Safety and efficacy of dual-axis rotational coronary angiography vs. standard coronary angiography.

OBJECTIVE: To determine the safety and efficacy of dual-axis rotational coronary angiography (DARCA) by directly comparing it to standard coronary angiography (SA). BACKGROUND: Standard coronary angiography (SA) requires numerous fixed static images of the coronary tree and has multiple well-documented limitations. Dual-axis rotational coronary angiography (DARCA) is a new rotational acquisition technique that entails simultaneous LAO/RAO and cranial/caudal gantry movement. This technological advancement obtains numerous unique images of the left or right coronary tree with a single coronary injection. We sought to assess the safety and efficacy of DARCA as well as determine DARCA's adequacy for CAD screening and assessment. METHODS: Thirty patients underwent SA following by DARCA. Contrast volume, radiation dose (DAP) and procedural time were recorded for each method to assess safety. For DARCA acquisitions, blood pressure (BP), heart rate (HR), symptoms and any arrhythmias were recorded. All angiograms were reviewed for CAD screening adequacy by two independent invasive cardiologists. RESULTS: Compared to SA, use of DARCA was associated with a 51% reduction in contrast, 35% less radiation exposure, and 18% shorter procedural time. Both independent reviewers noted DARCA to be at least equivalent to SA with respect to the ability to screen for CAD. CONCLUSION: DARCA represents a new angiographic technique which is equivalent in terms of image quality and is associated with less contrast use, radiation exposure, and procedural time than SA.

Republished: Successful treatment of direct carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV without arterial puncture: the transvenous triple-overlay embolization (TAILOREd) technique.

We report successful transvenous treatment of direct carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV using a novel triple-overlay embolization (TAILOREd) technique without the need for arterial puncture, which is known to be highly risky in this patient group. The TAILOREd technique allowed for successful treatment using preoperative MR angiography as a three-dimensional overlay roadmap combined with cone beam CT and live fluoroscopy, precluding the need for an arterial puncture.

Rapid prototyping: a new tool in understanding and treating structural heart disease.

As the appreciation of structural heart disease in children and adults has increased and as catheter-based closure procedures are now being performed in clinical practice, cardiovascular physicians have multiple compelling new reasons to better understand cardiac anatomic and spatial relationships. Current 2-dimensional imaging techniques remain limited both in their ability to represent the complex 3-dimensional relationships present in structural heart disease and in their capacity to adequately facilitate often complex corrective procedures. This review discusses the cardiovascular applications of rapid prototyping, a new technology that may not only play a significant role in the planning of catheter-based interventions but also may serve as a valuable educational tool to enhance the medical community's understanding of the many forms of structural heart disease.

Rotational vs. standard coronary angiography: an image content analysis.

OBJECTIVE: To evaluate the clinical utility of images acquired from rotational coronary angiographic (RA) acquisitions compared to standard "fixed" coronary angiography (SA). BACKGROUND: RA is a novel angiographic modality that has been enabled by new gantry systems that allow calibrated automatic angiographic rotations and has been shown to reduce radiation and contrast exposure compared to SA. RA provides a dynamic multiple-angle perspective of the coronaries during a single contrast injection. METHODS: The screening adequacy, lesion assessment, and a quantitative coronary analysis (QCA) of both SA and RA were compared by independent blinded review in 100 patients with coronary artery disease (CAD). RESULTS: SA and RA recognize a similar total number of lesions (P = 0.61). The qualitative assessment of lesion characteristics and severity between modalities was comparable and lead to similar clinical decisions. Visualization of several vessel segments (diagonal, distal RCA, postero-lateral branches and posterior-descending) was superior with RA when compared to SA (P < 0.05). A QCA comparison (MLD, MLA, LL, % DS) revealed no difference between SA and RA. The volume of contrast (23.5 +/- 3.1 mL vs. 39.4 +/- 4.1; P = 0.0001), total radiation exposure (27.1 +/- 4 vs. 32.1 +/- 3.8 Gycm(2); P = 0.002) and image acquisition time (54.3 +/- 36.8 vs. 77.67 +/- 49.64 sec; P = 0.003) all favored RA. CONCLUSION: Coronary lesion assessment, coronary screening adequacy, and QCA evaluations are comparable in SA and RA acquisition modalities in the diagnosis of CAD however RA decreases contrast volume, image acquisition time, and radiation exposure.

Successful treatment of direct carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV without arterial puncture: the transvenous triple-overlay embolization (TAILOREd) technique.

We report successful transvenous treatment of direct carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV using a novel triple-overlay embolization (TAILOREd) technique without the need for arterial puncture, which is known to be highly risky in this patient group. The TAILOREd technique allowed for successful treatment using preoperative MR angiography as a three-dimensional overlay roadmap combined with cone beam CT and live fluoroscopy, precluding the need for an arterial puncture.

