Entire Vessel Research Articles

In Vivo Assessment of Retinal Vascular Wall Dimensions

Retinal blood vessel diameter and arteriovenous ratio (AVR) are commonly used diagnostic parameters. Because vascular walls are typically not visible in funduscopy, clinical AVR estimation is based on the lumen rather than the entire vessel diameter. Here the authors used a transgenic mouse model to quantify AVR in vivo based on total vessel dimensions (wall and lumen). Confocal scanning laser ophthalmoscopy (cSLO) and indocyanine green angiography of the retinal vasculature were performed in wild-type and transgenic mice expressing green fluorescent protein (GFP) under the transcriptional control of the smooth muscle type α-actin (αSMA) promoter. Spectral-domain-OCT and ERG were performed to control for integrity of retinal structure and function in vivo and histology to demonstrate the location of GFP expression. Native cSLO imaging and angiography yielded only inner vessel diameters similar to those observed through clinical funduscopy. In αSMA-GFP mice, autofluorescence imaging of the GFP-marked vascular walls also allowed the determination of outer vessel diameters. The mean AVR based on either inner diameter (AVR(id) = 0.72 ± 0.08) or outer diameter (AVR(od) = 0.97 ± 0.09) measurements were significantly different (P < 0.01). Transgenic αSMA-GFP expression in murine vessel wall components allowed quantification of retinal vessel outer diameters in vivo. Although arterioles and venules differ in lumen and vessel wall width, they share a common outer diameter, leading to an AVR(od) close to unity. Because vessel walls are primary targets in common hypertensive and metabolic diseases, αSMA-GFP transgenic mice may prove valuable in the detailed assessment of such disorders in vivo.

Mineralogical and textural variation of silica minerals in hydrothermal flow-through experiments: Implications for quartz vein formation

We conducted hydrothermal flow-through experiments at 430 °C and 31 MPa to investigate the mechanism of silica precipitation on granite under crustal conditions. Two experiments were performed using different input solutions: a single-component Si solution, and a multi-component solution with minor Al, Na, and K. The degree of supersaturation with respect to quartz, Ω = CSi/CSi,Qtz,eq, where CSi and CSi,Qtz,eq indicate Si concentration in solutions and the solubility of quartz within water, respectively, decreased from 3–3.5 to <1.1 along the flow path. A variety of silica minerals formed during the experiments (opal-A, opal-C, chalcedony, and quartz), and their occurrences and modal abundances changed in response to Ω and the presence of additives in the solution. For near-equilibrium solutions (Ω ∼1.2), silica minerals were deposited on other surfaces in addition to quartz. In the single-component experiment, the dominant silica minerals changed in the order of opal-A → opal-C → quartz with decreasing Si concentration along the flow path. In contrast, in the multi-component experiment, quartz and minor chalcedony formed throughout the entire reaction vessel. This finding indicates that impurities (Na, K, and Al) in the solutions inhibited the precipitation of opal and enhanced the direct nucleation of quartz. The systematic appearance of metastable silica minerals were examined by nucleation processes and macroscopic precipitation kinetics. Our experimental results indicate that different precipitation mechanisms yield contrasting textures, which in turn suggests that vein textures can be used as indicators of solution chemistry within the fracture.

Spatial continuity incorporated multi-attribute fuzzy clustering algorithm for blood vessels segmentation

A three-dimensional representation of vasculature can be extremely important in image-guided neurosurgery, pre-surgical planning. In this paper, a spatial continuity incorporated multi-attribute fuzzy clustering algorithm (MAFCM_S) is proposed to segment entire blood vessels from TOF MRA images. This clustering method takes both the intensity information and the geometrical information into account, while most of the current clustering methods only deal with the former. In this method, a new dissimilarity measure, which integrates the intensity and the geometry shape dissimilarity, is introduced. Because of the presence of the geometrical information, the new measure is able to differentiate the pixels with similar intensity values within different geometrical shape structures. Experimental results show that the new algorithm can get better segmentation.

