Image-Guided Transbronchial Pulmonary Cryoablation with a Flexible Cryoprobe in Swine: Performance and Radiology-Pathology Correlation.

PURPOSE: To evaluate the performance of a prototype flexible transbronchial cryoprobe compared with that of percutaneous transthoracic cryoablation and to define cone-beam computed tomography (CT) imaging and pathology cryolesion features in an in vivo swine model. MATERIALS AND METHODS: Transbronchial cryoablation was performed with a prototype flexible cryoprobe (3 central and 3 peripheral lung ablations in 3 swine) and compared with transthoracic cryoablation performed with a commercially available rigid cryoprobe (2 peripheral lung ablations in 1 swine). Procedural time and cryoablation success rates for endobronchial navigation and cryoneedle deployment were measured. Intraoperative cone-beam CT imaging features of cryolesions were characterized and correlated with gross pathology and hematoxylin and eosin-stained sections of the explanted cryolesions. RESULTS: The flexible cryoprobe was successfully navigated and delivered to each target through a steerable guiding sheath (6/6). At 4 minutes after ablation, 5 of 6 transbronchial and 2 of 2 transthoracic cryolesions were visible on cone-beam CT. The volumes on cone-beam CT images were 55.5 cm3 (SE ± 8.0) for central transbronchial ablations (n = 2), 72.5 cm3 (SE ± 8.1) for peripheral transbronchial ablations (n = 3), and 79.5 cm3 (SE ±11.6) for peripheral transthoracic ablations (n = 2). Pneumothorax developed in 1 animal after transbronchial ablation and during ablation in the transthoracic cryoablation. Images of cryoablation zones on cone-beam CT correlated well with the matched gross pathology and histopathology sections of the cryolesions. CONCLUSIONS: Transbronchial cryoablation with a flexible cryoprobe, delivered through a steerable guiding sheath, is feasible. Transbronchial cryoablation zones are imageable with cone-beam CT, with gross pathology and histopathology similar to those of transthoracic cryoablation.

The Role of Physician-Driven Device Preference in the Cost Variation of Common Interventional Radiology Procedures.

PURPOSE: To analyze the impact of physician-specific equipment preference on cost variation for procedures typically performed by interventional radiologists at a tertiary care academic hospital. MATERIALS AND METHODS: From October 2017 to October 2019, data on all expendable items used by 9 interventional radiologists for 11 common interventional radiology procedure categories were compiled from the hospital analytics system. This search yielded a final dataset of 44,654 items used in 2,121 procedures of 11 different categories. The mean cost per case for each physician as well as the mean, standard deviation, and coefficient of variation (CV) of the mean cost per case across physicians were calculated. The proportion of spending by item type was compared across physicians for 2 high-variation, high-volume procedures. The relationship between the mean cost per case and case volume was examined using linear regression. RESULTS: There was a high variability within each procedure, with the highest and the lowest CV for radioembolization administration (56.6%) and transjugular liver biopsy (4.9%), respectively. Variation in transarterial chemoembolization cost was mainly driven by microcatheters/microwires, while for nephrostomy, the main drivers were catheters/wires and access sets. Mean spending by physician was not significantly correlated with case volume (P =.584). CONCLUSIONS: Physicians vary in their item selection even for standard procedures. While the financial impact of these differences vary across procedures, these findings suggest that standardization may offer an opportunity for cost savings.

CT Fluoroscopy for Image-Guided Procedures: Physician Radiation Dose During Full-Rotation and Partial-Angle CT Scanning.

