3D Roadmap Research Articles

Rotational Angiography for 3D Roadmapping of Catheter Interventions in Congenital Heart Disease: Comparison of a Diagnostic and a Low Dose Program

Objectives: To compare the image quality, accuracy and effective dose of the default diagnostic pro-gram with the low dose program. Methods: The diagnostic and low dose programs of three-dimen-sional rotational angiography were compared considering their signal to noise ratio, their carrier to noise ratio and their actual radiation dose in μGy⋅m2/kg. An anthropomorphic phantom underwent both types of scans to evaluate the effective dose. Comparative measurements of vessel diameters were taken in the diagnostic and the low dose program and compared to the angiography as exact basis. The image quality of the scans using the different programs was rated by a specialist physician. Results: The low dose scan does use significantly less radiation and still provides images, which are adequate for 3D navigation of catheter-based interventions. Conclusion: Three-dimensional rotational angiography can be applied with the low dose program and is sufficient for 3D navigation.

Model-based geometric calibration for medical x-ray systems.

Currently applied calibration approaches lead to satisfying 3D roadmapping overlay and 3D reconstruction accuracies; however, the required calibration times are extensive. The aim of this paper is the introduction of a novel model-based approach for geometric system calibrations, leading to a significant reduction of calibration times. By using physical insight into the system, a physical model is derived which can be exploited to predict geometric calibrations parameters. Model-parameters are estimated using a limited set of phantom-based measurement data. Effectively, the calibration procedure is recast to a parameter identification experiment. The potential of the proposed approach is illustrated by virtue of a benchmark object, successful reconstruction of a clinical phantom, and comparison to phantom-based accuracies. Accurate models are required to achieve the desired accuracies. Based on the results in this work, the approach seems to be feasible for practical applications; however, to achieve all the desired specifications, future research should focus on enhanced modeling techniques.

A novel tool for three-dimensional roadmapping reduces radiation exposure and contrast agent dose in complex endovascular interventions

The volume and complexity of endovascular procedures are increasing. Multidetector computed tomography (CT) made precise three-dimensional (3D) planning of these procedures possible, but intraoperative imaging, even with the use of modern flat-panel detectors, is limited to two dimensions. Flat detectors, however, allow C-arm cone-beam CT. This technology can be used to generate a 3D data set that can be fused with a preoperative high-resolution CT scan, thus generating a live 3D roadmap. We hypothesized that use of a novel image fusion software, VesselNavigator (Philips Healthcare, Best, The Netherlands), facilitates precise and expeditious procedures and therefore reduces radiation exposure and contrast agent dose. A retrospective review of patients undergoing standard aortobi-iliac endovascular aneurysm repair at our institution between January 2011 and April 2014 was performed. Conventional imaging was compared with VesselNavigator-assisted imaging, and a matched analysis based on body mass index (BMI) was performed because of the dependence of radiation dose on body habitus. Outcome parameters were procedure time, fluoroscopy time, radiation, and contrast agent dose. A total of 75 patients were identified. After matching based on BMI, control and VesselNavigator groups each had 16 patients with BMI of 27.0 ± 3.6 kg/m(2) and 27.0 ± 3.6 kg/m(2), respectively (mean ± standard deviation). R(2) was 6.37 × 10(-7). Radiation dose measured as air kerma was lower with VesselNavigator (1067 ± 470.4 mGy vs 1768 ± 696.2 mGy; P = .004). Fluoroscopy time was shorter (18.4 ± 6.8 minutes vs 26.8 ± 10.0 minutes; P = .01) and contrast agent dose was lower (37.4 ± 21.3 mL vs 77.3 ± 23.0 mL; P < .001) with VesselNavigator compared with control. Procedure time was also shorter with VesselNavigator (80.4 ± 21.2 minutes vs 110.0 ± 29.1 minutes; P = .005). Image fusion using VesselNavigator enhances the functionality of conventional fluoroscopy in standard endovascular aneurysm repair. It reduces radiation exposure to patients and providers. It also limits the amount of contrast agent and shortens the overall procedure length. The benefit of this technology is demonstrated on this typically straightforward procedure but may be even more useful for complex procedures.