Segmentation of linear structures from medical images

Abstract In this paper, an algorithm for the extraction of linear structures from medical images is implemented. Blood vessels in angiographic images have linear patterns. Hence, these features can be extracted easily using morphological operations. Blood vessels can be separated out as they have a specific Gaussian-like profile whose curvature varies smoothly along the vessel. In order to differentiate vessels from analogous background patterns, edge detection is performed and the application of linear filters like top-hat transformations can eliminate the background noise, thereby segmenting the entire blood vessels in the angiographic image. Such vessel extraction could help physicians in the computation of parameters related to blood flow.

Traumatic Pseudoaneurysm of the Middle Meningeal Artery Causing an Intracerebral Hemorrhage

Traumatic aneurysms comprise less than 1% of all intracranial aneurysms. Most of these aneurysms are actually false aneurysms, or pseudoaneurysms, which are caused by the rupture of entire vessel wall layers, with the wall of the aneurysm being formed by the surrounding cerebral structures. Traumatic pseudoaneurysms of the middle meningeal artery are also rare. Only four cases have been reported in the literature with intracerebral hematoma. In this paper, the authors report a case of a patient with a ruptured traumatic pseudoaneurysm of the MMA who presented with an intracerebral hematoma in the left temporal region immediately after trauma; the patient underwent endovascular treatment.

A general purpose diagnostic technique for marine diesel engines – Application on the main propulsion and auxiliary diesel units of a marine vessel

Diesel engines are widely used in marine applications (i.e. propulsion and auxiliaries) except from a few cases where gas or steam turbines are used. This is the result of their high efficiency, power concentration and reliability compared to other compatible or alternative power sources. The proper and efficient operation of the engines (main engine and diesel generator units) in marine applications is critical, and therefore techniques or systems that determine engine current condition and detect potential faults are extremely important. Furthermore, it is advantageous when such techniques can be applied on different engine configurations and provide reliable results, because on a vessel usually exist diesel engines of different type, i.e. the main propulsion unit is a large low-speed two-stroke diesel engine while the diesel generators are four-stroke medium or high speed engines. In the present work is described and evaluated for the first time the application of an improved diagnostic technique, developed by the authors, on both the main engine and the auxiliary units of a commercial marine vessel. The diagnostic technique is based on a thermodynamic simulation model. The simulation model embedded in the technique has been modified, namely an existing two-zone model is replaced by a multi-zone one. With this modification it is avoided model constant tuning with the operating conditions. This is extremely important for the diagnostic philosophy of the proposed technique. Using data from engine shop tests, the simulation model is calibrated (i.e. model constants are determined) and the engine reference condition is obtained. The simulation model is then used to estimate the current engine condition, using field measurements (i.e. cylinder pressure measurements, periphery data, etc.). From the results it is revealed that the diagnosis method provides detailed information for the operating condition of both engines and the values of parameters that cannot be measured on the field. To further evaluate the diagnostic procedure, results of the diagnosis analysis are compared with respective readings from existing instrumentation (i.e. brake power output, etc.), showing good agreement. From the investigation it is shown that the diagnostic technique can be applied on both engine types without modifications providing a useful integrated solution for the entire vessel power plant. This is extremely important because conventional systems are usually suitable only for the main engine even though auxiliary units are of significant importance.

Relationship between LDL, HDL, blood pressure and atheroma progression in the coronaries

To highlight clinical trials that have employed coronary artery imaging to evaluate the impact of medical therapies that target established cardiovascular risk factors. High resolution imaging of the entire vessel wall permits assessment of changes in the full extent of coronary atherosclerosis. Intensive lowering of LDL cholesterol and systolic blood pressure are associated with the greatest benefit in terms of slowing disease progression. Therapeutic approaches that promote the biological activity of HDL have the potential to promote regression of atherosclerotic plaque. Targeting inflammatory cascades may also have a beneficial effect on the extent and composition of coronary plaque. Intensive modification of established risk factors has a profound impact on the natural history of atheroma progression.

