Low-dose CT perfusion with projection view sharing.

Area of Science:

• Medical Imaging
• Radiology
• Image Reconstruction

Background:

• CT Perfusion (CTP) is a vital clinical tool but involves high radiation doses (CTDIvol ≥ 200 mGy).
• Developing low-dose CTP techniques is crucial for patient safety and reducing cumulative radiation exposure.
• Existing CTP methods often face a trade-off between radiation dose and image quality/diagnostic accuracy.

Purpose of the Study:

• To present and evaluate a novel low-dose CT Perfusion (CTP) technique.
• To adapt the K-space Weighted Image Contrast (KWIC) algorithm, originally for dynamic MRI, for CTP applications.
• To assess the feasibility of KWIC in reducing radiation dose while preserving CTP diagnostic accuracy.

Main Methods:

• KWIC reconstruction utilizes an angle-bisection scheme and a Fourier transform to create a "k-space" CT data space.
• It employs a projection view-sharing strategy to maintain spatiotemporal resolution in undersampled CTP data.
• Evaluations included numerical simulations on a digital phantom and clinical CTP cases, comparing KWIC to standard filtered back projection (FBP) at reduced dose levels (down to 12.5%).

Main Results:

• KWIC reconstruction showed no significant impact on key perfusion metrics (AUC, TTP, FWHM) even at 12.5% of the original dose.
• Normalized root-mean-square-error for AUC was low (0.04-0.07) compared to FBP.
• Quantitative metrics like cerebral blood flow (CBF) and cerebral blood volume showed no significant differences between KWIC and FBP reconstructions (P > 0.05).

Conclusions:

• The study demonstrates that KWIC effectively preserves CTP perfusion metrics while enabling substantial radiation dose reduction.
• KWIC offers a promising approach for safer, lower-radiation CTP imaging.
• Further research is needed for clinical implementation, particularly regarding rapid CT x-ray source switching.