Quantitative analysis of hyperpolarized 3He ventilation changes in mice challenged with methacholine

Area of Science:

• Pulmonary imaging
• Medical physics
• Respiratory research

Background:

• Asthma research benefits from detailed regional ventilation analysis.
• High-resolution (3)He MRI can visualize ventilation changes and airway narrowing.
• Current analysis relies on visual inspection, limiting quantitative insights.

Purpose of the Study:

• To develop and validate a postprocessing approach for quantitative analysis of (3)He MRI ventilation data.
• To create ventilation difference maps for improved visualization and quantification of regional ventilation changes.
• To assess the sensitivity of this method in mice challenged with methacholine (MCh).

Main Methods:

• Utilized high-resolution (3)He MRI to acquire lung ventilation images in mice.
• Developed a postprocessing technique to generate ventilation difference maps comparing pre- and post-MCh challenge states.
• Quantified ventilation changes using histogram analysis of the difference maps.

Main Results:

• Ventilation difference maps effectively visualized subtle airway caliber changes and regional ventilation alterations (hypoventilation and hyperventilation).
• The standard deviation of ventilation changes in the histogram plots increased with MCh dose (R(2) = 0.89).
• The developed quantitative method demonstrated higher sensitivity compared to threshold-based detection of ventilation defects.

Conclusions:

• The novel postprocessing approach enables sensitive, quantitative analysis of regional ventilation changes using (3)He MRI.
• This method provides valuable insights into asthma pathophysiology beyond visual assessment.
• The quantitative analysis of ventilation difference maps holds promise for advancing asthma research and diagnostics.