Outer Vessel Research Articles

Non-Linear Dynamics in Thermal and Reactive Fluid Flows

Fundamentals of non-linear dynamics in thermal and reactive fluid flows are presented with some recent topics. The concept of phase space, attractor, dimension, Poincare section will be summarized. The mixing and reaction in a high viscous fluid in an eccentric flow system of outer cylindrical vessel and inner cylindrical rod is discussed experimentally and numerically. The very slow alternative motion of the outer vessel and inner rod induces the chaotic motion with stretching and holding of fluid element without any turbulence and perturbations which enhances the mixing. The results show that there are two regions: one is a well-mixed region, that is a chaotic region, and the other is hardly mixed island region, that is a regular region. The experimental results of complex mixing and reaction patterns coincide well with numerical results not only qualitatively but quantitatively. This indicates that the complex phenomena observed is not a random one but the deterministic one even though the phenomena observed is very complex. The mixing in the static mixer, Kenics type static mixer, is discussed which shows the chaotic mixing in the steady state flow system by elements installed in the mixer. The results show that the elements with simple structure make stretching and holding effectively and then the mixing is enhanced extensively. The non-element mixing devices are discussed as well. The results show that the periodic flow variation makes the similar effect of the elements in the static mixer. A short term forward prediction is also demonstrated, using a Bunsen flame with burner rotation. When the burner is rotated, the flame tip starts to oscillate significantly because of the effect of the centrifugal force. When the rotating speed is increased, the oscillating motion becomes complex from a limit cycle to chaotic motion. The results demonstrated that the short term forward prediction can be done by using a concept of the chaotic dynamics. Through these interesting topics, I would like to emphasize the importance of non-linear dynamics, especially chaotic dynamics, in the thermal and reactive systems.

Turbo fast three‐dimensional carotid artery black‐blood MRI by combining three‐dimensional MERGE sequence with compressed sensing

In this study, we sought to investigate the feasibility of turbo fast three-dimensional (3D) black-blood imaging by combining a 3D motion-sensitizing driven equilibrium rapid gradient echo sequence with compressed sensing. A pseudo-centric phase encoding order was developed for compressed sensing-3D motion-sensitizing driven equilibrium rapid gradient echo to suppress flow signal in undersampled 3D k-space. Nine healthy volunteers were recruited for this study. Signal-to-tissue ratio, contrast-to-tissue ratio (CTR) and CTR efficiency (CTReff ) between fully sampled and undersampled images were calculated and compared in seven subjects. Moreover, isotropic high resolution images using different compressed sensing acceleration factors were evaluated in two other subjects. Wall-lumen signal-to-tissue ratio or CTR were comparable between the undersampled and the fully sampled images, while significant improvement of CTReff was achieved in the undersampled images. At an isotropic high spatial resolution of 0.7 × 0.7 × 0.7 mm(3) , all undersampled images exhibited similar level of the flow suppression efficiency and the capability of delineating outer vessel wall boundary and lumen-wall interface, when compared with the fully sampled images. The proposed turbo fast compressed sensing 3D black-blood imaging technique improves scan efficiency without sacrificing flow suppression efficiency and vessel wall image quality. It could be a valuable tool for rapid 3D vessel wall imaging.

IVUS guided stenting in moderate looking proximal coronary lesion

Intravascular ultrasound (IVUS) is an invasive modality which provides cross-sectional images of a coronary artery and both the lumen and outer vessel wall can be identified. IVUS has been found to be useful in decision making in intermediate lesion. Here we are describing an interesting case in which the patient had significant mid LAD bifurcation lesion along with a mild to moderate looking proximal LAD lesion. The IVUS was used to guide the intervention of an anatomically significant stenosis of proximal LAD which appeared to be a less significant on coronary angiography alone.

The thermal stress analysis and structure optimum of neck tube with vertical cryogenic insulated cylinders based on ANSYS

As an important support structure between inner and outer vessel in cryogenic insulated cylinders, the root of neck tube becomes the weakest link because of opening in inner upper end for connecting. The main purpose of this paper is to present a study of thermal stress analysis and structure optimum of the neck tube support system of cryogenic cylinders subjected to internal pressure, self weight, lateral inertia load and temperature difference with the aid of ANSYS tools. The cryogenic cylinders with different height-diameter (H/D) ratios are studied in this study, as well as a wide range of geometries of neck tube. A parametric study of the effects of neck tube on the maximum stresses in the vessels under different loading conditions was performed by finite element analysis method. As that the stress concentration mainly occurs at the vicinity area of the opening of the inner upper heads, how reinforcement ring affects the stress distribution is also discussed. The study results will serve as the available data for structure design and optimization of cryogenic cylinders.

