Three-dimensional Resolution Research Articles

MRI of the cervical spine with 3D gradient echo sequence at 3 T: initial experience

The aim of this study was to compare three-dimensional (3D) high resolution T2*-weighted gradient echo (3D FFE) magnetic resonance (MR) sequence with conventional 2D T2-weighted turbo spin echo (TSE) MR sequence for imaging of the cervical spine, especially to assess the detectability of the internal anatomy of the cervical spinal cord, i.e. to distinguish the grey and white matter. Fifteen volunteers were examined at 3.0T MR unit. Signal-to-noise (SNR), contrast-to-noise (CNR) and image homogeneity were evaluated. In the visual analysis, the visibility of anatomical structures of the cervical spine and artifacts were assessed. The nonparametric method of paired sample t-test was adopted to evaluate the differences between the sequences. The 3D FFE sequence provided better results for CNR, cerebrospinal fluid (CSF) versus white matter, grey matter, disk and bone. Moreover, it yielded good results for the CNR grey matter versus white matter. The butterfly-shaped "H" is clearly displayed in the 3D FFE sequence. The statistical analysis revealed the statistically significant difference between the 2D TSE and 3D FFE sequences for the contrast of CSF versus spinal cord (both grey matter and white matter). The 3D FFE sequence in MR imaging of the cervical spinal cord is superior in delineation of spinal cord anatomical structures compared to 2D TSE sequence.

Wall Imaging for Unilateral Intracranial Vertebral Artery Hypoplasia with Three-dimensional High-isotropic Resolution Magnetic Resonance Images.

Background:There are few studies for evaluating wall characteristics of intracranial vertebral artery hypoplasia (VAH). The aim of this study was to determine wall characteristics of VAH with three-dimensional volumetric isotropic turbo spin echo acquisition (3D VISTA) images and differentiate between acquired atherosclerotic stenosis and VAH.Methods:Thirty patients with suspicious VAH by luminograms were retrospectively enrolled between January 2014 and February 2015. The patients were classified as “acquired atherosclerotic stenosis” or “VAH” based on 3D VISTA images. The wall characteristics of VAH were assessed to determine the presence of atherosclerotic lesions, and the patients were classified into two subgroups (VAH with atherosclerosis and VAH with normal wall). Wall characteristics of basilar arteries and vertebral arteries were also assessed. The clinical and wall characteristics were compared between the two groups.Results:Five of 30 patients with suspicious VAH were finally diagnosed as acquired atherosclerotic stenosis by 3D VISTA images. 25 patients were finally diagnosed as VAH including 16 (64.00%) patients with atherosclerosis and 9 (36.00%) patients with normal wall. In the 16 patients with atherosclerosis, plaque was found in 9 patients, slight wall thickening in 6 patients, and thrombus and wall thickening in 1 patient. Compared with VAH patients with normal wall, VAH patients with atherosclerosis showed atherosclerotic basilar arteries and dominant vertebral arteries more frequently (P = 0.000).Conclusions:Three-dimensional VISTA images enable differentiation between the acquired atherosclerotic stenosis and VAH. VAH was also prone to atherosclerotic processes.

Plaques of Nonstenotic Basilar Arteries with Isolated Pontine Infarction on Three-dimensional High Isotropic Resolution Magnetic Resonance Imaging.

