TABLE 3

Impact of Attenuation Correction on Image Quality

ParameterCoDe8NCCoDe8ACP*95% CI
All tumor lesions (n = 54)
    T/NT ratio6.3 ± 5.27.5 ± 5.8<0.05−0.2, 2.8
    T/Bg ratio6.4 ± 58.9 ± 5.6<0.00051.4, 3.8
Assessment of lesions according to location
    Above diaphragm (n = 31)
        T/NT ratio7.1 ± 5.79.0 ± 6.4<0.04−0.1, 4.1
        T/Bg ratio7.5 ± 5.710.4 ± 6.2<0.0011.2, 4.6
    Below diaphragm (n = 23)
        T/NT ratio5.2 ± 4.35.6 ± 4.2NS−1.8, 2.5
        T/Bg ratio4.8 ± 3.37 ± 4.1<0.0030.4, 3.9
Assessment of lesion n of different sizes†
    Lesions <7.2 mL (n = 14)
        T/NT ratio6.2 ± 4.78.7 ± 5.3NS−0.2, 5.6
        T/Bg ratio6.6 ± 4.39.9 ± 4.4<0.011.2, 5.7
    Lesions 7.2–12.5 mL (n = 13)
        T/NT ratio6 ± 2.78.3 ± 7.6NS−2.0, 6.5
        T/Bg ratio6.5 ± 3.310.1 ± 6.9<0.03−0.1, 7.3
    Lesions 12.5–17.5 mL (n = 14)
        T/NT ratio7 ± 7.77.4 ± 6.3NS−2.6, 3.3
        T/Bg ratio6.4 ± 6.47.94 ± 4.6<0.03−0.8, 3.9
    Lesions >17.5 mL (n = 13)
        T/NT ratio6 ± 4.95.7 ± 3.5NS−3.1, 2.5
        T/Bg ratio6 ± 5.77.8 ± 6.6<0.03−0.04, 3.7

  • ↵* P < 0.05 was considered significant. NS = not significant.

  • ↵† Parameters evaluated: T/NT ratio and T/Bg ratio. Lesion size was measured by functional volumes. Descriptive statistics were used to define 4 subgroup limits.

  • Image sets compared were 1-in. NaI(Tl) crystals with and without attenuation correction (CoDe8NC and CoDe8AC).