In Vivo Assessment of Murine Elastase-induced Abdominal Aortic Aneurysm with High Resolution Magnetic Resonance Imaging

ObjectivesThere are, to date, no published non-invasive or longitudinal studies performed in mice to measure aortic diameter and wall thickness in an elastase-induced abdominal aortic aneurysm. This MRI study at 11.75 T aimed at evaluating the reliability of longitudinal in vivo aortic diameter and wall thickness measurements in this particular model. MethodsAdult male C57BL/6 mice underwent transient elastase or heat-inactivated elastase perfusion (controls). Aortic dilatation was measured before, during and immediately after elastase perfusion, and again 14 days after, with a calibrated ocular grid. MRI was performed just before initial surgery and at day 14 before harvest using an 11.75 T MR microscopy imager. ResultsAortic diameter was significantly greater in elastase-perfused mice compared to controls as measured by optic grid (1.150 ± 0.153 mm vs 0.939 ± 0.07 mm, P = 0.038) and according to MRI measurement of the outer diameter on spin echo images (1.203 ± 0.105 mm vs 1070 ± 0.048 mm, P = 0.0067). Aortic wall thickness was found to be significantly increased in elastase-perfused mice at day 14. ConclusionsThis study demonstrates in the mouse elastase-induced aneurysm model that characterization of aneurysm development by its inner and outer vessel diameter and vessel wall thickness can be carried out longitudinally using high resolution MRI without significant mortality.

The Quench Detection-Wire-Feedthrough Plug-In of W7-X

The stellarator fusion experiment Wendelstein 7-X (W7-X) is presently under assembly at the Greifswald branch of the Max-Planck-Institut für Plasmaphysik (IPP), Germany. To allow the steady-state operation, W7-X has a superconducting magnet system. It consists of 50 non planar coils, 20 planar coils, a superconducting bus bar system and 14 current leads. For continuous on-line monitoring of the superconducting state 1624 Quench Detection-wires (QD-wires) are connected at the joints of the coils and the bus bars. The signals of these wires must be fed through the Outer Vessel (OV) shell to the Quench Detection Units. The electrical feedthroughs, wires and wire connections have been designed and qualified for a test voltage of 13 kV under low gas pressure (Paschen test). Other important requirements are a maximum allowed integral helium leak-rate of l/s per QD-dome and a maximum allowed total heat load to the thermal shield of the OV of 140 W per QD-dome. The paper describes the design and qualification of the QD-Wire-Feedthrough-Plug-in, the assembly procedure as well as the tests carried out during and after assembly.

The Trim Coils for the Wendelstein 7-X Magnet System

The magnet system of the fusion experiment Wendelstein 7-X (W7-X) consists of superconducting as well as normal conducting coils. 50 non planar superconducting coils are forming the main field, 20 planar superconducting coils allow varying the shape of the plasma. Inside of the plasma vessel 10 normal conducting control coils will be placed to modify the strike points of the plasma at the divertor. In addition a set of five normal conducting trim coils has been designed to allow the correction of error fields and to increase the experimental flexibility. The coils will be placed at the outer surface of the outer vessel of W7-X. Four out of five coils have identical size and shape. They have dimensions of 3.5 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\times$</tex></formula> 3.3 meters with 48 turns and will be operated with currents of up to 1.8 kA. The other coil type has a smaller size of 2.8 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\times$</tex></formula> 2.2 meters, but a higher number of turns and a higher operating current of 1.95 kA. Both types of trim coils will be made of square copper hollow profile with an integrated cooling channel. Five independent power supplies will be used to energize the coils. The present concept is based on four-quadrant power supplies. The control system will allow the local control as well as the remote control of the five power supplies from an external control room.