Background:There are few studies for evaluating plaque characteristics of nonstenotic basilar arteries (BA). Our aim was to determine entire BA plaques with a three-dimensional volumetric isotropic turbo spin-echo acquisition (VISTA) and investigate the differences between the patients with and without isolated pontine infarction (IPI).Methods:Twenty-four consecutive symptomatic patients with nonstenotic BA on time of flight magnetic resonance angiography (TOF MRA) were enrolled from China-Japan Friendship Hospital between January 2014 and December 2014. BA was classified as “normal” or “irregular” based on TOF MRA, and “normal wall”, “slight wall-thickening”, and “plaque” based on three-dimensional VISTA images. Outcomes from MRA and VISTA were compared. Patients were categorized as IPI and non-IPI groups based on the diffusion-weighted imaging. Clinical and plaque characteristics were compared between the two groups.Results:A total of 1024 image slices including 311 (30.37%) plaque slices, 427 (41.70%) slight wall-thickening slices, and 286 (27.93%) normal wall slices for the entire BA from 23 patients were finally included for analysis. VISTA images detected plaques in all the 9 (100%) irregular MRA patients and 7 of 14 (50%) normal MRA patients. IPI was found in 11 (47.83%) patients. Compared to non-IPI group, the IPI group had a higher percentage of plaque slices (P = 0.001) and lower percentage of normal wall slices (P = 0.014) than non-IPI group.Conclusions:Three-dimensional VISTA images enable detection of BA plaques not visualized by MRA. BA plaques could be found in both the IPI and non-IPI group. However, IPI group showed plaques more extensively in BA than the non-IPI group.

Impact of the vertical velocity field on charging processes and charge separation in a simulated thunderstorm

A three-dimensional (3D) charging-discharging cloud resolution model was used to investigate the impact of the vertical velocity field on the charging processes and the formation of charge structure in a strong thunderstorm. The distribution and evolution of ice particle content and charges on ice particles were analyzed in different vertical velocity fields. The results show that the ice particles in the vertical velocity range from 1 to 5 m s−1 obtained the most charge through charging processes during the lifetime of the thunderstorm. The magnitude of the charges could reach 1014 nC. Before the beginning of lightning activity, the charges produced in updraft region 2 (updraft speed ⩾ 13 m s−1) and updraft region 1 (updraft speed between 5 and 13 m s−1) were relatively significant. The magnitudes of charge reached 1013 nC, which clearly impacted upon the early lightning activity. The vertical velocity conditions in the quasi-steady region (updraft speed between −1 and 1 m s−1) were the most conducive for charge separation on ice particles on different scales. Accordingly, a net charge structure always appeared in the quasi-steady and adjacent regions. Based on the results, a conceptual model of ice particle charging, charge separation, and charge structure formation in the flow field was constructed. The model helps to explain observations of the “lightning hole” phenomenon.

Tu1229 Endoluminal Functional Lumen Imaging Probe (EndoFLIP) During Peroral Endoscopic Myotomy (POEM) for Achalasia Predicts Postoperative Clinical Success: A Multicenter Case-Control Study

Background: Anorectal manometry is useful in evaluating and planning treatment in patients with fecal incontinence (FI) and other disorders of defecation. Traditional water perfusion techniques are limited to 4 to 8 radial measurements obtained via a pullback technique. Three-dimensional high resolution anorectal manometry (3D HRAM) employs solid state micro transducers and can obtain 257 data points during resting, squeeze, and bear down (simulated defecation) sequences. Data are then reconstructed into a 3D format showing functional anatomy. While differences are known to exist between patients with FI and obstruction, patients with mixed disorders (of FI and obstruction) are less well described Objective: To determine physiologic differences between groups of female patients with FI, obstructed defecation, and mixed disorders. In addition to known parameters of mean resting pressure and maximal squeeze pressure, relationships between rectoanal pressure differential and percent anal relaxation were sought among the groups. Methods Retrospective chart review of 50 female patients undergoing 3D HRAM between 1/1/ 13 and 6/1/14. Physiologic values including mean resting, and maximal squeeze pressures, percent anal relaxation, and rectoanal pressure differential were recorded. Analysis of variance test, and linear regression analysis was performed as appropriate. Results:Women with mixed defecatory disorders had sphincter pressure profiles that were significantly different from patients with pure FI or obstruction (table). While rectoanal pressure differential was not different among the groups, patients with mixed disorders had a significant linear relationship between rectoanal pressure differential and percent anal relaxation that was not seen among the pure FI or obstructed groups (figure). Conclusion: Mixed defecatory disorders are associated with a unique physiologic profile that can be characterized using 3D HRAM. The mixed defecatory group demonstrates relationships between physiologic parameters that are not seen the incontinent or obstructed groups. This data will be helpful in the planning treatment regimens.

