True Vessel Research Articles

Abstract TP201: Carotid Artery Flow as Determined by Real-Time Phase-Contrast Flow Mri and Neurovascular Ultrasound: a Comparative Study of Healthy Subjects

Background: The assessment of carotid artery flow by neurovascular ultrasound (nvUS) may be complemented by real-time phase-contrast (RT-PC) flow MRI which apart from quantitative flow parameters offers velocity distributions across the entire vessel lumen. Methods: The feasibility and diagnostic potential of RT-PC flow MRI was evaluated in 20 healthy volunteers in comparison to conventional nvUS. RT-PC flow MRI at 40 ms temporal resolution and 0.8 mm in-plane resolution resulted in velocity maps with low phase noise and high spatiotemporal accuracy by exploiting respective advances of a recent nonlinear inverse model-based reconstruction. Peak-systolic velocities (PSV), end-diastolic velocities (EDV), flow volumes and comprehensive velocity profiles were determined in the common, internal and external carotid artery on both sides. Results: Characteristics in pulsatility and laminar flow, including individual flow abnormalities shown on nvUS, could be reproduced and visualized in detail by RT-PC flow MRI. Fig. 1 shows a representative color-coded duplex sonography with doppler spectrum (A), flow volume measurement by RT-PC flow MRI (B) and a three-dimensional representation of through-plane velocities at peak systole (C) and end diastole (D) in the internal carotid artery. PSV to EDV differences revealed good agreement between both techniques, mean PSV and EDV were significantly lower and flow volumes were higher for MRI. Conclusions: Our findings suggest that RT-PC flow MRI may add to clinical diagnostics, e.g. by alterations of dynamic velocity distributions in patients with carotid stenosis. Lower PSV and EDV values than for nvUS mainly reflect the longer MRI acquisition time which attenuates short peak velocities, while higher flow volumes benefit from a proper assessment of the true vessel lumen.

Intracoronary Brachytherapy in the Era of Drug-Eluting Stents

Intracoronary brachytherapy (ICBT) is an effective percutaneous trans-luminal solution for in-stent restenosis (ISR). Our objective is to assess the feasibility, safety, and efficacy of ICBT as a treatment option for ISR. We retrospectively identified adult patients who underwent ICBT for ISR in our institution, between March 2015 and January 2017 in an IRB approved database. All lesions were treated with Y-90 source, with an activity of 1.66 gigabecquerel to a prescription depth of 2mm. Lesions were prescribed 18.4 Gy (n=35), for reference vessel diameter (RVD) of < 3.35 mm or 23 Gy (n=36) for RVD of ≥ 3.35mm. Demographic variables, rates of peri-procedural complications and incidence of target lesion revascularization (TLR) were collected. Predictors of TLR were determined using Cox proportional hazards modelling. We identified 60 patients treated to a total of 71 lesions with 11 patients undergoing a second ICBT procedure. The median age of patients was 66 years with a median follow-up of 5 months. All patients had hyperlipidemia, 63% were male, 98.3% were hypertensive, and 58.3% had diabetes. Never smokers, former smokers, and current smokers represented 49.3%, 39.4%, and 11.3% respectively. The number of previous ISR at the site of ICBT was known for 47 treatments with < 4 prior ISR in 56.8% and ≥4 in 43.2%. Number of stent layers at the site of ICBT was known for 58 lesions and was < 2 layers in 65.5% and ≥3 in 34.5%. Left anterior descending artery (LAD) was the most commonly treated vessel (32.4% of ICBT). The median true vessel diameter (TVD) was 3.4 mm (range, 2.5-4.5), median injury length was 32 mm (range, 5-120mm) and median number of dwell positions was 1 (range, 1-4). Fifteen lesions (21.1%) required TLR resulting in 6 and 12-month actuarial rates of ISR of 9% and 30.3% respectively. No peri-procedural myocardial infarctions, arrhythmias, vessel perforations or dissections were observed. Univariate analysis revealed an association between TLR and history of prior ICBT HR = 3.24 (95% CI 0.93 - 12.7 p = 0.065), fewer stent layers HR = 3.13 (95% CI 0.70 – 14.0 p = 0.14) and a higher number of previous ISR at the ICBT site HR = 2.25 (95% CI 0.71 to 7.14 p = 0.17). There was no statistically significant association between TLR and age (p = 0.36), sex (p = 0.57), DM (p = 0.46), smoking (p = 0.97), TVD (p = 0.76), radiation dose (p = 0.77) or number of dwell positions (p = 0.71). One patient has died resulting in an actuarial overall survival rate of 83.3% at 24 months. ICBT in the era of drug-eluting stents is a feasible and safe treatment option for patients with ISR with low rates of severe peri-procedural complications. This preliminary report suggests a history of prior ICBT may be associated with a higher rate of TLR after ICBT. For patients with in-stent restenosis in the era of drug-eluting stents, ICBT should be considered to minimize the risk of ISR.

