Dual source abdominal computed tomography: the effect of reduced X-ray tube voltage and intravenous contrast media dosage in patients with reduced renal function

BackgroundX-ray tube voltage (kVp) reduction increases intravenous contrast medium (CM) attenuation at computed tomography (CT), but tube output limits its use in large patients.PurposeTo evaluate the feasibility and image quality of reducing CM dose by low kVp and using dual X-ray source at liver CT.Material and MethodsPatients with estimated glomerular filtration rate (eGFR) 65 years with eGFR > 45 mL/min scanned using a standard abdominal protocol at 120 kVp after receiving 0.5 gI/kg.ResultsThere was no statistically significant difference in CNR, liver noise, or muscle noise at reduced CM protocols compared to the standard protocol: CNR was 4.6 (95% CI = 4.2–5.0) vs. 5.0 (95% CI = 4.5–5.5), liver noise was 11.1 (95% CI = 10.7–11.6) vs. 11.0 (95% CI = 10.5–11.6), muscle noise was 11.7 (95% CI = 11.2–12.1) vs. 10.8 (95% CI = 10.1–11.4). The mean SSDE was 70% higher with the reduced CM protocol.ConclusionCM dosage can be reduced by 40–50% with maintained measured noise and CNR in patients with BMIs of 15–36 kg/m2by lowering the tube voltage and dual-source CT scanning of the liver.