Nonunified integral imaging elemental image array generation method based on selective pixel sampling algorithm.

We propose a method based on the selective pixel sampling algorithm to generate a nonunified integral imaging (II) elemental image array (EIA) with reduced moiré patterns at a low rendering cost and high three-dimensional (3D) resolution. In the proposed method, the redundant 3D information is captured for the nonunified pixel arrangement of elemental images, and the moiré patterns are constrained by the constraint equations. The nonunified EIA's corresponding information is mapped from the obtained 3D information based on the selective pixel sampling algorithm. Appropriate experiments are carried out, and the experimental results show that the proposed method can increase the 3D display quality of the reconstructed 3D images in the II display and reduce rendering costs markedly in the generation of ultra-high-definition EIA.

Correlation of two-photon in vivo imaging and FIB/SEM microscopy.

Advances in the understanding of brain functions are closely linked to the technical developments in microscopy. In this study, we describe a correlative microscopy technique that offers a possibility of combining two-photon in vivo imaging with focus ion beam/scanning electron microscope (FIB/SEM) techniques. Long-term two-photon in vivo imaging allows the visualization of functional interactions within the brain of a living organism over the time, and therefore, is emerging as a new tool for studying the dynamics of neurodegenerative diseases, such as Alzheimer’s disease. However, light microscopy has important limitations in revealing alterations occurring at the synaptic level and when this is required, electron microscopy is mandatory. FIB/SEM microscopy is a novel tool for three-dimensional high-resolution reconstructions, since it acquires automated serial images at ultrastructural level. Using FIB/SEM imaging, we observed, at 10 nm isotropic resolution, the same dendrites that were imaged in vivo over 9 days. Thus, we analyzed their ultrastructure and monitored the dynamics of the neuropil around them. We found that stable spines (present during the 9 days of imaging) formed typical asymmetric contacts with axons, whereas transient spines (present only during one day of imaging) did not form a synaptic contact. Our data suggest that the morphological classification that was assigned to a dendritic spine according to the in vivo images did not fit with its ultrastructural morphology. The correlative technique described herein is likely to open opportunities for unravelling the earlier unrecognized complexity of the nervous system.Lay DescriptionNeuroscience and the understanding of brain functions are closely linked to the technical advances in microscopy. In this study we performed a correlative microscopy technique that offers the possibility to combine 2 photon in vivo imaging and FIB/SEM microscopy. Long term 2 photon in vivo imaging allows the visualization of functional interactions within the brain of a living organism over the time, and therefore, is emerging as a new tool to study the dynamics of neurodegenerative diseases, such as Alzheimer’s disease. However, light microscopy has important limitations in revealing synapses that are the connections between neurons, and for this purpose, the electron microscopy is necessary. FIB/SEM microscopy is a novel tool for three-dimensional (3D) high resolution reconstructions since it acquires automated serial images at ultrastructural level. This correlative technique will open up new horizons and opportunities for unravelling the complexity of the nervous system.

Confocal Laser Scanning Microscope, Raman Microscopy and Western Blotting to Evaluate Inflammatory Response after Myocardial Infarction

