Model-based vs hybrid iterative reconstruction technique in ultralow-dose submillisievert CT colonography

Area of Science:

• Medical Imaging
• Radiology
• Gastroenterology

Background:

• Low-dose CT colonography (CTC) is crucial for colorectal cancer screening.
• Optimizing reconstruction techniques is key to maintaining diagnostic accuracy at reduced radiation doses.

Purpose of the Study:

• To compare image quality of different reconstruction techniques in submillisievert ultralow-dose CTC.
• To correlate colonic findings with subsequent optical colonoscopy.

Main Methods:

• 58 patients underwent ultralow-dose CTC reconstructed with filtered back projection (FBP), hybrid iterative reconstruction (HIR), or model-based iterative reconstruction (MBIR).
• Image quality and endoluminal noise were assessed by two independent readers.
• Colonic lesions were evaluated and correlated with optical colonoscopy.

Main Results:

• Radiation dose was <1 mSv.
• HIR provided better endoluminal view image quality.
• MBIR yielded superior cross-sectional view image quality with the lowest endoluminal noise.
• Polyp detection was significantly better with HIR and MBIR compared to FBP.

Conclusions:

• Submillisievert ultralow-dose CTC is feasible with iterative reconstruction techniques.
• HIR and MBIR offer distinct advantages for endoluminal and cross-sectional views, respectively.
• FBP reconstruction may compromise lesion detection in ultralow-dose CTC.