Sialic acids regulate microvessel permeability, revealed by novel in vivo studies of endothelial glycocalyx structure and function.

Key points We have developed novel techniques for paired, direct, real‐time in vivo quantification of endothelial glycocalyx structure and associated microvessel permeability.Commonly used imaging and analysis techniques yield measurements of endothelial glycocalyx depth that vary by over an order of magnitude within the same vessel.The anatomical distance between maximal glycocalyx label and maximal endothelial cell plasma membrane label provides the most sensitive and reliable measure of endothelial glycocalyx depth.Sialic acid residues of the endothelial glycocalyx regulate glycocalyx structure and microvessel permeability to both water and albumin. The endothelial glycocalyx forms a continuous coat over the luminal surface of all vessels, and regulates multiple vascular functions. The contribution of individual components of the endothelial glycocalyx to one critical vascular function, microvascular permeability, remains unclear. We developed novel, real‐time, paired methodologies to study the contribution of sialic acids within the endothelial glycocalyx to the structural and functional permeability properties of the same microvessel in vivo. Single perfused rat mesenteric microvessels were perfused with fluorescent endothelial cell membrane and glycocalyx labels, and imaged with confocal microscopy. A broad range of glycocalyx depth measurements (0.17–3.02 μm) were obtained with different labels, imaging techniques and analysis methods. The distance between peak cell membrane and peak glycocalyx label provided the most reliable measure of endothelial glycocalyx anatomy, correlating with paired, numerically smaller values of endothelial glycocalyx depth (0.078 ± 0.016 μm) from electron micrographs of the same portion of the same vessel. Disruption of sialic acid residues within the endothelial glycocalyx using neuraminidase perfusion decreased endothelial glycocalyx depth and increased apparent solute permeability to albumin in the same vessels in a time‐dependent manner, with changes in all three true vessel wall permeability coefficients (hydraulic conductivity, reflection coefficient and diffusive solute permeability). These novel technologies expand the range of techniques that permit direct studies of the structure of the endothelial glycocalyx and dependent microvascular functions in vivo, and demonstrate that sialic acid residues within the endothelial glycocalyx are critical regulators of microvascular permeability to both water and albumin.

The impact of small motion on the visualization of coronary vessels and lesions in cardiac CT: A simulation study.

