MR imaging of the airways

Area of Science:

• Pulmonary Medicine
• Radiology
• Medical Imaging

Background:

• Standard lung function tests lack sensitivity for early peripheral airway changes.
• Computed tomography (CT) and X-ray are common but involve radiation.
• Magnetic resonance imaging (MRI) offers a radiation-free alternative for lung and airway assessment.

Purpose of the Study:

• To explore the capabilities of MRI in visualizing lung and airway morphology and function.
• To compare MRI's diagnostic potential against conventional imaging techniques.
• To highlight MRI's utility in research and clinical settings for airway diseases.

Main Methods:

• Non-contrast enhanced MRI for airway morphology.
• Dynamic, time-resolved MRI for expiratory airway collapse and air trapping.
• Hyperpolarized noble gas MRI (3He, 129Xe) for ventilation.
• Dynamic contrast-enhanced MRI (DCE MRI) for perfusion deficits.

Main Results:

• Non-contrast MRI visualizes airways to the 4th order, identifying bronchiectasis and tree-in-bud signs.
• Dynamic MRI detects expiratory collapse and air trapping.
• Hyperpolarized gas MRI visualizes ventilation, while DCE MRI shows perfusion deficits.
• Emerging MRI techniques show promise for ventilation/perfusion assessment.

Conclusions:

• MRI offers a unique combination of morphological and functional imaging for lung and airway diseases.
• It is valuable for research in conditions like COPD and asthma.
• MRI serves as a crucial tool for clinical imaging, particularly in cystic fibrosis.