Cardiac muscle necrosis is associated with inflammatory cascade that clears the infarct from dead cells and matrix debris, and then replaces the damaged tissue with scar, through three overlapping phases: the inflammatory phase, the proliferative phase and the maturation phase. Western blotting, laser confocal microscopy, Raman microscopy are valuable tools for studying the inflammatory response following myocardial infarction both humoral and cellular phase, allowing the identification and semiquantitative analysis of proteins produced during the inflammatory cascade activation and the topographical distribution and expression of proteins and cells involved in myocardial inflammation. Confocal laser scanning microscopy (CLSM) is a relatively new technique for microscopic imaging, that allows greater resolution, optical sectioning of the sample and three-dimensional reconstruction of the same sample. Western blotting used to detect the presence of a specific protein with antibody-antigen interaction in the midst of a complex protein mixture extracted from cells, produced semi-quantitative data quite easy to interpret. Confocal Raman microscopy combines the three-dimensional optical resolution of confocal microscopy and the sensitivity to molecular vibrations, which characterizes Raman spectroscopy. The combined use of western blotting and confocal microscope allows detecting the presence of proteins in the sample and trying to observe the exact location within the tissue, or the topographical distribution of the same. Once demonstrated the presence of proteins (cytokines, chemokines, etc.) is important to know the topographical distribution, obtaining in this way additional information regarding the extension of the inflammatory process in function of the time stayed from the time of myocardial infarction. These methods may be useful to study and define the expression of a wide range of inflammatory mediators at several different timepoints providing a more detailed analysis of the time course of the infarct.

Stochastic optimal control for aircraft conflict resolution under wind uncertainty

In this paper, a stochastic optimal control method is developed for determining three-dimensional conflict-free aircraft trajectories under wind uncertainty. First, a spatially correlated wind model is used to describe the wind uncertainty, and a probabilistic conflict detection algorithm using the generalized polynomial chaos method is proposed. The generalized polynomial chaos algorithm can quantify uncertainties in complex nonlinear dynamical systems with high computational efficiency. In addition, a numerical algorithm that incorporates the generalized polynomial chaos method into the pseudospectral method is proposed to solve the conflict resolution problem as the stochastic optimal control problem. The stochastic optimal control method is combined with the proposed conflict detection algorithm to solve the conflict resolution problem under the wind uncertainty. Through illustrative three-dimensional aircraft conflict detection and resolution examples with multiple heterogeneous aircraft, the performance and effectiveness of the proposed conflict detection and resolution algorithms are evaluated and demonstrated.

First Three-Dimensional Atomic Resolution Investigation of Thermally Grown Oxide on a FeCrAl Alloy

Thermally grown Al2O3 scales formed on a FeCrAl alloy, Kanthal APMT, were successfully analysed using pulsed green laser atom probe tomography. The alloy was exposed to 5 vol.% O2 + 95 vol.% N2 at 900 °C for 1 h, and covered by a thin layer of Al2O3. Cr segregation to some of the Al2O3 grain boundaries was observed. The continuous Cr-rich band, which contains a large number of Cr- and/or Fe- enriched nano-sized particles, was studied in detail. Four types of nanoparticles were found and analysed. Oxidation mechanisms at the initial stages are discussed based on the observations.

Latest Developments in Nuclear Emulsion Technology

Nuclear emulsion is high sensitive photographic film used for detection of three-dimensional trajectory of charged particles. These trajectories are recorded as tracks consist of a lot of silver grains. The size of silver grain is about 1μm, so that nuclear emulsion has submicron three-dimensional spatial resolution, which gives us a few mrad three-dimensional angular resolution. The important technical progress was speed-up of the read-out technique of nuclear emulsions built with optical microscope system. We succeeded in developing a high-speed three-dimensional read-out system named Super Ultra Track Selector (S-UTS) with the operating read-out speed of approximately 50 cm2/h. Nowadays we are developing the nuclear emulsion gel independently in Nagoya University by introducing emulsion gel production machine. Moreover, we are developing nuclear emulsion production technologies (gel production, poring and mass production). In this paper, development of nuclear emulsion technologies for the OPERA experiment, applications by the technologies and current development are described.

