13 research outputs found
DIRBoost - an algorithm for boosting deformable image registration. Application to lung CT intra-subject registration
No full textS.449-459We introduce a boosting algorithm to improve on existing methods for deformable image registration (DIR). The proposed DIRBoost algorithm is inspired by the theory on hypothesis boosting, well known in the field of machine learning. DIRBoost utilizes a method for automatic registration error detection to obtain estimates of local registration quality. All areas detected as erroneously registered are subjected to boosting, i.e. undergo iterative registrations by employing boosting masks on both the fixed and moving image. We validated the DIRBoost algorithm on three different DIR methods (ANTS gSyn, NiftyReg, and DROP) on three independent reference datasets of pulmonary image scan pairs. DIRBoost reduced registration errors significantly and consistently on all reference datasets for each DIR algorithm, yielding an improvement of the registration accuracy by 5-34% depending on the dataset and the registration algorithm employed.18Nr.
Topical drug delivery in chronic rhinosinusitis patients before and after sinus surgery using pulsating aerosols.
No full textObjectivesChronic rhinosinusitis (CRS) is a common chronic disease of the upper airways and has considerable impact on quality of life. Topical delivery of drugs to the paranasal sinuses is challenging, therefore the rate of surgery is high. This study investigates the delivery efficiency of a pulsating aerosol in comparison to a nasal pump spray to the sinuses and the nose in healthy volunteers and in CRS patients before and after sinus surgery.Methods(99m)Tc-DTPA pulsating aerosols were applied in eleven CRSsNP patients without nasal polyps before and after sinus surgery. In addition, pulsating aerosols were studied in comparison to nasal pump sprays in eleven healthy volunteers. Total nasal and frontal, maxillary and sphenoidal sinus aerosol deposition and lung penetration were assessed by anterior and lateral planar gamma camera imaging.ResultsIn healthy volunteers nasal pump sprays resulted in 100% nasal, non-significant sinus and lung deposition, while pulsating aerosols resulted 61.3+/-8.6% nasal deposition and 38.7% exit the other nostril. 9.7+/-2.0 % of the nasal dose penetrated into maxillary and sphenoidal sinuses. In CRS patients, total nasal deposition was 56.7+/-13.3% and 46.7+/-12.7% before and after sinus surgery, respectively (pConclusionIn contrast to nasal pump sprays, pulsating aerosols can deliver significant doses into posterior nasal spaces and paranasal sinuses, providing alternative therapy options before and after sinus surgery. Patients with chronic lung diseases based on clearance dysfunction may also benefit from pulsating aerosols, since these diseases also manifest in the upper airways
Can we continue research in splenectomized dogs? Mycoplasma haemocanis: Old problem - New insight
No full textWe report the appearance of a Mycoplasma haemocanis infection in laboratory dogs, which has been reported previously, yet, never before in Europe. Outbreak of the disease was triggered by a splenectomy intended to prepare the dogs for a hemorrhagic shock study. The clinical course of the dogs was dramatic including anorexia and hemolytic anemia. Treatment included allogeneic transfusion, prednisone, and oxytetracycline. Systematic follow-up (n=12, blood smears, antibody testing and specific polymerase chain reaction) gives clear evidence that persistent eradication of M. haemocanis is unlikely. We, therefore, had to abandon the intended shock study. In the absence of effective surveillance and screening for M. haemocanis, the question arises whether it is prudent to continue shock research in splenectomized dogs. Copyright (C) 2004 S. Karger AG, Basel
larvalign: Aligning Gene Expression Patterns from the Larval Brain of Drosophila melanogaster
No full textThe larval brain of the fruit fly Drosophila melanogaster is a small, tractable model system for neuroscience. Genes for fluorescent marker proteins can be expressed in defined, spatially restricted neuron populations. Here, we introduce the methods for 1) generating a standard template of the larval central nervous system (CNS), 2) spatial mapping of expression patterns from different larvae into a reference space defined by the standard template. We provide a manually annotated gold standard that serves for evaluation of the registration framework involved in template generation and mapping. A method for registration quality assessment enables the automatic detection of registration errors, and a semi-automatic registration method allows one to correct registrations, which is a prerequisite for a high-quality, curated database of expression patterns. All computational methods are available within the larvalign software package: https://github.com/larvalign/larvalign/releases/tag/v1.0.publishe
