Live Fluoroscopic Images Research Articles

E0563 Implantation of left ventricular epicardial lead guided by overlay ref for cardiac resynchronisation therapy

ObjectiveThis study was to report our initial experiences with cardiac resynchronisation therapy (CRT) guided by Overlay Ref for the treatment of heart failure.MethodsEleven patients with heart failure were enrolled in...

3D Road-Mapping in the Endovascular Treatment of Cerebral Aneurysms and Arteriovenous Malformations

3D road-mapping with syngo iPilot was used as an additional tool for assessing cerebral aneurysms and arteriovenous malformations (AVMs) for endovascular therapy. This method provides accurate superimposition of a live fluoroscopic image (native or vascular road-map) and its matching 2D projection of the 3D data set, delivering more anatomic information on one additional display. In the endovascular management of cases with complex anatomy, 3D road-mapping provides excellent image quality at the intervention site. This method can potentially reduce intervention time, the number of DSA runs, fluoroscopy time and the amount of contrast media used in a procedure, with reservation for these factors being mainly operator-dependent. 3D road-mapping probably does not provide any advantage in the treatment of cerebral aneurysms or AVMs with very simple configuration, and it should not be used when acquisition of an optimum 3D data set is not feasible.

WE‐E‐210A‐02: Emerging X‐Ray Fluoroscopic Guidance Technologies for Challenging Cardiovascular Interventions

X‐ray fluoroscopy remains the primary guidance modality for cardiac interventions due to its appealing combination of real‐time imaging, high spatial resolution, simplicity of use, and compatibility with conventional catheter devices. However fluoroscopy has well‐recognized limitations. The lack of depth resolution and poor soft tissue contrast in an x‐ray projection make it difficult to precisely position devices with respect to target cardiac structures. Ionizing radiation dose is an ongoing concern, particularly for interventions with long imaging times such as catheter‐based electrical mapping and ablation of atrial fibrillation.Technologies which reduce dose and add three‐dimensional context to the live fluoroscopic image offer a route towards overcoming these limitations. Scanning‐beam digital x‐ray (SBDX) is an inverse geometry fluoroscopic system that provides both dose reduction and real‐time tomosynthesis, a feature that can be exploited for image‐based 3D tracking of catheter electrodes. The operating principles of SBDX will be reviewed and recent investigations of 3D catheter tracking based on multiplanar tomosynthesis will be presented. Fusion of live fluoroscopy with roadmaps derived from pre‐acquired 3D image data (e.g. CT, MRI) can allow the interventionist to visualize structures lacking x‐ray contrast, or to perform novel therapies targeted to the physiologic status of cardiac tissue. A fluoroscopic fusion system for recanalization of chronically occluded arteries and for targeted stem cell therapy will be discussed.This lecture will provide an overview of the demands and constraints of fluoroscopically‐guided cardiovascular interventions, dose reduction and 3D catheter tracking capabilities enabled by the SBDX system, and clinical application of fluoroscopy fused with 3D roadmaps.This research was supported in part by NovaRay Medical, Inc. and NIH/NHLBI.Learning Objectives:1. Review the demands and constraints of fluoroscopically‐guided interventions2. Understand the principles of SBDX dose reduction and 3D catheter tracking3. Discuss x‐ray fluoroscopy combined with 3D imaging for cardiovascular interventions

A randomized comparison of the magnetic navigation system versus conventional percutaneous coronary intervention

A randomized comparison of the magnetic navigation system (MNS) to conventional guidewire techniques in percutaneous coronary interventions. The MNS precisely directs a magnetized guidewire in vivo through two permanent external magnets. A total of 111 consecutive patients were enrolled. Crossing success, crossing-/fluoroscopy times, and contrast usage were directly compared. Lesions were classified according to the AHA/ACC criteria. Three tertiles of vessel/lesion complexity [low (<5), medium (6-10) and high (>10)] were defined using 3D reconstructions and angiographic information. The crossing success for magnetic and the conventional wires were 93.3 and 95.6%, respectively. Crossing and fluoroscopy times were longer with the magnetic wires (72.9 +/- 50.3 sec vs. 58.1 +/- 47.2 sec, P < 0.001 and 66.2 +/- 44.1 sec vs. 55.2 +/- 44.4 sec, P = 0.03, respectively). In vessels with low and medium complexity the magnetic wires had significantly longer times (P < 0.001) but for those with high scores (>10) a trend towards shorter times was observed. The MNS resulted in a small but significant reduction in contrast usage (2.3 +/- 3.5 ml vs. 4.5 +/- 4.4 ml, P < 0.001). Moreover by superimposing a virtual roadmap of the vessel on the live fluoroscopy image 48% of the lesions were crossed without requiring contrast agents with the MNS. The MNS has comparable crossing success to conventional PCI. It is relatively slower but there is a trend to support a potential advantage in more complex vessels. By simultaneously employing a virtual roadmap there is a small but significant reduction in contrast usage.