PURPOSE: To determine physician radiation exposure when using partial-angle computed tomography (CT) fluoroscopy (PACT) vs conventional full-rotation CT and whether there is an optimal tube/detector position at which physician dose is minimized. MATERIALS AND METHODS: Physician radiation dose (entrance air kerma) was measured for full-rotation CT (360°) and PACT (240°) at all tube/detector positions using a human-mimicking phantom placed in a 64-channel multidetector CT. Parameters included 120 kV, 20- and 40-mm collimation, and 100 mA. The mean, standard deviation, and increase/decrease in physician dose compared with a full-rotation scan were reported. RESULTS: Physician radiation exposure during CT fluoroscopy with PACT was highly dependent on the position of the tube/detector during scanning. The lowest PACT physician dose was when the physician was on the detector side (center view angle 116°; -35% decreased dose vs full-angle CT). The highest PACT physician dose was with the physician on the tube side (center view angle 298°; +34% increased dose vs full-angle CT), all doses P <.05 vs full-rotation CT. CONCLUSIONS: Partial-angle CT has the potential to both significantly increase or decrease physician radiation dose during CT fluoroscopy-guided procedures. The detector/tube position has a profound effect on physician dose. The lowest dose during PACT was achieved when the physician was located on the detector side (ie, distant from the tube). This data could be used to optimize CT fluoroscopy parameters to reduce physician radiation exposure for PACT-capable scanners.

Improving IR Ergonomics Using a Flexible C-Arm System.

PURPOSE: To evaluate the impact of a versatile flexible ceiling-mounted C-arm on active table and gantry repositioning during interventions and its effect on operator discomfort, system usability, and patient safety compared with a traditional ceiling-mounted system. MATERIALS AND METHODS: There were 100 IR procedures studied: 50 in a traditional IR system (standard group) and 50 with a novel multiaxis ceiling-mounted system (test group). FlexArm was capable of multiple gantry rotation points allowing increased access to the patient in addition to 236 cm of lateral x-ray detector travel. For each procedure, both the table and the gantry repositioning were measured. Patient safety, patient/equipment repositioning effort, and physical discomfort were evaluated through an operator survey. RESULTS: Table repositioning was reduced from 42 to 16 instances per procedure (P < .001) in the test group compared with the standard group. The operators perceived less table and gantry repositioning effort (P < .0001) and decreased risks of equipment collisions, displacement of vascular access, and dislodgment of tubes/lines with the test group (P < .0001). Operator discomfort was reduced for all body areas in the test group over the standard group (P < .0001). CONCLUSIONS: The FlexArm system geometry enhances operator ergonomics, as there was a decrease need to move the table, leading to a perceived decrease in patient risk and decrease operator physical discomfort when compared to a traditional imaging system.

Fusion Imaging with a Mobile C-Arm for Peripheral Arterial Disease.

BACKGROUND: Fusion imaging makes it possible to improve endovascular procedures and is mainly used in hybrid rooms for aortic procedures. The objective of this study was to evaluate the feasibility of fusion imaging for femoropopliteal endovascular procedures with a mobile flat plane sensor and dedicated software to assist endovascular navigation. MATERIALS AND METHODS: Between May and December 2017, 41 patients requiring femoropopliteal endovascular revascularization were included. Interventions were carried out in a conventional surgical room equipped with a mobile plane sensor (Cios Alpha, Siemens). The numerical video stream was transmitted to an angionavigation station (EndoNaut (EN), Therenva). The software created an osseous and arterial panorama of the treated limb from the angiographies carried out at the beginning of procedure. After each displacement of the table, the software relocated the current image on the osseous panorama, with 2D-2D resetting, and amalgamated the mask of the arterial panorama. The success rates of creation of osseous and arterial panorama and the success of relocation were evaluated. The data concerning irradiation, the volume of contrast (VC) injected, and operative times were recorded. RESULTS: Osseous panoramas could be automatically generated for the 41 procedures, without manual adjustment in 33 cases (80.5%). About 35 relocations based on a 2D-2D resetting could be obtained in the 41 procedures, with a success rate of 85%. The causes of failure were a change in table height or arch angulation. The average duration of intervention was 74.5 min. The irradiation parameters were duration of fluoroscopy 17.8 ± 13.1 min, air kerma 80.5 ± 68.4 mGy, and dose area product 2140 ± 1599 µGy m2. The average VC was 24.5 ± 14 mL. CONCLUSIONS: This preliminary study showed that fusion imaging is possible in a nonhybrid room for peripheral procedures. Imagery of mobile C-arms can be improved for femoropopliteal endovascular procedures without heavy equipment. These imagery tools bring an operative comfort and could probably reduce irradiation and the injected VC. The clinical benefit must be evaluated in more patients in a randomized comparative study with a rigorous methodology.

