ObjectiveTo analyze the minimum dose of contrast media in cardiac enhanced CT scan at 70 kV tube voltage.
MethodsA total of 96 infants with critical congenital heart disease received cardiac enhanced CT scan were selected and randomly divided into group A, group B and group C (32 cases in each group).Non-ionic iodine contrast media (iodine concentration 320 mg/mL) was used, and the dose of contrast media in group A, B and C was 1.0, 1.5 and 2.0 mL/kg, respectively.Another 100 children less than 2-month old with endocardial macrovascular enhancement were randomly divided into group E and group F (50 cases in each group), with 80 kV and 100 kV tube voltage, respectively, at the same other scanning conditions.The noise, signal-to-noise ratio, subjective score, diagnostic accuracy, CT value of left and right ventricle and enhancement value (ΔHU) of ventricular septal were observed in group A, B and C; the radiation dose in experimental group, group E and F was compared; and the linear relationship between ΔHU of ventricular septum and contrast media dose was analyzed.
ResultsThere were no significant differences in subjective score, noise, signal-to-noise ratio and diagnostic accuracy among group A, B and C(P>0.05).The CT value of left ventricle and right ventricle and ΔHU of ventricular septum in group A, B and C increased gradually, the difference of which was statistically significant(P < 0.05).Compared with the experimental group, the radiation dose in group E and F increased gradually with the increase of tube voltage(P < 0.05).The linear regression formula between the ΔHU of ventricular septum and the dose of contrast media was: ΔHU=89.71+2.3×dose of contrast media, at the condition of ΔHU of ventricular septum ≥ 100 HU, the minimum dose of contrast media was 0.75 mL/kg.
ConclusionsThe minimum dose of contrast media for cardiac enhanced CT scan at 70 kV in infants was 0.75 mL/kg.
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