively studied CT images of
paranasal sinuses done for patients having symptoms of
sinus-related complaints and who had no ear symptoms
and no previous ear surgery. Randomly selected CT
images of the non-pathologic temporal bones belonging
to 100 subjects (200 ears) were included. The inclusion
criterion of this study was the non-pathologic temporal
bones. Informed written consent was signed by all
subjects to share in the study after explanation of its
purposes and the IRB approved the study.
Exclusion criteria included patients aged below 12 years,
history of surgery or trauma in the skull base, congenital
anomalies of the face, or paranasal sinus malignancies.
Data acquisition and post-processing
All examinations were done using multi-detector row
CT a 64 slice CT scan (light speed volume VCT, GE
medical system, Milwaukee, WI, USA) in helical mode.
The raw data was exported by DICOM software, and the
images were generated for the temporal region following
temporal bone imaging protocol. Scan parameters in-
clude tube voltage of 120 kV and a current of 180 mA.
Images were reconstructed using 0.5-mm-thick sections
at 0.5 increments, using a 512 × 512 matrix of 0.43 mm
pixel size and a field of view (FOV) of 22 × 22 cm. Im-
ages were displayed using a window center of 700 HU
and a window width of 4000 HU. CT images were ana-
lyzed and reviewed by all authors, and appropriate mea-
surements were done by the radiologist author with
more than 15 years of experience in CT imaging.
Calculation (Figs. 1,2,3, and 4)
The multiplanar reconstruction (MPR) technique was used
to reconstruct the CT images and to produce coronal, sa-
gittal, axial, and oblique axial images of the petrous tem-
poral bones. All landmarks around the STR and ST were
defined. To achieve uniformity throughout this cranio-
metric study and to resolve the asymmetry associated with
patient positioning, the Frankfort horizontal (Pfrk) plane
was taken to be the standard horizontal plane, which is de-
fined as the plane connecting the uppermost portions of
the right and left external auditory canals (portions) and
the inferior most portion of the infraorbital rim of the left
eye. The sagittal plane (Psag) was vertical to the horizontal
plane and was defined as the plane through the top of the
crista galli and the middle point of the line from the central
points of the right and left foramen spinosum. The coronal
plane(Pcor)wasdefinedastheplanethroughthelinefrom
the right and left foramen spinosum and was perpendicular
to both horizontal and sagittal planes [14,15].
Measurements
The multiplanar reconstruction (MPR) technique was
used to reconstruct the CT images and to produce
Fig. 1 a,bSupratubal recess (STR) (red arrows) in axial CT images and their relation to the ossicles and incudomalleal articulation. cThe right and
left STR formed of one cell. dThe right STR formed of multi-cells while the left one formed of one cell. eBoth the right and left STR) formed
of multi-cells
El-Anwar et al. Egyptian Journal of Radiology and Nuclear Medicine (2019) 50:49 Page 2 of 7
coronal, sagittal, and axial images of the petrous tem-
poral bones to identify the STR (Figs. 1,2,and3).
The width of the STR (STR-W) was represented by the
distance between the most lateral and inferior point to the
most medial and inferior point of the cog in the axial
plane. The length of the STR (STR-L) was represented by
a line parallel to the axis of incudomalleolar articulation
from the most anterior point of the STR to the line pass-
ing through the cog in axial plane (Figs. 1and 2).
The height of the STR (STR-H) was represented by
the superior-to-inferior (SI) distance from the tegmen
tympani to the cochleariform process and the most
superior point of the tympanic orifice of the ET, on
the coronal plane [12,16](Fig.2).
We classified the depth (antero-posterior) of the STR
into three grades based on the radiologic findings; grade
1 STR-L where STR depth less than 3 mm, grade 2 with
STR depth ranged between 3 and 5 mm, and grade 3
with STR depth more than 5 mm (Fig. 3).
The sinus tympani (ST) was identified in axial CT im-
ages with selection of the best image showing ST, prom-
ontory, and 3rd portion of the facial nerve canal. Types
of ST (A, B, and C) identified and registered according
to Marchioni et al. [13] classification.
The ST length (ST-L) was represented by the antero-
posterior diameter of ST, from a tangential line passing
through the anterior aspect of the facial nerve canal and
the promontory to the deepest point of ST. The ST
Fig. 2 Supratubal recess (STR) measurements. aAxial CT through the left STR, showing measurements of length (STR-L) and width (STR-W) of STR.