3D Superresolution Microscopy by Supercritical Angle Detection

Currently, two general approaches allow for three-dimensional resolution in localization microscopy. On one hand, the z position of single emitters can be determined from the shape of the point spread function (PSF) either by imaging two focal planes (bi-plane) or after PSF engineering (e.g. astigmatic PSF, double helix PSF or self-bending PSF). Nevertheless, the axial resolution is usually worse than the lateral one, which itself is compromised by the modification of the PSF. On the other hand, the z position can be extracted from relative intensities of single-molecule images when employing an interferometric detection scheme (iPALM, 4Pi-SMS). Unfortunately, such interferometric microscopes are very difficult to built and cumbersome to use. Here we present a fundamentally different way of achieving 3D resolution in localization microscopy, based on the principle of surface-generated fluorescence. This near-field fluorescence occurs when a fluorophore is in the vicinity of a water-glass interface. It is emitted into large angles above the critical angle and its intensity strongly depends on the distance of a fluorophore from the interface. By splitting high and low emission angles and imaging them simultaneously we can determine the precise axial position of single molecules from their relative intensities in the two channels. A theoretical analysis shows that isotropic resolution on the nanometer scale can be expected in a range of a few hundred nanometers above the coverslip, without compromising the lateral resolution. We developed a simplified setup that we calibrated with fluorescent beads and provided proof-of-principle by imaging DNA-origami tetraedra. We present first biological data on three-dimensional imaging of clathrin-coated pits and microtubules and discuss ideas for approaching the theoretical resolution limit.

Dual-Objective Pointillism Microscopy Setup with Interferometric and Astigmatic Detection

In recent years, under the general term of pointillism microscopy many techniques have been developed which employ sequential imaging of photoswitching fluorophores to circumvent the diffraction barrier in light microscopy (PALM, FPALM, STORM, dSTORM, etc.). Single molecules are localized in the plane perpendicular to the optical axis and several methods exist to obtain the axial coordinate, enabling three-dimensional imaging. The highest three-dimensional resolution in fluorescence microscopy can be obtained by combining pointillism microscopy with interferometric detection through two objectives (1). Here, the axial coordinate is acquired with great accuracy from intensity variations caused by interference. However, this approach is very demanding with respect to setup stability and sample preparation, as the coherence length of fluorescent molecules is in the range of 10 µm. Therefore already small changes in sample thickness and refractive index can prevent the coherent detection of a single fluorescent molecule. Another way to enhance localization accuracy by using two objectives is to employ this approach in combination with astigmatic detection, where the axial coordinate is calculated from astigmatism introduced by an additional cylindrical lens. This already yields a √2-fold increase of localization accuracy, as twice as many photons are collected (2), although the axial resolution of an interferometer is not reached. To make use of the advantages of both detection schemes, we built a setup offering interferometric as well as astigmatic detection. Movable mirrors allow choosing the detection pathway depending on the application and desired localization accuracy. We find that combining interferometric and astigmatic detection in one setup yields the most versatile instrument for studying a broad range of subcellular microcompartments. (1) G. Shtengel et al. Proc. Natl. Acad. Sci. U.S.A., 106(9):3125-3130, Mar 2009 (2) K. Xu et al. Nat. Methods, 9(2):185-188, Feb 2012

The micro-vascular morphological changes of the rat spinal cord after injury by Absorb-contrast imaging of synchrotron radiation

Objective Using the synchrotron radiation-based micro-computed tomography (SRμCT) to observe the changes of three-dimensional micro-vascular morphology structure after acute spinal cord injury in rat.Methods Eight male Sprague-Dawley rats were randomly divided into control group and injury group (n =4).Injury group were deal with improved Allen' s weight dropping to establish the acute spinal cord injury model.All rats were deal with ascending aorta angiography in the next day.Freezing the specimens for 24 hours and then scanned them in Shanghai Institute of Applied Physics,Chinese Academy of Sciences.Processed and reconstructed the Data to three-dimensional images.Results The SRμCT can show the micro-vascular structure of spinal cord in rat completely and clearly.Combining with control group,we can see the lack and fracture of the micro-vessels of spinal cord in injury group significantly.The number and diameter of the micro-vessels were decreased obviously.The average number of vascular in injury group was 77.25 ± 16.80,and the control group was 168.30 ± 12.79 ; The average diameter of vascular in injury group was (16.270 ± 1.201) μm,but the control group was (20.210 ± 1.094) μm.Significant differences were existed between control group and injury group (P ＜ 0.05).Conclusion The SRμCT can get the three-dimensional and high resolution imaging of micro-vessels in small animal' s spinal cord.The micro-circulation network structure of spinal cord was prominently destroyed after acute spinal cord injury.The blood circulation of spinal cord in injury areas and its vicinity was serious damaged. Key words: Synchrotron radiation; Spinal cord injury ; Micro-vessels ; Morphology

