Dose reduction for chest CT: comparison of two iterative reconstruction techniques

Area of Science:

• Medical Imaging
• Radiology
• Diagnostic Imaging

Background:

• Computed tomography (CT) scans at lower radiation doses often produce noisy, low-quality images.
• Iterative reconstruction techniques are employed to mitigate noise and enhance image quality in low-dose CT.

Purpose of the Study:

• To evaluate lesion detection and diagnostic acceptability of low-dose (LD) chest CT images (1.8 mGy CTDIvol).
• To compare image quality and diagnostic confidence using two iterative reconstruction techniques against standard-dose (SD) CT.

Main Methods:

• Low-dose (LD) and standard-dose (SD) chest CT datasets were acquired from 22 patients.
• LD images were reconstructed using SafeCT (C4, L1, L2) and Safire (S1, S2, S3) iterative algorithms.
• Three radiologists assessed lesion detection, margin visibility, normal structure visualization, and diagnostic confidence.

Main Results:

• No significant difference in lesion detection between LD and SD images.
• Visibility of ground-glass opacities, lesion margins, and normal structures remained unaffected.
• Some limitations in visualizing major fissures and pericardium were noted in a few LD cases.

Conclusions:

• Routine low-dose chest CT with iterative reconstruction provides diagnostic information comparable to standard-dose CT.
• Lesion detection, margin assessment, and diagnostic confidence are maintained irrespective of iterative reconstruction settings.
• Iterative reconstruction is a viable method for reducing radiation dose in chest CT without compromising diagnostic yield.