Dose classification scheme for computed tomography of the paranasal sinuses

Area of Science:

• Radiology
• Medical Imaging
• Diagnostic Imaging

Background:

• Computed tomography (CT) is crucial for paranasal sinus evaluation.
• Standardizing CT image quality based on radiation dose and diagnostic accuracy is essential.
• Objective measures are needed to complement subjective assessments of CT image quality.

Purpose of the Study:

• To establish objective and reproducible standards for paranasal sinus CT image quality.
• To correlate image quality with radiation dose and therapeutic validity.
• To define reliable metrics for assessing CT scan quality.

Main Methods:

• CT scans of 145 patients' paranasal sinuses were analyzed.
• Subjective image quality was assessed for functional endoscopic sinus surgery (FESS) planning.
• Objective pixel noise (standard deviation of CT number) was measured in regions of interest (ROIs) and compared to phantom measurements.

Main Results:

• Pixel noise in phantom images closely matched measurements in the masseter muscle ROI of patient images.
• Low-dose protocols (70-90 HU noise) with edge enhancement are suitable for pediatric patients, chronic sinusitis, and septum deviation.
• Standard protocols (50-70 HU noise) are recommended for FESS planning and postoperative control.

Conclusions:

• Water phantom measurements accurately reflect the clinical utility and image quality of paranasal sinus CT scans.
• The masseter muscle ROI provides a reliable alternative for estimating image quality and radiation dose class.
• Objective pixel noise measurement offers a standardized approach to CT quality control in paranasal sinus imaging.