Application of micro-CT in small animal imaging Schambach, Sebastian J.; Bag, Simona; Schilling, Lothar ...
Methods (San Diego, Calif.),
2010, 2010-Jan, 2010-01-00, 20100101, Letnik:
50, Številka:
1
Journal Article
Recenzirano
Over the past decade, the number of publications using micro-computed tomography (μCT) imaging in preclinical in vivo studies has risen exponentially. Higher spatial and temporal resolution are the ...key technical advancements that have allowed researchers to capture increasingly detailed anatomical images of small animals and to monitor the progression of disease in small animal models. The purpose of this review is to present the technical aspects of μCT, as well as current research applications. Our objectives are threefold: to familiarize the reader with the basics of μCT techniques; to present the type of experimental designs currently used; and to highlight limitations, future directions, in μCT-scanner research applications, and experimental methods. As a first step we present different μCT setups and components, as well as image contrast generation principles. We then present experimental approaches in order of the evaluated organ system. Finally, we provide a short summary of some of the technical limitations of μCT imaging and discuss potential future developments in μCT-scanner techniques and experimental setups.
We measured the properties of a novel combination of two Gas Electron Multipliers with a Micromegas for use as amplification devices in high-rate gaseous time projection chambers. The goal of this ...design is to minimize the buildup of space charge in the drift volume of such detectors in order to eliminate the standard gating grid and its resultant dead time, while preserving good tracking and particle identification performance. To characterize this micro-pattern gas detector configuration, we measured the positive ion back-flow and energy resolution at various element gains and electric fields, using a variety of gases, and additionally studied crosstalk effects and discharge rates. At a gain of 2000, this configuration achieves an ion back-flow below 0.4% and an energy resolution better than σ/E=12% for 55Fe X-rays.
A MAPS based vertex detector for the STAR experiment at RHIC Greiner, L.; Anderssen, E.; Matis, H.S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2011, Letnik:
650, Številka:
1
Journal Article
Recenzirano
The STAR experiment at RHIC is in the process of upgrading the inner detector region of the experiment to improve the vertex resolution. We describe the current design of a MAPS based vertex ...detector, which is the innermost and highest resolution detector of the set of three planned upgrade detectors. This detector will enable the identification of decay vertices displaced from the interaction vertex by 100–150
μm and extend the capabilities of the STAR detector in the heavy flavor domain. We present selected detector design characteristics and prototyping results, which help to validate the design in preparation for the construction of the detector.
Animal models developed in rats and mice have become indispensable in preclinical cerebrovascular research. Points of interest include the investigation of the vascular bed and the morphology and ...function of the arterial, capillary, and venous vessels. Because of their extremely small caliber, in vivo examination of these vessels is extremely difficult. In the present study we have developed a method to provide fast 3D in vivo analysis of cerebral murine vessels using volume computed tomography-angiography (vCTA).
Using an industrial X-ray inspection system equipped with a multifocus cone beam X-ray source and a 12-bit direct digital flatbed detector, high-speed vCTA (180 degrees rotation in 40 s. at 30 fps) was performed in anesthetized mice. During the scan an iodinated contrast agent was infused via a tail vein. Images were reconstructed using a filtered backprojection algorithm. Image analysis was performed by maximum intensity projection (MIP) and 3D volume reconstruction.
All mice tolerated i.v. injection of the iodinated contrast agent well. Smallest achievable voxel size of raw data while scanning the whole neurocranium was 16 mum. Anatomy of cerebral vessels was assessable in all animals, and anatomic differences between mouse strains could easily be detected. Mean vessel diameter was measured in C57BL/6 and BALBc mice. Changes of vessel caliber were assessable by repeated vCTA.
Ultra fast in vivo vCTA of murine cerebral vasculature is feasible at resolutions down to 16 mum. The technique allows the assessment of vessel caliber changes in living mice, thus providing an interesting tool to monitor different features such as vasospasm or vessel patency.
Purpose
Mice are often used as small animal models of brain ischemia, venous thrombosis, or vasospasm. This article aimed at providing an overview of the currently available methodologies for in vivo ...imaging of the murine cerebrovasculature and comparing the capabilities and limitations of the different methods.
Methods
Micro-computed tomography angiography (CTA) was performed during intra-arterial and intravenous administration of a contrast agent bolus. Digital subtraction angiography (DSA) was performed during intra-arterial administration of contrast agent using the micro-CT scanner. Time-of-flight (ToF) magnetic resonance (MR) angiography was performed using a small animal scanner (9.4 T) equipped with a cryogenic transceive quadrature coil. Datasets were compared for scan time, contrast-to-noise ratio (CNR), temporal and spatial resolution, radiation dose, contrast agent dose and detailed recognition of cerebrovascular structures.
Results
Highest spatial resolution was achieved using micro-CTA (16 ´ 16 ´ 16 µm) and DSA (14 ´ 14 µm). Compared to micro-CTA (20–40 s) and ToF-MRA (57 min), DSA provided highest temporal resolutions (30 fps) allowing analyses of the cerebrovascular blood flow. Highest mean CNR was reached using ToF-MRA (50.7 ± 15.0), while CNR of micro-CTA depended on the intra-arterial (19.0 ± 1.0) and intravenous (1.3 ± 0.4) use of agents. The CNR of DSA was 10.0 ± 1.8.
Conclusions
The use of dedicated small animal scanners allows cerebrovascular imaging in live animals as small as mice. As each of the methods analyzed has its advantages and limitations, choosing the best suited imaging modality for a defined question is of great importance. By this means the aforementioned methods offer a great potential for future projects in preclinical cerebrovascular research including ischemic stroke or vasospasm.
Vascular imaging in small rodents using micro-CT Schambach, Sebastian J.; Bag, Simona; Groden, Christoph ...
Methods (San Diego, Calif.),
2010, 2010-Jan, 2010-01-00, 20100101, Letnik:
50, Številka:
1
Journal Article
Recenzirano
In vivo animal models of neoplasm, stroke, subarachnoid hemorrhage, and other diseases involving alterations in vessel anatomy and diameter, require a fast and easy-to-use imaging tool that captures ...anatomical structure and biologic function data. Micro-computed tomography angiography (μCTA) offers high spatial and temporal resolution and is suitable to perform this task. However, conducting μCTA in small rodents, especially in mice, requires a high degree of accuracy and precision. This article describes a setup for in vivo μCTA in mice using both a bolus technique with a conventional contrast agent, as well as, angiography with a blood-pool contrast agent. Our setup in mice is at isotropic resolutions up to 16
μm with scanning times less than 1
min. The described protocol also addresses some of the technical challenges associated with the imaging of vascular structures in mice models.
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