Research ArticleImaging

Validation of Left Ventricular Ejection Fraction with the IQ•SPECT System in Small-Heart Patients

Hiroto Yoneyama, Takayuki Shibutani, Takahiro Konishi, Asuka Mizutani, Ryosuke Hashimoto, Masahisa Onoguchi, Koichi Okuda, Shinro Matsuo, Kenichi Nakajima and Seigo Kinuya
Journal of Nuclear Medicine Technology September 2017, 45 (3) 201-207; DOI: https://doi.org/10.2967/jnmt.116.188680

Article Figures & Data

Figures

  • FIGURE 1.
    FIGURE 1.

    Gated myocardial perfusion SPECT images of 67-y-old woman for whom echocardiographic measurements were 110 mL for ESV, 29 mL for EDV, and 73% for LVEF. (A) Conventional SPECT with QGS: EDV, 60 mL; ESV, 9 mL; and LVEF, 86%. (B) IQ•SPECT with QGS: EDV, 49 mL; ESV, 4 mL; and LVEF, 92%. (C) Conventional SPECT with cardioREPO: EDV, 71 mL; ESV, 12 mL; and LVEF, 84%. (D) IQ•SPECT with cardioREPO: EDV, 70 mL; ESV, 15 mL; and LVEF, 78%. HLA = horizontal long axis; SA = short axis; VLA = vertical long axis.

  • FIGURE 2.
    FIGURE 2.

    Average myocardial counts per pixel as measured from 45° left anterior oblique projection on conventional SPECT (A) and IQ•SPECT (B).

  • FIGURE 3.
    FIGURE 3.

    Bland–Altman analysis of LVEF on conventional SPECT with QGS vs. IQ•SPECT with QGS (A); conventional SPECT with QGS vs. echocardiography (B); IQ•SPECT with QGS vs. echocardiography (C); conventional SPECT with cardioREPO vs. IQ•SPECT with cardioREPO (D); conventional SPECT with cardioREPO vs. echocardiography (E); and IQ•SPECT with cardioREPO vs. echocardiography (F). Gray lines are mean ± 1.96 SD. Black lines are linear regression lines.

  • FIGURE 4.
    FIGURE 4.

    Myocardial perfusion SPECT images showing normal findings in 85-y-old man. (A) Conventional SPECT. (B) IQ•SPECT without attenuation or scatter correction. (C) IQ•SPECT with attenuation and scatter correction. HLA = horizontal long axis; SA = short axis; VLA = vertical long axis.

  • FIGURE 5.
    FIGURE 5.

    Myocardial perfusion SPECT images showing perfusion defect in inferolateral wall of 66-y-old man. (A) Conventional SPECT. (B) IQ•SPECT without attenuation or scatter correction. (C) IQ•SPECT with attenuation and scatter correction. (D) Invasive coronary angiography showing stenosis of left circumflex coronary artery (arrow), supporting the SPECT findings.

Tables

  • TABLE 1

    Patient Characteristics

    CharacteristicFinding
    Mean age ± SD (y)72.5 ± 9.4 (range, 28–88)
    Sex (n)
     Male77 (78.6%)
     Female21 (21.4%)
    Mean body mass index ± SD23.5 ± 3.1 (range, 16.4–32.8)
    Mean body height ± SD (cm)161.1 ± 9.4 (range, 134–189)
    Mean body weight ± SD (kg)61.7 ± 11.3 (range, 37–93.2)
    Tracer (n)
     Sestamibi2 (2%)
     Tetrofosmin96 (98%)
    Main risk factors (n)
     Obesity (body mass index > 25)30 (30.6%)
     Diabetes mellitus10 (10.2%)
     Abdominal aortic aneurysm37 (37.8%)
     Thoracic aortic aneurysm24 (24.5%)
     Angina pectoris10 (10.2%)
     Arteriosclerosis obliterans9 (9.2%)
     Previous coronary artery bypass surgery5 (5.1%)
     Aortic dissection5 (5.1%)
     Common iliac artery aneurysm3 (3.1%)
     Abnormal electrocardiographic pattern2 (2.0%)
     Renal artery aneurysm1 (1.0%)
     Hepatic artery aneurysm1 (1.0%)
     Aortic valve stenosis1 (1.0%)
  • TABLE 2

    Common SPECT Acquisition and Reconstruction Parameters

    ParameterConventional SPECTIQ•SPECT
    Reconstruction algorithmFiltered backprojectionOSCGM
    CollimatorLEHRSMARTZOOM
    Energy window140 keV ± 7.5%140 keV ± 7.5%
    Number of projections60 views (30 per detector)34 views (17 per detector)
    Rotation range360°208°
    Acquisition time (min)20 (35 s per projection)5 (9 s per projection)
    Magnification×1.45×1.00
    Rotation radius (cm)24–2528
    Number of iterationsQGS: 30, QPS: 10
    Number of subsetsQGS: 1, QPS: 3
    Updates30
    Gaussian filter (mm)9.6
    Butterworth filter (cycles/cm)QGS: 0.39, QPS: 0.52
    Matrix64 × 64128 × 128
    Pixel size (mm)6.64.8

    • LEHR = low-energy high-resolution; OSCGM = ordered-subset conjugate gradient minimization.

  • TABLE 3

    Comparison of EDV, ESV, and LVEF for Conventional SPECT, IQ•SPECT, and Echocardiography

    ParameterConventionalIQEchoConventional vs. IQConventional vs. echoIQ vs. echo
    QGS
     EDV (mL)77.0 ± 39.174.2 ± 36.8110.6 ± 38.3r = 0.98r = 0.77r = 0.77
     ESV (mL)30.0 ± 29.227.4 ± 27.340.6 ± 26.7r = 0.97r = 0.81r = 0.82
     LVEF (%)65.4 ± 13.868.4 ± 15.264.8 ± 11.6r = 0.86r = 0.63r = 0.64
    CardioREPO
     EDV (mL)87.9 ± 35.682.8 ± 34.0110.6 ± 38.3r = 0.98r = 0.77r = 0.75
     ESV (mL)28.1 ± 22.627.0 ± 22.440.6 ± 26.7r = 0.98r = 0.78r = 0.77
     LVEF (%)69.5 ± 10.669.5 ± 11.064.8 ± 11.6r = 0.80r = 0.60r = 0.65
    QGS (%)
     All LVEF65.4 ± 13.868.4 ± 15.264.8 ± 11.6P = 0.0002NSP = 0.019
     Small-heart LVEF75.0 ± 9.679.5 ± 8.370.1 ± 6.8P = 0.0005P = 0.0076P < 0.0001
    CardioREPO (%)
     All LVEF69.5 ± 10.669.5 ± 11.064.8 ± 11.6NSP < 0.0001P < 0.0001
     Small-heart LVEF72.3 ± 9.074.3 ± 8.370.1 ± 6.8NSNSP = 0.0068

    • Conventional = conventional SPECT; echo = echocardiography; IQ = IQ•SPECT; NS = not statistically significant.

    • Data are mean ± SD.

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