Mapping Regional Changes in Multiple-Timepoint Hyperpolarized Gas Ventilation Images and Validation by Radiologist...

Area of Science:

• Pulmonary Medicine
• Medical Imaging
• Computational Biology

Background:

• Hyperpolarized gas (HPG) magnetic resonance imaging (MRI) is an FDA-approved technique for assessing lung function and gas distribution in adults and children.
• This advanced imaging modality provides novel insights into respiratory system dynamics.

Purpose of the Study:

• To develop and validate an algorithm for generating regional ventilation change maps in patients with asthma, cystic fibrosis, and COPD.
• To compare these quantitative maps against qualitative radiologist assessments to determine accuracy and clinical utility.

Main Methods:

• Hyperpolarized 3He MRI was performed on 20 patients (9 asthmatics, 6 cystic fibrosis, 5 COPD) before and after treatment.
• Image processing involved N4ITK bias correction, smoothing, normalization, and registration for creating difference maps.
• Radiologists evaluated maps using a rubric assessing volume discrepancy and its causes.

Main Results:

• The algorithm-generated change maps showed good agreement with radiologist visual evaluations in 75% of cases (15/20).
• Minor to no volume disparities were observed in most cases, with only a few showing moderate to large differences.
• The technique identified short-term improvements (STI) in ventilation.

Conclusions:

• Regional ventilation change maps derived from HPG MRI are congruent with expert visual assessment.
• This quantitative approach shows promise as a valuable tool for longitudinal monitoring of ventilation changes in respiratory diseases.