Electronic tuneability of a structurally rigid surface intermetallic and Kondo lattice CePt5 Pt 111
No full textWe present an extensive study of the structure, composition, electronic, and magnetic properties of Ce Pt surface intermetallic phases on Pt 111 as a function of their thickness. The sequence of structural phases appearing in low energy electron diffraction may invariably be attributed to a single underlying intermetallic atomic lattice. Findings from both microscopic and spectroscopic methods prove compatible with CePt5 formation when their characteristic probing depth is adequately taken into account. The intermetallic film thickness serves as an effective tuning parameter which brings about characteristic variations of the cerium valence and related properties. Soft x ray absorption XAS and magnetic circular dichroism XMCD prove well suited to trace the changing Ce valence and to assess relevant aspects of Kondo physics in the CePt5 surface intermetallic. We find characteristic Kondo scales of the order of 102 K and evidence for considerable magnetic Kondo screening of the local Ce 4 amp; 8290; amp; 119891; moments. CePt5 Pt amp; 8289; 111 and related systems therefore appear to be promising candidates for further studies of low dimensional Kondo lattices at surface
Mechanisms of Cytokine Cascade Activation in Patients with Sepsis: Normal Cytokine Transcription Despite reduced CD14 Receptor Expression.
No full textHippoMaps: Multiscale cartography of human hippocampal organization
No full textThe hippocampus has a specialized microarchitecture, is situated at the nexus of multiple macroscale functional networks, contributes to numerous cognitive as well as affective processes and is highly susceptible to brain pathology across common disorders. These features make the hippocampus a model to understand how brain structure covaries with function, in both health and disease. Here we introduce HippoMaps, an open access toolbox and online data warehouse for the mapping and contextualization of subregional hippocampal data in the human brain ( http://hippomaps.readthedocs.io ). HippoMaps capitalizes on a unified hippocampal unfolding approach as well as shape intrinsic registration capabilities to allow for cross-participant and cross-modal data aggregation. We initialize this repository with a combination of hippocampal data spanning three-dimensional ex vivo histology, ex vivo 9.4-Tesla magnetic resonance imaging (MRI), as well as in vivo structural MRI and resting-state functional MRI obtained at 3 Tesla and 7 Tesla, together with intracranial encephalography recordings in patients with epilepsy. All code, data and tools are openly available online, with the aim of fostering further community contributions
Evaluation of Registration Methods on Thoracic CT: The EMPIRE10 Challenge
No full textContains fulltext :
96888.pdf (Publisher’s version ) (Open Access)EMPIRE10 (Evaluation of Methods for Pulmonary Image REgistration 2010) is a public platform for fair and meaningful comparison of registration algorithms which are applied to a database of intrapatient thoracic CT image pairs. Evaluation of nonrigid registration techniques is a nontrivial task. This is compounded by the fact that researchers typically test only on their own data, which varies widely. For this reason, reliable assessment and comparison of different registration algorithms has been virtually impossible in the past. In this work we present the results of the launch phase of EMPIRE10, which comprised the comprehensive evaluation and comparison of 20 individual algorithms from leading academic and industrial research groups. All algorithms are applied to the same set of 30 thoracic CT pairs. Algorithm settings and parameters are chosen by researchers expert in the configuration of their own method and the evaluation is independent, using the same criteria for all participants. All results are published on the EMPIRE10 website (http://empire10.isi.uu.nl). The challenge remains ongoing and open to new participants. Full results from 24 algorithms have been published at the time of writing. This paper details the organization of the challenge, the data and evaluation methods and the outcome of the initial launch with 20 algorithms. The gain in knowledge and future work are discussed