Coronary x-ray computed tomography angiography (CCTA) is used to non-invasively assess coronary artery geometry and has, combined with computational modeling, demonstrated the potential to identify physiologically significant lesions. These measurements require robust and accurate coronary imaging and delineation of vessels despite the presence of small motion. This simulation study characterizes the impact of small, uncorrected vessel drifts during data acquisition on the assessment of vessel intensity, diameter, and shape. We developed a digital phantom and simulated projection data for a clinical scanner geometry for a range of vessel drifts that can occur during relative vessel stasis (0 to 2 mm per 360° gantry rotation) for vessels between 0.2 and 3.0 mm in diameter (covering 0% through 93% stenosis of a 3 mm vessel). In addition to the impact of vessel drift, we evaluated the performance of half-scan acquisitions (relative to full-scans) over a range of gantry positions. The performance of FDK reconstructions was compared to an iterative technique and potential improvement in sampling from focal spot deflection and quarter detector offset was compared. At rest, vessel intensity and diameter were accurately obtained in vessels greater than 1.5 mm with all vessels appearing circular in shape (major-to-minor axis ratio ~1). Vessels between 1.5 and 0.2 mm in diameter demonstrated a rapid decrease in signal intensity with full width half maximum (FWHM) vessel diameters remaining above 0.75 mm as true vessel diameter decreased. Uncorrected vessel motion resulted in decreased vessel intensity, increased vessel diameter, and distortion of vessel shape. The extent of these changes depended on both the position of the gantry as well as the reconstruction approach (half- vs. full-scan). FDK reconstruction results depended on choice of filter with Ram-Lak results yielding comparable performance to an unconstrained iterative reconstruction. Focal spot deflection and quarter detector offset did not result in large changes in performance, likely due to the high sampling density near the isocenter. Despite improvement in gantry speed and acquisition of coronary images during cardiac phases that have relatively stationary vessels, small coronary drifts (0-2 mm per 360° rotation) have been reported and if uncorrected, can present challenges to visual grading and computational modeling of stenoses because vessels will appear dimmer, larger, and more ellipsoidal in shape. The impact of a particular motion depends on the gantry position, the use of half vs. full-scan acquisitions, and the reconstruction technique.

Underwater noise footprint measurements on a survey vessel

The potential impact of man-made underwater noise on the marine environment is receiving increased attention. Shipping is one of the main sources of such anthropogenic noise. In order to understand the underwater soundscape considerable effort is being placed on generating underwater noise maps, based on using AIS data to provide details of vessel locations and operational characteristics. A key input for noise mapping models is an adequate knowledge of the source strength and characteristics for each vessel. Currently the sources are usually assumed omnidirectional, given the limited data on the true vessel radiation pattern. As part of the EU SONIC (Suppression of underwater Noise Induced by Cavitation) project measurements were undertaken on a small survey vessel, operating under realistic conditions at sea in shallow water. An autonomous recorder was used to measure the sound pressure as a function of range and azimuth. The vessel made a repeated runs past the autonomous recorder for a variety of different ranges. This has enabled the vessel noise footprint to be measured as a function of frequency and speed for the vessel, showing how the azimuthal characteristics change with frequency.

Comparison of 3-dimensional and 2-dimensional quantitative coronary angiography and intravascular ultrasound for functional assessment of coronary lesions

BackgroundThree-dimensional quantitative coronary angiography (3D-QCA) reportedly allows more accurate delineation of true vessel geometry when compared with standard two-dimensional (2D) QCA and has been validated by intravascular ultrasound (IVUS). This study sought to compare diagnostic efficiency of 2D- and 3D-QCA, and IVUS in identifying hemodynamically significant coronary stenoses as determined by fractional flow reserve (FFR). MethodsForty-two lesions in 40 patients were assessed by FFR, IVUS, and 2D- and 3D-QCA. Correlations between FFR values and anatomical parameters obtained by 2D- and 3D-QCA and IVUS were analyzed. The receiver operating characteristic (ROC) curves were used to compare the diagnostic accuracy of the parameters for predicting FFR≤0.80. ResultsMean FFR value was 0.75±0.13. FFR≤0.80 was observed in 28 lesions (67%). Of IVUS measurements, minimum lumen area (MLA) well correlated with FFR values (r=0.71, p<0.001). Of 3D- and 2D-QCA measurements, minimum lumen diameter (MLD) correlated best with FFR values (r=0.79, p<0.01; r=0.68, p<0.01, respectively), followed by MLA (r=0.76, p<0.01; r=0.67, p<0.01, respectively). The area under the ROC curve for 3D-QCA MLD was greater than those for 2D-QCA MLD (p=0.03) and 2D-QCA MLA (p=0.03). On the other hand, the AUC for 3D-QCA MLD, 3D-QCA MLA, and IVUS MLA were not significantly different. Conclusions3D-QCA is more useful than 2D-QCA and possibly comparable to IVUS in the assessment of functional stenosis severity. When FFR is not available, 3D-QCA MLA and MLD may assist in the assessment of functional severity of intermediate lesions.