REAL-TIME IMAGE GUIDANCE FOR OPEN VASCULAR NEUROSURGERY USING DIGITAL ANGIOGRAPHIC ROADMAPPING

Angiographic roadmapping, commonly used for catheter navigation in endovascular procedures, is the superimposition of a live fluoroscopic image on a previously stored digitally subtracted angiogram. We evaluated this technique for the first time as a method for image-guided navigation during surgical resection of intracranial and spinal vascular lesions. After obtaining Institutional Review Board approval, we retrospectively reviewed 38 procedures in 35 patients at two centers performed by one neurosurgeon in which intraoperative roadmapping was used as an image-guided navigation tool for surgical resection of cranial and spinal arteriovenous malformations or fistulae. This technique requires femoral or radial artery access and a portable vascular C-arm capable of digitally subtracted angiogram and roadmap angiography in the operating room suite. Once a roadmap identifying the vascular lesion is obtained, a sterile radiopaque instrument is placed over the skin/wound to precisely localize the lesion in multiple dimensions. Angiographic roadmapping was used for resection of seven spinal arteriovenous malformations or fistulae, 23 cranial arteriovenous malformations or fistulae, one aneurysm, two carotid-cavernous fistulae, and transtorcular embolization of five vein of Galen malformations. In all cases, the technique helped us to make precisely localized incisions, avoid unnecessary bone removal, and readily directed us to the vascular lesion. In several cases, it allowed localization of small fistulae not visible on magnetic resonance imaging or computed tomographic angiography scans. Finally, this approach facilitated immediate angiographic confirmation of complete resection at the end of each case. Angiographic roadmapping is an effective intraoperative navigation tool for resection of vascular lesions that has not been previously described and offers several advantages to frameless stereotaxy.

Magnetic Navigation in Percutaneous Coronary Intervention

Magnetic navigation is the use of adjustable magnetic fields to precisely direct wires and equipment for clinical applications. It is a recently developed option that is now available for interventional cardiology. Procedures are based on the production of a three-dimensional reconstruction of the vessel lumen from standard angiographic images. Knowledge of the positions of the table and image intensifier during angiography allows calculation of the vessel coordinates in real space within the patient's chest. The applied magnetic field can be changed at any time to redirect the wire tip in order to improve navigation through complex and tortuous anatomy. The digital information of the coronary reconstruction can be used in further novel ways. Firstly, the integration of multislice computerized tomography images adds information about the path of the previous lumen of chronic total occlusions. Secondly, the computed center-line of the reconstructed vessel can be superimposed onto the live fluoroscopy images as a three-dimensional guide. The combination of improved navigation together with the other available system features may improve time, contrast, and material usage in a range of coronary lesions. Future potential developments include improvements in equipment and software, and potential therapeutic strategies under consideration include the use of equipment to perform remote control procedures, and the integration of the system to improve bone marrow-derived stem cell delivery.

Integrated X-ray & Magnetic Resonance imaging (XMR) -a novel strategy for guiding pulmonary vein ablation

Background: We have developed a technique based on optical tracking to co-register magnetic resonance (MR) and X-ray images in the same patient. This allows the real-time overlay of registered MR derived cardiovascular anatomy onto live X-ray fluoroscopy images and the reconstruction of the position of catheters seen during fluoroscopy in this anatomy. Ten pulmonary vein (PV) isolation procedures were performed to examine the utility of this integrated X-ray-MR guidance approach.