Surgically placed radiopaque markers: Proof-of-concept of a novel technique to facilitate percutaneous interventions in neonates and infants.

OBJECTIVES: Aim of this study was to evaluate feasibility and benefit of self-designed, radiopaque markers as a novel technique in neonates and infants with shunt- or duct-dependent lesions. BACKGROUND: Surgically placed radiopaque markers have the potential to facilitate postoperative percutaneous interventions. METHODS: All consecutive children with surgically placed radiopaque markers involving systemic-to-pulmonary artery connections or arterial ducts in the context of hybrid palliation and subsequent cardiac catheterization between January 2013 and March 2019 were included in this analysis. Our primary endpoint was our concept's feasibility, which we defined as a combination of surgical feasibility and the percutaneous intervention's success. Secondary endpoint was the rate of complications resulting from the surgical procedure or during catheterization. RESULTS: Radiopaque markers that reveal the proximal entry of a surgical shunt or the arterial duct proved to be a feasible and beneficial approach in 25 postoperative catheterizations. The markers' high accuracy enabled easy probing and proper stent positioning in 13 neonates with a median age and weight of 121 days (range 9-356) and 4.7 kg (1.6-9.4) at the intervention. No procedural complications or unanticipated events associated with the radiopaque marker occurred. The markers were never lost, never migrated, and caused no local obstructive lesion. Surgical removal was straightforward in all patients. CONCLUSIONS: Radiopaque markers are a promising and refined technique to substantially facilitate target vessel access and enabling the accurate positioning of stents during postoperative percutaneous procedures.

Endobronchial Navigation Guided by Cone-Beam CT-Based Augmented Fluoroscopy without a Bronchoscope: Feasibility Study in Phantom and Swine.

PURPOSE: To evaluate the accuracy of cone-beam computed tomography (CT)-based augmented fluoroscopy (AF) image guidance for endobronchial navigation to peripheral lung targets. METHODS: Prototypic endobronchial navigation AF software that superimposed segmented airways, targets, and pathways based on cone-beam CT onto fluoroscopy images was evaluated ex vivo in fixed swine lungs and in vivo in healthy swine (n = 4) without a bronchoscope. Ex vivo and in vivo (n = 3) phase 1 experiments used guide catheters and AF software version 1, whereas in vivo phase 2 (n = 1) experiments also used an endovascular steerable guiding sheath, upgraded AF software version 2, and lung-specific low-radiation-dose protocols. First-pass navigation success was defined as catheter delivery into a targeted airway segment solely using AF, with second-pass success defined as reaching the targeted segment by using updated AF image guidance based on confirmatory cone-beam CT. Secondary outcomes were navigation error, navigation time, radiation exposure, and preliminary safety. RESULTS: First-pass success was 100% (10/10) ex vivo and 19/24 (79%) and 11/15 (73%) for in vivo phases 1 and 2, respectively. Phase 2 second-pass success was 4/4 (100%). Navigation errors were 2.2 ± 1.2 mm ex vivo and 4.9 ± 3.2 mm and 4.0 ± 2.6 mm for in vivo phases 1 and 2, respectively. No major device-related complications were observed in the in vivo experiments. CONCLUSIONS: Endobronchial navigation is feasible and accurate with cone-beam CT-based AF image guidance. AF can guide endobronchial navigation with endovascular catheters and steerable guiding sheaths to peripheral lung targets, potentially overcoming limitations associated with bronchoscopy.

Feasibility of Augmented Reality-Guided Transjugular Intrahepatic Portosystemic Shunt.

