Filip Banovac

Navigation with Electromagnetic Tracking for Interventional Radiology Procedures: A Feasibility Study

PURPOSEnTo assess the feasibility of the use of preprocedural imaging for guide wire, catheter, and needle navigation with electromagnetic tracking in phantom and animal models.nnnMATERIALS AND METHODSnAn image-guided intervention software system was developed based on open-source software components. Catheters, needles, and guide wires were constructed with small position and orientation sensors in the tips. A tetrahedral-shaped weak electromagnetic field generator was placed in proximity to an abdominal vascular phantom or three pigs on the angiography table. Preprocedural computed tomographic (CT) images of the phantom or pig were loaded into custom-developed tracking, registration, navigation, and rendering software. Devices were manipulated within the phantom or pig with guidance from the previously acquired CT scan and simultaneous real-time angiography. Navigation within positron emission tomography (PET) and magnetic resonance (MR) volumetric datasets was also performed. External and endovascular fiducials were used for registration in the phantom, and registration error and tracking error were estimated.nnnRESULTSnThe CT scan position of the devices within phantoms and pigs was accurately determined during angiography and biopsy procedures, with manageable error for some applications. Preprocedural CT depicted the anatomy in the region of the devices with real-time position updating and minimal registration error and tracking error (<5 mm). PET can also be used with this system to guide percutaneous biopsies to the most metabolically active region of a tumor.nnnCONCLUSIONSnPreviously acquired CT, MR, or PET data can be accurately codisplayed during procedures with reconstructed imaging based on the position and orientation of catheters, guide wires, or needles. Multimodality interventions are feasible by allowing the real-time updated display of previously acquired functional or morphologic imaging during angiography, biopsy, and ablation.

Electromagnetic Tracking for Image-Guided Abdominal Procedures: Overall System and Technical Issues

This paper summarizes our work over the past several years in developing an image-guided system based on electromagnetic tracking for abdominal interventions. The paper begins with a review of computer-aided surgery and electromagnetic tracking. We next describe our image-guided system along with phantom and animal studies. We then present some technical issues in improving accuracy including pivot calibration, dynamic referencing, and registration using two 5 degree-of-freedom sensors. Electromagnetic tracking has great potential for assisting physicians in precision placement of instruments during minimally invasive interventions. However, the accuracy of these systems needs to be validated in the clinical environment and issues such as respiratory motion and organ deformation need to be addressed

Intratumoral CD3 and CD8 T-cell Densities Associated with Relapse-Free Survival in HCC

Tumor immune infiltration is a prognostic marker for relapse in patients with colorectal cancer. The Immunoscore methodology was extended to patients with hepatocellular carcinoma. The Immunoscore could predict the risk of postsurgical relapse and duration of relapse-free survival. Immune cells that infiltrate a tumor may be a prognostic factor for patients who have had surgically resected hepatocellular carcinoma (HCC). The density of intratumoral total (CD3+) and cytotoxic (CD8+) T lymphocytes was measured in the tumor interior and in the invasive margin of 65 stage I to IV HCC tissue specimens from a single cohort. Immune cell density in the interior and margin was converted to a binary score (0, low; 1, high), which was correlated with tumor recurrence and relapse-free survival (RFS). In addition, the expression of programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) was correlated with the density of CD3+ and CD8+ cells and clinical outcome. High densities of both CD3+ and CD8+ T cells in both the interior and margin, along with corresponding Immunoscores, were significantly associated with a low rate of recurrence (P = 0.007) and a prolonged RFS (P = 0.002). In multivariate logistic regression models adjusted for vascular invasion and cellular differentiation, both CD3+ and CD8+ cell densities predicted recurrence, with odds ratios of 5.8 [95% confidence interval (CI), 1.6–21.8] for CD3+ and 3.9 (95% CI, 1.1–14.1) for CD8+. Positive PD-L1 staining was correlated with high CD3 and CD8 density (P = 0.024 and 0.005, respectively) and predicted a lower rate of recurrence (P = 0.034), as well as prolonged RFS (P = 0.029). Immunoscore and PD-L1 expression, therefore, are useful prognostic markers in patients with HCC who have undergone primary tumor resection. Cancer Immunol Res; 4(5); 419–30. ©2016 AACR.

Effect of multimodality treatment on overall survival for patients with metastatic or recurrent HPV-positive head and neck squamous cell carcinoma.

The optimal treatment for patients with recurrent human papillomavirus (HPV)‐positive head and neck cancer is poorly understood.

