Can We Perform CT of the Appendix with Less Than 1 mSv? A De-escalating Dose-simulation Study

Area of Science:

• Radiology
• Medical Imaging
• Radiation Dose Optimization

Background:

• Appendiceal CT scans are crucial for diagnosing appendicitis.
• Optimizing radiation dose is essential, especially in young adults.
• Iterative reconstruction (IR) techniques offer potential for dose reduction.

Purpose of the Study:

• To determine the lowest achievable radiation dose for appendiceal CT using IR in young adults.
• To evaluate the diagnostic performance of reduced-dose CT protocols compared to standard protocols.

Main Methods:

• Prospective study of 30 patients undergoing 2.0-mSv CT for suspected appendicitis.
• Low-dose CT images (1.5, 1.0, and 0.5 mSv) were generated using a simulation tool and knowledge-based IR.
• Non-inferiority tests compared lower doses to the standard 2.0-mSv CT using pooled area under the receiver-operating-characteristic curve (AUC).

Main Results:

• For abdominal radiologists, 1.5-, 1.0-, and 0.5-mSv CT were non-inferior to 2.0-mSv CT.
• For non-abdominal radiologists, 1.5- and 1.0-mSv CT were non-inferior, but 0.5-mSv CT was not.
• Reader experience influenced diagnostic performance at lower radiation doses.

Conclusions:

• A 1.0-mSv appendiceal CT is diagnostically equivalent to a 2.0-mSv CT for both abdominal and non-abdominal radiologists.
• A 0.5-mSv CT is non-inferior to 2.0-mSv CT only for abdominal radiologists.
• Reader expertise is a key factor in the diagnostic efficacy of low-dose CT imaging.