Intimal dissection of the hepatic artery following transarterial embolization for hepatocellular carcinoma: An intraoperative problem in adult living donor liver transplantation

The objective of this study was to describe the relationship between intimal dissection (ID) in the recipient hepatic artery (HA) and transarterial embolization (TAE) and highlight the reconstructive methods for the different types of ID encountered in living donor liver transplantation (LDLT). Fifty-four patients with hepatocellular carcinoma underwent LDLT. ID was classified as mild, moderate, or severe, and this classification was based on the extent of intimal injury. Mild, moderate, or severe ID were defined as ID that was less than one-quarter of the circumference of the HA, had reached one-half of the circumference of the HA, or was more than one-half of the circumference of the HA or involved the entire vessel wall, respectively. The reconstructive methods were based on the severity of ID encountered. Forty patients underwent TAE before LDLT, and 23 of these patients (57.5%) had ID. Nine patients had mild ID, 6 had moderate ID, and 8 had severe ID. In the 14 patients who did not undergo TAE, 4 had ID (28.6%; 3 mild and 1 severe). The other 10 patients (71.4%) had normal HA. In mild and moderate ID, the native HA was used after trimming of the HA until a healthy segment was encountered. In severe ID, the HA was reconstructed with alternative vessels. Two HA thromboses occurred postoperatively. TAE increased the risk of developing ID 2-fold. There was no graft loss or mortality in this series due to HA complications. In conclusion, ID of the HA is associated with pretransplant TAE among hepatocellular carcinoma patients undergoing LDLT. Intraoperative recognition of this complication and trimming until good vessel quality is encountered or using alternative vessels are important.

Mean Volume Flow Estimation in Pulsatile Flow Conditions

To verify a previously reported three-dimensional (3D) ultrasound method for the measurement of time-average volumetric blood flow, experiments were performed under pulsatile flow conditions, including in vivo investigations, and results were compared with accepted, but invasive, “gold standard” techniques. Results showed that volume averaging results in the correct time-average volume flow without the need for cardiac gating. Unlike other currently employed methods, this method is independent of Doppler angle, flow profile and vessel geometry. A GE Logiq 9 ultrasound system (GE Medical Systems, Milwaukee, WI, USA) and a four-dimensional (4D) 10L and 4D 16L probe were used to acquire 3D Doppler measurements in the femoral and carotid arteries of four canines. Two invasive blood flow meters were used (electromagnetic for one canine and ultrasonic for three canines) as the gold standard techniques. Transcutaneous color flow measurements were taken to obtain 3D volume data sets encompassing the vessel. Constant depth planes were used to integrate color flow pixels encompassing the entire vessel cross-section. Power Doppler data were used to correct for partial volume effects. An artificial stenosis was induced to vary the ambient volume flow. Unrestricted, bidirectional flow was measured as high as 400 mL min -1. Several flow restrictions were imposed that decreased the measured volumetric flow rate to as low as 30 mL min -1. All flow rate estimates ( n = 38) were plotted against results obtained via the gold standards. A general line fit resulted in y = 0.926 x - 0.87 (r 2 = 0.95), which corresponds to a 0.6% flow offset relative to the average flow rate of 142 mL min -1, as well as a 7.4% error in the linearity of our estimate. A secondary curve fit was performed that required the slope to be 1 and the intercept to be 0, which yielded an r 2-value of 0.93. The percent-error distribution was computed and fitted to a Gaussian function, which yielded μ = -7.04% and σ = 9.52%. Theoretical studies were conducted to estimate the expected error in our volume flow measurements as a function of number of samples (N) used for averaging pulsatile waveforms. Experiments showed the same 1 / N dependence as theory. Direct comparisons of volume flow rate estimates using volumetric color Doppler and independent standards showed that our method has good accuracy under in vivo pulsatile blood flow conditions. (E-mail: greentom@umich.edu)

Microfoam formation in a capillary

The ultrasound-induced formation of bubble clusters may be of interest as a therapeutic means. If the clusters behave as one entity, i.e., one mega-bubble, its ultrasonic manipulation towards a boundary is straightforward and quick. If the clusters can be forced to accumulate to a microfoam, entire vessels might be blocked on purpose using an ultrasound contrast agent and a sound source. In this paper, we analyse how ultrasound contrast agent clusters are formed in a capillary and what happens to the clusters if sonication is continued, using continuous driving frequencies in the range 1–10 MHz. Furthermore, we show high-speed camera footage of microbubble clustering phenomena. We observed the following stages of microfoam formation within a dense population of microbubbles before ultrasound arrival. After the sonication started, contrast microbubbles collided, forming small clusters, owing to secondary radiation forces. These clusters coalesced within the space of a quarter of the ultrasonic wavelength, owing to primary radiation forces. The resulting microfoams translated in the direction of the ultrasound field, hitting the capillary wall, also owing to primary radiation forces. We have demonstrated that as soon as the bubble clusters are formed and as long as they are in the sound field, they behave as one entity. At our acoustic settings, it takes seconds to force the bubble clusters to positions approximately a quarter wavelength apart. It also just takes seconds to drive the clusters towards the capillary wall. Subjecting an ultrasound contrast agent of given concentration to a continuous low-amplitude signal makes it cluster to a microfoam of known position and known size, allowing for sonic manipulation.