PURPOSE: To investigate an augmented reality (AR)-guided endovascular puncture to facilitate successful transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: An AR navigation system for TIPS was designed. Three-dimensional (3D) liver models including portal and hepatic vein anatomy were extracted from preoperative CT images. The 3D models, intraoperative subjects, and electromagnetic tracking information of the puncture needles were integrated through the system calibration. In the AR head-mounted display, the 3D models were overlaid on the subjects, which was a liver phantom in the first phase and live beagle dogs in the second phase. One life-size liver phantom and 9 beagle dogs were used in the experiments. Imaging after puncture was performed to validate whether the needle tip accessed the target hepatic vein successfully. RESULTS: Endovascular punctures of the portal vein of the liver phantom were repeated 30 times under the guidance of the AR system, and the puncture needle successfully accessed the target vein during each attempt. In the experiments of live canine subjects, the punctures were successful in 2 attempts in 7 beagle dogs and in 1 attempt in the remaining 2 dogs. The puncture time of needle from hepatic vein to portal vein was 5-10 s in the phantom experiments and 10-30 s in the canine experiments. CONCLUSIONS: The feasibility of AR-based navigation facilitating accurate and successful portal vein access in preclinical models of TIPS was validated.

Potential impacts of a novel integrated extracorporeal-CPR workflow using an interventional radiology and immediate whole-body computed tomography system in the emergency department.

Extracorporeal cardiopulmonary resuscitation (ECPR) can be associated with increased survival and neurologic benefits in selected patients with out-of-hospital cardiac arrest (OHCA). However, there remains insufficient evidence to recommend the routine use of ECPR for patients with OHCA. A novel integrated trauma workflow concept that utilizes a sliding computed tomography (CT) scanner and interventional radiology (IR) system, named a hybrid emergency room system (HERS), allowing emergency therapeutic interventions and CT examination without relocating trauma patients, has recently evolved in Japan. HERS can drastically shorten the ECPR implementation time and more quickly facilitate definitive interventions than the conventional advanced cardiovascular life support workflow. Herein, we discuss our novel workflow concept using HERS on ECPR for patients with OHCA.

Comparing Mobile C-Arm with a Hybrid Operating Room for Imaging in Fenestrated Stent-Graft Endovascular Abdominal Aortic Aneurysm Repair.

BACKGROUND: To evaluate the advantages of a hybrid operating room (OR) (group 2) compared with a fluoroscopic mobile C-arm (group 1) during fenestrated stent-graft endovascular aneurysm repair (f-EVAR). METHODS: This single-center study retrospectively analyzed prospectively collected data of consecutive patients treated with f-EVAR for short-necked, juxtarenal, and suprarenal aortic aneurysms between January 2006 and July 2016. Primary end points were technical success and perioperative complications. Secondary end points included 30-day and 1-year mortality as well as target vessel patency. RESULTS: About 96 patients were treated (85 men; 74.1 ± 6.3 years); 46 patients (48%) belonging to group 1 and 50 (52%) patients belonging to group 2. Technical success was achieved in 92.7% of the procedures (group 1 91.3% vs. group 2 94%, P = 0.72). Significantly more complex interventions were performed in group 2 (n = 38 of 50) compared with group 1 (n = 14 of 46; P < 0.001), in which primarily renal f-EVAR interventions were performed. In group 2, significantly less contrast was used (median 150 mL vs. 100 mL; P < 0.001). The 30-day mortality in group 1 was 9% and 2% in group 2 (P = 0.14), and 1-year survival was also not significantly different between both groups. Target visceral vessel primary patency was significantly higher in group 1 (87.6% vs. 85.5% [P = 0.006] and 83.8% vs. 78.3% [P = 0.03]) at 6 and 12 months, respectively). There was no significant difference in renal artery primary patency at 6 and 12 months. CONCLUSIONS: Immediate and 1-year outcomes after f-EVAR for abdominal aortic aneurysm were comparable using a hybrid OR compared with a mobile C-arm, despite the use of significantly more complex stent grafts in the patients treated in the hybrid OR. The use of a hybrid OR may assist in achieving satisfying results in complex f-EVAR.

