Lean body weight-based contrast injection protocol in liver CT: optimization of contrast medium dose

Objectives: To evaluate liver enhancement and image quality of abdominal CECT examinations acquired with multiple LBW-based contrast medium injection protocols. Material & Methods: One hundred fifty patients who underwent a clinically indicated CECT examination were prospectively and randomly assigned to one of the following contrast medium injection protocol groups: A, 700 mg iodine(I)/kg of LBW; B, 650 mgI/kg of LBW; and C, 600 mgI/kg of LBW. Liver signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and magnitude of contrast enhancement (ΔHU) were calculated. Subjective image quality was assessed with 5-point Likert scale. Results: The final population included 145 patients (64 females), with 50, 48, and 47 in group A, B, and C, respectively. Group A showed significantly higher SNR, CNR and ΔHU than group B (p =.018, p =.004, and p =.031, respectively) and group C (p =.024, p =.043, and p =.004). Group B had similar SNR, CNR, and ΔHU to group C (all p = 1). ΔHU was < 50 HU in 2, 7, and 11 patients in group A (48.2 ± 0.1), B (43.7 ± 5), and C (44.4 ± 5), respectively. Group A achieved the highest scores in terms of overall image quality, artifacts, and diagnostic confidence (both scores: 4; IQRs: 4–5) compared to group B (both scores: 3; IQRs: 3–5; p ≥.037) and group C (overall image quality score: 3; IQR: 2–5; p =.011. Artifact and diagnostic confidence score: 3; IQR: 1–4; p ≥.009). Conclusions: A dosage of 700 mgI/kg of LBW yields optimal liver enhancement and grants higher image quality compared to lower contrast medium dosages.