Peripheral Magnetic Resonance Angiography With Continuous Table Movement in Combination With High Spatial and Temporal Resolution Time-Resolved MRA With a Total Single Dose (0.1 mmol/kg) of Gadobutrol at 3.0 T

To prove the concept of peripheral continuous table movement (CTM) MR-angiography (MRA) in combination with high spatial and temporal resolution time-resolved TWIST-MRA in a single MR-examination at 3.0 T with a single dose (0.1 mmol/kg) of gadobutrol in total. We included 22 consecutive patients (15 m/7 f, mean age: 64 years) referred for peripheral MRA with clinical symptoms of peripheral arterial occlusive disease Fontaine stages II-IV. All of them underwent both CTM-MRA (TR: 2.4 ms/TE: 1.0 ms/flip angle: 21 degree) of the entire run-off vessels and TWIST-MRA (TR: 2.8 ms/TE: 1.1 ms/flip angle: 20 degree) of the calf station during a single MR-examination. All examinations were performed on a 3.0 T MR system (Tim Trio). Spatial resolution of the CTM-MRA datasets was technically limited to an acquired resolution of 1.2 x 1.2 x 1.96 mm3 reconstructed to 1.2 mm isotropic. The TWIST-MRA was acquired with 1.1 x 1.1 x 1.35 mm3 and reconstructed to 1.1 mm isotropic with a temporal resolution of 5.5 seconds in the calf station. A total of 0.1 mmol/kg BW gadobutrol diluted 1:1 with saline was injected at a flow rate of 1.5 mL/s of which 0.07 mmol/kg was administered for the CTM-MRA and 0.03 mmol/kg for the TWIST-MRA. CTM-MRA run off datasets were qualitatively assessed using a 4 point scale (4 = excellent, 1 = nondiagnostic) followed by TWIST-MRA datasets for the calf using the same scale. Additional relevant findings only visible in the TWIST-MRA were documented. All datasets could be evaluated with a total of 397 assessable segments. CTM-MRA was diagnostic in 99% (393/397 segments) with image quality judged as excellent in 54% (213/397 segments), good in 42% (14/397), and moderate in 4% (14/397) of analyzed segments respectively. Nondiagnostic image quality was seen in 1% (4/397 segments). Venous overlay in the calf station was found in 27% (6/22 patients). TWIST-MRA was diagnostic in 100% (115/115 segments), throughout with good or excellent image quality. In 14 of 22 patients additional relevant findings were detected by TWIST-MRA. Single-dose gadobutrol CTM-MRA in combination with a high spatial and temporal resolution TWIST-MRA at 3.0 T is a reliable technique with good image quality. Despite the use of single dose contrast agent large field of view coverage and dynamic images can be acquired. Because of its robustness, this imaging approach of the vasculature has great potential for a broad clinical use.

Grayscale intravascular ultrasound: Current concepts in percutaneous coronary interventions

Compared with angiography alone, intravascular ultrasound (IVUS) provides far greater detail with regard to the entire coronary vessel. IVUS has given valuable insight into the mechanisms of coronary atherosclerosis, plaque rupture, and stabilization as well as bare metal and drug-eluting stent mechanisms of restenosis and thrombosis. Additionally, IVUS-derived principles of expansion, apposition, and lesion coverage can aid in optimizing stent deployment and acute procedural results. Ultimately, its use may prevent adverse events related to percutaneous revascularization.