Urgent endovascular repair for ruptured aortic aneurysm using computed tomography image fusion

Abdominal aortic aneurysm rupture remains a cardiovascular catastrophe with strikingly high morbidity and mortality rates. Endovascular aneurysm repair management has recently emerged as a valuable treatment modality for ruptured abdominal aortic aneurysm, but better outcomes have to be reached. Image fusion may potentially improve perioperative outcomes in selected patients, guiding navigation and device implantation and limiting contrast dosage during interventions. We report an 83-year-old man presenting with an 80-mm infrarenal aortic aneurysm rupture suitable for endovascular aneurysm repair. Endovascular navigation and stent graft deployment were achieved using computed tomography image fusion for the first reported case in English.

A NEW IMAGING METHOD FOR PERCUTANEOUS CORONARY INTERVENTION OF CHRONIC TOTAL OCCLUSIONS: REAL TIME CARDIAC COMPUTED TOMOGRAPHY AND CORONARY ANGIOGRAPHY IMAGE REGISTRATION

Chronic total occlusions (CTO) guide software (prototype, SIEMENS) provides online navigational guidance in the CTO percutaneous coronary intervention (PCI) through the display of computed tomography angiography (CTA) image information as a 3D roadmap side-by-side with live angiography images. The

Respiratory motion model based correction for improving the targeting accuracy of MRI-guided intracardiac electrophysiology procedures

Background Recently, there is an increased interest in using MRI to guide electrophysiology (EP) procedures as an alternative to X-ray fluoroscopy guidance, due to its excellent soft tissue contrast and lack of radiation. However, there exist tradeoffs between different MRI guidance schemes. Realtime 2D MR sequences are able to capture heart motion during an interventional setting, while sacrificing imaging quality, whereas high-resolution prior 3D roadmaps are static and do not reflect the respiratory motion of the heart. In this work, we explore the feasibility of deriving a motion model from these two complementary datasets, and evaluate its potential for improving the targeting accuracy of MRI-guided EP procedures.

Update on New Tools for Three-dimensional Navigation in Endovascular Procedures.

Three-dimensional (3D) guidance for endovascular procedures has developed over the last decade from 3D rotational angiography to the use of dynamic 3D roadmap techniques. The latest development is image merging. This technique combines real-time feedback of fluoroscopy with optimal soft-tissue contrast of previously performed computed tomography (CT) or magnetic resonance angiography. Merging of CT angiography and cone-beam CT/fluoroscopic images is feasible, and preliminary results look promising. Merging will allow us to further reduce radiation exposure, contrast dose, and procedural time, and its main use and benefit will be in complex endovascular interventions.

3D ablation catheter localisation using individual C-arm x-ray projections

Cardiac ablation procedures during electrophysiology interventions are performed under x-ray guidance with a C-arm imaging system. Some procedures require catheter navigation in complex anatomies like the left atrium. Navigation aids like 3D road maps and external tracking systems may be used to facilitate catheter navigation.As an alternative to external tracking a fully automatic method is presented here that enables the calculation of the 3D location of the ablation catheter from individual 2D x-ray projections. The method registers a high resolution, deformable 3D attenuation model of the catheter to a 2D x-ray projection. The 3D localization is based on the divergent beam projection of the catheter. On an individual projection, the catheter tip is detected in 2D by image filtering and a template matching method. The deformable 3D catheter model is adapted using the projection geometry provided by the C-arm system and 2D similarity measures for an accurate 2D/3D registration. Prior to the tracking and registration procedure, the deformable 3D attenuation model is automatically extracted from a separate 3D cone beam CT reconstruction of the device. The method can hence be applied to various cardiac ablation catheters. In a simulation study of a virtual ablation procedure with realistic background, noise, scatter and motion blur an average 3D registration accuracy of 3.8 mm is reached for the catheter tip. In this study four different types of ablation catheters were used. Experiments using measured C-arm fluoroscopy projections of a catheter in a RSD phantom deliver an average 3D accuracy of 4.5 mm.

