Image-based guidance of percutaneous abdomen intervention based on markers for semi-automatic rigid registration.

Abstract

IntroductionFor percutaneous abdomen intervention (e.g. liver radiofrequency (RF) tumor ablation, liver biopsy), surgeons lack real-time visual feedback about the location of the needle on planning images, typically computed tomography (CT). One difficulty lies in tracking and synchronizing both the tool movement and the patient breathing motion.AimTo verify the correspondence between rigid registration fiducial registration error signal and breathing phase.Material and methodsDesigned markers that are clearly visible both in planning CT and on the patient during the intervention are proposed. Registration and breathing synchronization is then performed by a point-based approach. The method was tested in a clinical environment on 10 patients with liver cancer using 3D abdominal CT in the exhale position. Median rigid fiducial registration error (FRE) in the breathing cycle was used as a criterion to distinguish the inhale and exhale phase.ResultsThe correlation between breathing phase and FRE value can be observed for every patient. We obtained mean median FRE equal to 9.37 mm in exhale positions and 15.56 mm in the whole breathing cycle.ConclusionsThe presented real time approach, based on FRE calculation, was integrated in the clinical pipeline, and can help to select the best respiratory phase for needle insertion for percutaneous abdomen intervention, in cases where only 3D CT is performed. Moreover, this method allows semi-automated rigid registration to establish the correspondence between preoperative patient anatomical model and patient position.

Estimation of respiratory breathing signal from 2D US sequences and 4DCT of the liver

“…The tracking of markers attached to the breathing part of the patient can produce surrogate breathing signal [7]. The previous worked [8,9] showed that could be useful for real-time comparison online patient breathing phase and phase estimation from CT images. …”