Enhanced interstitial flow as a contributing factor in neointima formation: (shear) stressing vascular wall cell types other than the endothelium

AS BLOOD FLOWS THROUGH the vascular network, it creates fluid mechanical forces that can be predicted based on established physical principles of fluid dynamics. The major components of flow-generated force in the vasculature include pressure and shear stress, both of which are imparted directly onto the vessel wall. The realization that different patterns (laminar vs. oscillatory), magnitudes (high vs. low), and spatial gradients of shear stress can influence the overall vessel homeostasis has led to an intense investigation into how shear stress regulates the structural and functional phenotype of the blood vessel. Through the work of many dedicated laboratories, we are now certain that shear stress exerts a profound effect on endothelial cells which line all vessels. The endothelium, in turn, can communicate the condition of the hemodynamic environment to which it is exposed to underlying vascular components such as smooth muscle and adventitial fibroblasts, resulting in a propagation of shear stress effects to the entire vessel wall. To illustrate this point, changes in shear stress are perceived by the endothelium and converted in biochemical signals, which are then relayed to enzyme systems that generate vasoactive substances such as nitric oxide (NO). Through a paracrine effect, NO activates the molecular machinery that governs smooth muscle contractility, thereby translating changes in shear stress into an alteration of vessel diameter. In the normal, intact vasculature, the endothelial layer forms an interface between the blood and the remaining components of the vascular wall. Thus vascular smooth muscle and adventitial fibroblasts are remote from the actual hemodynamic shear forces. As a result, the direct influence of shear stress on these mural cell types has received little attention. Rather, the stretch generated via the rhythmic expansion and contraction of the vessel wall with each successive pulse of pressure and bloodflow appears to be the dominant hemodynamic stimuli for smooth muscle and, potentially, adventitial cells. Indeed, cyclic stretch has been shown to activate mechanotransduction pathways that lead to functional responses in these cell, and readers are directed to an excellent review in this area (4). So, if smooth muscle and adventitial cells are shielded, in a relative sense, from shear stress and are most responsive to hemodynamic-imposed stretch, the influences of shear stress would seem to be of little concern in these cell types. However, if one considers the forces produced by the flow of interstitial fluid through the vessel wall, then shear stress forces may in fact be an important factor in regulating smooth muscle cells and vessel wall integrity. This concept may have clinical ramifications given that factors which enhance interstitial flow (i.e., chemical or mechanical injury to the endothelium and inflammation and hypertension induced enhancement of vascular permeability) are associated with vessel remodeling and neointima formation. The basic notion that vascular smooth muscle and fibroblasts are responsive to shear stress has been tested by several investigative teams in the past. Laminar shear stress ranging from 10 to

Assessment of extracranial–intracranial bypass patency with 64-slice multidetector computerized tomography angiography

Extracranial-intracranial (EC/IC) bypass is a useful procedure for the treatment of cerebral vascular insufficiency or complex aneurysms. We explored the role of multidetector computed tomography angiography (MDCTA), instead of digital subtraction angiography (DSA), for the postoperative assessment of EC/IC bypass patency. We retrospectively analyzed a consecutive series of 21 MDCTAs from 17 patients that underwent 25 direct or indirect EC/IC bypass procedures between April 2003 and November 2007. Conventional DSA was available for comparison in 13 cases. MDCTA used a 64-slice MDCT scanner (Aquilion 64, Toshiba). The proximal and distal patencies were analyzed independently on MDCTA and DSA by a neuroradiologist and a neurosurgeon. The bypass was considered patent when the entire donor vessel was opacified without discontinuity from proximal to distal ends and was visibly in contact with the recipient vessel. MDCTA depicted the patency status in every patient. Bypasses were patent in 22 cases, stenosed in one, and occluded in two. DSA always confirmed the results of the MDCTA (sensitivity = 100%, 95% CI = 0.655-1.0; specificity 100%, 95% CI = 0.05-1.0). MDCTA is a non-invasive and accurate exam to assess the postoperative EC/IC bypass patency and is a promising technique in routine follow-up.