Mutual information based respiration detection

Abstract Percutaneous Transluminal Coronary Angioplasty (PTCA) is currently the preferred method for the treatment of coronary artery disease in vivo. During the intervention, images of the coronary arteries filled with a radiopaque contrast agent are acquired (angiography) in order to localize the lesion. One of these images is then displayed on a monitor. It serves as a roadmap that is afterwards utilised to navigate the interventional instruments to the lesion under constant low-dose X-ray surveillance (fluoroscopy). The fluoroscopic live images are displayed in real-time on a second monitor next to the roadmap monitor. It is desirable to provide for each fluoroscopic image an angiographic roadmap that exhibits a similar position and shape of the coronary vessels. To accomplish this goal, the respiration status in every (pre-recorded) angiographic and (live) fluoroscopic image has to be quantified in order to display angiographic roadmaps matching to the live fluoroscopic image. We present a method that estimates the respiration status of a patient from grey-level X-ray fluoroscopic images based on their similarity to a reference frame applying a mutual information (MI) similarity measure.

Virtual fluoroscopy: computer-assisted fluoroscopic navigation.

In vitro accuracy assessment of a novel virtual fluoroscopy system. To investigate a new technology combining image-guided surgery with C-arm fluoroscopy. Fluoroscopy is a useful and familiar technology to all musculoskeletal surgeons. Its limitations include radiation exposure to the patient and operating team and the need to reposition the fluoroscope repeatedly to obtain surgical guidance in multiple planes. Fluoroscopic images of the lumbar spine of an intact, unembalmed cadaver were obtained, calibrated, and saved to an ). A was used for the sequential insertion of a light-emitting diode-fitted probe into the pedicles of L1-S1 bilaterally. The trajectory of a "virtual tool" corresponding to the tracked tool was overlaid onto the saved fluoroscopic views in real time. Live fluoroscopic images of the inserted pedicle probe were then obtained. Distances between the tips of the virtual and fluoroscopically displayed probes were quantified using the image-guided computer's measurement tool. Trajectory angle differences were measured using a standard goniometer and printed copies of the workstation computer display. The surgeon's radiation exposure was measured using thermolucent dosimeter rings. Excellent correlation between the virtual fluoroscopic images and live fluoroscopy was observed. Mean probe tip error was 0.97 +/- 0.40 mm. Mean trajectory angle difference between the virtual and fluoroscopically displayed probes was 2.7 degrees +/- 0.6 degrees. The thermolucent dosimeter rings measured no detectable radiation exposure for the surgeon. Virtual fluoroscopy offers several advantages over conventional fluoroscopy while providing acceptable targeting accuracy. It enables a single C-arm to provide real-time, multiplanar procedural guidance. It also dramatically reduces radiation exposure to the patient and surgical team by eliminating the need for repetitive fluoroscopic imaging for tool placement.

Digital coronary roadmapping as an aid for performing coronary angioplasty

In an attempt to improve visualization of the position of the guidewire and dilatation balloon during coronary angioplasty, a method was developed called digital coronary roadmapping. With this method a digitally acquired coronary angiogram is interlaced with the live fluoroscopic image of the guidewire and balloon catheter. The digital coronary angiogram is superimposed at the same magnification and radiologic projection as the live fluoroscopic image onto the video monitor above the catheterization table. The digital roadmap image thus provides immediate feedback to the angiographer to assist in directing the guidewire into the appropriate coronary artery branch and to help in placement of the balloon so that it straddles the site of stenosis.

Angiography assisted by a new videostore system.

A new videostore system which has been developed in conjunction with Thermal Controls Ltd. enables television images made during X-ray intensifier fluoroscopy to be stored and then superimposed in subtraction on live fluoroscopy images. For angiography the system is used in the following way. First, contrast is injected through the catheter and the resulting image stored (Fig. 1a). After this, live fluoroscopy provides a subtracted image of the vessel system. It is then easier to guide the catheter into the right vessel as a map of the vessel system is displayed on the screen during fluoroscopy (Fig. 1b). The use of subtraction assists arterial visualization when there are complex overlying structures (Fig. 2a, 2b).

Electronic radiography in stereotaxic thrombosis of intracranial aneurysms and catheter embolization of cerebral arteriovenous malformations.

An electronic radiographic technique which utilizes a television fluoroscopic system coupled with a disc recorder is described. Images from this system can be combined with live fluoroscopic images, allowing rapid and accurate catheterization of intracerebral arteries in embolization of cerebral artery arteriovenous malformations. This procedure can also be used in stereotaxic transcerebral thrombosis of intracranial aneurysms by injection with tissue adhesive. This system gives lower radiation dosage to patient and operator, decreases procedure time, and allows instantaneous retrieval of information.