Can iterative reconstruction improve imaging quality for lower radiation CT perfusion? Initial experience

Area of Science:

• Radiology
• Medical Imaging
• Neuroscience

Background:

• CT Perfusion (CTP) is crucial for assessing cerebral blood flow post-carotid stenting.
• Iterative Reconstruction (IR) algorithms offer potential radiation dose reduction in CT imaging.
• Comparing IR and Filtered Back Projection (FBP) algorithms is essential for optimizing CTP protocols.

Purpose of the Study:

• To evaluate the impact of IR versus FBP on CTP perfusion parameters.
• To compare imaging quality and radiation dose between IR and FBP at standard and reduced CT doses.
• To determine if IR enhances perfusion parameter accuracy at lower radiation doses.

Main Methods:

• Forty patients with carotid stenosis underwent CTP with two tube current groups (100 mAs and 80 mAs).
• CT datasets were reconstructed using both IR and FBP algorithms.
• Signal-to-noise ratios (SNRs) and quantitative perfusion parameters (CBF, CBV, MTT) were analyzed.

Main Results:

• The lower dose group (80 mAs) achieved a 20% radiation dose reduction (2.06 mSv vs 2.56 mSv).
• IR images showed significantly higher SNRs compared to FBP images.
• No significant differences in perfusion parameter imaging scores were observed between IR and FBP, or between dose groups.

Conclusions:

• Reduced dose CTP (20% lower) effectively identifies oligemic tissue in post-stenting follow-up without IR.
• IR did not significantly alter absolute perfusion parameter values or improve SNRs at reduced doses.
• Alternative methods are needed to enhance SNRs in low tube current CTP protocols.