Multiscale vessel tracking.

A method is presented that uses a vectorial multiscale feature image for wave front propagation between two or more user defined points to retrieve the central axis of tubular objects in digital images. Its implicit scale selection mechanism makes the method more robust to overlap and to the presence of adjacent structures than conventional techniques that propagate a wave front over a scalar image representing the maximum of a range of filters. The method is shown to retain its potential to cope with severe stenoses or imaging artifacts and objects with varying widths in simulated and actual two-dimensional angiographic images.

Blood pool contrast-enhanced MRA: improved arterial visualization in the steady state.

Blood pool agents (BPAs) for contrast-enhanced magnetic resonance angiography (CE-MRA) allow prolonged imaging during the steady state when the agent is distributed through the complete vascular system. This increases both the spatial resolution and the contrast resolution. However, simultaneous venous and arterial enhancement hampers interpretation. For the pelvic region of the vasculature, it is shown that arterial visualization in this equilibrium phase can be improved if the central arterial axis (CAA) is known. However, manually obtaining this axis is not feasible in clinical practice. Therefore, a method is presented that utilizes images acquired during the first pass of the contrast agent to find the CAA in the steady-state data with minimum user initialization. The accuracy of the resulting CAA is compared with tracings of three observers in six patient datasets. It was found that the mean difference between the semiautomatic method and the manual delineation is 1.32 mm in the steady-state data, and that the resulting CAA was always within the arterial lumen, which is an important prerequisite for both improved visualization and segmentation.

Intra-procedural coronary intervention planning using hybrid 3-dimensional reconstruction techniques.

RATIONALE AND OBJECTIVES: The purpose of this study was to develop a method to assist the cardiologist in planning an interventional procedure while the patient is on the catheterization table. MATERIALS AND METHODS: A rotational single plane x-ray system is used to acquire images while rapidly rotating the C-arm around the patient. Based on electrocardiogram-selected projections, both a volumetric cone-beam reconstruction of the coronary tree as well as a three-dimensional model of the vessel segment of interest is generated. This information is used to compute the appropriateness of a range of different viewing angles with respect to the overlap and foreshortening of the vessel segment of interest during the cardiac cycle which results in an interactive optimal view map. RESULTS: The proposed method has been tested on patient data and several phantom objects. The results show that both an accurate 3D model of a vessel segment of interest and its associated optimal view map can be generated to predict an appropriate gantry angle for subsequent image acquisition. CONCLUSION: The method provides an appropriate and feasible tool to assist interventional cardiologists in planning a coronary intervention while the patient is still on the catheterization table following diagnostic coronary angiography.

Enhanced stent visualization: a case series demonstrating practical applications during PCI.

BACKGROUND: Visualization of coronary stents is increasingly challenging due to the reduction in stent strut thickness to improve deliverability. On the other hand stent expansion and precise implantation in the target vessel are important in optimizing short and long-term outcomes of stent-based revascularization. Stentboost Subtract is a novel X-ray technique that improves visualization of deployed stents in the coronary arteries. Using motion compensation and integration of multiple non-contrast projection images from a fixed gantry position, this new technique depicts stent morphology allowing assessment of stent expansion and extent of overlap with adjacent stents. We present a case series in which enhanced stent visualization (ESV) facilitated interventions. METHODS: The clinical and angiographic characteristics of 6 cases utilizing ESV were reviewed. All ESV acquisitions in this case series utilized an 8 in. field of view (FOV), 3 ml/sec. for a total of 6 ml of contrast, and placement of balloon markers in the region of interest. RESULTS: The cases presented significantly facilitated the identification of bifurcation stenting techniques, precise stent positioning, stent underexpansion and assisted with defining stent-vessel wall relationship that was additive to intravascular ultrasound. CONCLUSIONS: ESV is a novel tool used in coronary interventions that facilitates non-invasive assessment of stent positioning, expansion and stent-vessel interactions. This inexpensive ESV technique is complimentary to IVUS and in some cases obviates its need.

Coronary computed tomographic angiography in the cardiac catheterization laboratory: current applications and future developments.

The last few years have seen a marked increase in the number of cardiac CT scans performed, regardless of reimbursement issues and concerns about radiation dose. New-generation multidetector CT (MDCT) scanners with wide craniocaudal coverage (256 slices and beyond) have the potential to further improve diagnostic capability compared with that of the existing generation of MDCT scanners. New dose-reduction technologies are now available on these scanners, enabling high-quality coronary imaging with a significant reduction in radiation dose. This article addresses some of these advances and discusses how cardiac CT and its derived information can be used in the preparation and execution of catheter coronary angiography and percutaneous coronary interventions.

