Optimization of Contrast Agent Dose in CT With Lean Body Weight

Contrast Agent With Lean Body Weight

This study evaluates the different enhancement using a contrast agent dose in computed tomography based on total body weight or based on lean body weight. Half of participants will receive contrast agent dose based on their total body weight, while the other half will receive a dose based on their lean body weight. Our hypothesis is that if contrast agent is administered not basing on total body weight but on lean body weight it is possible to obtain equal or better quality of enhanced images, a reduction of the variability of contrast enhancement, and also a dose reduction in some patients (overweight ones).

Patients will undergo a CT scan of abdomen (multi-phasic) with contrast agent and will be measured: total body weight (TBW), height, lean body weight (LBW) and body mass index (BMI) through formulas known in literature and with a balance for bioelectrical impedance analysis. There is no administration of drugs other than those indicated in the request of the treating physician. Contrast agent dose: IOPAMIRO® (Iopamidol) is an x-ray contrast medium of the new generation of non-ionic compounds, which are watersoluble because the molecular structure incorporates hydrophilic groups. Recommended dosage (ml) is 0.5-2.0/kg. Single injection volume depends on the vascular area to be examined. IOMERON® (Iomeprolo) is an x-ray contrast medium of the new generation of non-ionic compounds, which are watersoluble because the molecular structure incorporates hydrophilic groups. Recommended dosage (ml) is 0.5-2.0/kg. Single injection volume depends on the vascular area to be examined. Patients will be randomly assigned to undergo one of the two contrast agent protocols. Control group (TBW protocol): patients will receive a contrast agent dose based on their TBW as a standard clinic protocol with a dose of 0.40 gI/kg of TBW. There are no differences compared to clinical practice. Experimental group (LBW protocol): patients will receive a contrast agent dose based on their calculated LBW to test our hypothesis with a dose of 0.65 gI/kg of LBW, derived from our pilot study (LBW\_01 approved 10/11/2016, registration number 160/int/2016). If radiologists prefer a more enhanced examination, only scanning with contrast agent will be repeated with the standard dose as the standard clinical protocol.

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