STR-L: the deepest anterior to posterior diameter (arrowhead) parallel to incudomalleal axis (red arrow). STR-W: distance between medial and
lateral borders of cog (curved yellow arrow). b,cMeasurement of STR height (STR-H) in coronal CT, from tegmen tympani to the cochleariform
process (red arrows), adjacent to the tensor tympani muscle. The cochleariform process separates the tensor tympani (hypoattenuating focus
superolateral to the cochleariform process) from the bony Eustachian tube (inferomedially)
Fig. 3 Grades of the depth of STR. Axial CT images through the STR, showing the three grades of the depth of STR. aGrade 1: shallow STR. bGrade 2:
medium-sized STR. cGrade 3: deep STR
El-Anwar et al. Egyptian Journal of Radiology and Nuclear Medicine (2019) 50:49 Page 3 of 7
width (ST-W) was represented by the widest transverse
diameter of ST.
Statistics
All data are shown as means and standard deviation
(SD). All statistical data were analyzed with the SPSS
25.0 (SPSS, Inc., Chicago, IL).
Results were compared statistically using the SPSS
program version 25.0 (Chicago, Illinois, USA). When P
value was less than 0.05, it was considered statistically
significant.
Results
Two hundred ears of 100 subjects were included in the
current study: 46 (46%) females and 54 (54%) males.
Their age ranged from 12 to 76 years; mean age was
38 ± 13.29 years (Table 1).
The ST types were found to be type A in 56 ears
(28%), type B in 142 ears (71%), and type C in 2 ears
(1%) (Fig. 4).
The STR is formed of solitary cell in 159 ears (79.5%)
and multiple cells (multi-cells) in 41 ears (20.5%)
(Fig. 1).
The mean length (anterior-posterior depth) of the STR
(STR-L) was 4.17 ± 0.86 mm with a range of 2.36 to 7.85
mm (4.22 ± 0.91 mm with a range of 2.36 to 7.44 mm at
the right ears and 4.13 ± 0.81 mm with a range of 2.73 to
7.85 mm at the left ears), while the mean length in male
was 4.28 ± 0.84 mm (range 2.73–6.97) and in female was
4.05 ± 0.88 mm (range 2.36–7.85). No significant differ-
ence was observed in the length of the STR between the
right and left ears (P< 0.4609) or between male and fe-
male subjects (P< 0.0605) (Table 1).
The STR grading of its anterior-posterior depth was
grade 1 (< 3 mm) in 12 ears (6%), grade 2 (3–5 mm) in
160 ears (80%), and grade 3 (> 5 mm) in 28 ears (14%)
(Table 2).
The mean width of the STR (STR-W) was 3.55 ± 0.65
mm with a range of 1.04 to 5.57 mm. The mean width
was 3.52 ± 0.62 mm with a range of 2.37 to 5.48 mm at
the right ears and 3.59 ± 0.68 mm with a range of 1.04 to
5.57 mm at the left ears, while the mean width in male
was 3.58 ± 0.7 mm with a range of 1.04 to 5.57 mm and
in female was 3.52 ± 0.6 with a range of 2.04 to 5.48 mm.
No significant difference was observed in the width of
the supratubal recess (STR-W) between the right and
left ears (P< 0. 4477) or between male and female sub-
jects (P< 0. 5172) (Table 1).
The mean height (superior-inferior depth) of the STR
(STR-H) was 3.64 ± 0.7 mm with a range of 2.3 to 5.88
mm (3.6 ± 0.68 mm with a range of 2.37 to 5.88 mm at
the right ears and 3.68 ± 0.7 mm with a range of 2.33 to
5.74 mm at the left ears). While the mean height in male
was 3.66 ± 0.75 mm with a range of 2.33 to 5.88 mm and
in female was 3.61 ± 0.62 with a range of 2.3 to 5.45 mm.
No significant difference was observed in the height (su-
perior-inferior depth) of the STR (STR-H) between the
right and left ears (P< 0.474) or between male and fe-
male subjects (P< 0.6118) (Table 1).
The mean length of the ST (ST-L) was 2.52 ± 0.5 mm
with a range of 1.36 to 3.97 mm (2.51 ± 0.51 mm with a
range of 1.36 to 3.63 mm at the right ears and 2.52 ± 0.5
mm with a range of 1.39 to 3.97 mm at the left ears),
while the mean length in male was 2.47 ± 0.5 mm with a
range of 1.39 to 3.63 mm and in female was 2.56 ± 0.5
with a range of 1.36 to 3.97 mm. No significant differ-
ence was observed in the length of the sinus tympani
(ST-L) between the right and left ears (P< 0.8888) or be-
tween male and female subjects (P< 0. 206) (Table 1).