A Variable Neighborhood Search Heuristic for Three-dimensional Conflict Resolution Model

This paper investigates a Variable Neighborhood Search (VNS) for a three-dimensional air traffic conflict resolution model. The conflict resolution problem in Air Traffic Management (ATM) is solved by changing the maneuvering dimensions of aircrafts, such as lateral and vertical maneuvers. Compared with existing methods, such as mixed-integer linear optimization approaches that change one or two dimensions of the velocity vector, our algorithm proposes three neighborhoods for conflict resolution based on changes in all three dimensions of the velocity vector of aircrafts. The approach could resolve both horizontal and vertical conflicts. Simulation studies demonstrate that aircrafts could perform various maneuvers to avoid collisions in a three-dimensional space.

RETRACTED: Single-proton spin detection by diamond magnetometry.

Extending magnetic resonance imaging to the atomic scale has been a long-standing aspiration, driven by the prospect of directly mapping atomic positions in molecules with three-dimensional spatial resolution. We report detection of individual, isolated proton spins by a nitrogen-vacancy (NV) center in a diamond chip covered by an inorganic salt. The single-proton identity was confirmed by the Zeeman effect and by a quantum coherent rotation of the weakly coupled nuclear spin. Using the hyperfine field of the NV center as an imaging gradient, we determined proton-NV distances of less than 1 nm.

Compensation of Missing Wedge Effects with Sequential Statistical Reconstruction in Electron Tomography

Electron tomography (ET) of biological samples is used to study the organization and the structure of the whole cell and subcellular complexes in great detail. However, projections cannot be acquired over full tilt angle range with biological samples in electron microscopy. ET image reconstruction can be considered an ill-posed problem because of this missing information. This results in artifacts, seen as the loss of three-dimensional (3D) resolution in the reconstructed images. The goal of this study was to achieve isotropic resolution with a statistical reconstruction method, sequential maximum a posteriori expectation maximization (sMAP-EM), using no prior morphological knowledge about the specimen. The missing wedge effects on sMAP-EM were examined with a synthetic cell phantom to assess the effects of noise. An experimental dataset of a multivesicular body was evaluated with a number of gold particles. An ellipsoid fitting based method was developed to realize the quantitative measures elongation and contrast in an automated, objective, and reliable way. The method statistically evaluates the sub-volumes containing gold particles randomly located in various parts of the whole volume, thus giving information about the robustness of the volume reconstruction. The quantitative results were also compared with reconstructions made with widely-used weighted backprojection and simultaneous iterative reconstruction technique methods. The results showed that the proposed sMAP-EM method significantly suppresses the effects of the missing information producing isotropic resolution. Furthermore, this method improves the contrast ratio, enhancing the applicability of further automatic and semi-automatic analysis. These improvements in ET reconstruction by sMAP-EM enable analysis of subcellular structures with higher three-dimensional resolution and contrast than conventional methods.

Prediction Technology for Top Gas Reservoir of Oil and Gas Reservoir of Three-Dimensional Seismic Pre-Stack Parameters: Application in Jinzhou South Oil and Gas Field in Bohai Sea