Interobserver variability in physician-modified endograft planning by comparison with a three-dimensional printed aortic model

With the increasing application of fenestrated and physician-modified endografting for aneurysm repair, there is increasing concern about the accuracy of vessel position measurements based on computed tomography scans. Inaccuracies in measurements may result in a "window-shutter" or "eclipsing" phenomenon whereby the fenestration may not overlie the vessel ostium completely. We hypothesized that vessel position measurements from reconstructed imaging do not represent the true vessel position as obtained from a three-dimensional (3D) printed physical model of the visceral aortic segment. Medical 3D modeling software was used to develop the 3D reconstructions, which were then exported to the 3D printing software. This allowed 3D models to be physically generated. The distances to the top and bottom and the angle of each of the celiac, superior mesenteric, right renal, and left renal arteries were recorded. These same measurements were obtained by each of the blinded reviewers in addition to the aortic diameter at the midpoint of each of these vessels. Measurements were compared with intraclass correlation coefficient, nonparametric Spearman rank correlation test, and one-sample t-test to assess accuracy and precision. Statistical significance was set at P< .05 for all tests. Both the individual measurements and the average of the measurements were statistically accurate (significant) for the bottom of the superior mesenteric artery and the top and bottom of both the right and left renal arteries. There was variability and inaccuracy in all visceral vessel angles and in the bottom of the celiac artery (the top and the angle of the celiac artery were the arbitrary referents). Whereas the visceral vessel orifices are largely accurately assessed and measured, the vessel angles are not. This may lead to an eclipsing phenomenon, which may contribute to branch or fenestrated vessel failure and therefore reintervention. Further efforts should assess the clinical significance of the eclipsing phenomenon and should target accurate and appropriate fenestration construction to prevent long-term morbidity.

Targeted True Lumen Re-Entry With the Outback Catheter

Purpose: To report a single-center experience with the Outback re-entry device for targeted distal true lumen re-entry during subintimal recanalization of chronic total occlusions (CTOs) and compare the results with a systematic review of the literature. Methods: Between February 2011 and July 2013, 104 Outback devices were employed in 91 patients (mean age 64±9 years; 57 men) for subintimal recanalization of 100 vessels with CTOs after initial failure of spontaneous reentry. Fifty-two cases involved a retrograde approach to aortoiliac occlusions and 48 were re-entry attempts in infrainguinal CTOs. Outcome measures included complications and technical success, defined as successful targeted re-entry at the preplanned site of the distal true lumen. To evaluate device accuracy, the re-entry distance (between the point of true vessel reconstitution and the eventual re-entry point) was measured. Results: Outback success was 93% (93/100); only 7 cases failed owing to heavy calcification (5/52 aortoiliac vs 2/48 infrainguinal, p=0.44). Re-entry was highly accurate, with a re-entry distance of ~1 cm in both subgroups (1.2±0.1 cm in aortoiliac vs 1.3±0.1 cm in infrainguinal, p=0.40). There were no major and 17 minor complications (9/52 aortoiliac vs 8/48 infrainguinal, p=0.93). Results are in line with the systematic review that identified 11 studies (only 1 randomized trial) involving mostly the femoropopliteal segment (119 aortoiliac and 464 infrainguinal segments). The pooled Outback success rate was 90% (95% confidence interval 85% to 94%) and the pooled complication rate was 4.3% (95% confidence interval 1.6% to 8.3%). Conclusion: The Outback device is safe and has a very high rate of achieving targeted true lumen re-entry, which minimizes the sacrifice of healthy vessel in the aortoiliac and infrainguinal arteries.

