Can fully iterative reconstruction technique enable routine abdominal CT at less than 1 mSv?

Area of Science:

• Radiology
• Medical Imaging
• Computational Imaging

Background:

• Routine abdomen CT scans often involve significant radiation exposure.
• Low-dose CT (LDCT) protocols aim to reduce radiation dose while maintaining diagnostic image quality.
• Advanced reconstruction algorithms are crucial for improving image quality in LDCT.

Purpose of the Study:

• To evaluate the effectiveness of the forward projected model-based reconstruction technique (FIRST) for lesion detection in low-dose abdomen CT.
• To compare the performance of FIRST reconstructions against standard filtered back projection (FBP) in routine abdomen CT.
• To assess the feasibility of achieving diagnostic image quality at radiation doses below 1 mSv.

Main Methods:

• A prospective study involving 37 adult patients undergoing routine abdomen CT.
• LDCT scans were acquired immediately after standard-dose CT (SDCT).
• LDCT images were reconstructed using FIRST (Standard and Strong levels), and SDCT images using FBP. Lesion detection and image quality were assessed by two radiologists.

Main Results:

• FIRST reconstructions (LD-FIRST-STD) enabled detection of 38 out of 46 true positive lesions identified on SDCT.
• Diagnostic confidence was optimal with LD-FIRST-STD, irrespective of lesion size.
• Higher radiation dose (SDCT) had a mean CTDIvol of 13 mGy compared to LDCT's 2.2 mGy.

Conclusions:

• FIRST facilitates optimal lesion detection in routine abdomen CT at radiation doses below 1 mSv.
• The technique is particularly effective for patients with a body mass index (BMI) of ≤25.8 kg/m².
• FIRST represents a promising advancement for reducing radiation exposure in abdominal CT examinations without compromising diagnostic accuracy for eligible patients.