helium-3-atom and Emphysema

Chronic obstructive pulmonary disease (COPD) and emphysema are characterized by functional and structural damage which increases the spaces for gaseous diffusion and impairs oxygen exchange. Here we explore the potential for hyperpolarized (HP) 3He MRI to characterize lung structure and function in a large-scale population-based study. Participants (n = 54) from the Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study, a nested case-control study of COPD among participants with 10+ packyears underwent HP 3He MRI measuring pAO2, apparent diffusion coefficient (ADC), and ventilation. HP MRI measures were compared to full-lung CT and pulmonary function testing. High ADC values (>0.4 cm2/s) correlated with emphysema and heterogeneity in pAO2 measurements. Strong correlations were found between the heterogeneity of global pAO2 as summarized by its standard deviation (SD) (p < 0.0002) and non-physiologic pAO2 values (p < 0.0001) with percent emphysema on CT. A regional study revealed a strong association between pAO2 SD and visual emphysema severity (p < 0.003) and an association with the paraseptal emphysema subtype (p < 0.04) after adjustment for demographics and smoking status. HP noble gas pAO2 heterogeneity and the fraction of non-physiological pAO2 results increase in mild to moderate COPD. Measurements of pAO2 are sensitive to regional emphysematous damage detected by CT and may be used to probe pulmonary emphysema subtypes. HP noble gas lung MRI provides non-invasive information about COPD severity and lung function without ionizing radiation.

Topics: Atherosclerosis; Case-Control Studies; Emphysema; Helium; Humans; Isotopes; Male; Oxygen; Partial Pressure; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema

Topics: alpha 1-Antitrypsin Deficiency; Carbon Monoxide; Diffusion; Diffusion Magnetic Resonance Imaging; Disease Progression; Emphysema; Helium; Humans; Isotopes; Longitudinal Studies; Lung; Male; Prospective Studies; Pulmonary Disease, Chronic Obstructive; Single-Case Studies as Topic; Tomography, X-Ray Computed

In this study, we compared a newly developed multibreath simultaneous alveolar oxygen tension and apparent diffusion coefficient (P. Both single-breath and multibreath simultaneous P. The multibreath protocol decreased the ventilation defect volumes by an average of 12.9 ± 6.6%. The multibreath sequence generated nonphysiological P. Multibreath P

Topics: Adult; Aged; Case-Control Studies; Diffusion Magnetic Resonance Imaging; Emphysema; Female; Helium; Humans; Isotopes; Male; Middle Aged; Oxygen; Partial Pressure; Pulmonary Alveoli; Pulmonary Disease, Chronic Obstructive; Respiration

Pulmonary ventilation may be visualized and measured using hyperpolarized (3)He magnetic resonance imaging (MRI) while emphysema and its distribution can be quantified using thoracic computed tomography (CT). Our objective was to phenotype ex-smokers with COPD based on the apical-to-basal distribution of ventilation abnormalities and emphysema to better understand how these phenotypes change regionally as COPD progresses. We evaluated 100 COPD ex-smokers who provided written informed consent and underwent spirometry, CT and (3)He MRI. (3)He MRI ventilation imaging was used to quantify the ventilation defect percent (VDP) for whole-lung and individual lung lobes. Regional VDP was used to generate the apical-lung (AL)-to-basal-lung (BL) difference (ΔVDP); a positive ΔVDP indicated AL-predominant and negative ΔVDP indicated BL-predominant ventilation defects. Emphysema was quantified using the relative-area-of-the-lung ≤-950HU (RA950) of the CT density histogram for whole-lung and individual lung lobes. The AL-to-BL RA950 difference (ΔRA950) was generated with a positive ΔRA950 indicating AL-predominant emphysema and a negative ΔRA950 indicating BL-predominant emphysema. Seventy-two ex-smokers reported BL-predominant MRI ventilation defects and 71 reported AL-predominant CT emphysema. BL-predominant ventilation defects (AL/BL: GOLD I = 18%/82%, GOLD II = 24%/76%) and AL-predominant emphysema (AL/BL: GOLD I = 84%/16%, GOLD II = 72%/28%) were the major phenotypes in mild-moderate COPD. In severe COPD there was a more uniform distribution for ventilation defects (AL/BL: GOLD III = 40%/60%, GOLD IV = 43%/57%) and emphysema (AL/BL: GOLD III = 64%/36%, GOLD IV = 43%/57%). Basal-lung ventilation defects predominated in mild-moderate GOLD grades, and a more homogeneous distribution of ventilation defects was observed in more advanced grade COPD; these differences suggest that over time, regional ventilation abnormalities become more homogenously distributed during disease progression.

Topics: Aged; Aged, 80 and over; Contrast Media; Emphysema; Female; Forced Expiratory Volume; Helium; Humans; Isotopes; Lung; Magnetic Resonance Imaging; Male; Middle Aged; Phenotype; Plethysmography; Pulmonary Disease, Chronic Obstructive; Pulmonary Ventilation; Residual Volume; Smoking Cessation; Tomography, X-Ray Computed