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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 23  |  Issue : 3  |  Page : 164-169

Computed tomographic scan utilization in the diagnosis of otorhinolaryngological diseases


1 Department of Radiology, School of Medicine, University of Benin, Benin City, Nigeria
2 Department of Radiology, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria

Date of Submission18-Sep-2019
Date of Decision29-Oct-2019
Date of Acceptance29-Apr-2020
Date of Web Publication7-Oct-2020

Correspondence Address:
Dr. Festus Oghanina Ehigiamusoe
Department of Radiology, School of Medicine, University of Benin, Benin City, Edo State
Nigeria
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DOI: 10.4103/smj.smj_47_19

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  Abstract 


Background: Having an audit of common otorhinolaryngological diseases diagnosed on computed tomography (CT) scan in our environment is important as it will help elucidate the sociodemographics and pattern of referral for CT scan from an ear, nose, and throat (ENT) clinic as well as CT findings. Materials and Methods: The request forms as well as the CT scan reports of 203 patients who were referred from the ENT clinic between 2006 and 2014 and had CT scan were retrieved from our records. All CT scans were done using a four-slice BrightSpeed helical GE CT scan machine. Out of the 214 patients recruited for this study, only 203 patients were unanimously agreed upon by the authors as the remaining 11 patients had incomplete data. Results: There were 124 males (61.1%) and 79 females (38.9%). The mean age of patients with nasopharyngeal tumor was 40.67 ± 26.01 years, laryngeal tumor was 57.47 ± 15.64 years, antrochoanal carcinoma was 46.05 ± 22.95 years, and sinusitis was 44.96 ± 17.19 years, while that of otitis media was 43.33 ± 23.60 years. A total of 177 patients representing 87.2% of the study population had one or two pathological findings on CT scan. Sinusitis accounted for most findings on CT scan (12.8%), followed by laryngeal tumor (10.7%) and antrochoanal carcinoma (10.2%). Others were choanal polyp (9.7%), nasopharyngeal tumors (9.2%), rhinitis (6.1%), mastoiditis (5.1%), and mucocele of the sinuses (4.6%). Juvenile angiofibroma (1.0%) and palatal masses (1.0%) were the least in terms of occurrence of all ENT conditions. Conclusion: Common findings on CT scan of the ENT in our environment have been documented.

Keywords: Computed tomography, diagnosis, disease, otorhinolaryngology, utilization


How to cite this article:
Ehigiamusoe FO, Obi-Egbedi-Ejakpovi EB. Computed tomographic scan utilization in the diagnosis of otorhinolaryngological diseases. Sahel Med J 2020;23:164-9

How to cite this URL:
Ehigiamusoe FO, Obi-Egbedi-Ejakpovi EB. Computed tomographic scan utilization in the diagnosis of otorhinolaryngological diseases. Sahel Med J [serial online] 2020 [cited 2020 Oct 25];23:164-9. Available from: https://www.smjonline.org/text.asp?2020/23/3/164/297455




  Introduction Top


Diseases of the ears and sinuses can be assessed by plain radiography, but these have some limitations such as superimposition of structures and problem of ideal positioning when radiographs are taken.[1] Laryngoscopy can only assess the mucosal surface leaving undetected masses in the submucosa, paraglottic region, and laryngeal cartilages.[2] To obviate these limitations, computed tomography (CT) scan comes in handy as it can show detailed extent of masses in three dimensions. In fact, there is a trend of rapidly growing CT utilization in otolaryngology.[3],[4],[5] In the field of otolaryngology, the most common radiological imaging modality used is CT, regarded by many to be the gold standard diagnostic study for imaging of the paranasal sinuses for inflammatory disease.[6]

In so far as CT scan has the advantage of imaging in three-dimensional planes, its demerits should also be assessed. CT scan is known to have high dose of radiation exposure compared to other imaging modalities; hence, there is growing concern over its usage. John and James[7] opined that CT is regarded as the greatest source of the collective radiation dose in the US, and approximately 75% of radiation exposure (excluding background sources) in the US has been attributed to CT. Hence, there is a need to regulate its usage by making sure the referrals for CT scan are appropriately indicated and also using the as low as reasonably achievable principle. A good audit of CT usage in each specialty will also help to ensure the above aim is achieved. Magnetic resonance imaging (MRI) has soft-tissue resolution better than CT scan, but it is not readily available. Another major advantage of MRI over CT scan is that it does not make the use of ionizing radiation.