Use of Multimodal Interventional Radiology with an Intracerebral Artery Stent Retriever for Acute Superior Mesenteric Artery Thrombosis: A Case Report.

Acute superior mesenteric artery thrombosis is usually fatal; however, early intravascular treatment using a mechanical thrombectomy device can be an effective intervention. A 70-year-old man with atrial fibrillation presented with sudden abdominal pain; superior mesenteric artery thrombosis was confirmed using contrast-enhanced computed tomography. Thrombolysis, mechanical fragmentation, aspiration, and thrombectomy were successfully performed using the Trevo® XP ProVue stent retriever via a brachial approach, and intestinal necrosis was avoided. Thus, intravascular treatment of superior mesenteric artery thrombosis can be performed using a relatively low-profile catheter and a brachial artery approach, allowing the implementation of a multimodal interventional radiological approach tailored for individual cases.

Endovascular Infrarenal Aortic Aneurysm Repair Performed in a Hybrid Operating Room Versus Conventional Operating Room Using a C-Arm.

BACKGROUND: To compare contrast usage and radiation exposure during endovascular aneurysm repair (EVAR) using mobile C-arm imaging in a conventional operating room (OR) or fixed angiographic equipment in a hybrid OR (HR). METHODS: A retrospective unicenter study from May 2016 to August 2019. All consecutive patients undergoing standard EVAR were included. Patients were divided into 2 groups. Group OR included EVARs performed in a conventional OR with a mobile C-arm (May 2016 to April 2018) and group HR included EVARs performed with a fixed angiographic equipment in an HR (May 2018 to August 2019). Data collected included patient demographics, aneurysm diameter, neck length, radiation dose: median dose-area product (DAP), fluoroscopy time, total operative time, contrast use, and 30-day clinical outcomes. RESULTS: A total of 77 patients were included in the study (42 patients in group OR and 35 patients in group HR). There was no difference in age, body mass index (BMI), mean aneurysm, and neck length between groups. Patients in the group HR received less contrast volume (108.6 mL [±41.5] vs. 162.5 mL [±52.6]; P < 0.001), but higher radiation dose (154 Gy cm2 [±102.9] vs. 61.5 Gy cm2 [±42.4]; P < 0.001). There were no differences in fluoroscopy time (20.4 min [±8.5] vs. 23.2 min [±12.4]; P = 0.274) and total operative time (106.4 [±22.3] vs. 109.4 [±25.8]; P = 0.798). No difference was found in terms of 30-day complication rates or operative mortality between groups. DAP was positively correlated with BMI in the group OR (Spearman's rank correlation coefficient rs, 0.580; P < 0.001), but no correlation could be seen in the group HR (rs, 0.408; P = 0.028). CONCLUSIONS: Routine EVAR performed in a hybrid fixed-imaging suite may be associated with less contrast usage, but higher radiation exposure in our center. The significantly higher radiation exposure when the mobile C-arm is replaced by an HR should not be underestimated.

A Dual-layer Detector for Simultaneous Fluoroscopic and Nuclear Imaging.

