Flow Volume Loop and Regional Ventilation Assessment Using Phase-Resolved Functional Lung (PREFUL) MRI: Comparison...

Area of Science:

• Pulmonary Medicine
• Medical Imaging
• Radiology

Background:

• Regional flow volume loop ventilation-weighted noncontrast-enhanced proton lung MRI (PREFUL-MRI) is a novel technique for assessing regional lung ventilation.
• Validation with ¹²⁹ Xenon MRI (¹²⁹ Xe-MRI), a direct visualization of ventilation, is needed in healthy volunteers and patients with cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD).

Purpose of the Study:

• To compare regional ventilation and regional flow volume loops measured by PREFUL-MRI with ¹²⁹ Xe-MRI.
• To correlate these measurements with lung function test parameters.

Main Methods:

• A retrospective study involving 20 COPD patients, 8 CF patients, and 6 healthy volunteers.
• PREFUL-MRI and ¹²⁹ Xe-MRI were acquired at 1.5T. Ventilation defect percentage (VDP) was calculated using regional ventilation (RV) and regional flow volume loops (RFVL) from PREFUL-MRI, and ¹²⁹ Xe-MRI.
• Lung function tests, including forced expiratory volume in 1 second (FEV₁), were performed.

Main Results:

• VDP measured by PREFUL-MRI and ¹²⁹ Xe-MRI showed significant correlation (r = 0.62-0.69, P < 0.05) with each other and with lung function parameters.
• Combined RV and RFVL PREFUL defect maps correlated strongly with lung function tests (e.g., FEV₁, r = -0.87, P < 0.05).
• Combined PREFUL defect maps demonstrated better regional agreement with ¹²⁹ Xe-MRI defects (Dice coefficient 0.413) and higher VDP values (P = 0.04).

Conclusions:

• Combined RV and RFVL PREFUL defect maps may enhance sensitivity for detecting mild airway obstruction.
• These maps show strong correlation with lung function test parameters, suggesting clinical utility in evaluating lung ventilation.
• PREFUL-MRI, particularly with combined RV and RFVL analysis, offers a valuable, noninvasive method for assessing regional lung ventilation.