It is the key of using the oil layer efficiently to avoid the top gas reservoir of the oil and gas reservoir in the development of the offshore oilfield. The oil reservoir in the second member of the Shahejie Formation of the Jinzhou South Oilfield in the Bohai Sea is a complex oil and gas reservoir of top gas, narrow oil ring and edge water. The oil and gas reservoir is longitudinally divided into multiple sets of fluid systems, and the gas-oil interfaces of different fault blocks are not consistent with large differences. The positions of the gas-oil interfaces and oil-water interfaces need to be determined precisely in the development and design of the horizontal wells on the drilling platforms, so as to prevent the premature gas channeling and water invasion of the production wells. Thus the identification of the top gas reservoir is particularly important. In this paper, we used seismic attribute analysis, pre-stack elastic parameter coordinate rotation method fluid detection and other technologies to identify the top gas reservoir of the oil and gas reservoir in the second member of the Shahejie Formation of the Jinzhou South Oilfield in the Bohai Sea, and obtained good application effects. Key words : Oil and gas reservoir; Top gas reservoir; Three-dimensional seismic high resolution amplitude preservation processing; Seismic attributes; Pre-stack elastic parameter coordinate rotation method; Fluid detection

Hysterosalpingo contrast sonography (HyCoSy): let's make the point!

The accurate evaluation of tubal patency as well of the morphologic characteristics of the uterine cavity is a fundamental step in the diagnostic work-up for infertility. Hysteroscopy and laparoscopy and dye have long been regarded as the reference methods to assess uterine morphology and tubal patency, respectively. However, their technical and clinical limitations have supported the introduction of an emerging technique: hysterosalpingo contrast sonography (HyCoSy), which has recently been improved with the use of modern contrast agents and three-dimensional resolution. A systematic literature search was performed in electronic databases (PubMed and Scopus). Key search terms included Hysterosalpingo contrast sonography (HyCoSy), Tubal patency, Infertility, Uterine cavity, Ultrasounds. HyCoSy has proved to be as reliable as laparoscopic techniques in the assessment of tubal patency and uterine morphology, and also it overcomes such major drawbacks as hospitalization, radiation exposure, anesthesia and use of iodinated contrast media. All in all, HyCoSy is considered as a safe and well tolerated outpatient procedure, which apparently favors the onset of spontaneous pregnancies. This paper provides a comprehensive overview of the literature dealing with HyCoSy to support its use as a first-line technique in standard infertility work-up.

Assessment of the relationship between morphological emphysema phenotype and corresponding pulmonary perfusion pattern on a segmental level.

Distinct morphological emphysema phenotypes were assessed by CT to show characteristic perfusion defect patterns. Forty-one patients with severe emphysema (GOLD III/IV) underwent three-dimensional high resolution computed tomography (3D-HRCT) and contrast-enhanced magnetic resonance (MR) perfusion. 3D-HRCT data was visually analyzed for emphysema phenotyping and quantification by consensus of three experts in chest-radiology. The predominant phenotype per segment was categorized as normal, centrilobular, panlobular or paraseptal. Segmental lung perfusion was visually analyzed using six patterns of pulmonary perfusion (1-normal; 2-mild homogeneous reduction in perfusion; 3-heterogeneous perfusion without focal defects; 4-heterogeneous perfusion with focal defects; 5-heterogeneous absence of perfusion; 6-homogeneous absence of perfusion), with the extent of the defect given as a percentage. 730 segments were evaluated. CT categorized 566 (78%) as centrilobular, 159 (22%) as panlobular and 5 (<1%) as paraseptal with no normals. Scores with regards to MR perfusion patterns were: 1-0; 2-0; 3-28 (4%); 4-425 (58%); 5-169 (23%); 6-108 (15%). The predominant perfusion pattern matched as follows: 70 % centrilobular emphysema - heterogeneous perfusion with focal defects (score 4); 42% panlobular--homogeneous absence of perfusion (score 5); and 43% panlobular--heterogeneous absence of perfusion (score 6). MR pulmonary perfusion patterns correlate with the CT phenotype at a segmental level in patients with severe emphysema. • MR perfusion patterns correlate with the CT phenotype in emphysema. • Reduction of MR perfusion is associated with loss of lung parenchyma on CT • Centrilobular emphysema shows heterogeneous perfusion reduction while panlobular emphysema shows loss of perfusion.