Improvement of the accuracy of liver lesion DCEUS quantification with the use of automatic respiratory gating

Objectives: To evaluate the efficiency of automatic respiratory gating (ARG) in reducing respiratory motion-induced artefacts from dynamic contrast-enhanced ultrasound (DCEUS) acquisitions and to assess the impact of ARG on DCEUS quantification parameters in patients with liver malignancies.

Methods: Twenty-five patients with liver metastasis were imaged with DCEUS. The lognormal indicator dilution model was fitted on time-intensity curves extracted from hepatic lesions with and without the use of ARG and DCEUS quantification parameters were extracted. The goodness of fit was assessed using the coefficient of determination (R (2) LN ). The effect respiration had on the data was assessed using the respiration amplitude (RA) metric. Pearson's correlation coefficient (r) was used to assess the correlation between R (2) LN and RA with and without the use of ARG.

Results: The RA parameter was strongly correlated with R (2) LN (r = -0.96, P = 7.412 × 10(-15)) and this correlation became weaker with ARG (r = -0.64, P = 5.449 × 10(-4)). ARG significantly influenced the values of the quantification parameters extracted (P ≤ 0.05). The RA was significantly decreased when ARG was used (P = 1.172 × 10(-6)).

Conclusions: ARG has a significant impact on the quantification parameters extracted and it has been shown to improve the accuracy of liver lesion DCEUS.

Key points: • ARG has a significant impact on DCEUS quantification parameters. • ARG can improve the modelling of liver lesion haemodynamics using DCEUS quantification. • ARG significantly reduces the respiration amplitude of DCEUS lesion time-intensity curves.