Fig. 4 Sinus tympani (ST) (STR) measurements and types. aAxial
CT images showing the right and left Sinus tympani (ST) (red
arrows). bMeasurement of right ST length and width (ST-L & ST-W)
in axial CT image. c–eDifferent types of ST; yellow arrow points to
ST and red arrow points to the facial nerve. The green lines
passing through the floor of the ST and the outer wall of the facial
nerve canal demonstrate the relation between ST and facial nerve.
cType A ST: small sinus tympani without medial or posterior
extension in relation to the facial nerve. dType B ST: deep sinus
tympani with medial extension but without posterior extension in
relation to the facial nerve. eType C ST: large and deep sinus
tympani with medial and posterior extension in relation to the
facial nerve
El-Anwar et al. Egyptian Journal of Radiology and Nuclear Medicine (2019) 50:49 Page 4 of 7
The mean width of the ST (ST-W) was 1.82 ± 0.78 mm
with a range of 0.55 to 7.31 mm (1.75 ± 0.6 mm with a
range of 0.55 to 4.23 mm at the right ears and 1.89 ± 0.93
mm with a range of 0.65 to 7.31mm at the left ears), while
the mean width in male was 1.78 ± 0.82 mm with a range
of 0.55 to 7.31 mm and in female was 1.86 ± 0.73 with a
range of 1.01 to 5.94 mm. No significant difference was
observed in the width of the sinus tympani (ST-W) be-
tween the right and left ears (P< 0.2052) or between male
and female subjects (P< 0.4705) (Table 1).
No significant relationship was detected between ST
types and STR grading (P= 0.3, X
2
= 4.874) (Table 3).
Discussion
Our study highlighted two major anatomic landmarks
and sites in the middle ear (STR and ST); one should be
familiar with these landmarks to be able to describe nor-
mal and pathologic middle ear findings and provide an
accurate CT interpretation and preoperative surgical as-
sessment. HRCT is a major tool for imaging evaluation
of the middle ear. HRCT offers excellent delineation of
soft tissue abnormalities against a background of air
(middle ear cavity, EAC, mastoid air cells) and allows ex-
cellent preoperative assessment of bone changes and/or
involvement.
The STR is a common site of recurrent cholesteatoma,
in both congenital and acquired cholesteatomas; how-
ever, it was not clearly recognized why cholesteatoma
formed so easily in the STR [9]. The prevalence of re-
sidual cholesteatoma is high following mastoidectomy.
Even though, otoendoscopy is helpful to reduce retro-
tympanic residual cholesteatoma, anterior attic (STR) re-
sidual still represents a problem particularly with the
canal wall up technique [17]. Thus, the surgeons di-
rected their attention to the ST and STR due to their
frequent involvement by cholesteatoma and their rela-
tions to important structures. But, the STR and ST have
received scanty attention and in the radiological litera-
ture [12,17–19] without detailed description. We tried
in our current study to use HRCT to assess both STR
Table 1 Analysis of the STR and ST measurements using mean ± SD and range (in millimeter)
Total Male Female Right Left
Number of subjects 100 54 46 100 100
Number of the ears 200 108 92 100 100
STR-L Mean ± SD 4.17 ± 0.86 4.28 ± 0.84 4.05 ± 0.88 4.22 ± 0.91 4.13 ± 0.81
Range 2.36–7.85 2.73–6.97 2.36–7.85 2.36–7.44 2.73–7.85
Pvalue (ttest) 0.0605 (1.8881) NS 0.4609 (0.7387) NS
STR-W Mean ± SD 3.55 ± 0.65 3.58 ± 0.7 3.52 ± 0.6 3.52 ± 0.62 3.59 ± 0.68
Range 1.04–5.57 1.04–5.57 2.04–5.48 2.37–5.48 1.04–5.57
Pvalue (ttest) 0.5172 (0.6489) NS 0.4477 (0.7607) NS
STR-H Mean ± SD 3.64 ± 0.69 3.66 ± 0.75 3.61 ± 0.62 3.6 ± 0.68 3.68 ± 0.7
Range 2.3–5.88 2.33–5.88 2.3–5.45 2.3–5.88 2.33–5.74
Pvalue (ttest) 0.6118 (0.5083) NS 0.474 (0.7173) NS
ST-L Mean ± SD 2.52 ± 0.5 2.47 ± 0.5 2.56 ± 0.5 2.51 ± 0.51 2.52 ± 0.5
Range 1.36–3.97 1.39–3.63 1.36–3.97 1.36–3.63 1.39–3.97
Pvalue (ttest) 0.206 (1.2687) NS 0.8888 (0.14) NS