Multimodal angiographic assessment of cerebral arteriovenous malformations: a pilot study

PurposeWe describe our protocol of three-dimensional (3D) Roadmap intracranial navigation and image fusion for analysis of the angioarchitecture and endovascular treatment of brain arteriovenous malformations (AVMs).MethodsWe performed superselective catheterization of...

VesselNavigator: A Novel Tool for Advanced 3D Roadmapping for Complex Endovascular Interventions

VesselNavigator: A Novel Tool for Advanced 3D Roadmapping for Complex Endovascular Interventions

2D versus 3D roadmap for uterine artery catheterization: impact on several angiographic parameters

Three-dimensional (3D) roadmap is a recently developed imaging technique used to guide diagnostic and interventional catheter-directed procedures and mainly evaluated for neurovascular procedures. Few data with regard to efficacy and radiation dose are currently available in literature. To evaluate the use of 3D roadmap technique as compared with the conventional two-dimensional (2D) roadmap for uterine artery catheterization and embolization during uterine fibroid embolization and assess the potential impact on radiation dose, contrast load, and total procedure time. In this prospective study, 40 patients were randomly assigned to the 2D or 3D roadmap technique for uterine artery catheterization. Demographic data, specifically the patient's age, weight, height, pelvic circumference, and total uterine and fibroid volume were recorded. Exposure parameters, contrast load, and procedure time were recorded and organ doses for ovaries and uterus were calculated. Demographic data did not differ between the groups. Catheterization and embolization of both uterine arteries were feasible in all patients, although in one patient in the 3D group, a focal dissection of the proximal uterine artery occurred. No significant difference in estimated ovarian dose was found in the 3D versus 2D group (P = 0.07). Total procedure time was shorter in the 2D group (P = 0.01) and no difference in total contrast load was seen (P = 0.17). Both roadmap techniques are effective imaging-guided tools for uterine artery catheterization, without difference in terms of radiation exposure or contrast load. The total procedure time is shorter in the 2D group.

What the SWIFT and TREVO II Trials Tell Us About the Role of Endovascular Therapy for Acute Stroke

The Solitaire With the Intention for Thrombectomy (SWIFT) trial1 and the TREVO II trial,2 published online in Lancet in August 2012, are important trials in the history of endovascular therapy for acute ischemic stroke for several reasons. First, both randomized trials compared a new technology, 2 versions of a stent-retriever, with a previously Food and Drug Administration-cleared technology, the Merci Retriever. The latest iteration of the Merci Retriever, which had been cleared for use since 2005, is a flexible nitinol wire with distal corkscrew-shaped coil loops with attached filaments. Stent-retriever technology is based on self-expanding stents that can be fully deployed and then retrieved about 5 minutes later, after migration of the thrombus through the stent struts.3 Retrievable stents were introduced in 2010 in experienced, high-volume comprehensive European stroke centers with increased rates of recanalization in a shorter time compared with intra-arterial thrombolysis.4 The Merci Retriever and retrievable stents are distal thrombectomy devices that require navigation of the device through and beyond the site of occlusion without image-guidance of a high-resolution biplane or 3D roadmap. In contrast, proximal thrombectomy devices allow a safe, image-guided approach to the site of occlusion and aspiration of the thrombus. These 2 randomized trials broke the trend of single-arm trials comparing a new technology with the intravenous heparin arm of the randomized PROACT II trial study, which was completed in 1998.5 The goal of past single-arm trials, used for both the Merci Retriever6,7 and Penumbra Aspiration System,8 was to obtain 510k clearance by the FDA, or regulatory approval in other countries, for thrombectomy in acute ischemic stroke. However, no randomized trial of these devices has demonstrated improved clinical outcome by a thrombectomy device compared with standard therapy, whether intravenous tissue-type plasminogen activator (tPA) within 3 and …

