ANALYSIS OF ANATOMICAL VARIANTS OF FRONTAL SINUS OUTFLOW TRACT (FSOT) BY MULTIPLANAR RECONSTRUCTION MDCT SCAN IMAGES.

Background: The width of frontal sinus outflow tract is determined by pneumatisation pattern of frontal recess cell. The purpose of this study is to determine correlation between volume of agger Nasi cell (ANC) with frontal beak thickness, A-P length of frontal isthmus (FI) and frontal recess (FR). Materials and Methods: A cross sectional study was conducted in 140 adult patients who had computed tomography (CT) brain done in HUSM from Jan 2010 to June 2018. Multiplanar reconstructed images then retrieved from PACS system. Prevalence and pattern of pneumatisation of frontal recess cell reviewed. Agger Nasi cell volume measured with analysis of its correlation to frontal beak thickness, length of frontal recess and frontal isthmus done by researcher using Pearson correlation test. Result: ANC found in 131 out of 140 adult patients (93.6%). Mean ANC volume 434.48 with standard deviation of 256.63. For frontal beak (FB) thickness, anterior-posterior (A-P) length of FI & FR, mean values were 6.24 (SD 1.61), 7.06 (SD 2.92) and 4.95 (SD 2.97) respectively. No significant correlation was found between volume of ANC with FB thickness, A-P length of FI and FR. Conclusion: There was no statistically significant correlation between volume of ANC with the frontal beak thickness, anterior posterior length of frontal isthmus and frontal recess (p>0.05). Since ANC is commonly found in population, it is still essential for radiologist to consider reporting the ANC volume and pattern of pneumatisation when endoscopic surgery is planned. [ABSTRACT FROM AUTHOR]