Feasibility of percutaneous transabdominal portosystemic shunt creation

Abstract. Evaluation of the anatomic feasibility of the percutaneous transabdominal puncture of selected portal and hepatic veins in patients with cirrhosis was performed. This approach would become the framework for an image-guided robot-assisted needle drive mechanism for use in transjugular intrahepatic portosystemic shunt (TIPS) creation. Retrospective analysis of 10 CT and 14 MRI axial abdominal studies was carried out to determine whether single simultaneous transabdominal puncture of portal and hepatic veins was possible. A necessary modification of the TIPS procedure was tested in an ex vivo porcine model under fluoroscopy. Eighteen of 24 patients (75%) had intrahepatic vascular anatomy amenable to a single transabdominal puncture. Successful catheterization of portal and hepatic veins using a modified approach for TIPS was accomplished in two ex vivo porcine livers. A suitable anatomic approach for modified TIPS is present in a majority of patients with cirrhosis. Feasibility of the technique using this anatomic approach was confirmed in two ex vivo porcine models. This study serves as an initial step in a novel technical approach to TIPS using a new anatomic approach for this procedure. The French version of this article is available in the form of electronic supplementary material and can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00276-002-0040-7.Résumé. Nous avons évalué la faisabilité anatomique de la ponction percutanée trans-pariétale de veines porte et hépatiques dans des cas sélectionnées chez des patients cirrhotiques. Cette voie dabord pourrait devenir le cadre dune technique dinsertion daiguille assistée par robot et guidée par imagerie pour créer des shunts porto-systémiques intra-hépatiques trans-jugulaires (transjugular intrahepatic portosystemic shunt, TIPS). Lanalyse rétrospective de 10 scanners et de 14 IRM de labdomen en coupes axiales a été réalisée pour déterminer si une simple ponction trans-pariétale simultanée des veines porte et hépatiques était possible. Nous avons testé une modification nécessaire de la technique du TIPS sur un modèle porcin ex vivo sous radioscopie. 18 des 24 patients (75%) avaient une anatomie vasculaire intra-hépatique accessible à une ponction trans-pariétale unique. Un cathétérisme des veines porte et hépatiques utilisant une technique modifiée de TIPS a été réussi sur deux foies de porc ex vivo. Une voie dabord anatomique fiable pour création dun TIPS existe chez la majorité des patients cirrhotiques. La faisabilité de la technique utilisant cette voie dabord anatomique a été confirmée sur deux modèles porcins ex vivo. Cette étude sert détape initiale à une nouvelle voie dabord pour la création dun TIPS.

CT-directed robotic biopsy testbed: user interface and coordinate transformations

Abstract CT-guided percutaneous biopsy is a widely accepted practice in the medical field. Because efficient and safe CT-guided percutaneous interventions require accurate needle placement, there are limitations to the accuracy obtainable using free-hand techniques, particularly for small or deeply situated target areas. In addition, CT-directed percutaneous biopsy can be tedious and time consuming, since frequent re-imaging may be required. As a demonstration platform, we are developing a robotic biopsy testbed incorporating a mobile CT scanner, a small “needle driver” robot, and a localizer. This testbed will be used to compare robotically assisted biopsy to the current manual technique. The testbed will also allow us to investigate software architectures for integrating various hardware and software components. This testbed is the first step in developing the robotically assisted biopsy system of the future. In this paper, we present the overall concept and then provide details about the user interface and coordinate transformations.

Feasibility of image-guided abdominal interventions using a novel magnetic position sensing device in an interventional radiology suite

This was an initial study to evaluate the accuracy of a new magnetic localizing system (AURORA™) in the interventional radiology environment. This work is part of our research effort to incorporate magnetic tracking in an image-guided system for minimally invasive abdominal interventions.

Integrated PET/CT Guidance System for Oncologic Interventional Radiology

Interventional radiology procedures such as radiofrequency ablation are a vital component of minimally invasive cancer treatment, and use of these techniques is on the rise. At the same time, PET imaging has revolutionized the care of cancer patients with its ability to rapidly and accurately screen for the presence of neoplastic disease. Our goal is to bring the full power of PET imaging into the arena of interventional radiology, by developing an integrated image guidance system using co-registered PET and CT to enable new and improved cancer therapies. Within the current system, we have several modular components built around an open source software framework. The first component is a respiratory compensation system for matching the PET image (acquired under free breathing) to the CT image (acquired at end-inspiration). The second component is a system for performing registration between CT and fluoroscopy to enable the PET information to be brought into the interventional workspace. As an alternative to fluoroscopy guidance, we have also developed a third component for using electromagnetic tracking, which can determine the position of tools in the treatment field without ionizing radiation. Finally, we have respiratory phantoms to simulate a wide variety of breathing motion and provide a robust testing platform for our system. We are currently testing the system using these phantoms in preparation for future animal and clinical trials.