Evaluation of Sinonasal Diseases by Computed Tomography

Abstract

Introduction: Computed Tomography (CT) plays an important diagnostic role in patients with sinonasal diseases and determines the treatment. The CT images clearly show fine structural architecture of bony anatomy thereby determining various anatomical variation, extent of disease and characterization of various inflammatory, benign and malignant sinonasal diseases.

Aim: To evaluate sensitivity and specificity of CT in diagnosis of sinonasal diseases and to characterise the benign and malignant lesions with the help of various CT parameters. Also, to correlate findings of CT with histo-pathological and diagnostic nasal endoscopy/ Functional Endoscopic Sinus Surgery (FESS) findings.

Materials and methods: In this hospital based prospective study 175 patients with symptomatic sinonasal diseases were evaluated by clinical diagnosis and 16 slice Multi Detector Computed Tomography (MDCT). The details of findings of nasal endoscopy, Functional Endoscopic Sinus Surgery (FESS), histopathological examination and fungal culture were collected in all those cases where those investigations were done. All those findings were correlated with CT findings and statistical analysis was done by using Test statistics (sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) and accuracy), Chi-Square test and Z-test for single proportions. Software used in the analysis was SPSS 17.0 version and graph pad prism 6.0 version and p < 0.05 was considered as statistically significant.

Results: CT diagnosis had higher sensitivity, specificity, PPV and NPV in diagnosing various sinonasal diseases in comparison to clinical diagnosis. On correlating CT diagnosis with final diagnosis, congenital conditions have 100% sensitivity and specificity. Chronic sinusitis has 98.3% sensitivity and 97.8% specificity. For fungal sinusitis the sensitivity was 60% and specificity was 99.3%. Polyps have sensitivity of 94.4% and specificity of 98.1%. Benign neoplasms have sensitivity of 90.9% and specificity of 99.2%, malignant neoplasms have sensitivity of 94.1% and specificity of 99.3%. The p-value in all instances was <0.05, i.e. <0.0001 indicating the significance of the findings.

Conclusion: CT is the modality of choice in imaging the sinonasal region for evaluating various congenital, inflammatory, benign and malignant pathologies and associated complications thereby planning the further management of the patient. CT is the best modality of choice for evaluating the bone erosion or destruction. The potential pitfalls to differentiate on CT are fungal sinusitis and dense secretions.

Keywords: Diagnostic nasal endoscopy; Functional endoscopic sinus surgery; Sinonasal pathologies.

[Table/Fig-5]:

Bilateral pansinusitis.

[Table/Fig-6a & b]:

Left antrochoanal polyp: Axial and coronal CT image showing homogeneous soft tissue attenuating mass extending from antrum to choana with widening of maxillary ostium.

[Table/Fig-10a & b]:

Nasopharyngeal angiofibroma: Axial plain and post contrast CT shows soft tissue attenuating mass in nasopharynx widening the sphenopalatine foramen and showing intense post contrast enhancement.

[Table/Fig-11a, b & c]:

Right inverted papilloma: Axial and Coronal CT shows lobulated soft tissue attenuating mass in right nasal cavity extending into maxillary sinus with adjacent bony remodeling.

[Table/Fig-12 a, b & c]:

Squamous cell carcinoma: CT images show soft tissue enhancing mass in left maxillary sinus with bony destruction of surrounding walls and extra sinus extension.