Multireader Determination of Clinically Significant Obstruction Using Hyperpolarized ¹²⁹Xe-Ventilation MRI

Area of Science:

• Pulmonary Medicine
• Medical Imaging
• Radiology

Background:

• Airway obstruction significantly impacts respiratory health.
• Hyperpolarized (HP) ¹²⁹Xe-MRI is an advanced imaging technique for assessing lung ventilation.
• Quantifying ventilation defects is crucial for diagnosing and managing obstructive lung diseases.

Purpose of the Study:

• To determine the magnitude and distribution of ventilation defect scores (VDS) from HP ¹²⁹Xe-MRI.
• To associate VDS with clinically relevant airway obstruction.
• To establish a VDS threshold for detecting airway obstruction.

Main Methods:

• 76 subjects (48 healthy, 20 asthma, 8 COPD) underwent HP ¹²⁹Xe-MRI and spirometry.
• Airway obstruction was defined by FEV₁/FVC < 70%.
• Five readers assigned VDS (0-100%); ROC analysis determined the optimal threshold.

Main Results:

• Patients with airway obstruction had significantly higher VDS than healthy subjects (p < 0.0001).
• VDS significantly correlated with disease severity (r = 0.66, p < 0.0001).
• An optimal VDS threshold of 12.4% ± 6.1% was identified for detecting airway obstruction.

Conclusions:

• A ¹²⁹Xe-MRI VDS of 12.4% or greater signifies clinically significant airway obstruction.
• HP ¹²⁹Xe-MRI is a reliable tool for assessing ventilation defects in obstructive lung diseases.
• This study provides a quantitative imaging biomarker for airway obstruction.