Computerized tomographic scan has been available in the Western world since 1973, but its usage in Nigeria started in the late 1980s, and its degree of penetration of medical practice has been tremendous.[8] A lot of studies of CT scan usage in head injuries and other related matters as well as in the abdomen have been done in our environment, but to our knowledge, none has shown emphasis on otolaryngological diseases. This study attempts to retrospectively assess the sociodemographics and pattern of referral for CT scan from an ear, nose, and throat (ENT) clinic as well as CT findings at the University of Benin Teaching Hospital.


  Materials and Methods Top


This was a retrospective study carried out between 2006 and 2014 in the Department of Radiology of the University of Benin Teaching Hospital, a multispecialty center with referrals from Edo state and the neighboring states of Delta, Kogi, Ondo, and Ekiti.

All the request forms as well as the CT scan reports of 214 patients who were referred to the ENT clinic between 2006 and 2014 and had CT scan were retrieved from our radiology records. All CT scans were done using a four-slice Bright Speed helical GE CT scan machine (1999 model manufactured in France).

Out of the 214 patients recruited for this study, only 203 patients were unanimously agreed upon by the authors as the remaining 11 patients had incomplete data. The patients' demographic details, indications for CT scan, and CT scan findings were obtained.

Data was recorded in Microsoft Excel spreadsheet. Data were analyzed using SPSS version 16 (Chicago). Continuous variables were recorded as means and standard deviation while categorical variables are presented as percentages. Means of 2 groups were compared using student's t-test while categorical variables were compared using Chi-squared test. Correlation was assessed with the Pearson correlation test. Confidence interval of 95% was used. P ≤ 0.05 was considered statistically significant.

Ethical clearance dated 25th August 2016; ref number ABUTH/HREC/W2/2016 was obtained.


  Results Top


There were a total of 203 patients, out of which 124 were males (61.1%) and 79 were females (38.9%). The mean age of the study population was 43.2 ± 2.1 years, with that of the males being 44.3 ± 2.1 years and that of females being 41.4 ± 2.2 years. Further analysis of the indications for CT scan showed that the mean age for those with otitis media was 36.5 ± 20.1 years, those with sinonasal tumors was 48.8 ± 22.5 years, those with nasopharyngeal tumor was 33.6 ± 21.5 years, while those with laryngeal masses was 59.8 ± 14.8 years. A breakdown of the demographics of the CT scan findings showed that the mean age of patients with nasopharyngeal tumor was 40.67 ± 26.01 years, laryngeal tumor was 57.47 ± 15.64 years, antrochoanal carcinoma was 46.05 ± 22.95 years, sinusitis was 44.96 ± 17.19 years, while that of otitis media was 43.33 ± 23.60 years. Patients at the extremes of age were fewer in this study, while those in the age group of 51–60 years had the highest population (19.2%), as shown in [Table 1].
Table 1: Age and sex distribution

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Suspected tumors (71.9%) formed the bulk of indication for patients referred from ENT unit for CT scan; this was followed by inflammatory conditions (25.1%). The least was congenital causes which accounted for 0.5%. Among the suspected tumors, sinonasal tumor (17.9%) was the highest, followed by nasopharyngeal tumors (10.3%). Others were laryngeal tumor (8.1%), oropharyngeal tumors (2.7%), and palatal masses (1.3%). Rhinosinusitis accounted for most of the inflammatory conditions (9.9%). This is shown in [Table 2] and [Table 3].
Table 2: Classification of disease entities referred from ear, nose, and throat for computed tomography scan

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Table 3: Indications for computed tomography scan in ORL

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A total of 177 patients representing 87.2% of the study population had one or two pathological findings on CT scan, while the remaining 26 patients (12.8%) had normal CT scans. A total of 196 abnormal findings were seen on CT scan. Inflammatory changes in the sinuses (sinusitis) accounted for most findings on CT scan (12.8%), followed by laryngeal tumor (10.7%) and antrochoanal carcinoma (10.2%). Others were choanal polyp (9.7%), nasopharyngeal tumors (9.2%), rhinitis (6.1%), mastoiditis (5.1%), and mucocele of the sinuses (4.6%). Juvenile angiofibroma (1.0%) and palatal masses (1.0%) were the least in terms of occurrence of all ENT conditions. However, some non-ENT conditions accounted for about 30% of all findings on CT scan. These included retention cyst, lymphoproliferative disease, tracheal injury, fibrous dysplasia, dentigerous cyst, osteomyelitis of the calvarium, goiter, parotid gland tumors, and lymphoma. These are shown in [Table 4].
Table 4: Findings on computed tomographic scan

