Purpose
To evaluate the impact of the use of lean body weight (LBW)-based contrast material (CM) dose and bolus tracking technique on portal venous phase abdominal CT image quality.
Materials and methods
IRB-approved prospective study; informed consent was acquired. In the period July–November 2023, we randomly selected 105 oncologic patients scheduled for a portal venous phase abdominal CT to undergo our experimental protocol (i.e., 0.7 gI/Kg of LBW CM administration and bolus tracking on the liver). Included patients had performed a “standard” portal venous phase abdominal CT (i.e., 0.6 gI/Kg of total body weight (TBW) contrast material administration and 70 s fixed delay) on the same scanner within the previous 12 months. One reader evaluated CT images measuring liver, portal vein, kidney cortex, and spleen attenuation; values were normalized to paraspinal muscles.
Results
Median administered contrast dose (350 mgI/mL CM) was 99 mL (IQR: 81–115 mL) using the experimental protocol and 110 mL (IQR: 100–120 mL) using the standard one (p < 0.0001). Median acquisition delay using the experimental protocol was 65” (IQR 59–73”). Median normalized hepatic enhancement was significantly higher using the experimental protocol (1.97, IQR: 1.83–2.47 vs. 1.86, IQR: 1.58–2.11; p < 0.0001). Median normalized portal vein enhancement was significantly higher using the experimental protocol (3.43, IQR: 2.73–4.04 vs. 2.91, IQR: 2.58–3.41; p < 0.0001). No statistically significant differences were found in the kidneys’ cortex and aorta normalized enhancement (p > 0.05).
Conclusion
The combination of LBW-based CM dose administration and bolus tracking allows a significant CM dose reduction and a significant liver and portal vein enhancement increase.
Clinical relevance statement
Lean body weight-based contrast material (CM) dose administration and bolus tracking technique in portal venous phase CT scans overcome differences in body composition and hemodynamics, improving reproducibility. It allows a significant CM dose reduction with increased liver and portal vein enhancement.
Key Points
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Lean body weight (LBW)-based contrast material (CM) dosing could be superior to total body weight dosing.
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Portal venous phase CT with a liver bolus tracking technique improved liver and spleen enhancement with a reduced contrast dose.
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The combination of LBW-based CM dosing and liver bolus tracking technique enables more “customized” CT examinations.