3-D imaging using row-column-addressed arrays with integrated apodization - part i: apodization design and line element beamforming.

This paper investigates the effect of transducerintegrated apodization in row-column-addressed arrays and presents a beamforming approach specific for such arrays. Row-column addressing 2-D arrays greatly reduces the number of active channels needed to acquire a 3-D volume. A disadvantage of row-column-addressed arrays is an apparent ghost effect in the point spread function caused by edge waves. This paper investigates the origin of the edge waves and the effect of introducing an integrated apodization to reduce the ghost echoes. The performance of a λ/2-pitch 5-MHz 128 + 128 row-column-addressed array with different apodizations is simulated. A Hann apodization is shown to decrease imaging performance away from the center axis of the array because of a decrease in main lobe amplitude. Instead, a static roll-off apodization region located at the ends of the line elements is proposed. In simulations, the peak ghost echo intensity of a scatterer at (x,y, z) = (8, 3, 30) mm was decreased by 43 dB by integrating roll-off apodization into the array. The main lobe was unaffected by the apodization. Simulations of a 3-mm-diameter anechoic blood vessel at 30 mm depth showed that applying the transducer-integrated apodization increased the apparent diameter of the vessel from 2.0 mm to 2.4 mm, corresponding to an increase from 67% to 80% of the true vessel diameter. The line element beamforming approach is shown to be essential for achieving correct time-of-flight calculations, and hence avoid geometrical distortions. In Part II of this work, experimental results from a capacitive micromachined ultrasonic transducer with integrated roll-off apodization are given to validate the effect of integrating apodization into the line elements.

"You're My True Vessel": Knowledge and Digital Fan Culture Discussed on the Basis of Mediumship and Possession in Supernatural's Narrative and Fandom

Portrayals of mediumship in modern Western television narratives need to be seen as part of a broader phenomenon of the presence of religious elements in Western media, a phenomenon I argue expresses a longing for grand narratives in contemporary Western society. The portrayal and mediatization of religious elements in television narratives as well as their discussion in digital fan culture are part of what I would call a transformation process of knowledge and in particular knowledge of religious phenomena. More specifically, digital fan culture allows for an engagement with discursive transformation processes of knowledge and thus influences what is perceived as knowledge in society. Therefore, religious studies needs to pay closer attention to television narratives and the way fans interact with these narratives to create knowledge about religious practices. This article focuses on how the elements of “possession” and “mediumship” are being transformed by the US American TV series Supernatural and its fan culture. I argue that we can see at least two transformation processes here: the transformation and transplantation of religious concepts and practices (in the case of this article the idea of the human body as spirit medium) into a television context, and the transformation of these concepts and practices through digital fan culture. In its discussion of fan culture, the article looks at and analyzes fan based websites and how they present, discuss and imagine the body-medium.

Abstract 17712: Comparison of Three-Dimensional and Two-Dimensional Quantitative Coronary Angiography and Intravascular Ultrasound for the Functional Assessment of Coronary Lesions