Evaluation of Automated 2D-3D Image Overlay System Utilizing Subtraction of Bone Marrow Image for EVAR: Feasibility Study

To evaluate the automated 2D-3D image overlay system ("3D Roadmap") for use during endovascular aneurysm repair (EVAR) in the hybrid operating theater. Datasets of preoperative CT images were modified to subtract dense bone marrow to improve the visualization of vasculature on the overlaid image, and allow for accurate navigation of the endovascular devices. The 3D-CT overlay image was registered on the 2D fluoroscopy image to mark the iliac crest and lumbar vertebrae on both images as landmarks. Arteriography was performed only twice to confirm the precision of the position of renal artery and the final evaluation. Twenty patients underwent EVAR with Medtronic Endurant, Gore Excluder, or COOK Zenith using "3D Roadmap". The origin of the renal artery and iliac bifurcation were registered with complete accuracy in 10 patients (50%). The lower renal artery deviated toward the cranial side less than 3 mm in six patients. In all cases, EVAR was successful, and completed with the volume of contrast material limited to 43.8 ± 3.1 mL. "3D Roadmap" was confirmed to be valuable for visualization of vessel origin in a fused image and for reduction of contrast material during EVAR.

Three-dimensional rotational angiography is preferable to conventional two-dimensional techniques for uterine artery embolization

We aimed to investigate the potential benefits of three-dimensional rotational angiography (3DRA) compared to two-dimensional (2D) roadmapping to visualize the uterine artery (UA) origins during uterine artery embolization (UAE) procedures. Sixty-three UAE cases performed under 3DRA guidance were reviewed retrospectively to determine if there was an optimal angiographic projection angle for identifying UA origin. Digital subtraction angiogram (DAS)-like images of the pelvic vessels were generated from the 3DRA scans at six different angles: left anterior oblique (LAO) 25°, 35°, 45°; and right anterior oblique (RAO) 25°, 35°, 45°. Two experienced interventional radiologists assessed if these angles could effectively serve as a roadmap to guide catheterization of the UA. Assessment was validated against original 3DRA scans to determine the percentage of true and false positives. No single projection angle was found that could consistently be utilized for UA catheterization. The projection angles used during 3D roadmapping for both the left and right UA showed two clusters with both a wide spread: RAO 20° to 50° and LAO 20° to 50°. More than 50% of the DSA-like images at RAO and LAO 45° appeared to be adequate for UA catheterization, but validation against the 3DRA revealed 28% of these images were suboptimal and deceptive, due to unappreciated overlapping vessels. No standard projection angles can be recommended with 2D roadmapping to consistently visualize UA origin. The 3DRA can be as a useful tool for UAE to achieve reliable and consistent visibility of the UA origin.

Integration of cardiac and respiratory motion into MRI roadmaps fused with x‐ray

Volumetric roadmaps overlaid on live x-ray fluoroscopy may be used to enhance image guidance during interventional procedures. These roadmaps are often static and do not reflect cardiac or respiratory motion. In this work, the authors present a method for integrating cardiac and respiratory motion into magnetic resonance imaging (MRI)-derived roadmaps to fuse with live x-ray fluoroscopy images, and this method was tested in large animals. Real-time MR images were used to capture cardiac and respiratory motion. Nonrigid registration was used to calculate motion fields to deform a reference end-expiration, end-diastolic image to different cardiac and respiratory phases. These motion fields were fit to separate affine motion models for the aorta and proximal right coronary artery. Under x-ray fluoroscopy, an image-based navigator and ECG signal were used as inputs to deform the roadmap for live overlay. The in vivo accuracy of motion correction was measured in four swine as the ventilator tidal volume was varied. Motion correction reduced the root-mean-square error between the roadmaps and manually drawn centerlines, even under high tidal volume conditions. For the aorta, the error was reduced from 2.4 ± 1.5 mm to 2.2 ± 1.5 mm (p < 0.05). For the proximal right coronary artery, the error was reduced from 8.8 ± 16.2 mm to 4.3 ± 5.2 mm (p < 0.001). Using real-time MRI and an affine motion model it is feasible to incorporate physiological cardiac and respiratory motion into MRI-derived roadmaps to provide enhanced image guidance for interventional procedures. A method has been presented for creating dynamic 3D roadmaps that incorporate cardiac and respiratory motion. These roadmaps can be overlaid on live X-ray fluoroscopy to enhance image guidance for cardiac interventions.