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[Table 5] shows the sensitivity and specificity of CT scan in detecting some of the disease entities referred from the ENT clinic.
Table 5: Sensitivity and specificity of computed tomographic scan in detecting some ear, nose, and throat diseases

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This retrospective study covered a period of 9 years, from 2006 to 2014. A steady increase in referrals for CT scan in ENT was noticed from 2006 to 2012. However, a decline was observed from 2012 to 2014, as shown in [Figure 1].
Figure 1: Pie chart showing computed tomography scan usage per year

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  Discussion Top


In the past in most developing countries, diagnoses were based on assessment of presenting symptoms and findings on clinical examination. Little or no attention was paid to radiological investigations as part of patients' workup due to the dearth of radiological equipment such as CT scan or to the relatively high cost of such investigations where available. This had the disadvantage of wrong diagnosis being made at times or complications of diseases being missed. When diagnosis was based on clinical examination alone, there was a surge in ear infection between 1980 and 1996, and it suggested that the current approach to preventing and treating middle ear inflammation is not adequate without radiological imaging.[9],[10] Our study showed a steady increase in referrals from ENT for CT scan examination from 2006 to 2012 and then suddenly dropped after then. This initial stepwise increase in CT referrals from ENT could be due to the awareness of the potential imaging capability inherent in CT scan as it is regarded by many as the imaging modality of choice, especially in paranasal sinus diseases.[6]

Nasopharyngeal tumor has the highest incidence in southern China and Hong Kong where it is 20 cases per 100,000 person-years while it is lowest in the United States with an incidence of <1 case per 100,000 person-years.[11],[12] In Nigeria, it is seen as the most common head-and-neck tumor.[13],[14] It is most common in patients between 40 and 60 years of age.[15] This is in tandem with our study which showed the mean age of occurrence of nasopharyngeal tumor to be 40.67 ± 26.01 years in those that were diagnosed on CT scan. The occurrence at this age could be due to the fact that exposure to risk factors such as alcohol consumption and cigarette smoking is seen to be maximal at this age. Over the years, CT scan has been used for the detection and staging of nasopharyngeal tumors but has been replaced by MRI due to the excellent soft-tissue resolution of the latter. However, it is still being very useful in planning for radiotherapy and for detecting distant metastasis when combined with PET (positron emission tomography).[15],[16],[17],[18],[19] Our center does not have the luxury of MRI; hence, CT scan is the only cross-sectional imaging modality at our disposal.

Furthermore, our study showed sinusitis as the most common CT finding in patients referred from ENT. The mean age of those with sinusitis detected on CT was 44.96 ± 17.19 years. Bhattacharyya[20] reported that chronic rhinosinusitis was the most common CT diagnosis in sinonasal disorders, and the mean age of occurrence in that study was 43.2 ± 0.6 years. This is similar to our study. Sinusitis is one of the most common diseases encountered by primary health-care givers, and when uncomplicated, it does not require imaging. Radiological imaging becomes pertinent when medical treatment fails repeatedly. When plain radiography is used, it is limited as it only shows positive findings in about 60% of the cases.[19] CT scan helps in the diagnosis and management of recurrent and chronic sinusitis or to define the anatomy of the sinuses before surgery such as functional endoscopic sinus surgery.[21],[22] A coronal CT scan of the sinuses is most important as it shows all the sinuses as well as their relations. The disturbance of the osteomeatal complex forms the basis for the pathogenesis of recurrent sinusitis. This complex can best be elucidated by coronal CT. Findings such as sinus opacification, mucosal thickening, air-fluid level, and others are better defined on CT scan.[21]