Purpose To develop and evaluate a dual-layer detector capable of acquiring intrinsically registered real-time fluoroscopic and nuclear images in the interventional radiology suite. Materials and Methods The dual-layer detector consists of an x-ray flat panel detector placed in front of a γ camera with cone beam collimator focused at the x-ray focal spot. This design relies on the x-ray detector absorbing the majority of the x-rays while it is more transparent to the higher energy γ photons. A prototype was built and dynamic phantom images were acquired. In addition, spatial resolution and system sensitivity (evaluated as counts detected within the energy window per second per megabecquerel) were measured with the prototype. Monte Carlo simulations for an improved system with varying flat panel compositions were performed to assess potential spatial resolution and system sensitivity. Results Experiments with the dual-layer detector prototype showed that spatial resolution of the nuclear images was unaffected by the addition of the flat panel (full width at half maximum, 13.6 mm at 15 cm from the collimator surface). However, addition of the flat panel lowered system sensitivity by 45%-60% because of the nonoptimized transmission of the flat panel. Simulations showed that an attenuation of 27%-35% of the γ rays in the flat panel could be achieved by decreasing the crystal thickness and housing attenuation of the flat panel. Conclusion A dual-layer detector was capable of acquiring real-time intrinsically registered hybrid images, which could aid interventional procedures involving radionuclides. Published under a CC BY-NC-ND 4.0 license. Online supplemental material is available for this article.

Accuracy of a CT-Ultrasound Fusion Imaging Guidance System Used for Hepatic Percutaneous Procedures.

PURPOSE: To evaluate the accuracy of a fusion imaging guidance system using ultrasound (US) and computerized tomography (CT) as a real-time imaging modality for the positioning of a 22-gauge needle in the liver. MATERIALS AND METHODS: The spatial coordinates of 23 spinal needles placed at the border of hepatic tumors before radiofrequency thermal ablation were determined in 23 patients. Needles were inserted up to the border of the tumor with the use of CT-US fusion imaging. A control CT scan was carried out to compare real (x, y, z) and virtual (x', y', z') coordinates of the tip of the needle (D for distal) and of a point on the needle located 3 cm proximally to the tip (P for proximal). RESULTS: The mean Euclidian distances were 8.5 ± 4.7 mm and 10.5 ± 5.3 mm for D and P, respectively. The absolute value of mean differences of the 3 coordinates (|x' - x|, |y' - y|, and |z' - z|) were 4.06 ± 0.9, 4.21 ± 0.84, and 4.89 ± 0.89 mm for D and 3.96 ± 0.60, 4.41 ± 0.86, and 7.66 ± 1.27 mm for P. X = |x' - x| and Y = |y' - y| coordinates were <7 mm with a probability close to 1. Z = |z' - z| coordinate was not considered to be larger nor smaller than 7 mm (probability >7 mm close to 50%). CONCLUSIONS: Positioning errors with the use of US-CT fusion imaging used in this study are not negligible for the insertion of a 22-gauge needle in the liver. Physicians must be aware of such possible errors to adapt the treatment when used for thermal ablation.

Computer-Assisted Instrument Navigation Versus Conventional C-Arm Fluoroscopy for Surgical Instrumentation: Accuracy, Radiation Time, and Radiation Exposure.

OBJECTIVE. Compared with open procedures, minimally invasive surgical procedures are associated with increased radiation exposure and long-term health risks. Ultralow radiation imaging coupled with image enhancement and instrument tracking (ULRI-IE/IT) is a new image modifier that allows a computer to show real-time movement of an instrument as it is adjusted, mimicking live fluoroscopy but without continuous radiation production. The purpose of this study was to determine the accuracy and radiation output of ULRI-IE/IT compared with unassisted conventional fluoroscopy in a variety of surgical procedures. MATERIALS AND METHODS. Physicians of various specialties were asked to identify the ideal location for instrumentation in various spinal, orthopedic, pain, and physiatric procedures and then place an instrument in this location in a cadaver both with and without ULRI-IE/IT assistance. Whether ULRI-IE/IT was used was randomly assigned to reduce the impact of learning. Radiation exposure, time to place the instrument, and the number of images required to achieve accurate positioning were recorded for each procedure. These were compared for unassisted and ULRI-IE/IT-assisted fluoroscopy to determine the utility of ULRI-IE/IT in minimally invasive instrumentation. RESULTS. Twenty-three trials of nine procedures by five physicians were completed both with and without assistance of ULRI-IE/IT. The procedures ranged from percutaneous pedicle screw insertion to foramen ovale ablation. Total time to localize the instrument for all 23 cases was 31.2% longer without assistance. Use of ULRI-IE/IT reduced the total number of images per case by 74.8% and radiation exposure by 91.8%. With ULRI-IE/IT, physicians were able to successfully place the instrument in the correct location on the first attempt in 82.6% of trials and in the second attempt in all trials versus a mean of 4.65 images needed for unassisted fluoroscopy. CONCLUSION. Use of ULRI-IE/IT can dramatically reduce radiation output and the number of images acquired and time required to perform fluoroscopic procedures.