Simulation of the Neutral Inventory in the Pilot‐PSI Beam

AbstractThe Eunomia code is used to study the neutral species in and near a hydrogen plasma beam. Eunomia is a non‐linear Monte Carlo transport code that solves the neutral equilibrium, given a fixed background plasma. The code is developed to study the neutral inventory of Pilot‐PSI and Magnum‐PSI, linear devices developed to study plasma surface interactions in similar conditions as expected in the ITER divertor. Results show the influence of elastic collisions and the outer vessel wall on the neutral species. In the center of the 2 cm diameter Pilot‐PSI beam the results show a strong coupling to the plasma. Only millimeters away from the center, the neutral flow, temperature and density are strongly influenced by recombination processes at the vessel wall (© 2012 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Compartmental Tissue Distribution of Antibody Therapeutics: Experimental Approaches and Interpretations

Monoclonal antibodies have provided many validated and potential new therapeutic candidates for various diseases encompassing the realms of neurology, ophthalmology, immunology, and especially oncology. The mechanism of action for these biological molecules typically involves specific binding to a soluble ligand or cell surface protein in order to block or alter a molecular pathway, induce a desired cellular response, or deplete a target cell. Many antigens reside within the interstitial space, the fluid-filled compartment that lies between the outer endothelial vessel wall and the plasma membranes of cells. This mini-review examines the concepts relevant to the kinetics and behavior of antibodies within the interstitium with a special emphasis on radiometric measurement of quantitative pharmacology. Molecular probes are discussed to outline chemical techniques, selection criteria, data interpretation, and relevance to the study of antibody pharmacokinetics. The importance of studying the tissue uptake of antibodies at a compartmental level is highlighted, including a brief overview of receptor occupancy and its interpretation in radiotracer studies. Experimental methods for measuring the spatial composition of tissues are examined in terms of relative vascular, interstitial, and cellular volumes using solid tumors as a representative example. Experimental methods and physiologically based pharmacokinetic modeling are introduced as distinct approaches to distinguish between free and bound fractions of interstitial antibody. Overall, the review outlines the available methods for pharmacokinetic measurements of antibodies and physiological measurements of the compartments that they occupy, while emphasizing that such approaches may not fully capture the complexities of dynamic, heterogeneous tumors and other tissues.

Novel methodology for 3D reconstruction of carotid arteries and plaque characterization based upon magnetic resonance imaging carotid angiography data

In this study, we present a novel methodology that allows reliable segmentation of the magnetic resonance images (MRIs) for accurate fully automated three-dimensional (3D) reconstruction of the carotid arteries and semiautomated characterization of plaque type. Our approach uses active contours to detect the luminal borders in the time-of-flight images and the outer vessel wall borders in the T1-weighted images. The methodology incorporates the connecting components theory for the automated identification of the bifurcation region and a knowledge-based algorithm for the accurate characterization of the plaque components. The proposed segmentation method was validated in randomly selected MRI frames analyzed offline by two expert observers. The interobserver variability of the method for the lumen and outer vessel wall was −1.60%±6.70% and 0.56%±6.28%, respectively, while the Williams Index for all metrics was close to unity. The methodology implemented to identify the composition of the plaque was also validated in 591 images acquired from 24 patients. The obtained Cohen's k was 0.68 (0.60–0.76) for lipid plaques, while the time needed to process an MRI sequence for 3D reconstruction was only 30 s. The obtained results indicate that the proposed methodology allows reliable and automated detection of the luminal and vessel wall borders and fast and accurate characterization of plaque type in carotid MRI sequences. These features render the currently presented methodology a useful tool in the clinical and research arena.

CORIUM BEHAVIOR IN THE LOWER PLENUM OF THE REACTOR VESSEL UNDER IVR-ERVC CONDITION: TECHNICAL ISSUES

Corium behavior in the lower plenum of the reactor vessel during a severe accident is very important, as this affects a failure mechanism of the lower head vessel and a thermal load to the outer reactor vessel under the IVR-ERVC (In-Vessel corium Retention through External Reactor Vessel Cooling) condition. This paper discusses the state of the art and technical issues on corium behavior in the lower plenum, such as initial corium pool formation characteristics and its transient behavior, natural convection heat transfer in various geometries, natural convection heat transfer with a phase change of melting and solidification, and corium interaction with a lower head vessel including penetrations of the ICI (In-Core Instrumentation) nozzle are discussed. It is recommended that more detailed analysis and experiments are necessary to solve the uncertainties of corium behavior in the lower plenum of the reactor vessel.

