Ultralow-Dose Dynamic Expiratory CT and Repeated Imaging Enhance Evaluation for Tracheomalacia

Area of Science:

• Radiology and Imaging
• Pediatric Pulmonology

Background:

• Tracheomalacia (TM) is a common airway condition in children.
• Traditional dynamic tracheal CT has limitations in reliably diagnosing TM.
• Novel imaging protocols are needed to improve diagnostic accuracy.

Purpose of the Study:

• To evaluate a novel ultralow-dose dynamic expiratory computed tomography (CT) protocol with repeated imaging.
• To compare the diagnostic reliability of this new protocol against traditional dynamic tracheal CT for identifying TM.
• To assess the impact of the novel protocol on radiation dose and TM severity grading.

Main Methods:

• Retrospective evaluation of 184 ultralow-dose dynamic CTs for TM.
• Protocol includes 1 inspiration and 2 forced expirations (DE1, DE2).
• Comparison of tracheal narrowing (DE1, DE2, DEmax) and TM grade reliability.

Main Results:

• The novel protocol (DEmax) identified significantly more airway narrowing and diagnosed TM 31-35% more often than single expiratory scans (DE1, DE2).
• DEmax revealed a more severe distribution of TM.
• Reliability for tracheal narrowing was good, and for TM grade, it was moderate.
• The mean effective radiation dose was 2.55 mSv.

Conclusions:

• Dynamic expiratory CT with 2 expiratory acquisitions enhances TM evaluation.
• This protocol offers a reliable, noninvasive screening option for TM.
• The minimal increase in radiation dose is acceptable for improved diagnostic yield.