Xenon ventilation imaging using dual-energy computed tomography in asthmatics: initial experience

Area of Science:

• Pulmonary Medicine
• Radiology
• Medical Imaging

Background:

• Asthma is a chronic respiratory disease characterized by airway inflammation and hyperresponsiveness.
• Accurate assessment of ventilation abnormalities is crucial for understanding asthma severity and guiding treatment.
• Current imaging techniques may have limitations in fully characterizing ventilation defects in asthma.

Purpose of the Study:

• To evaluate the feasibility and effectiveness of xenon ventilation computed tomography (CT) for detecting and quantifying ventilation abnormalities in patients with asthma.
• To correlate imaging findings with pulmonary function test (PFT) parameters and airway dimensions.

Main Methods:

• Twenty-two stable asthmatic patients underwent single-phase, whole-thorax, dual-energy CT after inhaling 30% xenon.
• Ventilation defects were assessed using a color-coded xenon map and quantified by a defect score.
• Airway wall dimensions were measured, and correlations between defect score, PFTs, and airway dimensions were analyzed.

Main Results:

• Sixteen asthmatics exhibited peripheral ventilation defects (mean defect score: 6.6 ± 4.2).
• Patients with defects showed significantly lower FEV1 and thicker airway walls compared to defect-free patients (P=0.04 and P=0.02).
• Defect score negatively correlated with FEV1/FVC ratio and corrected diffusing capacity, and positively with lung volumes.

Conclusions:

• Xenon ventilation CT is feasible for visualizing ventilation defects in asthmatics.
• The presence and extent of ventilation defects are associated with more severe airflow limitation and airway wall thickening.
• Xenon ventilation CT findings correlate with key pulmonary function parameters in asthma.