Image Inversion Spectral-Domain Optical Coherence Tomography Optimizes Choroidal Thickness and Detail through Improved Contrast

This study was conducted to determine whether there were significant differences in choroidal thickness, contrast, outer choroidal vessel (OCV), and choroidal-scleral junction (CSJ) visualization in inverted versus upright spectral-domain optical coherence tomography (SD-OCT). Images were captured on Bioptigen SD-OCT, Zeiss Cirrus HD-OCT, and Heidelberg Spectralis in 42 eyes of 21 healthy subjects. Average choroidal thickness across a fovea-centered 4-mm segment was determined with MATLAB. Quantitative measures of choroidal contrast were measured and CSJ assessed by applying a score of 0 to 3. OCV was determined by counting choroidal vessels ≥ 200 μm. Mean choroidal thickness was greater in inverted versus upright images captured by Bioptigen (P ≤ 0.003) and Spectralis (P ≤ 0.015). Choroidal thickness varied significantly between the three machines (P < 0.05). Contrast was higher in inverted versus upright images captured by Bioptigen (P ≤ 0.02) and Spectralis (P < 0.001), but not in Cirrus (P > 0.10, both observers). CSJ score was highest in the following: Spectralis inverted = Spectralis EDI > Cirrus upright > Bioptigen inverted. Mean OCV was highest in Spectralis inverted mode. The most favorable modes to visualize CSJ and OCV are the Spectralis EDI, Spectralis inverted, Cirrus upright, and Bioptigen inverted. These modes demonstrate the highest outer choroidal contrast and choroidal thickness measurements. Choroidal thickness cannot be compared between machines due to conversion factor differences. Future studies and construction of automated segmentation and detection software should take these benefits and pitfalls into account.

The Superconducting Magnet System of the Stellarator Wendelstein 7-X

The stellarator fusion experimental device Wendelstein 7-X (W7-X) is presently under assembly at the Greifswald branch of the Max-Planck-Institut fur Plasmaphysik, Germany. The superconducting magnet system consists of 50 nonplanar coils, 20 planar coils, a superconducting bus system, and 14 current leads. It is organized in seven electrical circuits with ten coils, the bus system for the interconnection, and two current leads each. The magnet system is cooled by supercritical helium. It is enclosed in a cryostat with an outer diameter of 16 m formed by the plasma vessel and the outer vessel. There are five different types of nonplanar coils having dimensions of 3.5 × 2.5 × 1.5 meters in maximum and a weight of about 5.5 tons. The two different types of the planar coils are nearly circular coils with a diameter of up to 4.5 m and a weight of about 3 tons. The superconducting bus bar system connects the coils to each other and provides the connection to the current leads inside the cryostat. All types of coils and the bus system use the W7-X superconductor, a forced flow cable-in-conduit superconductor with 243 copper stabilized NbTi strands with an outer aluminum-alloy jacket. The current leads provide the transfer of the electrical current from the room temperature bus bar system outside the cryostat to the superconducting parts inside the cryostat. Their special feature is the upside-down orientation with the cold end at the top.

Carotid Atherosclerotic Plaque Progression and Change in Plaque Composition Over Time: A 5-Year Follow-Up Study Using Serial CT Angiography

Serial in vivo imaging of atherosclerosis is important for understanding plaque progression and is potentially useful in predicting cardiovascular events and monitoring treatment efficacy. This prospective study aims to quantify temporal changes in carotid atherosclerotic plaque volume and plaque composition using MDCTA. In 109 patients with TIA or ischemic stroke, serial MDCTA of the carotid arteries was performed after 5.3 ± 0.7 years. The carotid bifurcation was semiautomatically registered for paired baseline follow-up datasets. Outer vessel wall and lumen boundaries were defined using semiautomated segmentation tools. Plaque component volumes were measured using HU thresholds. Annual changes in plaque volume and plaque component proportions were calculated. One-hundred-ninety-three carotid arteries were analyzed. Plaque volume decreased in 31% and increased in 69% of vessels (range -5.6-10.1%/year). Overall, plaque volume increased 1.2% per year (95% CI, 0.8-1.6, P ≤ .001). Plaque composition changed significantly from BL (fibrous 66.4%, lipid 28.8%, calcifications 4.8%): fibrous tissue decreased by 1.5%, lipid decreased by 1.8%, and calcification increased by 3.3% (P < .001). Intraobserver reproducibility of all volume and proportion measurements was good (ICC 0.78-1.00) and interobserver reproducibility was moderate (ICC 0.76-0.99). Changes in carotid plaque burden and plaque composition can be quantified by using serial MDCTA. Plaque burden development is a heterogeneous and slow process.

