Table 2 Simulated prospective acquisition time versus optimal acquisition time.

From: Contrast timing optimization of a two-volume dynamic CT pulmonary perfusion technique

Triggering offsets (HU)

V1

V2

Time difference (s)

RMSE

P value

Time difference (s)

RMSE

P value

40

0.61 ± 0.61

0.86

< 0.05

− 0.61 ± 0.98

1.16

< 0.05

60

0.87 ± 0.66

1.03

< 0.05

− 0.34 ± 0.96

1.02

< 0.05

80

1.05 ± 0.66

1.24

< 0.05

− 0.17 ± 0.90

0.91

0.252

100

1.20 ± 0.69

1.37

< 0.05

− 0.03 ± 0.85

0.85

0.921

120

1.38 ± 0.72

1.56

< 0.05

0.16 ± 0.83

0.84

0.056

140

1.53 ± 0.77

1.70

< 0.05

0.31 ± 0.82

0.88

< 0.05

  1. The “Time Difference” shows the time difference between each bolus-tracking simulation and the optimal acquisition timing. The optimal acquisition timing is obtained from the gamma variate fitting AIF curve, where V1 at the second derivative peak of AIF and V2 at the AIF peak.
  2. RMSE root mean square error. If the p-value is 0.05 or lower, the result is considered as significant difference.
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