Real-time X-ray-based 4D image guidance of minimally invasive interventions

A new technology is introduced that enables real-time 4D (three spatial dimensions plus time) X-ray guidance for vascular catheter interventions with acceptable levels of ionising radiation. The enabling technology is a combination of low-dose tomographic data acquisition with novel compressed sensing reconstruction and use of prior image information. It was implemented in a prototype set-up consisting of a gantry-based flat detector system. In pigs (n = 5) angiographic interventions were simulated. Radiation dosage on a per time base was compared with the "gold standard" of X-ray projection imaging. Contrary to current image guidance methods that lack permanent 4D updates, the spatial position of interventional instruments could be resolved in continuous, spatial 4D guidance; the movement of the guide wire as well as the expansion of stents could be precisely tracked in 3D angiographic road maps. Dose rate was 23.8 μGy/s, similar to biplane standard angiographic fluoroscopy, which has a dose rate of 20.6 μGy/s. Real-time 4D X-ray image-guidance with acceptable levels of radiation has great potential to significantly influence the field of minimally invasive medicine by allowing faster and safer interventions and by enabling novel, much more complex procedures for vascular and oncological minimally invasive therapy. • Real-time 4D (three spatial dimensions plus time) angiographic intervention guidance is realistic. • Low-dose tomographic data acquisition with special compressed sensing-based algorithms is enabled. • Compared with 4D CT fluoroscopy, this method reduces radiation to acceptable levels. • Once implemented, vascular interventions may become safer and faster. • More complex intervention approaches may be developed.

An integrated platform for image-guided cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an effective procedure for patients with heart failure but 30% of patients do not respond. This may be due to sub-optimal placement of the left ventricular (LV) lead. It is hypothesized that the use of cardiac anatomy, myocardial scar distribution and dyssynchrony information, derived from cardiac magnetic resonance imaging (MRI), may improve outcome by guiding the physician for optimal LV lead positioning. Whole heart MR data can be processed to yield detailed anatomical models including the coronary veins. Cine MR data can be used to measure the motion of the LV to determine which regions are late-activating. Finally, delayed Gadolinium enhancement imaging can be used to detect regions of scarring. This paper presents a complete platform for the guidance of CRT using pre-procedural MR data combined with live x-ray fluoroscopy. The platform was used for 21 patients undergoing CRT in a standard catheterization laboratory. The patients underwent cardiac MRI prior to their procedure. For each patient, a MRI-derived cardiac model, showing the LV lead targets, was registered to x-ray fluoroscopy using multiple views of a catheter looped in the right atrium. Registration was maintained throughout the procedure by a combination of C-arm/x-ray table tracking and respiratory motion compensation. Validation of the registration between the three-dimensional (3D) roadmap and the 2D x-ray images was performed using balloon occlusion coronary venograms. A 2D registration error of 1.2 ± 0.7 mm was achieved. In addition, a novel navigation technique was developed, called Cardiac Unfold, where an entire cardiac chamber is unfolded from 3D to 2D along with all relevant anatomical and functional information and coupled to real-time device detection. This allowed more intuitive navigation as the entire 3D scene was displayed simultaneously on a 2D plot. The accuracy of the unfold navigation was assessed off-line using 13 patient data sets by computing the registration error of the LV pacing lead electrodes which was found to be 2.2 ± 0.9 mm. Furthermore, the use of Unfold Navigation was demonstrated in real-time for four clinical cases.

