Deformation correction for image guided liver surgery: An intraoperative fidelity assessment

Abstract

Background While systems of 3-D image-guided surgery (IGS) are a valuable adjunct across numerous procedures, differences in organ shape between that reflected in the preoperative image data and the intraoperative state can compromise the fidelity of such guidance based on the image. In this work, we assessed in real time a novel, 3-D IGS platform that incorporates soft tissue deformation i. Methods A series of 125 alignment evaluations were performed across 20 patients. During the operation, the surgeon assessed the liver by swabbing an optically tracked stylus over the liver surface and viewing the IGS display. Each patient had approximately 6 intraoperative comparative evaluations. For each assessment, one of only two types of alignments were considered - conventional rigid and novel deformable. The series of alignment types used was randomized and blinded to the surgeon. The surgeon provided a rating, R, from −3 to +3 for each display as compared to the previous display, whereby a negative rating indicated degradation in fidelity and a positive rating an improvement. Results A statistical analysis of the series of rating data by the clinician indicated that the surgeons were able to perceive an improvement (defined as a R > 1) of the model-based registration over the rigid registration (p = 0.01) as well as a degradation (defined as R < −1) when the rigid registration was compared with the novel deformable guidance information(p = 0.03). Conclusions This study provides evidence of the benefit of deformation correction in providing an accurate location for the liver for use in IGS systems.

Development of augmented‐reality applications in otolaryngology–head and neck surgery

“…During hepatic surgery, they used real‐time data obtained from instruments tracked along the liver surface. They were then able to appropriately adjust the relationships of their preoperative models . Paulus et al introduced a physics‐based model in which a single monocular camera was used to detect topographical changes of anatomy due to deformation; the preoperative AR images were then adjusted accordingly .…”

Multiphysics modeling toward enhanced guidance in hepatic microwave ablation: a preliminary framework

“…Both surface-based methods have demonstrated effective correction of soft-tissue deformation in phantom and clinical applications for hepatic resection. [26][27][28][29][30] With respect to thermal dose guidance, predictive, biophysical modeling of MWA presents a strong alternative to the manufacturer-provided estimates of ablation outcome by utilizing numerical approaches to solve the physical governing equations defining energy deposition and heat transfer. Other direct thermographic measurement strategies such as MR 31 and US 32 thermography are on the horizon, but these also have high technical and economic hurdles for practical use in the operating room or interventional suite.…”

Marker-Based Registration for Large Deformations - Application to Open Liver Surgery

“…The depth information of LRS is matched with the model thanks to a modified Iterative Closest Point (ICP) algorithm. In [24] authors provides evidence of benefits of deformation correction with an evaluation across 20 patients. Nevertheless, the method remains sensitive to unavoidable occlusions of the liver (for instance by the hand of the surgeons), and the ICP may provide misscorrespondences for large deformations.…”

“…The initial registration (including segmentation of the contour and initial rigid alignment) has been performed in approximately 5 minutes (with a frame rate in the simulation of 40 FPS). Then the tracking method was applied for 10 minutes providing 2 For later investigation, the hardware part could be replaced by all in one commercial system such as the system used in [24] 3 The study was approved by the local ethics committee, and the patient gave informed consent prior to the procedure. convincing registration results even for large deformations and occlusions by the hands of surgeons or when the organ is pushed inside the abdominal cavity.…”