Estimation of the rigid-body motion from three-dimensional images using a generalized center-of-mass points approach

We present an analytical method for the estimation of rigid-body motion in sets of three-dimensional (3-D) SPECT and PET slices. This method utilizes mathematically defined generalized center-of-mass points in images, requiring no segmentation. It can be applied to compensation of the rigid-body motion in both SPECT and PET, once a series of 3-D tomographic images are available. We generalized the formula for the center-of-mass to obtain a family of points comoving with the object\u27s rigid-body motion. From the family of possible points we chose the best three points which resulted in the minimum root-mean-square difference between images as the generalized center-of-mass points for use in estimating motion. The estimated motion was used to sum the sets of tomographic images, or incorporated in the iterative reconstruction to correct for motion during reconstruction of the combined projection data. For comparison, the principle-axes method was also applied to estimate the rigid-body motion from the same tomographic images. To evaluate our method for different noise levels, we performed simulations with the MCAT phantom. We observed that though noise degraded the motion-detection accuracy, our method helped in reducing the motion artifact both visually and quantitatively. We also acquired four sets of the emission and transmission data of the Data Spectrum Anthropomorphic Phantom positioned at four different locations and/or orientations. From these we generated a composite acquisition simulating periodic phantom movements during acquisition. The simulated motion was calculated from the generalized center-of-mass points calculated from the tomographic images reconstructed from individual acquisitions. We determined that motion-compensation greatly reduced the motion artifact. Finally, in a simulation with the gated MCAT phantom, an exaggerated rigid-body motion was applied to the end-systolic frame. The motion was estimated from the end-diastolic and end-systolic images, and used to sum them into a summed image without obvious artifact. Compared to the principle-axes method, in two of the three comparisons with anthropomorphic phantom data our method estimated the motion in closer agreement to the Polaris system than the principal-axes method, while the principle-axes method gave a more accurate estimation of motion in most cases for the MCAT simulations. As an image-driven approach, our method assumes angularly com plete data sets for each state of motion. We expert this method to be applied in correction of respiratory motion in respiratory gated SPECT, and respiratory or other rigid-body motion in PET. © 2006 IEEE

Transcript-indexed ATAC-seq for precision immune profiling.

T cells create vast amounts of diversity in the genes that encode their T cell receptors (TCRs), which enables individual clones to recognize specific peptide-major histocompatibility complex (MHC) ligands. Here we combined sequencing of the TCR-encoding genes with assay for transposase-accessible chromatin with sequencing (ATAC-seq) analysis at the single-cell level to provide information on the TCR specificity and epigenomic state of individual T cells. By using this approach, termed transcript-indexed ATAC-seq (T-ATAC-seq), we identified epigenomic signatures in immortalized leukemic T cells, primary human T cells from healthy volunteers and primary leukemic T cells from patient samples. In peripheral blood CD4+ T cells from healthy individuals, we identified cis and trans regulators of naive and memory T cell states and found substantial heterogeneity in surface-marker-defined T cell populations. In patients with a leukemic form of cutaneous T cell lymphoma, T-ATAC-seq enabled identification of leukemic and nonleukemic regulatory pathways in T cells from the same individual by allowing separation of the signals that arose from the malignant clone from the background T cell noise. Thus, T-ATAC-seq is a new tool that enables analysis of epigenomic landscapes in clonal T cells and should be valuable for studies of T cell malignancy, immunity and immunotherapy

Robust Obstacle Detection based on Dense Disparity Maps

Obstacle detection is an important component for many autonomous vehicle navigation systems. Several methods for obstacle detection have been proposed using various active sensors such as radar, sonar and laser range finders. Vision based techniques have the advantage of low cost and provide a large amount of information about the environment around an intelligent vehicle. This paper deals with the development of an accurate and efficient vision based obstacle detection method which relies on a wavelet analysis. The development system will be integrated on the Cybercar platform which is a road vehicle with fully automated driving capabilities

Single-cell RNA-seq supports a developmental hierarchy in human oligodendroglioma

Although human tumours are shaped by the genetic evolution of cancer cells, evidence also suggests that they display hierarchies related to developmental pathways and epigenetic programs in which cancer stem cells (CSCs) can drive tumour growth and give rise to differentiated progeny. Yet, unbiased evidence for CSCs in solid human malignancies remains elusive. Here we profile 4,347 single cells from six IDH1 or IDH2 mutant human oligodendrogliomas by RNA sequencing (RNA-seq) and reconstruct their developmental programs from genome-wide expression signatures. We infer that most cancer cells are differentiated along two specialized glial programs, whereas a rare subpopulation of cells is undifferentiated and associated with a neural stem cell expression program. Cells with expression signatures for proliferation are highly enriched in this rare subpopulation, consistent with a model in which CSCs are primarily responsible for fuelling the growth of oligodendroglioma in humans. Analysis of copy number variation (CNV) shows that distinct CNV sub-clones within tumours display similar cellular hierarchies, suggesting that the architecture of oligodendroglioma is primarily dictated by developmental programs. Subclonal point mutation analysis supports a similar model, although a full phylogenetic tree would be required to definitively determine the effect of genetic evolution on the inferred hierarchies. Our single-cell analyses provide insight into the cellular architecture of oligodendrogliomas at single-cell resolution and support the cancer stem cell model, with substantial implications for disease management

Versorgungstechniken in der Hernienchirurgie:Analyse von Verfahrenswahl und Risikofaktoren in einer monozentrischen retrospektiven Kohortenstudie

Die postoperative Narbenhernie gilt mit einer Inzidenz von 10% als häufigste Spätkomplikation in der Viszeralchirurgie. Diese retrospektive Kohortenstudie untersucht Risikofaktoren für das Auftreten von Rezidiven in Abhängigkeit unterschiedlicher Techniken der Narbenherniotomie und bewertet dementsprechend die gewählte Operationstechnik. In der Klinik für Allgemein- und Viszeralchirurgie des Universitätsklinikums Münster sind im Untersuchungszeitraum vom 01.01.2009 bis zum 14.02.2014 die Daten von insgesamt 260 Patienten ausgewertet worden. Nach durchschnittlich 37,73 (SD=18,246) Monaten ist eine Nachbeobachtung in Form einer telefonischen Befragung bezüglich der postoperativen Lebensqualität und Rezidivoperationen durchgeführt worden. Die statistische Auswertung mittels Kaplan-Meier-Methode und anschließendem Log-Rang-Test identifizierte das Geschlecht (p=0,01), den Body-Mass-Index (p=0,015), das Netzmaterial (p=0,015) und die Netzüberlappung (p=0,000) als signifikante Risikofaktoren für eine Rezidivoperation. Im Hinblick auf die Operationstechnik erzielte die Netzimplantation in der Sublay-Technik signifikant bessere Ergebnisse im Vergleich zur Onlay-Technik (p=0,005). Die Kombination unterschiedlicher Netze erreichte diesbezüglich kein Signifikanzniveau. Unter Ausschluss von Komplikationen zeigte sich bei der Sublay-Technik ein phWert von 0,028 im Vergleich mit bestehendem Fasziendefekt und mehrdimensionalen Rekonstruktionen. Mehrdimensionale Rekonstruktionstechniken sollten im weiteren Verlauf in prospektiven Studien untersucht werden