Table 1.

Tips for performing vascular CEUS

	Tip
Focus	Place the focus just deep to the target vessel in order to achieve homogeneous energy distribution over the imaging plane.
Gain	The gain should be adjusted at the beginning of the examination so that no UCA signals are lost due to non-detection (too low gain) or obscuration by noise and erased because of signal saturation (too high gain). The image prior to UCA administration should be virtually black except for highly echogenic structures like the diaphragm, which are helpful for orientation.
Dynamic range	The dynamic range (range of signal intensities displayed) should be wide if fine differences of enhancement are sought (as in lesion characterization) but can be kept low to make the blood vessels stand out more brightly, with good contrast with the background.
Frame rate	A frame rate of ≥10 Hz (or frames per second) is useful for assessing wash-in patterns of focal liver lesions or fast-flowing blood as in some endoleaks, but at the expense of microbubble disruption.
UCA dose	Carefully choose the UCA dose, as too high a dose will result in flare (signal saturation) and acoustic shadowing deep to the microbubbles, whereas too low a dose may cause inadequate enhancement.
MI	The MI should be properly adjusted. Too high of an MI will cause microbubble disruption, particularly in the near field, whereas too low of an MI will lead to poor visualization of the far field (e.g., aortic applications).
Video clips	Video clips should be recorded for re-evaluation of pathology, such as in cases of endoleak characterization.
Prolonged scanning	Prolonged scanning in the same plane should be avoided as it causes disruption of microbubbles in a specific location, a phenomenon observed more commonly in applications involving the parenchymal organs.
Great depth	CEUS imaging at great depth is always a challenge due to wave attenuation, limiting the depth penetration of low-MI waves.
	When possible, a lower insonation frequency can be used (with slightly lower spatial resolution) or different and suitable imaging windows should be chosen to bring the examined organ closer to the transducer (e.g., the lateral decubitus position for evaluation of renal vascularity).

CEUS, contrast-enhanced ultrasonography; UCA, ultrasonographic contrast agent; MI, mechanical index.