ST-W Mean ± SD 1.82 ± 0.78 1.78 ± 0.82 1.86 ± 0.73 1.75 ± 0.6 1.89 ± 0.93
Range 0.55–7.31 0.55–7.31 1.01–5.94 0.55–4.23 0.65–7.31
Pvalue (ttest) 0.4705 (0.723) NS 0.2052 (1.2712) NS
STR supratubal recess, ST sinus tympani, STR-L STR length, STR-W STR width, STR-H STR height, ST-L ST length, ST-W ST width, SD Standard
deviation, NS Non-significant
Table 2 STR length (anterior-posterior depth) grading
Grade 1 Grade 2 Grade 3
Measurement in mm < 3 mm 3–5mm >5mm
Number of ears 12 160 28
Percent 6% 80% 14%
Table 3 Supratubal recess (STR) grading in relation to sinus
tympani (ST) types
ST type Type A Type B Type C Total Pvalue
STR grade
Grade 1 4 (33%) 8 (67%) 0 (0%) 12 (6%) 0.3 NS
X
2
= 4.874
Grade 2 41 (25.6%) 118 (73.8%) 1 (0.6%) 160 (80%)
Grade 3 11 (39%) 16 (57%) 1 (4%) 28 (14%)
Total 56 (28%) 142 (71%) 2 (1%) 200 (100%)
NS non-significant, X
2
chi-square
El-Anwar et al. Egyptian Journal of Radiology and Nuclear Medicine (2019) 50:49 Page 5 of 7
and ST in details defining their measurements in all di-
rections and provide a new classification of the STR.
HRCT of the temporal bone is therefore a useful guide
to the surgeon because it provides information regarding
the extent of disease as well as possible anatomic varia-
tions and potential complications that may be avoided
during surgery [20]. We used 64 HRCT scanner that is
sufficient to improve the image quality and better delin-
eation of middle ear structures [21,22].
Effective doses in sinus CT are 0.5–0.9 mSv and in ear
CT are 0.3–0.6 mSv [23]. Because CT examinations of
the paranasal sinus and ear presented the highest dose
to eye lens of 35.3 mGy [24], lead lined eye shield was
used in the current work to minimize exposure of the
eye and lens to radiation.
The ST is a posterior outpouching of the retrotympa-
num delimited by the mastoid part of the facial nerve
and pyramidal eminence laterally and vestibule medially
[19,24] (Fig. 4).
During cholesteatoma surgery, the cholesteatoma may
be located and missed in the depth of the ST that repre-
sents an important surgical challenge due to the con-
formation and position of the ST [25]. Marchioni et al.
[19] stated that when cholesteatoma involves the ST,
there are two clinically important risks: first is the po-
tential risk of residual disease due to incomplete removal
of the cholesteatoma, and second is the increased risk
for ossicular discontinuity and hearing loss due to cho-
lesteatoma within the ST. Therefore, the CT-derived
morphology of the ST could help the surgeon in the pre-
operative assessment [13].
In our current retrospective study on 200 ears CT, we
confirm the data published by Marchioni et al. [13] who
reviewed HRCT scan of the temporal bones. We were
able to confirm the presence of their described three ST
variations and codify their incidence: 28% for type A,
71% for type B, and 1% for type C. So, based on our
data, ST type B is the most common morphological ST
conformation, and ST Type A is less common that is
similar to previous findings [13,19]. In addition, we de-
fined the exact measurements of the ST.
On the other hand, STR is bounded anteriorly by the root
of zygomatic arch, medially by the anterior part of the tym-
panic facial nerve and geniculate ganglion, posteriorly by
the cog, laterally by the scutum, and superiorly by the teg-
men tympani (separates it from the dura mater) [12].
The STR could be involved by different pathologic
processes. In both congenital and acquired cholesteato-
mas, the STR has been shown to be the common site of
recurrence [12,18]. Familiarity with the CT appearance
of this space facilitates recognition of its early pathologic
changes or its involvement in extensive lesions.
Our study shows that the STR is an anatomic struc-
ture that is consistently identified on HRCT scans. Thus,
preoperative CT assessment will give orientation for
STR configuration.
