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MRI and Ultrasound Robotic Assisted Biopsy

Periodic Reporting for period 3 - MURAB (MRI and Ultrasound Robotic Assisted Biopsy)

Okres sprawozdawczy: 2019-01-01 do 2020-06-30

The MURAB project had the ambition to revolutionise the way cancer screening and muscle diseases are researched for patients and has the potential to save lives by early detection and treatment. The project intended to create a new paradigm in which, the precision of great medical imaging modalities like MRI and Ultrasound are combined with the precision of robotics in order to target the right place in the body. This has been achieved by identifying a target using Magnetic Resonance Imaging (MRI) and then use a robot with an ultrasound (US) probe to match the images and navigate to the right location. This has been done thanks to a new innovative technique, which has been developed in the project and called Tissue Active Slam (TAS) which uses different techniques and modalities, like elastography, in order to cope with the deformation of the tissues. Such a procedure has the potential to drastically improve the clinical workflow and save lives by ensuring an exact targeting of (small) lesions, which are visible under MRI and not under US.Technologies developed within MURAB also have the potential to improve other clinical procedures. Clinically, two applications will be targeted and validated in the project: breast cancer diagnostics (MUW and ZGT) and muscle disease diagnostics (UMCN). Considering the potential for the market, industrial partners are involved with expertise in the delivery of safe robotics components and applications (KUKA), as well as with great knowledge and ambition in pushing innovation to the medical market (SIEMENS).

The following phases have been included in the MURAB project:

1. MRI acquisition and lesion localization
2. MRI to base coordinates
3. Ultrasound scanning
4. Deformable tissue modelling and fusion
5. Elastography
6. Robotic control and SLAM for needle biopsy
University of Twente coordinated the management activities needed to run a successful and productive project. Biweekly consortium telephone conferences were organized to exchange information about progress, unforeseen challenges and to make decisions for the next steps . Weekly internal project meetings took place in different locations and in concomitance with workshops, conferences and summer school, as described in the technical report.

The MURAB project was presented at the relevant imaging robotics conferences. The MURAB system was tested on more than 100 volunteers with 3D US of the front lower leg muscle. Realistic breast phantoms were designed to investigate the MRI interfacing for the proper acquisition of the data, as well as the US imaging. MRI and 3D US measurements for both breast and muscle on healthy volunteers was performed. A cone structure was designed to scan the breast with a Siemens ABVS transducer. Another acquisition method makes use of the KUKA robotic arm by moving the US transducer to get the B-mode scans. The 3D US volume is updated after each B-mode image acquisition. Each image was integrated into a target volume using a modify nearest neighbor algorithm. A mathematical framework for SLAM has been developed including simulations and validation setup. A cross-correlation-based tissue motion estimation algorithm was tested to estimate the lesion displacement induced by needle insertion or other external motion. US images and MRI images were registered using the external surface of the tissue on both breast and muscle. The geometric registration combined affine and thin plate spline functions, while a second approach based on finite element method (FEM) deformation was also tested. Due to the real-time constraints that are hard to be accomplished with the FEM modeling, a geometry-based dynamics (PBD) algorithm was also implemented.

Multimodal markers (i.e. visible in different diagnostic images such as MRI and US) were designed. They are fully compatible with the robotic scanning and are used to support the scanning trajectory alignment and the image registration process.
Several prototypes of the end effector were designed. The end effector was integrated with the KUKA robotic arm.

The robotic head is equipped with stereo camera and a small light projector that helps in the localization of the multi-modality markers attached to the skin. A 3DOF mechanism was implemented to aim the biopsy needle in the plane of the US probe which is rigidly attached to the robotic arm.

An implementation of an automatic trajectory to be followed by the robotic arm equipped with the end effector was tested. Hybrid force-motion control for reactive control needed during the scanning phase was designed.
An innovative sensor that enables a 2D linear US probe to do elastography measurements was designed. The sensor consists of an acoustically transparent material that envelopes the US probe and the pressure at the tissue-US probe interface is determined by analyzing the US image.

Each of the components of the MURAB system was tested in pre-clinical (in vitro) environment. A market analysis and health technology assessments (HTA) have been performed. Subparts if the MURAB setup have been tested in-vivo.

Multiple articles have been published in relevant robotic imaging journals. In addition, there are several articles still in draft or under revision. Furthermore, several patents are currently in the filing process.
Several progresses beyond the state of the art were achieved: new methods for 3D US acquisition and reconstruction, real-time methods for multimodal image registration, new methods for the calibration of the deformable models and compensation of the deformations, prototypes of a robotic head for breast and muscle biopsies, new methods for the control of a robotic arm to perform the 3D US scanning of a soft tissue, identification of materials for the realization of multimodal markers, a new pad sensor to be attached to the US probe for elastography measurements. A new method for interactive scanning has been developed (SLAM) including the use of image feedback on robotic scanning.
Some of these realizations may become commercial products by themselves (e.g. multimodal markers, image acquisition system, US pressure sensor).
Most of the technologies developed so far were integrated in the MURAB robotic system and tested on realistic phantoms of the breast and of the leg. Subparts were tested in-vivo. The consortium prepared the hardware and software for clinical trials and the for the approval required by the ethical committee, however it was not possible to finalise the clinical testing due to the outbreak of the COVID-19 pandemic. A complete analysis of the market and of the business model was performed by Siemens. This analysis comprised studies about: potential markets, market size, costs of the MURAB procedure and comparison with the cost of a standard procedure, number of MRI guided biopsies in the countries involved in the consortium and the potential number of MURAB installations within a country.
Also, the possibility to extend the MURAB system to other cases (e.g. liver, kidneys) may lead to a major socio-economic impact of the project.