Assessment of the relationship between morphological emphysema phenotype and corresponding pulmonary perfusion pattern on a segmental level.

PURPOSE: Distinct morphological emphysema phenotypes were assessed by CT to show characteristic perfusion defect patterns. MATERIAL/
METHODS: Forty-one patients with severe emphysema (GOLD III/IV) underwent three-dimensional high resolution computed tomography (3D-HRCT) and contrast-enhanced magnetic resonance (MR) perfusion. 3D-HRCT data was visually analyzed for emphysema phenotyping and quantification by consensus of three experts in chest-radiology. The predominant phenotype per segment was categorized as normal, centrilobular, panlobular or paraseptal. Segmental lung perfusion was visually analyzed using six patterns of pulmonary perfusion (1-normal; 2-mild homogeneous reduction in perfusion; 3-heterogeneous perfusion without focal defects; 4-heterogeneous perfusion with focal defects; 5-heterogeneous absence of perfusion; 6-homogeneous absence of perfusion), with the extent of the defect given as a percentage.
RESULTS: 730 segments were evaluated. CT categorized 566 (78%) as centrilobular, 159 (22%) as panlobular and 5 (<1%) as paraseptal with no normals. Scores with regards to MR perfusion patterns were: 1-0; 2-0; 3-28 (4%); 4-425 (58%); 5-169 (23%); 6-108 (15%). The predominant perfusion pattern matched as follows: 70 % centrilobular emphysema - heterogeneous perfusion with focal defects (score 4); 42% panlobular--homogeneous absence of perfusion (score 5); and 43% panlobular--heterogeneous absence of perfusion (score 6).
CONCLUSION: MR pulmonary perfusion patterns correlate with the CT phenotype at a segmental level in patients with severe emphysema. KEY POINTS: • MR perfusion patterns correlate with the CT phenotype in emphysema. • Reduction of MR perfusion is associated with loss of lung parenchyma on CT • Centrilobular emphysema shows heterogeneous perfusion reduction while panlobular emphysema shows loss of perfusion.