On-line multi-slice computed tomography interactive overlay with conventional X-ray: a new and advanced imaging fusion concept.

BACKGROUND: Computed tomography (CT) has revolutionized noninvasive cardiovascular evaluations. Complicated percutaneous procedures require precise imaging guidance that conventional X-ray is often unable to provide. By combining X-ray imaging with real-time, interactive, CT-based landmarks, interventional procedures could be facilitated. We describe two cases using the first CT/Live X-ray overlay in which this technology shows its potential. CASE REPORTS: A 31-year-old male with an anatomically complicated atrial septal defect (ASD) was referred for percutaneous closure. Transesophageal echocardiography (TEE) revealed an inferior location of the ASD complicated by it's proximity to a prominent Eustachian ridge. The CT was used to create a patient-specific physical model in preparation for the procedure and an in-lab real-time CT overlay allowing successful closure. A second case of a 41-year-old male with coronary artery disease status-post coronary artery bypass, aortic valve replacement (AVR), and aortic root replacement with an abnormal coronary computed tomography angiogram (CTA). In a prior procedure years ago the saphenous vein graft (SVG) to the left anterior descending artery (LAD) could not be cannulated during invasive angiography, given the patient's complicated and unusual anatomy. Using CT overlay, the superiorly and anteriorly located SVG was cannulated successfully. DISCUSSION: CT/Live X-ray overlay provided an adequate anatomical intra-procedural ASD evaluation, defect sizing, and guidance in one case and localization of an anatomically challenging graft ostium in the other case. Adding the CT landmarks as an overlay to traditional X-ray techniques provides a revolutionary and advanced imaging fusion concept that should improve procedural success.

Projection-based motion compensation and reconstruction of coronary segments and cardiac implantable devices using rotational X-ray angiography.

Cardiologists use two-dimensional projection images in conventional X-ray coronary angiography for the assessment of three-dimensional structures. During minimally invasive interventions there is a need to clearly visualize and analyze contrast filled coronary arteries, surrounding tissue, and implanted devices. Three-dimensional reconstruction of these structures is challenging due to the cardiac and respiratory motion. In this paper we describe a method to automatically generate motion compensated reconstructions of various structures using rotational X-ray angiography. The method uses markers on a device or guide wire to identify and estimate the motion of an object or region of interest in order to register and motion compensate the projection images to generate a motion compensated reconstruction. The method is evaluated on 20 rotational acquisitions and the average marker couple detection rate is 84% for cardiac stents, 90% for closure devices and 20% for contrast filled coronaries. The projection images are motion compensated based on the semi-automatically detected markers and subsequently used for reconstruction. We conclude that it is feasible to reconstruct cardiac stents, closure devices, contrast filled coronaries, and calcified plaques using rotational X-ray angiography.

Determination of optimal viewing regions for X-ray coronary angiography based on a quantitative analysis of 3D reconstructed models.

Current expert-recommended views for coronary angiography are based on heuristic experience and have not been scientifically studied. We sought to identify optimal viewing regions for first and second order vessel segments of the coronary arteries that provide optimal diagnostic value in terms of minimizing vessel foreshortening and overlap. Using orthogonal 2D images of the coronary tree, 3D models were created from which patient-specific optimal view maps (OVM) allowing quantitative assessment of vessel foreshortening and overlap were generated. Using a novel methodology that averages 3D-based optimal projection geometries, a universal OVM was created for each individual coronary vessel segment that minimized both vessel foreshortening and overlap. A universal OVM model for each coronary segment was generated based on data from 137 patients undergoing coronary angiography. We identified viewing regions for each vessel segment achieving a mean vessel foreshortening value of 5.8 +/- 3.9% for the left coronary artery (LCA) and 5.6 +/- 3.6% for the right coronary artery (RCA). The overall mean overlap values achieved were 8.7 +/- 7.9% for the LCA and 4.6 +/- 3.2% for the RCA. This scientifically-based OVM evaluation of coronary vessel segments provides the means to facilitate acquisitions during coronary angiography and interventions that minimize imaging inaccuracies related to foreshortening and overlap, improving the accuracy, efficiency, and safety of diagnostic and interventional coronary procedures.

The effect of automated marker detection on in vivo volumetric stent reconstruction.

