Dynamic contrast enhanced ultrasound in gastrointestinal diseases: A current trend or an indispensable tool?

Table 1 Dynamic contrast-enhanced ultrasound parameters in time-intensity curve

Abbreviation	Parameter	Definition	Unit
AT	Arrival time	Time from administration of UCA to the beginning of the curve	s
AUC or WiWoAUC	Area under the curve or wash-in and wash-out area under the curve	Total area under the curve	AIU
FT	Fall time	Time from PE to point where tangent of descending curve across x-axis	s
IMAX or MI	Maximum intensity	Maximum intensity of the curve	AIU
MTT	Mean transit time	Mean time taken by contrast to pass through the ROI	s
PE	Peak enhancement	Maximum intensity of the curve	AIU
PI	Peak intensity	Maximum intensity of the curve	AIU
Pw	Slope coefficient of wash-in	Coefficient of the enhancement wash-in slope	AIU × s
RT	Rise time	Time from PE to point where tangent of ascending curve across x-axis	s
TPI or TTP or TP	Time to peak	Time from the beginning of the curve to peak	s
WiAUC	Wash-in area under the curve	AUC from the beginning of the curve to PE	AIU × s
WoAUC	Wash-out area under the curve	AUC from the PE to the end of the curve	AIU × s
WiR	Wash-in rate	Tangent at the ascending part of the curve	AIU × s
WoR	Wash-out rate	Tangent at the descending part of the curve	AIU × s

AIU: Absolute intensity unit; ROI: Region of interest; UCA: Ultrasound contrast agent.