Submilisievert ultralow-dose CT colonography using iterative reconstruction technique: a feasibility study

Area of Science:

• Radiology
• Medical Imaging

Background:

• Computed tomography (CT) colonography is a standard imaging technique for symptomatic patients and screening.
• Reducing radiation dose in CT imaging is a significant concern, driving advancements in reconstruction technologies.

Purpose of the Study:

• To evaluate the image quality of ultralow-dose CT colonography (sub-millisievert) using a hybrid iterative reconstruction technique.
• Assess the feasibility of dose reduction in CT colonography without compromising image quality.

Main Methods:

• Sixteen patients underwent CT colonography with standard and ultralow-dose protocols.
• Ultralow-dose datasets were reconstructed using filtered back projection (FBP) and hybrid iterative reconstruction (IR).
• Radiologists assessed image quality parameters, including distension, wall smoothness, noise, and artifacts, on a five-point scale.

Main Results:

• The mean radiation dose for ultralow-dose scans was 0.42 mSv, compared to 5.48 mSv for standard scans.
• Ultralow-dose CT colonography with IR yielded evaluable image quality in all segments.
• Ultralow-dose CT colonography with FBP resulted in poor or unacceptable image quality in 61% of segments.

Conclusions:

• Hybrid iterative reconstruction is a feasible technique for reducing CT colonography radiation dose below 1 mSv.
• Further large-scale studies are needed to determine if such low doses impact polyp detection rates.