Introduction: Three-dimensional (3-D) quantitative coronary angiography (QCA) reportedly allows a more accurate depiction of true vessel geometry when compared with standard two-dimensional (2-D) QCA and has been validated by intravascular ultrasound (IVUS). Although IVUS is currently thought to provide the most accurate measurements of vessel geometry and lesion severity, 3-D QCA measurements can be performed on existing standard coronary angiography images without the need for additional time or equipment during the procedure. Hypothesis: We assessed the hypothesis that 3-D QCA measurements and IVUS are comparable in accuracy in predicting physiologically significant stenosis assessed by fractional flow reserve (FFR). Methods: Forty lesions in 38 patients were assessed by FFR, IVUS, and 2-D and 3-D QCA. Correlations between anatomical data and FFR were analyzed. The area under the receiver-operating characteristic (ROC) curve (AUC) was calculated to identify the accuracy of predicting FFR ≤0.80. Results: Mean FFR value was 0.75 ± 0.13. FFR ≤0.80 was observed in 26 lesions (65%). Of all measurements of lesion severity obtained by IVUS, minimum lumen diameter (MLD) (r = 0.80, p &lt;0.001) and minimum lumen area (MLA) (r = 0.72, p &lt;0.001) were well correlated with FFR values. Of all 3-D QCA measurements, MLA correlated best with FFR values (r = 0.75, p &lt;0.001). Of all 2-D QCA measurements, MLD correlated best with FFR values (r = 0.58, p &lt;0.001). The AUC were 0.95 for MLA by IVUS, 0.93 for MLD by IVUS, 0.93 for MLA by 3-D QCA, and 0.78 for MLD by 2-D QCA (Figure). Conclusions: Anatomical parameters obtained by 3-D QCA and IVUS correlate better with FFR values than those obtained by 2-D QCA. The predictive value of 3-D QCA for reduced FFR is comparable to IVUS measurements.

A successful treatment for a lesion of chronic total occlusion with contralateral angiography in a single radial access

A 50-year-old man was admitted due to effort chest pain. Coronary angiogram showed a total occlusion of LAD. The 5-French JL 3.5 was engaged into the left coronary artery. The XT-A guidewire was advanced to the distal of the occluded lesion. Contralateral angiography was performed using JL 3.5. The guiding catheter was pullback from the left coronary orifice leaving the guidewire at LAD, and the catheter tip was rotated clockwise to right coronary cusp for right coronary angiography. We could confirm that the guidewire was in the true lumen vessel.

Retinal Vessels Segmentation Using Supervised Classifiers for Identification of Cardio Vascular Diseases

The risk of cardio vascular diseases can be identified by measuring the retinal blood vessel. The identification of wrong blood vessel may result in wrong clinical diagnosis. This proposed system addresses the problem of identifying the true vessel by vascular structure segmentation. In this proposed model the segmented vascular structure is modelled as a vessel segment graph and the true vessels are identified by using supervised classifier approach. This paper proposes a post processing step in diagnose cardiovascular diseases which can be identified by tracking a true vessel from the optimal forest in the graph given a set on constraints.

Physical properties of surface outcrop cataclastic fault rocks, Alpine Fault, New Zealand

We present a unified analysis of physical properties of cataclastic fault rocks collected from surface exposures of the central Alpine Fault at Gaunt Creek and Waikukupa River, New Zealand. Friction experiments on fault gouge and intact samples of cataclasite were conducted at 30–33 MPa effective normal stress (σn′) using a double‐direct shear configuration and controlled pore fluid pressure in a true triaxial pressure vessel. Samples from a scarp outcrop on the southwest bank of Gaunt Creek display (1) an increase in fault normal permeability (k = 7.45 × 10−20 m2 to k = 1.15 × 10−16 m2), (2) a transition from frictionally weak (μ = 0.44) fault gouge to frictionally strong (μ = 0.50–0.55) cataclasite, (3) a change in friction rate dependence (a‐b) from solely velocity strengthening, to velocity strengthening and weakening, and (4) an increase in the rate of frictional healing with increasing distance from the footwall fluvioglacial gravels contact. At Gaunt Creek, alteration of the primary clay minerals chlorite and illite/muscovite to smectite, kaolinite, and goethite accompanies an increase in friction coefficient (μ = 0.31 to μ = 0.44) and fault‐perpendicular permeability (k = 3.10 × 10−20 m2 to k = 7.45 × 10−20 m2). Comminution of frictionally strong (μ = 0.51–0.57) cataclasites forms weaker (μ = 0.31–0.50) foliated cataclasites and fault gouges with behaviors associated with aseismic creep at low strain rates. Combined with published evidence of large magnitude (Mw ∼ 8) surface ruptures on the Alpine Fault, petrological observations indicate that shear failure involved frictional sliding within previously formed, velocity‐strengthening fault gouge.