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.

Three-dimensional C-arm Cone-beam CT: Applications in the Interventional Suite

C-arm cone-beam computed tomography (CT) with a flat-panel detector represents the next generation of imaging technology available in the interventional radiology suite and is predicted to be the platform for many of the three-dimensional (3D) roadmapping and navigational tools that will emerge in parallel with its integration. The combination of current and unappreciated capabilities may be the foundation on which improvements in both safety and effectiveness of complex vascular and nonvascular interventional procedures become possible. These improvements include multiplanar soft tissue imaging, enhanced pretreatment target lesion roadmapping and guidance, and the ability for immediate multiplanar posttreatment assessment. These key features alone may translate to a reduction in the use of iodinated contrast media, a decrease in the radiation dose to the patient and operator, and an increase in the therapeutic index (increase in safety-vs-benefit ratio). In routine practice, imaging information obtained with C-arm cone-beam CT provides a subjective level of confidence factor to the operator that has not yet been thoroughly quantified.

Through silicon via: From the CMOS imager sensor wafer level package to the 3D integration

A wide range of requests coming from customer appears to demonstrate the feasibility of the TSV for a large range of via size and via AR either for process point of view or for performances point of view. The main application in the market is the CMOS image sensor with the integration of via at AR1. Now based on this first wafer level package of CMOS Image Sensor (CIS), the integration on the z axe will continue by the wafer lens integration for a continuous form factor and low cost module. First 3Di applications with TSV is entering the market with the via-last approach, more simply to be developed in semiconductor manufacturing in order to secure the 3Di technologies and to promote the 3Di to customers. Then specific design and electrical models will be developed and optimized allowing a fast and prosperous development of the via-first approach. A challenge in the modelisation of the TSV is the understanding of the mechanical impact of the trench and the metal filling on the behavior of the CMOS components and the reliability. These types of researches are progressing in various institutes and are essential for an increasing integration of TSV. Because actually, the technology continues to drive the 3D roadmap, the mechanical and thermal modelisation and 3D design tool need to be more activated to be developed faster in order to optimize the 3D module. Then the electrical testing will be a real challenge to be able to distinguish drift in the right strata, to be able to isolate a via within more than 10000 via in a module. The electrical testing will be strictly linked to mechanical and electrical failure analysis to get feed-back in technology, actual drawback of the 3D development. The cost of the 3Di and the TSV integration is more and more important and looks as a primary driver even if the functionalities increase faster than cost! Some steps have been already identified to be more costly steps: bonding and via filling. Indeed, throughput and material used have a direct impact on the final price. Continuous perspectives of TSV integration are progressing in order to optimise actual applications or to develop new integration. First challenging integration is the interposers with 3D interconnection allowing devices mounting on both side, like passive device integration or building of micro-cooling channels. The main interest of the 3D silicon interposer is the fact that it can connect chips at different locations and sizes, as example memory over digital IC. The usage of silicon as an interposer leads to an increase in the cost, but it will boost performances and reduce power consumption. One other advantage of the introduction of 3D interposer is the simplification of the required substrate implying a better mismatch of CTE lowering the packaging failure. In the wafer level package, TSV is now introduced to reduce the package footprint and mainly simplify the capping of device, similar to that for the MEMS. Indeed by integrating TSV, the capping must only protect the device against external environment, and not also take into account the electrical path in the bond layer degrading the hermiticity performance. To finish this paper, the sentence of Yann Guillou is the right situation: “The (3D) roadmaps need to be based on application requirements and not driven by technology ONLY. 3D Integration with TSV is not a scaling based concept Does it make sense today to think about submicron via diameter or dice thinner than 30 μm for example?” Applications need to take a risk by using 3D TSV technology!