The aim of the present study was to evaluate the attenuation and image quality (IQ) of a body weight–adapted contrast media (CM) protocol compared with a fixed injection protocol in computed tomography (CT) of the liver at 90 kV.
One hundred ninety-nine consecutive patients referred for abdominal CT imaging in portal venous phase were included. Group 1 (n = 100) received a fixed CM dose with a total iodine load (TIL) of 33 g I at a flow rate of 3.5 mL/s, resulting in an iodine delivery rate (IDR) of 1.05 g I/s. Group 2 (n = 99) received a body weight–adapted CM protocol with a dosing factor of 0.4 g I/kg with a subsequent TIL adapted to the patients' weight. Injection time of 30 seconds was kept identical for all patients. Therefore, flow rate and IDR changed with different body weight. Patients were divided into 3 weight categories; 70 kg or less, 71 to 85 kg, and 86 kg or greater. Attenuation (HU) in 3 segments of the liver, signal-to-noise ratio, and contrast-to-noise ratio were used to evaluate objective IQ. Subjective IQ was assessed by a 5-point Likert scale. Differences between groups were statistically analyzed (P < 0.05 was considered statistically significant).
No significant differences in baseline characteristics were found between groups. The CM volume and TIL differed significantly between groups (P < 0.01), with mean values in group 1 of 110 mL and 33 g I, and in group 2 of 104.1 ± 21.2 mL and 31.2 ± 6.3 g I, respectively. Flow rate and IDR were not significantly different between groups (P > 0.05). Body weight–adapted protocoling led to more homogeneous enhancement of the liver parenchyma compared with a fixed protocol with a mean enhancement per weight category in group 2 of 126.5 ± 15.8, 128.2 ± 15.3, and 122.7 ± 21.2 HU compared with that in group 1 of 139.9 ± 21.4, 124.6 ± 24.8, and 116.2 ± 17.8 HU, respectively.
Body weight–adapted CM injection protocols result in more homogeneous enhancement of the liver parenchyma at 90 kV in comparison to a fixed CM volume with comparable objective and subjective IQ, whereas overall CM volume can be safely reduced in more than half of patients.
From the Department of Radiology and Nuclear Medicine; and CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, the Netherlands.
Received for publication July 9, 2018; and accepted for publication, after revision, September 12, 2018.
This manuscript has not received any funding. The authors report no conflicts of interest. However, the authors declare relationships with the following companies: All authors report institutional research grants from Bayer and Siemens. C.M. also receives institutional grants from Bayer and personal fees (speakers' bureau) from Bayer. J.E.W. reports additional institutional research grants from Agfa, Bayer, GE, Philips, Optimed, and Siemens, and personal fees (speakers' bureau) from Siemens and Bayer, outside the submitted work.
Correspondence to: Bibi Martens, MD, Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, P. Debyelaan 25 PO Box 5800, 6202 AZ Maastricht, the Netherlands. E-mail: firstname.lastname@example.org.