PREVALENCE OF INCIDENTAL FINDINGS IN MAXILLARY SINUS USING CONE BEAM COMPUTED TOMOGRAPHY – A RETROSPECTIVE STUDY

Shilpa Syam^1*, Uma Maheswari¹

ABSTRAC

Maxillary sinus pathologies and normal variations in the sinus anatomy can result in complications during surgical interventions. Hence, maxillofacial radiologists should be knowledgable regarding thes radiographic findings poiting to pathologies/variations.

To study the prevalence of various incidental findings in the maxillary sinus region using cone beam computed tomography (CBCT). This was a retrospective- cross sectional study. CBCT scans of sixty patients who have been advised radiographs exclusively for dental complaints were retrospectively collected and examined for maxillary sinus pathologies. Their frequencies as well as unilateral/ bilateral involvement were recorded and analyzed. The most prevalent incidental finding of the maxillary sinus was mucosal thickening followed by septations. Few cases presented with infrequent findings like sinus floor discontinuity and root canal sealant inside the sinus. Significant maxillary sinus pathologies may present without any associated symptoms. Hence, oral radiologists examining CBCT scans should mandatorily evaluate the entire volume of the scan and any abnormal finding must be identified and reported to the clinician.

Keywords: Maxillary antrum, Incidental finding, Cone beam computed tomography, Mucosal thickening, Sinus opacification

Introduction

Maxillary sinus pathologies are frequently encountered by dentists during the radiographic assessment of patients with teeth-related complaints. Also, maxillary sinus pathologies are observed as incidental radiographic findings in asymptomatic patients who are evaluated for implant assessment, endodontic therapy, impacted/ supernumerary teeth and orthodontic correction [1]. A variety of imaging modalities including plain films as well as advanced radiographs provide visualization of maxillary sinus. Computed tomography, although is the gold standard out of these, has limitations of high radiation exposure and cost [2, 3]. Cone beam computed tomography (CBCT) which is being widely used now by the dentists for an array of indications, also is a good option for studying maxillary sinus. Despite of its poor soft tissue contrast, CBCT images can aid in viewing inflammatory pathologies and sinus opacification [4].

The prevalence of maxillary sinus pathologies in asymptomatic patients ranged widely between 10.9 % and 69.1 % across studies in literature [5-9]. Maxillary sinus abnormalities can be classified as developmental, inflammatory, cystic, calcifications or neoplasms [10]. The most commonly encountered being the lesions of imflammatory origin. Radiographically, these may appear as mucosal thickening (MT) or as sinus opacification (SO) [11]. The presence of an air-fluid level can also be a sign of inflammation implying acute sinus disease [12]. The cystic lesions of maxillary sinus can be retention cysts or mucoceles. Blockage of secretory ducts of seromucinous glands causing submucosal accumulation of secretions result in a pseudocyst called the mucous retention cyst. This is viewed in radiographs well defined non corticated, smooth, dome shaped, mostly sessile radiopaque mass [13]. Mucoceles on the other hand are expansile destructive masses due to a blocked sinus ostium and can appear as completely opacified maxillary sinus [14]. Maxillary sinus polyps are formed by thickened mucous membrane of chronically inflamed sinus which form polypoid folds which may be isolated or multiple [15].

Deposition of mineral salts such as calcium phosphate and calcium carbonate around the nidus results in a maxillary antrolith. Smaller antroliths are asymptomatic and are discovered as incidental findings [16, 17]. Radiographically, these appear as radiopaque structures of varying densities, with a well-defined periphery. They can have smooth or irregular borders and at times an internal structure resembling laminations [18].

Hence, it is evident that numerous pathologies can develop asymptomatically in the maxillary sinus region. Because we dentists evaluate CBCT scans of patients that involve the maxillary sinus region in our day-to-day practice, we must be knowledgeable to identify such lesions and advise proper management when necessary. This study aimed to assess the prevalence of various incidental findings in the maxillary sinus region using CBCT.

Materials and Methods

CBCT scans of sixty patients who were referred to the oral radiology department of a dental college were collected retrospectively. CBCT scans covering either the upper arch alone or both upper and lower arches, allowing adequate visualization of bilateral maxillary sinus regions, were included. Patients who were advised to radiograph exclusively for dental complaints were included and those suspected of having sinus-related pathologies clinically were excluded. Patients below the age of 18 years and those above 50 years were excluded from the study.

A thickening of mucosal membrane measuring > 3mm was considered pathological (Figure 1). Also, homogenously radiopaque mass with a convex/ polypoid shape, of any etiology, was radiographically recorded as a polypoidal thickening (PT). In addition to the frequency of various pathologies (Figure 2), the involvement of the sinus by the lesion was also noted and recorded as unilateral or bilateral.

Results and Discussion

The most prevalent incidental finding was MT followed by separations, OPA, air-fluid level, PT, antrolith, and sinus floor discontinuity. Root canal sealant was observed in one case which was the least prevalent abnormal finding. Also most of the pathologies had a bilateral presentation whereas less than half of the cases showed a unilateral involvement (Figures 3 and 4).