New drug eluting stents are less radiopaque than bare metal stents and therefore difficult to see with conventional X-ray coronary angiography. 2D StentBoost and intravascular ultrasound (IVUS) are routinely used to evaluate stent deployment and vessel apposition during a percutaneous coronary intervention. IVUS images give cross-sectional information about the stent lumen and surrounding tissue. 2D StentBoost is a boosted angiogram sequence and visualizes the geometry of the deployed stent from a fixed viewing direction. Three-dimensional motion compensated volumetric stent reconstruction has been developed to give insight into the 3D geometry of the stent. Markers on the balloon wire are used to motion compensate cardiac rotational angiography acquisitions. In this paper we present the effect of automated marker detection on in vivo volumetric cardiac stent reconstructions. Automated or semi-automated marker detection reduces user interaction, potentially reduces total processing time, and increases detection results which leads to higher quality of stent reconstructions.

Rotational angiography (RA) and three-dimensional imaging (3-DRA): an available clinical tool.

Being able to accurately choose an optimal view for stent positioning, non foreshortened length and to avoid side branches is imperative during therapeutic procedures. Traditional imaging limitations may include the selection of an incorrectly sized stent, inaccurate placement, and/or the need for additional stents. With the use of newer acquisition techniques and three-dimensional (3-D) modeling/reconstructions this can be minimized. We present a case in which with the assistance of 3-D and its computer derived optimal view, and optimal length, a significant amount of vessel foreshortening was eliminated therefore improving the procedural outcome.

Initial clinical experience of selective coronary angiography using one prolonged injection and a 180 degrees rotational trajectory.

OBJECTIVE: Evaluate the safety of prolonged coronary injections during a rotational acquisition covering 180 degrees. BACKGROUND: Rotational angiography has been adapted to coronary angiography and shown to reduce radiation and contrast exposure. Three-dimensional (3D) reconstructions and other advanced applications require imaging over a 180 degrees -arc with a single but longer injection of larger contrast volumes. METHODS: Thirty patients referred for angiography were enrolled. Blood pressure (BP), heart rate (HR), symptoms, and ectopy were recorded before-and-after injections. RESULTS: Pre and post-injection HRs for the LCA/RCA were not statistically different (LCA-pre-injection 63+/-13 bpm vs. LCA-post-injection 62+/-11 bpm, P=0.54 and RCA-pre-injection 65+/-12 bpm vs. RCA-post-injection 65+/-10, P=0.88). Central aortic pressure values were not statistically different for the RCA injections (RCA-systolic-pre-injection 118+/-14 mm Hg vs. RCA-systolic-post-injection 112+/-25 mm Hg, P=0.15, and RCA diastolic-pre-injection 69+/-9 mm Hg vs. RCA-diastolic-post-injection 60+/-10 mm Hg, P=0.88) but were statistically significant for the LCA injections (LCA systolic-pre-injection 122+/-19 mm Hg vs. LCA-systolic-post-injection 116+/-17 mm Hg, P=0.0004, and LCA-diastolic-pre-injection 69+/-10 mm Hg vs. LCA-diastolic-post-injection 65+/-9 mm Hg, P=0.0007). There were no symptoms or electrical events documented during or immediately post-injection. CONCLUSION: This study demonstrates the feasibility and safety of longer coronary injections. There were no significant HR changes, clinically insignificant pressure changes, and no adverse reactions. Additional studies will be needed to assure its safety in a larger and clinically more varied patient population.

3D reconstruction of coronary stents in vivo based on motion compensated X-ray angiograms.

A new method is introduce for the three-dimensional (3D) reconstruction of the coronary stents in-vivo utilizing two-dimensional projection images acquired during rotational angiography (RA). The method is based on the application of motion compensated techniques to the acquired angiograms resulting in a temporal snapshot of the stent within the cardiac cycle. For the first time results of 3D reconstructed coronary stents in vivo, with high spatial resolution are presented. The proposed method allows for a comprehensive and unique quantitative 3D assessment of stent expansion that rivals current x-ray and intravascular ultrasound techniques.

3D MRA coronary axis determination using a minimum cost path approach.

A method is introduced to automatically find the coronary axis based on two or more user-defined points, even in the presence of a severe stenosis. The coronary axis is determined by finding a minimum cost path (MCP) in a feature image in which the tubular-like structures are enhanced. The results of the proposed method were compared with manually drawn central axes to estimate the accuracy. In 32 3D TFE-EPI acquisitions of patients and volunteers, 14 right coronary arteries (RCAs), 15 left anterior descending arteries (LADs), and eight left circumflex arteries (LCXs) were manually tracked twice by two operators to determine a reference axis and to assess the inter- and intra-user variability. On average, the maximum distance to the reference axis, based on only two user-defined points, is less than 1.5 mm; the average distance is around 0.65 mm, which is less than the average in-plane resolution. The results of the method are comparable to those of the manual operators.