Systematic feasibility analysis of performing elastography using reduced dose CT lung image pairs

Area of Science:

• Medical Imaging
• Biophysics
• Radiology

Background:

• Computer tomography (CT) elastography offers patient-specific lung biomechanical property assessment.
• Reducing radiation dose in CT scans is crucial for patient safety and broader clinical adoption.

Purpose of the Study:

• To investigate the feasibility of performing CT elastography using simulated lower dose CT scans.
• To evaluate the accuracy of lung elastography with reduced radiation exposure.

Main Methods:

• Eight patient CT image pairs at 40 mAs served as baseline.
• Synthetic low mAs CT scans (30, 25, 20 mAs) were generated, simulating noise.
• Deformable image registration calculated deformation vector fields (DVFs) from inhalation/exhalation pairs.
• Model-based elasticity estimation optimized elasticity to match DVFs.

Main Results:

• DVFs from low mAs scans showed minor differences (avg. 1.41 mm) compared to baseline.
• Elastography results using low mAs DVFs closely matched baseline elasticity (avg. differences 0.65-0.76 kPa).
• CT elastography provided equivalent results despite simulated dose reduction.

Conclusions:

• CT elastography is feasible and accurate with image pairs acquired at radiation doses as low as 20 mAs.
• This finding supports the use of low-dose CT for lung elastography.
• The study expands the potential clinical applications of CT-based elastography.