Endovascular Treatment of Large Intracranial Aneurysms by Neuroform Stent-Assisted Coil Placement

Large intracranial aneurysms represent huge therapeutic challenges for neurosurgeons and endovascular therapists. Since they may involve entire vessels or be irregular in shape, the ratio of complete obliteration of these aneurysms with detachable coils is low and the incidence of recanalisation is very high. So the technique of stent-assisted coil placement was designed for the treatment of large intracranial aneurysms. We report our experience in the treatment of large or complex and wide-necked aneurysms using Neuroform stent-assisted coil placement. Thirty-six patients harboring large intracranial aneurysms were treated by Neuroform stent-assisted coil placement. Thirty-five Neuroform stents were delivered and deployed at the desired location. Of the 35 aneurysms successfully stented, all the aneurysms were occluded with stent-assisted coiling. Twenty-six were totally occluded, four achieved subtotal occlusion, and five incomplete occlusion at the end of the procedure. There were no complications related to the procedure except the migration of stents in two cases. All the patients recovered well. Though Neuroform stent-assisted coil placement may be a favorable technique for treatment of large intracranial aneurysms, further study is necessary to assess the long-term outcome.

Dosimetry study for -radiation treatment of in-stent restenosis

Intravascular brachytherapy (IVBT) has been recognised as a treatment modality for reducing coronary restenosis after angioplasty and stent-implantation procedures. For the treatment of in-stent restenosis using beta-emitter (188)Re, delivering adequate doses to the entire vessel wall is not possible without the potential of overdosing tissues. A method to measure the dose distribution, perturbation and percentage depth dose using plane-parallel and cylindrical tissue-equivalent phantoms has been developed. Good agreement was found between experimental results and Monte Carlo simulation performed using MCNP4C code. The dose given to the affected area in the vascular region for intravascular radiation treatment was 15-30 Gy. Dose inhomogeneity beyond the stent surface decreased significantly with increasing radial distance. In the region close to the stent outer surface (>0.5-mm radial distance), a dose reduction of 11-17% due to the stent was observed. However, the dose perturbations due to the physical properties of metallic stents were found to be significant in IVBT for in-stent restenosis by using measured dose profiles in phantoms. The method can provide accuracy in beta isotope in vivo dosimetry results for treatments involving short-range dose distributions and provide a relatively high-level spatial resolution for detection.

English

Filament-wound composite pressure vessels are an important type of high-pressure container that is widely used in the commercial and aerospace industries. The pressure vessels with integrated end domes develop hoop stresses that are twice longitudinal stresses and when isotropic materials like metals are used for realizing the hardware, the material is not fully utilized in the longitudinal/meridonial direction resulting in over weight components. On the other hand FRP composite materials with their higher specific strength and moduli and tailoribility characteristics will result in reduction of weight of the structure. The determination of a proper winding angle and thickness is very important to decrease manufacturing difficulties and to increase structural efficiency. In this study, material characterization of FRP of carbon T300/Epoxy for various configurations as per ASTM standards is experimentally determined using filament winding and matched die mould technique. The mechanical and physical properties thus obtained are used in the design of the composite shell. The design of the composite shell is described in detail. Netting analysis is used for the calculation of hoop and helical thickness of the shell. A balanced symmetric ply sequence for carbon T300/epoxy is considered for the entire pressure vessel. Progressive failure analysis of composite pressure vessel with geodesic end domes is carried out. A software code SHELL Solver is developed using Classical Lamination-theory to determine matrix crack failure, burst pressure values at various positions of the shell. The results can be utilized to understand structural characteristics of filament wound pressure vessels with integrated end domes.Defence Science Journal, 2009, 59(1), pp.73-81, DOI:http://dx.doi.org/10.14429/dsj.59.1488

In vivo 3D modeling of the femoropopliteal artery in human subjects based on x‐ray angiography: Methodology and validation