Scintillator Purification in the Borexino Detector

1. Borexino overview Borexino is an international experiment located in the underground Gran Sasso National Laboratory in Italy. The design of Borexino is based on the principle of graded shielding (see Fig. 1), with the scintillator at the center of a series of concentric shells of increasing radiopurity, and the entire detector located 1400 meter underneath the Gran Sasso mountain [1]. The 278 tons of scintillator, composed of pseudocumene (PC) and 1.5 g/l of the fluor 2,5-diphenyloxazole (PPO), are contained in a thin (125 m) nylon inner vessel (IV) with a radius of 4.25 m. Within the IV, a fiducial mass (FV) of 100 tons can be defined by software selection of the events, based on their reconstructed position using timing data from the photomultipliers (PMT). A second nylon outer vessel (OV)

Human umbilical cord mesenchymal stem cells as treatment of adjuvant rheumatoid arthritis in a rat model

To investigate the effect of human umbilical cord stem cells, both mesenchymal and hematopoietic (CD34+), in the treatment of arthritis. Mesenchymal stem cells (MSCs) and hematopoietic (CD34+) stem cells (HSC) were isolated from human umbilical cord blood obtained from the umbilical cord of healthy pregnant donors undergoing full-term normal vaginal delivery. MSC, HSC, methotrexate (MTX) and sterile saline were injected intra-articularly into the rat hindpaw with complete freunds adjuvant (CFA) induced arthritis after the onset of disease (day 34), when arthritis had become well established (arthritis score ≥ 2). Arthritic indices were evaluated and the levels of interleukin (IL)-1, tumor necrosis factor (TNF)-α and interferon (IFN)-γ and anti-inflammatory cytokine IL-10 in serum were determined using enzyme-linked immunosorbent assay. Animals of all groups were sacrificed 34 d after beginning treatment, except positive control (PC) which was sacrificed at 10, 21 and 34 d for microscopic observation of disease progression. We used hematoxylin, eosin and Masson's trichrome stains for histopathological examination of cartilage and synovium. The mean arthritis scores were similar in all groups at 12 and 34 d post immunization, with no statistical significant difference. Upon the injection of stem cells (hematopoietic and mesenchymal), the overall arthritis signs were significantly improved around 21 d after receiving the injection and totally disappeared at day 34 post treatment in MSC group. Mean hindpaw diameter (mm) in the MSC rats was about half that of the PC and MTX groups (P = 0.007 and P = 0.021, respectively) and 0.6 mm less than the HSC group (P = 0.047), as indicated by paw swelling. Associated with these findings, serum levels of TNF-α, IFN-γ and IL-1 decreased significantly in HSC and MSC groups compared to PC and MTX groups (P < 0.05), while the expression of IL-10 was increased. Histopathological examination with H and E stain revealed that the MTX treated group showed significant reduction of leucocytic infiltrate and hypertrophy of the synovial tissue with moderate obliteration of the joint cavity. Stem cells treated groups (both hematopoietic CD34+ and mesenchymal), showed significant reduction in leucocytic infiltrate and hypertrophy of the synovial tissue with mild obliteration of the joint cavity. With Masson's trichrome, stain sections from the PC group showed evidence of vascular edema of almost all vessels within the synovium in nearly all arthritic rats. Vacuoles were also visible in the outer vessel wall. The vessel became hemorrhagic and finally necrotic. In addition, there was extensive fibrosis completely obliterating the joint cavity. The mean color area percentage of collagen in this group was 0.324 ± 0.096, which was significantly increased when compared to the negative control group. The mean color area percentage of collagen in hematopoietic CD34+ and mesenchymal groups was 0.176 ± 0.0137 and 0.174 ± 0.0197 respectively, which showed a marked decrement compared to the PC group, denoting a mild increase in synovial tissue collagen fibers. MSC enhance the efficacy of CFA-induced arthritis treatment, most likely through the modulation of the expression of cytokines and amelioration of pathological changes in joints.

