Radiation dose reduction and image quality improvement with ultra-high resolution temporal bone CT using deep...

Area of Science:

• Medical Imaging
• Radiology
• Computed Tomography (CT)

Background:

• High-resolution CT (HR-CT) is crucial for visualizing fine details in anatomical structures like the temporal bone.
• Radiation dose reduction is a continuous goal in medical imaging to minimize patient risk.
• Deep learning reconstruction (DLR) algorithms offer potential for improving image quality and reducing dose in CT.

Purpose of the Study:

• To assess the radiation dose reduction capabilities of an ultra-high resolution CT (UHR-CT) scanner utilizing deep learning reconstruction (DLR).
• To compare the image quality of UHR-CT with DLR against conventional high-resolution CT (HR-CT) for temporal bone imaging.
• To determine if UHR-CT with DLR can achieve diagnostic image quality comparable to or better than HR-CT at reduced radiation doses.

Main Methods:

• UHR-CT scans of cadaveric temporal bones were acquired at varying dose levels (CTDIvol: 4.6-79 mGy) using a 1024^2 matrix and 0.25 mm slice thickness, reconstructed with DLR and hybrid iterative reconstruction (HIR).
• HR-CT images were acquired using a standard protocol (120 kV/220 mAs; CTDIvol: 54.2 mGy) with a 512^2 matrix and 0.5 mm slice thickness.
• Two radiologists evaluated image quality for seven structures on a five-point scale, calculating a global image quality score for each protocol.

Main Results:

• UHR-CT with DLR at 120 kV/220 mAs (50.9 mGy) and 140 kV/220 mAs (79 mGy) achieved the highest global image quality scores (4.88 ± 0.32 and 4.85 ± 0.35, respectively).
• HR-CT at 120 kV/220 mAs and UHR-CT at 120 kV/20 mAs had the lowest image quality scores (3.14 ± 0.75 and 2.97 ± 0.86, respectively).
• All DLR-reconstructed UHR-CT protocols demonstrated superior image quality compared to HR-CT with HIR.

Conclusions:

• UHR-CT combined with DLR enables significant radiation dose reduction, up to tenfold, compared to HR-CT with HIR.
• This technique successfully maintains or enhances image quality for temporal bone visualization.
• UHR-CT with DLR represents a promising advancement for dose-efficient, high-quality CT imaging.