Research ArticleCardiology

Quantification and Determination of Normal 123I-Meta Iodobenzylguanidine Heart-to-Mediastinum Ratio (HMR) from Cardiac SPECT/CT and Correlation with Planar HMR

Raza Alvi, Edward J. Miller, Taraneh Hashemi Zonouz, Veronica Sandoval, Noor Tariq, Rachel Lampert, Albert J. Sinusas and Yi-Hwa Liu
Journal of Nuclear Medicine April 2018, 59 (4) 652-658; DOI: https://doi.org/10.2967/jnumed.117.197152

Article Figures & Data

Figures

  • FIGURE 1.
    FIGURE 1.

    Flowchart of patient study, 123I-mIBG planar and SPECT imaging, and data analyses.

  • FIGURE 2.
    FIGURE 2.

    Planar-HMR quantification methods: planar images with heart and mediastinal ROIs (A–C) and schematics showing relative positions of heart and mediastinal regions in 2D (D). SPECT HMR quantification methods from fused SPECT/CT images: coregistered central SPECT and CT slices of heart and mediastinal regions (E–G) and schematics showing relative positions of heart and 2 different mediastinal regions in 3D (H).

  • FIGURE 3.
    FIGURE 3.

    Correlations between planar HMR quantified using region-growing ROI and SPECT HMRs calculated on basis of 3 background (BKG) regions: HMRBKG-LM (A), HMRBKG-CL (B), and HMRBKG-UM (C), and correlation between planar and SPECT mean counts in heart ROI (D).

  • FIGURE 4.
    FIGURE 4.

    Correlations of SPECT HMRBKG-UM at 180 min versus (A) 120 min, (B) 90 min, and (C) 30 min, after 123I-mIBG injection.

Tables

  • TABLE 1

    Early and Delayed Planar HMR for Intra- and Interobserver Analysis

    Traditional methodElliptic methodRegion-growing method
    ReproducibilityEarly HMRDelayed HMREarly HMRDelayed HMREarly HMRDelayed HMR
    Intraobserver
     First measurement2.01 ± 0.182.12 ± 0.251.97 ± 0.172.09 ± 0.221.99 ± 0.192.14 ± 0.25
     Second measurement1.98 ± 0.192.08 ± 0.261.95 ± 0.162.07 ± 0.211.97 ± 0.172.12 ± 0.23
     ICC0.890.870.940.930.970.97
     95% confidence interval0.67−0.960.66–0.970.72−0.990.74−0.980.92−0.990.82–0.99
    Interobserver
     First observer2.01 ± 0.202.12 ± 0.251.97 ± 0.172.13 ± 0.231.99 ± 0.192.14 ± 0.25
     Second observer1.97 ± 0.232.09 ± 0.261.98 ± 0.192.12 ± 0.252.00 ± 0.202.11 ± 0.25
     ICC0.800.860.950.950.980.98
     95% confidence interval0.52−0.920.62–0.950.92−0.990.91−0.990.95−0.990.94−0.99
  • TABLE 2

    Washout Rates for Intra- and Interobserver Analysis

    Traditional methodElliptic methodRegion-growing method
    ReproducibilityWRWRBKG-correctedWRWRBKG-correctedWRWRBKG-corrected
    Intraobserver
     First measurement20.7 ± 5.115.0 ± 9.921.6 ± 4.517.0 ± 8.921.8 ± 4.617.6 ± 9.1
     Second measurement21.5 ± 4.916.5 ± 9.522.6 ± 5.119.9 ± 8.322.8 ± 5.320.2 ± 8.7
     ICC0.840.800.920.820.940.86
     95% confidence interval−0.16−0.96−0.18−0.940.76−0.960.55−0.930.79−0.970.64−0.94
    Interobserver
     First observer20.7 ± 5.115.0 ± 9.921.6 ± 4.517.0 ± 8.921.8 ± 4.617.6 ± 9.1
     Second observer21.5 ± 4.618.1 ± 8.121.3 ± 5.017.4 ± 9.021.6 ± 5.018.0 ± 9.1
     ICC0.860.750.940.800.960.85
     95% confidence interval0.60−0.970.50−0.920.84−0.970.51−0.920.88−0.980.60−0.94
  • TABLE 3

    SPECT HMR and Intra- and Interobserver Analysis

    ReproducibilityHMRBKG-UMHMRBKG-LMHMRBKG-CL
    Intraobserver
     First measurement8.0 ± 1.25.7 ± 1.33.9 ± 1.3
     Second measurement7.9 ± 1.25.6 ± 1.34.0 ± 1.3
     Mean LLN(5.6 + 5.6)/2 = 5.6(3.0 + 3.0)/2 = 3.0(1.4 + 1.4)/2 = 1.4
     ICC0.960.960.95
     95% confidence interval0.909–0.9850.911–0.9950.893–0.985
    Interobserver
     First observer8.0 ± 1.25.7 ± 1.33.9 ± 1.3
     Second observer8.0 ± 1.35.5 ± 1.34.0 ± 1.25
     Mean LLN(5.6 + 5.4)/2 = 5.5(3.0 + 3.0)/2 = 3.0(1.4 + 1.5)/2 = 1.45
     ICC0.950.970.95
     95% confidence interval0.903–0.9890.941–0.9940.894–0.983
  • TABLE 4

    LLN for SPECT HMRBKG-UM

    Time after injectiont = 180 mint = 120 mint = 90 mint = 30 min
    Mean ± SD8.0 ± 1.27.3 ± 1.16.8 ± 1.15.5 ± 1.1
    LLN5.65.14.63.3

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