Recurring Extracranial Internal Carotid Artery Vasospasm Detected by Intravascular Ultrasound

A 24-year-old woman presented with headache and left-sided focal signs following multiple episodes of right monocular visual impairment. Magnetic resonance angiography revealed a decreased vascular image intensity due to a suspicious stenosis in the right internal carotid artery (ICA). The stenosis was not demonstrated on duplex sonography as it was beyond the field of view of the investigation. Intravascular ultrasound (IVUS) revealed that the outer vessel diameter was significantly reduced during stenosis, supporting the presence of vasospasm. Idiopathic recurrent extracranial ICA vasospasm was diagnosed. Recurrent vasospasms of extracranial ICA may be a distinct entity that can cause ischemic stroke.

Postangioplasty restenosis followed with magnetic resonance imaging in an atherosclerotic rabbit model.

Rationale and Objectives. Testing a quantitative, noninvasive method to assess postangioplasty vessel wall changes in an animal model. Material and Methods. Six New Zealand white rabbits were subjected to atherosclerotic injury, including cholesterol-enriched diet, deendothelialization, and percutaneous transluminal angioplasty (PTA) in the distal part of abdominal aorta (four weeks after deendothelialization). The animals were examined with a 1.5T MRI scanner at three times as follows: baseline (six weeks after diet start and two days after PTA) and four weeks and 10 weeks after-PTA. Inflow angiosequence (M2DI) and proton-density-weighted sequence (PDW) were performed to examine the aorta with axial slices. To identify the inner and outer vessel wall boundaries, a dynamic contour algorithm (Gradient Vector Flow Snakes) was applied to the images, followed by calculation of the vessel wall dimensions. The results were compared with histopathological analysis. Results. The wall thickness in the lesion was significantly higher than in the control region at 4 and 10 weeks, reflecting induction of experimentally created after-angioplasty lesion. At baseline, no significant difference between the two regions was present. Conclusions. It is possible to follow the development of vessel wall changes after-PTA with MRI in this rabbit model.

Manufacturing and assembly of the plasma- and outer vessel of the cryostat for Wendelstein 7-X

Wendelstein 7-X is an advanced helical stellarator, which is presently under construction at the Greifswald branch of IPP. A set of 70 superconducting coils arranged in five modules provides a twisted shaped magnetic cage for the plasma and allows steady state operation. Operation of the magnet system at cryogenic temperatures requires a cryostat which provides thermal protection and gives access to the plasma. The main components of the cryostat are the plasma vessel, the outer vessel, the ports, and the thermal insulation. The German company, MAN Diesel & Turbo SE Deggendorf (former MAN DWE GmbH Deggendorf), is responsible for the manufacture and assembly of the plasma vessel, the outer vessel and the thermal insulation. This paper describes the manufacturing and assembly technology of the plasma and outer vessel of the cryostat for Wendelstein 7-X.

Multi-feature-based plaque characterization in ex vivo MRI trained by registration to 3D histology

We present a new method for automated characterization of atherosclerotic plaque composition in ex vivo MRI. It uses MRI intensities as well as four other types of features: smoothed, gradient magnitude and Laplacian images at several scales, and the distances to the lumen and outer vessel wall. The ground truth for fibrous, necrotic and calcified tissue was provided by histology and μCT in 12 carotid plaque specimens. Semi-automatic registration of a 3D stack of histological slices and μCT images to MRI allowed for 3D rotations and in-plane deformations of histology. By basing voxelwise classification on different combinations of features, we evaluated their relative importance. To establish whether training by 3D registration yields different results than training by 2D registration, we determined plaque composition using (1) a 2D slice-based registration approach for three manually selected MRI and histology slices per specimen, and (2) an approach that uses only the three corresponding MRI slices from the 3D-registered volumes. Voxelwise classification accuracy was best when all features were used (73.3 ± 6.3%) and was significantly better than when only original intensities and distance features were used (Friedman, p < 0.05). Although 2D registration or selection of three slices from the 3D set slightly decreased accuracy, these differences were non-significant.