Ultra-low-dose chest CT with iterative reconstruction does not alter anatomical image quality

Area of Science:

• Radiology and Imaging Science
• Medical Physics
• Diagnostic Imaging Technology

Background:

• Chest CT scans are crucial for diagnosing various conditions.
• Radiation dose is a significant concern in CT imaging.
• Iterative reconstruction (IR) techniques offer potential for dose reduction while maintaining image quality.

Purpose of the Study:

• To evaluate the impact of dose reduction using iterative reconstruction (IR) on chest CT image quality.
• To compare image quality metrics between standard, low-dose, and ultra-low-dose CT protocols.
• To assess the diagnostic confidence in anatomical structure visualization at reduced radiation doses.

Main Methods:

• Chest CT scans were performed on 18 human cadavers using reference (RP-CT), low-dose (LD-CT), and ultra-low-dose (ULD-CT) protocols.
• Data were reconstructed using Filter-Back-Projection (FBP) and IR (SAFIRE®) algorithms.
• Quantitative image quality parameters (SNR, CNR) and qualitative assessments by radiologists were analyzed.

Main Results:

• Dose reduction of 80% (LD-CT) and 95% (ULD-CT) was achieved compared to RP-CT.
• IR significantly improved Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR) in dose-reduced protocols.
• Radiologists rated LD-CT images as excellent/good and ULD-CT images as good/fair, with 95% confidence in anatomical analysis across all protocols.

Conclusions:

• Dose reduction below 1 mGy is feasible for chest CT using IR.
• IR enables high-quality chest CT examinations with significantly reduced radiation exposure.
• These findings support the use of IR for dose optimization in clinical practice.