Laryngeal carcinoma represents about 25% of all head-and-neck tumors and has an incidence of 2.5%–17.2%/100,000/year, which is highest at 50–70 years of age. Over 90% of laryngeal cancers are squamous cell carcinoma, with about 65% occurring at the glottic level [Figure 2], 30% at supraglottic level, and 5% at infraglottic level.[23],[24],[25] The mean age of those diagnosed as laryngeal carcinoma on CT in our study was 57.47 ± 15.64 years which is congruent with the literature above. However, the histological type could not be ascertained in these patients as the results were unavailable due to inadequate and improper record filing. The sensitivity and specificity of CT scan detecting laryngeal carcinoma in our study were 76.2% and 98.9%, respectively. Li et al.[26] discovered that for the detection of any thyroid cartilage invasion in laryngeal carcinoma, the sensitivity was 85% and specificity was 75%. Fiber-optic laryngoscopy can adequately assess the mucosa but not the submucosa, muscle layer, or laryngeal cartilages in laryngeal carcinoma. The cross-sectional imaging modalities such as CT come into light in this scenario. When used in combination with clinical history and laryngoscopy, the accuracy rate of CT scan in TNM (tumor size, nodes, and metastases) staging of laryngeal carcinoma could reach 80%.[27] In laryngeal carcinoma, CT scan will show a mass in the glottis, supraglottic, or infraglottic region. There may be lytic or sclerotic changes in the laryngeal cartilage. At some other times, the only visible finding may be asymmetry of the vocal cords.[24]
Figure 2: (a) An axial computed tomography scan image of the larynx showing a tumor at the glottis level with narrowing of airway. (b) Axial computed tomography scan image of the nasopharynx showing a nasopharyngeal tumor with narrowing of the adjacent airway

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Only 11 cases of clinically diagnosed otitis media were referred for CT scan, but five cases were confirmed to have it on CT scan in this study. Our study showed the sensitivity and specificity of CT scan detection of otitis media to be 83.3% and 97.0%, respectively. Sadoghi et al.[28] opined that CT scan could demonstrate the presence of disease in the mastoid cavity and the middle ear, size and aeration of mastoid system, ossicular presentation and continuity, and fistula of the mastoid cavity to skin with sensitivities equal to 100% and specificities >93%. In our study, four of the radiologically diagnosed otitis media were complicated by mastoiditis. A good diagnosis of otitis media can be made by clinical examination without need of radiological imaging, but in the setting of recurrence and complications, radiological imaging becomes indispensable.[29] This study buttresses the importance of CT scan in complicated otitis media as all cases of otitis media complicated by mastoiditis were properly diagnosed on CT scan. On CT scan, otitis media may appear as a soft-tissue density in the middle ear, thickening or bulging of the tympanic membrane, and perforation of the membrane. The chronic phase may show as bony erosion or sclerosis of the mastoid air cells.[29]

We carried out a retrospective study. The major constraints were that some data were missing and some record might have been lost.


  Conclusion Top


This study has enumerated the common indications for CT scan referrals from ENT and the CT scan findings. A great limitation of this study was the inability to ascertain the histological diagnosis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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Bhattacharyya N. Trends in otolaryngologic utilization of computed tomography for sinonasal disorders. Laryngoscope 2013;123:1837-9.  Back to cited text no. 20
    
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Li B, Bobinski M, Gandour-Edwards R, Farwell DG, Chen AM. Over staging of cartilage invasion by multidetector CT scan for laryngeal cancer and its potential effect on the use of organ preservation with chemoradiation. Br J Radiol 2011;84:64-9.  Back to cited text no. 26
    
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Wu J, Zhao J, Li Z, Yang W, Liu Q, Yang Z, et al. Comparison of CT and MRI in Diagnosis of Laryngeal Carcinoma with Anterior Vocal Commissure Involvement. Sci. Rep. 2016; 6: 30353.  Back to cited text no. 27
    
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Sadoghi M, Yazdani N, Sharifian H, Saidi M, Isadparasti Y. The validity of computed tomography in complicated chronic otitis media. Iran J Radiol 2007;4:175-9.  Back to cited text no. 28
    
29.
Trojanowska A, Drop A, Trojanowski P, Rosińska-Bogusiewicz K, Klatka J, Bobek-Billewicz B. External and middle ear diseases: Radiological diagnosis based on clinical signs and symptoms. Insights Imaging 2012;3:33-48.  Back to cited text no. 29
    


    Figures

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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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