Evaluation of a novel, patient-mounted system for CT-guided needle navigation-an ex vivo study.

PURPOSE: To describe the features of a novel patient-mounted system for CT-guided needle navigation, the Puncture Cube System (PCS), and to evaluate the accuracy and efficiency of the PCS by (a) applying numerical simulations and (b) by conducting punctures using the system in comparison to punctures using the free-hand method (FHM). METHODS: The PCS consists of a self-adhesive cube that is attached to the patient, with multiple through-holes in the upper and lower template plate and dedicated software that, using a computer vision algorithm, recognizes the cube in a planning scan. The target in the image dataset is connected by a line, here "virtual needle," which passes through the cube. For any chosen path of the virtual needle, the entry points for the needle into the cube are displayed by the software for the upper and lower template on-the-fly. The possible exactness of the system was investigated by using numerical simulations. Next, 72 punctures were performed by 6 interventionists using a phantom to compare for accuracy, time requirement, and number of CT scans for punctures with the system to the FHM ex vivo (phantom study). RESULTS: The theoretical precision to arrive at targets increased with the distance of the target but remained low. The mean error for targets up to 20 cm below the lower plate was computed to be well below 0.5 mm, and the worst-case error stayed below 1.3 mm. Compared to a conventional free-hand procedure, the use of the navigation system resulted in a statistically significantly improved accuracy (3.4 mm ± 2.3 mm versus FHM 4.9 mm ± 3.2 mm) and overall lower intervention time (168 s ± 28.5 s versus FHM 200 s ± 44.8 s). Furthermore, the number of CT scans was reduced to 2.3 versus FHM 2.8). CONCLUSION: The PCS is a promising technique to improve accuracy and reduce intervention time in CT-guided needle navigations compared to the FHM.

Fusion Imaging for EVAR with Mobile C-arm.

BACKGROUND: Fusion imaging is a technique that facilitates endovascular navigation but is only available in hybrid rooms. The goal of this study was to evaluate the feasibility of fusion imaging with a mobile C-arm in a conventional operating room through the use of an angionavigation station. METHODS: From May 2016 to June 2017, the study included all patients who underwent an aortic stent graft procedure in a conventional operating room with a mobile flat-panel detector (Cios Alpha, Siemens) connected to an angionavigation station (EndoNaut, Therenva). The intention was to perform preoperative 3D computerized tomography/perioperative 2D fluoroscopy fusion imaging using an automatic registration process. Registration was considered successful when the software was able to correctly overlay preoperative 3D vascular structures onto the fluoroscopy image. For EVAR, contrast dose, operation time, and fluoroscopy time (FT) were compared with those of a control group drawn from the department's database who underwent a procedure with a C-arm image intensifier. RESULTS: The study included 54 patients, and the procedures performed were 49 EVAR, 2 TEVAR, 2 IBD, and 1 FEVAR. Of the 178 registrations that were initialized, it was possible to use the fusion imaging in 170 cases, that is, a 95.5% success rate. In the EVAR comparison, there were no difference with the control group (n = 103) for FT (21.9 ± 12 vs. 19.5 ± 13 min; P = 0.27), but less contrast agent was used in the group undergoing a procedure with the angionavigation station (42.3 ± 22 mL vs. 81.2 ± 48 mL; P < 0.001), and operation time was shorter (114 ± 44 vs. 140.8 ± 38 min; P < 0.0001). CONCLUSIONS: Fusion imaging is feasible with a mobile C-arm in a conventional operating room and thus represents an alternative to hybrid rooms. Its clinical benefits should be evaluated in a randomized series, but our study already suggests that EVAR procedures might be facilitated with an angionavigation system.

