Anatomical distribution of 3He apparent diffusion coefficients in severe chronic obstructive pulmonary disease.

Purpose: To evaluate the anatomical distribution of apparent diffusion coefficients (ADC) using hyperpolarized helium-3 (3He) MRI in chronic obstructive pulmonary disease (COPD).

Materials And Methods: Hyperpolarized 3He MRI was performed in eight healthy and seven COPD subjects under breathhold conditions in the supine position to determine ADC values from diffusion-weighted images and evaluate anterior-posterior (AP) and superior-inferior (SI) differences.

Results: ADC differences between anterior and posterior slices, DeltaAP, was 0.06 +/-0.01 cm2/second for healthy volunteers and 0.04 +/-0.02 cm2/second for COPD subjects and was significant for each subject (P < 0.01). The AP ADC gradient was -3.98 x 10(-3) +/-0.59 cm2/second/cm for healthy volunteers and -2.04 x 10(-3) +/-0.89 cm2/second/cm for COPD subjects. The difference in ADC between superior and inferior regions of interest (ROIs), DeltaSI, was 0.02 +/-0.02 cm2/second for healthy volunteers and 0.10 +/-0.09 cm2/second for COPD subjects, which was significant for each subject (P < 0.05). The SI ADC gradient was -0.63 x 10(-3) +/-2.23 cm2/second/cm for healthy volunteers and -6.61 x 10(-3) +/-6.68 cm2/second/cm for COPD subjects. DeltaAP, AP-gradient, and SI-gradient were significantly different between healthy volunteers and COPD subjects (P < 0.05).

Conclusion: In all subjects, ADC anatomical differences were significant and mean ADC was dependent on anatomic location and disease status.