Research ArticleClinical Investigation
Open Access

Comparability of Quantifying Relative Lung Ventilation with Inhaled 99mTc-Technegas and 133Xe in Patients Undergoing Evaluation for Lung Transplantation

Ashwin Singh Parihar, Joyce C. Mhlanga, Henry D. Royal and Barry A. Siegel
Journal of Nuclear Medicine January 2025, 66 (1) 104-109; DOI: https://doi.org/10.2967/jnumed.124.268801

Article Figures & Data

Figures

  • Figure
  • FIGURE 1.
    FIGURE 1.

    Study workflow.

  • FIGURE 2.
    FIGURE 2.

    Planar scintigraphy images obtained after inhalation of 133Xe in posterior projection (A) and 99mTc-Technegas in posterior and anterior projections (B) in patient with representative images of semiautomated ROIs used for deriving relative ventilation percentages. Measured relative ventilation of left lung was 58% with 133Xe, 60% on posterior 99mTc-Technegas image, and 57% with 99mTc-Technegas geometric mean. BG = background.

  • FIGURE 3.
    FIGURE 3.

    Scatterplots showing comparison of relative left lung ventilation percentages obtained on posterior 133Xe images with those obtained using 99mTc-Technegas on posterior image (A) and with geometric mean method (B). Heat map shows maximal clustering of sampled data points in region of 40%–55%. Dotted maroon line represents line of equality. Blue line represents trend line with local regression smoothing and span of 90%. Note strong positive correlation between relative ventilation percentage of left lung as measured on posterior projection 133Xe images with posterior projection 99mTc-Technegas images, with trend line close to line of equality. Scatterplot helps in identifying overall trend as well as outliers (those with >15% difference, marked by arrows). Relatively lower slope toward higher percentages is likely due to fewer data points and effect from outlier.

  • FIGURE 4.
    FIGURE 4.

    Bland–Altman plot showing comparison of relative left lung ventilation percentages obtained on posterior 133Xe and 99mTc-Technegas images (A: posterior 99mTc-Technegas; B: geometric mean 99mTc-Technegas). Vertical axis shows difference between percentages obtained from 133Xe and 99mTc-Technegas, whereas horizontal axis is mean of 2 percentages. Orange line is line of equality, denoting no difference in percentages obtained using 2 methods. Blue line represents mean difference between 133Xe and 99mTc-Technegas percentages. Green lines represent ±15% difference limits. Maroon lines represent 95% CI limits for mean. 2 outliers with >15% difference in percentages are marked with rd arrows.

  • FIGURE 5.
    FIGURE 5.

    Posterior planar images obtained after inhalation of 133Xe (A) and 99mTc-Technegas (B) in patient with >15% discordance between relative ventilation percentages obtained using 2 techniques. Note overall heterogeneity of 133Xe distribution with visual suggestion of relatively better ventilated left lung (A). Heterogeneity is more marked on 99mTc-Technegas image (B), which, in addition to prominent left–right lung ventilation difference, also highlights relatively better ventilated left lower lung than left upper lung. Measured relative ventilation of left lung was 57% on 133Xe and 79% on 99mTc-Technegas.

  • FIGURE 6.
    FIGURE 6.

    Posterior planar images obtained after inhalation of 133Xe (A) and 99mTc-Technegas (B) in patient with >15% discordance between relative ventilation percentages obtained using the 2 techniques. Although appearance looks largely similar, note increased central deposition of 99mTc-Technegas in left lung (B, arrows) and increased activity in right lung base. Measured relative ventilation of left lung was 19% on 133Xe and 36% on 99mTc-Technegas.

Tables

  • TABLE 1.

    Correlation Coefficients for Relative Ventilation of Left Lung Expressed as Percentage as Measured on Posterior Projection 133Xe and 99mTc-Technegas Images

    ParameterrP
    Left lung: 133Xe and posterior 99mTc-Technegas0.79 (95% CI, 0.69–0.86)<0.0001
    Left lung: 133Xe and geometric mean from 99mTc-Technegas0.77 (95% CI, 0.65–0.85)<0.0001
    Left lung: 133Xe and anterior 99mTc-Technegas0.70 (95% CI. 0.56–0.80)<0.0001
  • TABLE 2.

    Visual Assessment of 99mTc-Technegas Images in Terms of Homogeneity of Radiotracer Distribution and Deposition of Radiotracer in Central and Peripheral Airways

    ParameterScore 0 (n)Score 1 (n)Score 2 (n)Score 3 (n)
    Heterogeneity*1928225
    Central deposition†3717182
    Peripheral deposition†501581

    • ↵* Heterogeneity scoring: 0 = homogeneous, 1 = mildly heterogeneous, 2 = moderately heterogeneous, 3 = severely heterogeneous.

    • ↵† Central or peripheral deposition scoring: 0 = no central/peripheral deposition, 1 = mildly increased deposition, 2 = moderately increased deposition, 3 = markedly increased deposition.

Additional Files

Back to top

In this issue

Print
Download PDF
Article Alerts
Email Article
Citation Tools
Bookmark this article

Jump to section

Keywords