SAVI SCOUT as a Novel Localization and Surgical Navigation System for More Accurate Localization and Resection of Pulmonary Nodules.

Background. Current techniques for localization and resection of lung nodules carry many intraoperative challenges for surgeons. This article proposes a new localization method for diagnosis and treatment of pulmonary nodules, which provides a navigational system for more accurate lung resection. Methods. We report the case of a 77-year-old female with a pulmonary nodule of the right lower lobe. A nonradioactive localization technology, known as SAVI SCOUT (Cianna Medical Inc, Aliso Viejo, CA), was placed by interventional radiology under computed tomography guidance preoperatively. Using the SCOUT Wire-Free Radar Localization System, the pulmonary nodule was robotically localized and resected. SCOUT removal was confirmed using the Trident Specimen Radiology System. The efficacy of this procedure was evaluated in terms of ease of use and procedure time by interventional radiology, surgical resection accuracy, diagnostic accuracy, simplicity, and ease to implement this technology in an existing hospital. Results. The SCOUT system allowed for the first reported case of successful SCOUT placement in lung tissue, targeted the pulmonary nodule intraoperatively, and facilitated accurate lung resection. Conclusions. The SCOUT system shows promising advancements in the ability to eliminate many challenges currently seen with lung nodule localization and resection.

Electromagnetic tracking of flexible robotic catheters enables "assisted navigation" and brings automation to endovascular navigation in an in vitro study.

OBJECTIVE: Combining three-dimensional (3D) catheter control with electromagnetic (EM) tracking-based navigation significantly reduced fluoroscopy time and improved robotic catheter movement quality in a previous in vitro pilot study. The aim of this study was to expound on previous results and to expand the value of EM tracking with a novel feature, assistednavigation, allowing automatic catheter orientation and semiautomatic vessel cannulation. METHODS: Eighteen users navigated a robotic catheter in an aortic aneurysm phantom using an EM guidewire and a modified 9F robotic catheter with EM sensors at the tip of both leader and sheath. All users cannulated two targets, the left renal artery and posterior gate, using four visualization modes: (1) Standard fluoroscopy (control). (2) 2D biplane fluoroscopy showing real-time virtual catheter localization and orientation from EM tracking. (3) 2D biplane fluoroscopy with novel EM assisted navigation allowing the user to define the target vessel. The robotic catheter orients itself automatically toward the target; the user then only needs to advance the guidewire following this predefined optimized path to catheterize the vessel. Then, while advancing the catheter over the wire, the assisted navigation automatically modifies catheter bending and rotation in order to ensure smooth progression, avoiding loss of wire access. (4) Virtual 3D representation of the phantom showing real-time virtual catheter localization and orientation. Standard fluoroscopy was always available; cannulation and fluoroscopy times were noted for every mode and target cannulation. Quality of catheter movement was assessed by measuring the number of submovements of the catheter using the 3D coordinates of the EM sensors. A t-test was used to compare the standard fluoroscopy mode against EM tracking modes. RESULTS: EM tracking significantly reduced the mean fluoroscopy time (P < .001) and the number of submovements (P < .02) for both cannulation tasks. For the posterior gate, mean cannulation time was also significantly reduced when using EM tracking (P < .001). The use of novel EM assisted navigation feature (mode 3) showed further reduced cannulation time for the posterior gate (P = .002) and improved quality of catheter movement for the left renal artery cannulation (P = .021). CONCLUSIONS: These results confirmed the findings of a prior study that highlighted the value of combining 3D robotic catheter control and 3D navigation to improve safety and efficiency of endovascular procedures. The novel EM assisted navigation feature augments the robotic master/slave concept with automated catheter orientation toward the target and shows promising results in reducing procedure time and improving catheter motion quality.