Image Based Assessment and Comparison of Nebulizer Efficiency: Feasibility Study

Introduction: The performance of nebulizer was indirectly evaluated by the size of aerosol, urinary concentration of drug et al. We used SPECT/CT to directly evaluate the performance of Mesh Nebulizer compared to Jet nebulizer. Methods: Eight volunteers were enrolled in this study. Each volunteer inspired aerosol with mesh and jet nebulizer on the different days. 10mL solution with 5mCi Tc99m-DTPA was loaded in each nebulizer. Before inhalation, volunteer was trained to regularly inspire the aerosol. Volunteer inspired aerosol for 30 seconds, and immediately acquired lung SPECT/CT image by Discovery 670 (GE Healthcare, Milwaukee, WI). Image was manually segmented from CT images for upper airway and lungs. We measured the nebulized activity, the nebulized volume, and percentage injected dose(%ID) values of each VOIs from upper airway and lungs. Difference of %ID for each nebulizer was analyzed by non-parametric test: Wilcoxon-singed rank test.All statistical analyses were done with SPSS software (version). A P value of < 0.05 was considered statistically significant. Results: The participants comprised young people without any underlying pulmonary disease (3 females and 2 males; mean age 26.6 ± 5.3) and older people with underlying pulmonary disease (1 female and 2 males; mean age: 65.3 ± 9.1). There were no significant differences in breathing number for 30 seconds of nebulizer inhalation time or inhaled volume within- subject using Jet and Mesh nebulizer ( P value > 0.05). There was no significant difference in delivery efficiency for upper airway between Jet and Mesh nebulizer (P value = 0.483) However, delivery efficiency for lung was significant higher in Mesh nebulizer compared with Jet nebulizer (P = 0.036). Total delivery efficiency of upper airway and lung was significantly higher in Mesh nebulizer. Conclusions: The current study provided the feasibility of image based assessment of delivery efficiency for nebulizer using SPECT/CT. SPECT/CT could enable to not only visualize the distribution of drug delivery through nebulizer, but also quantification of delivery efficiency to each anatomical area of upper airway and lungs.