We reported that STR is commonly formed of solitary
cell (79.5%), while in 20.5% of the ears, it is formed of
multiple cells. These results are in agreement with the
results of the recent study of Hong et al. [9]. STR depth
in the current study was 4.17 ± 0.86 mm with a range of
2.36 to 7.85 that is near to mean detected by Marchioni
et al. [12] (5.1 ± 1.46 mm).
We introduced a new grading system for classification
of the depth (anterior-posterior depth) of the STR into
three grades based on the HRCT findings: grade 1
(depth < 3 mm), grade 2 (depth 3–5 mm), and grade 3
(depth > 5 mm). We found that grade 2 STR was the most
common (80%) followed by the deep STR (grade 3, 14%)
while the shallow STR (grade 1) was the lease common (6%).
We found that there was no significant relationship
between ST types and STR grading, so the depth of each
of them is not associated with or expect depth of the
other recess and the STR and ST should be assessed
radiologically as a separate entity.
In deep STR (types 2 and 3), surgeons need to be
ready to use of angled (45°) endoscope and drill the an-
terior portion of the scutum mostly.
These newly suggested preoperative CT measurements
and new STR grades are applicable, measurable in children
and adult, and reliable. Therefore, they can be used as good
predictors for the STR visibility during cholestetoma sur-
gery and predict the need for the incus and malleus head
removal and or otoendoscopy use to access the recess with
different measurement. In addition, these will help to in-
crease attention of the radiologists and the otosurgeons to
the CT evaluation of these important regions.
It seems intuitive that the deeper the ST and the larger
STR, the higher the risk of residual disease. So, second
look surgery could be expected more in type C ST and
grade 3 STR. Adding of the ST types and STR grading
to the preoperative CT check list is recommended. Fur-
ther studies focused on that topic in cholesteatoma pa-
tients are required.
Our study has some limitations; the study was con-
ducted on non-pathological temporal bones, and further
studies discussing changes in ST and STR measurements
in cases of cholesteatoma are required. Also, our study
did not discuss the age-related changes in ST and STR
parameters due to lack of a considerable number of sub-
jects in childhood age.
Conclusion
The described measurements and grading of STR and
ST allow otosurgeons and radiologist to assess such cru-
cial and potentially hidden areas. The degree of surgical
visibility of the ST and STR during middle ear surgery
can depend on these measurements and classification.
El-Anwar et al. Egyptian Journal of Radiology and Nuclear Medicine (2019) 50:49 Page 6 of 7
Abbreviations
ET: Eustachian tube; HRCT: High-resolution computed tomography;
MPR: Multiplanar reconstruction; SD: Standard deviation; ST: Sinus tympani;
STR: Supratubal recess; STR-H: Height of the supratubal recess; STR-L: Length
of the supratubal recess; STR-W: Width of the supratubal recess
Acknowledgements
The authors thank all the study participants for their patience and support.
Authors’contributions
MWE suggested and developed the research idea; followed up the work
progress; reviewed literature; defined the study protocol, interpretation, and
analysis of collected data; wrote the manuscript; assisted in preparing the
figures; performed the statistical analysis; followed up the work progress; and
approved the submitted version. DBE performed the data acquisition and
post-processing; performed CT assessment and measurements; kept the rec-
ord of patients’information; tabulated data, interpretation, and analysis of
collected data; assisted in writing methods and revising the written manu-
script; prepared the figures, and approved the submitted version. AOK made
initial arrangements and coordination with the Radiodiagnosis Department,
reviewed the written manuscript, revised the manuscript critically for import-
ant intellectual content, and approved the submitted version. AE reviewed
the written manuscript, revised the manuscript critically for important intel-
lectual content, and approved the submitted version. All authors have read
and approved the manuscript.
Funding
The authors declare no financial support or interest to this study.
Availability of data and materials
The datasets used and/or analyzed during the current study are available
from the corresponding author on reasonable request.
Ethics approval and consent to participate
Informed written consent was signed by all subjects to share in the study
after explanation of its purposes. Zagazig University IRB approved the study
(2016).
Consent for publication
All patients included in this research gave written informed consent to
publish the data contained within this study. If the patient was less than 16
years old, deceased, or unconscious when consent for publication was
requested, written informed consent for the publication of this data was
given by their parent or legal guardian.
Competing interests
The authors declare that they have no competing interests.
Author details
1
Otorhinolaryngology-Head and Neck Surgery Department, Faculty of
Medicine, Zagazig University, Zagazig, Egypt.
2
Radiodiagnosis Department,
Faculty of Medicine, Benha University, Benha, Egypt.
Received: 6 June 2019 Accepted: 23 September 2019
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