Ivan Bricault

CT and MR Compatible Light Puncture Robot: Architectural Design and First Experiments

This paper presents a new robotic architecture designed to perform interventional CT/MR procedures, particularly punctures. Such procedures are very popular nowadays for diagnostic or therapeutic purposes. Innovations concerning the robotic architecture, materials and energy sources are exposed. We also introduce the control loop we use to check the movements and the positioning of the robot, including a new method to localize the robot thanks to the images coming from the imaging devices (CT or MRI). Finally, the results of the first experiments are presented.

Light Puncture Robot for CT and MRI Interventions

The new robot named light puncture robot (LPR), has an original compact body-supported architecture, which is naturally able to follow the patients body surface respiratory movements for abdominal and thoracic percutaneous procedures, which is compatible with CT, open MRI, and closed MRI. It is entirely made of plastic and uses MR-compatible pneumatic actuators powered by compressed air. It is localized via an image-based control using a localization device that is totally integrated to the robot. The physician is also included in the control loop, since he/she selects the target and the entry point and supervises the whole process.

LPR: A CT and MR-Compatible Puncture Robot to Enhance Accuracy and Safety of Image-Guided Interventions

Image-guided percutaneous interventions are common procedures used for diagnosis or therapeutic purposes. The clinical demand for such interventions is growing since they are minimally invasive. To increase the quality of the operations and provide optimal accuracy and safety to patients, puncture robots may be very helpful. This paper presents a new robotic architecture designed to perform abdominal and thoracic punctures under computer tomography (CT) or MRI guidance. Innovations concerning the robotic architecture, materials, and energy sources are described. Segmentation and registration algorithms have been developed to localize the robot on images coming from CT or MRI devices, and a specific control loop is used to verify the movements and the positioning of the robot. The results of the initial experiments made under CT and MRI environments are presented.

Interventional radiology robot for CT and MRI guided percutaneous interventions

This paper introduces a new patient-mounted CT and MRI guided interventional radiology robot for percutaneous needle interventions. The 5 DOF robot uses ultrasonic motors and pneumatics to position the needle and then insert it progressively. The needle position and inclination can be registered in the images using two strategically placed fiducials visible in both imaging modalities. A first prototype is presented and described in terms of its sterilization, CT and MRI compatibility, and precision. Tests showed that 1) it is entirely sterilizable with hydrogen peroxide gas, 2) no image artifacts or deformations are noticeable in the CT and MRI images, 3) does not affect the SNR of MR images, and 4) its mechanical error is less than 5mm.

Computer-Assisted Bronchoscopy: Aims and Research Perspectives

The introduction of spiral computed tomography (CT) of the thoracic cavity has allowed the development of new visualization tools. These tools provide a three-dimensional (3-D) endoluminal reconstruction of the tracheobronchial tree, as it would be viewed through a fibroscopic instrument. However, 3-D reconstruction techniques cannot replace conventional fibroscopy, which remains indispensable for obtaining histological samples. Furthermore, when CT-detected mediastinal or parenchymal lesions are not seen during fiberoptic bronchoscopy, guiding transbronchial needle biopsy is a major challenge. Computer-guided transbronchial biopsy involves the fusion of image data from both CT slices and bronchoscopic video sequences. This fusion is described in this paper in two parts. First, we present a segmentation process, using mathematical morphology operators, in order to analyze the video sequence and localize the bronchoscopic camera within the tracheobronchial tree. Second, we present tools used to match this localization knowledge with CT data. Finally, we produce images that create a bronchoscopic augmented reality, using elements extracted from the CT examination.

Helical CT with multiplanar and three-dimensional reconstruction of nonneoplastic abnormalities of the trachea

Helical CT is being increasingly used for the evaluation of suspected tracheal diseases. Although nonneoplastic and noninfectious diseases of the trachea are rare, their appearance on CT images may be highly suggestive of the diagnosis. High quality multiplanar and 3D reconstructions including 3D surface-shaded display and virtual bronchoscopy are helpful to characterize tracheal abnormalities and to demonstrate the location and extent of the diseases.

EASL and AASLD recommendations for the diagnosis of HCC to the test of daily practice

To evaluate the diagnostic performance of CT, MRI and CEUS alone and in combination, for the diagnosis of HCC between 10 and 30 mm, in a large population of cirrhotic patients.

Multi-Level Strategy for Computer-Assisted Transbronchial Biopsy

The Computer-Assisted Transbronchial Biopsy project involves the registration, without any external localization device, of a pre-operative 3D CT scan of the thoracic cavity (showing a tumor that requires a needle biopsy), and an intra-operative endoscopic 2D image sequence, in order to provide an assistance to a transbronchial puncture of the tumor. Because of the specific difficulties resulting from the processed data, original image processing methods were elaborated and a multi-level strategy is introduced. For each analysis level, the relevant information to process and the corresponding algorithms are defined. This multi-level strategy then achieves the best possible accuracy.

Paradoxical emboli: demonstration using helical computed tomography of the pulmonary artery associated with abdominal computed tomography

Abstract. We report the case of a 60-year-old woman with a recent history of a cerebrovascular accident. Because of clinical suspicion of pulmonary embolism and negative Doppler ultrasound findings of the lower limbs, spiral computed tomography of the pulmonary artery was performed and demonstrated pulmonary emboli. We emphasize the role of computed tomography of the abdomen, performed 3 min after the thoracic acquisition, which showed an unsuspected thrombus within the abdominal aorta and the left renal artery with infarction of the left kidney. Paradoxical embolism was highly suspected on computed tomography data and confirmed by echocardiography which demonstrated a patent foramen ovale.

Design and Validation of a CT- and MRI-Guided Robot for Percutaneous Needle Procedures

This paper describes the design and evaluation of the second generation of a robotic system called the light puncture robot for thoracic and abdominopelvic interventional radiology procedures under CT and MRI guidance. It is mounted on the patients body and positions and inserts the needle according to the trajectory and target chosen by the radiologist in the image. The mechanical design is described in detail along with its forward and inverse kinematics. The robot can be segmented and registered fully automatically in both imaging modalities. Phantom experiments in the CT scanner and preliminary feasibility experiments in the MRI are described, showing a targeting accuracy of 3.3 ± 1.7 mm in gelatin for depths ranging from 30 to 90 mm and needle orientations of -13° to +15° about normal from the patients skin. A detailed error analysis is discussed along with potential improvements in the system. The potential clinical advantages of the system include higher targeting accuracy for complex dual obliquity trajectories, the need for fewer images, and improved accessibility to MRI-guided interventions.