A posteriori respiratory gating in contrast ultrasound for assessment of hepatic perfusion.
An original strategy is proposed to minimize the impact of respiratory motion on hepatic contrast-enhanced ultrasound studies. It is based on the a posteriori triggering of dynamic image sequences. It was tested on perfusion studies acquired with a high temporal resolution (8 images s-1) to enable parametric imaging. A respiratory component was first estimated by independent component analysis. The estimation of the local minima and maxima of this curve enabled us to select two subsets of frames, corresponding to the end-of-inspiration plane and to the end-of-expiration plane. Both subsets were simultaneously analysed using factor analysis of medical image sequences. This method identified the main contrast uptake kinetics and their associated localizations. The global strategy was validated firstly on a simulated study and then applied to 11 patients' studies. In both cases, the frame selection was judged relevant and a necessary preliminary step before applying methods of parametric imaging. In conclusion, the a posteriori gating method that is proposed is a first step towards local quantification of hepatic contrast-enhanced ultrasound studies.
Renault
G
G
INSERM U678, University Pierre et Marie Curie, CHU Pitié-Salpêtrière, 91 Boulevard de l'Hôpital, 75634 Paris Cedex 13, France. gilles.renault@imed.jussieu.fr
Tranquart
F
F
Perlbarg
V
V
Bleuzen
A
A
Herment
A
A
Frouin
F
F
D003198:Computer Simulation; D003287:Contrast Media; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D008099:Liver / Q000000981:diagnostic imaging*; D009038:Motion; D010477:Perfusion; D012119:Respiration; D014463:Ultrasonography
D003287:Contrast Media