Perspective on the Use of True Vessel Characterization Imaging in Interventional Cardiology Clinical Practice

Intracoronary near infrared spectroscopy (NIRS), incorporated in the True Vessel Characterization (TVC) Imaging System™, is a novel method for the identification and quantification of lipid composition in coronary plaques. The main advantage of NIRS over other plaque characterisation methods is its ability to directly identify chemical composition – the primary use of spectroscopy for other applications. NIRS by itself does not display structures, but a combination device with co-registered intravascular ultrasound (IVUS) has been developed to give simultaneous and complementary structural and compositional information. Identification of lipid core plaque with NIRS hypothetically has the potential to optimise the length of vessel to stent and to lead to effective utilisation of embolic protection devices in the native coronaries, identifying the exact location of lipid-core lesions at high risk of distal embolisation. The NIRS-IVUS device also has promise in the identification of vulnerable plaque, which may lead to strategies to prevent future coronary events.

Coronary Artery Center-Line Extraction Using Second Order Local Features

Of interest is the accurate and robust delineation of vessel center-lines for complete arterial tree structure in coronary angiograms which is an imperative step towards 3D reconstruction of coronary tree and feature-based registration of multiple view angiograms. Most existing center-line tracking methods encounter limitations in coping with abrupt variations in local artery direction and sudden changes of lumen diameter that occur in the vicinity of arterial lesions. This paper presents an improved center-line tracing algorithm for automatic extraction of coronary arterial tree based on robust local features. The algorithm employs an improved scanning schema based on eigenvalues of Hessian matrix for reliable identification of true vessel points as well as an adaptive look-ahead distance schema for calculating the magnitude of scanning profile. In addition to a huge variety of clinical examples, a well-established vessel simulation tool was used to create several synthetic angiograms for objective comparison and performance evaluation. The experimental results on the accuracy and robustness of the proposed algorithm and its counterparts under difficult situations such as poor image quality and complicated vessel geometry are presented.

SHA 042. ECG an important diagnostic test in cases of Duchene muscular dystrophy

tool of interest to those who primarily engaged in research. IVUS since then became a resource for true luminal and vessel wall Histo-pathological definitions that provided invaluable details. However since the era of good old balloon angioplasty the role of IVUS remained limited to certain applications that included among others angiographic borderline lesions, limited dissections, ambiguous angiographic findings, calcifications and to a lesser extent thrombi. The era of Drug Eluting Stenting (DES) brought additional challenges to modern Per-cutaneous Coronary Interventions (PCI) including issues of Stent sizes and deployment pressures, issues of Stent mal-apposition acute or acquired and Geographic miss. Many of these concerns remained under estimated until we were shocked with the scare of stent thrombosis early late or very late by 2006. The role of IVUS hence became much more contributing and set additional standards of Stent deployment techniques; Of particular importance, the various niche applications like Left Main, Bifurcational, Osteal Stenting and increasing off-label applications of long overlapping stents. IVUS as well enhanced our ability to define causes of stent failures including stent fractures, other stent deformities and malappositions. More recently IVUS introduced forward imaging catheters that are likely to enhance the safety and success of Chronic Total Occlusion Interventions. In addition to grey scale IVUS the introduction of Histo-Pathological simulations using Virtual Histology (VH) and more recently i-map technology is increasingly becoming a niche application for detecting vulnerable plaque providing better definition of Thin Cap Fibro Atheroma (TICFA) that emerged as potential cause of Acute Coronary Syndromes (ACS) and Stent failure when associated with geographic miss. With more outcome trials and emerging additional therapies VH-IVUS is likely to provide An emerging strategy of potential remedial approaches for Vulnerable plaque including lesion pacification whether by intensive medical therapy or possibly Stenting.

