Cone-beam Computed Tomography of the Paranasal Sinuses: Comparison Study with Multidetector Computed Tomography

Abstract

Objectives: Cone-beam computed tomography (CBCT) in sinonasal imaging is fairly novel and remains limited to date. This study aimed to compare (1) the image quality of CBCT and multidetector computed tomography (MDCT), and (2) the eye lens dose for paranasal sinus imaging between these two modes of imaging. Methods: This study was approved by an institutional ethics review board. Sixteen patients underwent CT imaging of their paranasal sinuses for the evaluation of chronic rhinosinusitis using both CBCT and MDCT. The eye lens dose was measured using lithium fluoride thermoluminescent dosimeters during each scan. The scans were read independently by two readers for the presence of sinonasal opacification, artefacts, clarity of osseous structures and soft tissues (based on 5-point grading scales). The interclass coefficient was used to assess interobserver variability. Results: The mean eye lens dose was 1.0 mGy on CBCT and 1.4 mGy on MDCT. Respective grading scores for opacification, artefacts, osseous structures, and soft tissues were 4.3, 3.9, 4.0 and 2.0 on CBCT compared with 4.2, 4.3, 4.6 and 4.2 on MDCT. Score differences between CBCT and MDCT for artefacts, osseous structures, and soft tissues were statistically significant (p < 0.05). Conclusion: The image quality of CBCT scans was generally inferior, but adequate for screening purposes in the assessment of opacification and osseous detail. Compared with MDCT scans, the mean eye lens dose with CBCT was also lowered by 25%.