Endovascular revascularization of the femoropopliteal (FP) artery has been limited by high rates of restenosis and stent fracture. The unique physical forces that are applied to the FP artery during leg movement have been implicated in these phenomena. The foundation for measuring the effects of physical forces on the FP artery in a clinically relevant environment is based on the ability to develop 3D models of this vessel in different leg positions in vivo in patients with peripheral arterial disease (PAD). By acquiring paired angiographic images of the FP artery, and using angiography-based 3D modeling algorithms previously validated in the coronary arteries, the authors generated 3D models of ten FP arteries in nine patients with PAD with the lower extremity in straight leg (SL) and crossed leg (CL) positions. Due to the length of the FP artery, overlapping paired angiographic images of the entire FP artery were required to image the entire vessel, which necessitated the development of a novel fusion process in order to generate a 3D model of the entire FP artery. The methodology of angiographic acquisition and 3D model generation of the FP artery is described. In a subset of patients, a third angiographic view (i.e., validation view) was acquired in addition to the standard paired views for the purpose of validating the 3D modeling process. The mean root-mean-square (rms) error of the point-to-point distances between the centerline of the main FP artery from the 2D validation view and the centerline from the 3D model placed in the validation view for the SL and CL positions were 0.93 +/- 0.19 mm and 1.12 +/- 0.25 mm, respectively. Similarly, the mean rms error of the same comparison for the main FP artery and sidebranches for the SL and CL positions were 1.09 +/- 0.38 mm and 1.21 +/- 0.25 mm, respectively. A separate validation of the novel fusion process was performed by comparing the 3D model of the FP artery derived from fusion of 3D models of adjacent FP segments with the 2D validation view incorporating the region of fusion. The mean rms error of vessel centerline points of the main FP artery, the main FP artery plus directly connected sidebranches, and the mean rms error of upstream, downstream, and sidebranch directional vectors at bifurcation points in the overlap region were 1.41 +/- 0.79 mm, 2.13 +/- 1.12 mm, 3.16 +/- 3.72 degrees, 3.60 +/- 5.39 degrees, and 8.68 +/- 8.42 degrees in the SL position, respectively, and 1.29 +/- 0.35 mm, 1.61 +/- 0.78 mm, 4.68 +/- 4.08 degrees, 3.41 +/- 2.23 degrees, and 5.52 +/- 4.41 degrees in the CL position, respectively. Inter- and intraobserver variability in the generation of 3D models of individual FP segments and the fusion of overlapping FP segments were assessed. The mean rms errors between the centerlines of nine 3D models of individual FP segments generated by two independent observers, and repeated measurement by the same observer were 2.78 +/- 1.26 mm and 3.50 +/- 1.15 mm, respectively. The mean rms errors between the centerline of four 3D models of fused overlapping FP segments generated by two independent observers, and repeated measurement by the same observer were 4.99 +/- 0.99 mm and 5.98 +/- 1.22 mm, respectively. This study documents the ability to generate 3D models of the entire FP artery in vivo in patients with PAD in both SL and CL positions using routine angiography, and validates the methodologies used.

First Application of Cellular Nonlinear Network Methods to the Real-Time Identification of Hot Spots in JET

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In order to qualify materials and develop integrated scenarios for ITER, Joint European Torus (JET) is going to operate with a new wall consisting of beryllium in the main chamber and tungsten in the divertor. These new materials will require particular care when the machine operates, considering that they are much more vulnerable than the present combination of graphite and stainless steel. Early detection of hot spots, which are regions of the first wall where the temperature approaches dangerous levels, is considered one essential element in the safety strategy. In this paper, cellular nonlinear networks (CNNs) are applied to the task of detecting hot spots in the infrared images of JET wide-angle camera. The ability of the CNNs to process the pixels of the images in parallel makes this technology a very good candidate for this task. Various algorithms are presented, which can locate the hot regions in any part of the image with a temporal resolution on the order of 60 ms, which is considered adequate for safety purposes at JET. In addition to the frame-by-frame static identification of the hot spots, their evolution in time is also followed to determine if they approach dangerous parts of the vacuum vessel. The potential of the CNNs would therefore allow for the implementation of alternative protection strategies, such as following the increase and displacement of the hot spots inside the entire vacuum vessel and identifying particles dropping into the plasma. </para>

Karakteristike najstarije slavenske keramike. Primjer lonca iz objekta SO 11 s nalazišta Murska Sobota - Nova Tabla

Prilog analizira značajke rane slavenske proizvodnje keramike na temelju nalaza iz prvog horizonta naseljavanja na širem području Murske Sobote. Osim očitih razlika, u odnosu prema starijim keramičkim proizvodima kasne antike kao i onima iz mlađe faze naseljavanja tog prostora, u prilogu su prikazani i rezultati apsolutnih datacija toga najstarijeg horizonta.