Multicentre experience with the BridgePoint devices to facilitate recanalisation of chronic total coronary occlusions through controlled subintimal re-entry

The major challenge for the interventional treatment of chronic total coronary occlusion (CTO) is a low primary success rate. A common problem is the passage of the recanalisation wire into a subintimal position. New devices, which were evaluated in the first multicentre study in CTOs resistant to a conventional wire approach, may help to facilitate a controlled re-entry into the true lumen. The aim of this study was to assess the safety and efficacy of this approach, with successful true lumen distal wire passage as the primary endpoint. Forty-two patients were enrolled in four centres with high expertise in PCI for CTOs. All CTOs were of at least three months duration, and were initially attempted with dedicated recanalisation wires. After failure to pass or creation of a subintimal dissection, the BridgePoint devices were applied, consisting of a ball-tipped catheter (CrossBoss) to pass the proximal occlusion cap, and a flat-shaped balloon catheter (Stingray catheter) to be inflated within the subintimal space to guide the re-entry into the true vessel lumen with a special wire (Stingray guidewire). The primary endpoint was met in 67% of all patients. A higher success rate seemed to be possible when all devices were used in sequenced beginning with the CrossBoss, and in the case of a subintimal passage, followed by the Stingray. True lumen re-entry failed because of the loss of distally contrast filling and thus loss of a target for re-entry, and by a failure to advance the Stingray balloon far enough distal and parallel to the distal lumen. There were no severe device related complications. In patients with complex CTOs referred to dedicated centres with high experience in CTOs, these results demonstrate the potential of a guided re-entry from a subintimal wire position by use of the BridgePoint devices.

The Diffuse Hyperdense Intracranial Circulation Sign

A 53-year-old man arrived in our Emergency Department comatose, with a GCS of E1V1M4, with unreactive 4-mm pupils, present corneal reflexes, and absent oculocephalics. His noncontrast head computed tomography (CT) revealed hyperdensity of the bilateral MCAs and basilar artery (Figure, upper left), as well as the sagittal sinus (SS) mimicking a “delta sign” of SS thrombosis (Figure, upper right). The “hyperdense artery sign” is an indicator of poor prognosis in acute stroke.1 However, it is important to recognize diffuse hyperdensity of the arteries and venous sinuses, which signify either elevated hematocrit (56% in our patient), polycythemia (smoking or polycthemia vera), or severe dehydration/hemoconcentration.2 This finding may create a “false-positive” dense artery sign unrelated to the true occluded vessel(s), which was a vertebrobasilar dissection/embolism in our case (Figure, bottom left, intracranial MRA demonstrating occluded right vertebral artery (V3) and narrowed V4 segment as well as occluded left PCA P1-P2 junction from a distally propagated embolism. Figure, bottom right, intracranial and extracranial MRA (gadolinium bolus) demonstrating an occluded right V3 vertebral artery segment).

Serial intravascular ultrasound assessment of changes in coronary atherosclerotic plaque dimensions and composition: an update

This manuscript reviews the use of serial intravascular ultrasound (IVUS) examination of coronary atherosclerosis in recent observational studies and randomized trials that revealed the effects of cholesterol-lowering and lipid-modifying therapies and offered novel insight into plaque progression and regression. We discuss the value of plaque progression-regression as complementary imaging endpoint and potential surrogate marker of cardiovascular event risk. In addition, the progress in serial assessment of coronary plaque composition and plaque vulnerability by radiofrequency-based analyses is reviewed. Finally, we report on the evaluation of true vessel remodelling in recent serial IVUS trials and discuss the future perspective of serial invasive imaging of coronary atherosclerosis.