Ventilation heterogeneity in ex-smokers without airflow limitation

Acad Radiol. 2015 Aug;22(8):1068-78. doi: 10.1016/j.acra.2015.04.006. Epub 2015 May 23.


Rationale and objectives: Hyperpolarized (3)He magnetic resonance imaging (MRI) ventilation abnormalities are visible in ex-smokers without airflow limitation, but the clinical relevance of this is not well-understood. Our objective was to phenotype healthy ex-smokers with normal and abnormally elevated ventilation defect percent (VDP).

Materials and methods: Sixty ex-smokers without airflow limitation provided written informed consent to (3)He MRI, computed tomography (CT), and pulmonary function tests in a single visit. (3)He MRI VDP and apparent diffusion coefficients (ADCs) were measured for whole-lung and each lung lobe as were CT measurements of emphysema (relative area [RA] with attenuation ≤-950 HU, RA950) and airway morphology (wall area percent [WA%], lumen area [LA] and LA normalized to body surface area [LA/BSA]).

Results: In 42 ex-smokers, there was abnormally elevated VDP and no significant differences for pulmonary function, RA950, or airway measurements compared to 18 ex-smokers with normal VDP. Ex-smokers with abnormally elevated VDP reported significantly greater (3)He ADC in the apical lung (right upper lobe [RUL], P = .02; right middle lobe [RML], P = .04; and left upper lobe [LUL], P = .009). Whole lung (r = 0.40, P = .001) and lobar VDP (RUL, r = 0.32, P = .01; RML, r = 0.46, P = .002; right lower lobe [RLL], r = 0.38, P = .003; LUL, r = 0.35, P = .006; and left lower lobe, r = 0.37, P = .004) correlated with regional (3)He ADC. Although whole-lung VDP and CT airway morphology measurements were not correlated, regional VDP was correlated with RUL LA (r = -0.37, P = .004), LA/BSA (r = -0.42, P = .0008), RLL WA% (r = 0.28, P = .03), LA (r = -0.28, P = .03), and LA/BSA (r = -0.37, P = .004).

Conclusions: Abnormally elevated VDP in ex-smokers without airflow limitation was coincident with very mild emphysema detected using MRI and regional airway remodeling detected using CT representing a subclinical obstructive lung disease phenotype.

Keywords: Hyperpolarized (3)He magnetic resonance imaging; airways disease; computed tomography; emphysema.

Publication types

  • Comparative Study
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Emphysema / physiopathology*
  • Female
  • Helium*
  • Humans
  • Image Interpretation, Computer-Assisted / methods
  • Isotopes
  • Magnetic Resonance Imaging / methods*
  • Male
  • Pulmonary Disease, Chronic Obstructive / physiopathology
  • Pulmonary Ventilation*
  • Radiopharmaceuticals
  • Reference Values
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Smoking / physiopathology*
  • Smoking Cessation*


  • Isotopes
  • Radiopharmaceuticals
  • Helium