[Virtual organization in the digital age of radiology - principle and solution for radiologic research?].

The research project "VICORA - Virtual Institute for Computer-Assisted Radiology", funded by the German Federal Ministry of Education and Research, was initiated in the year 2000. Its virtual organization brings together physical science, engineering, information technology, clinical radiology and the medical technology industry. In the German radiology research domain VICORA serves as a model for interdisciplinary collaboration for the changing radiology paradigm illustrated by a "radiologycube".

Image reconstruction and performance evaluation for ECG-gated spiral scanning with a 16-slice CT system.

We present an image reconstruction approach and a performance evaluation for ECG-gate cardiac spiral scanning with recently introduced 16-slice CT equipment. We present an extension of the Adaptive Cardio Volume (ACV) reconstruction approach for ECG-gated multislice spiral scanning. We discuss the image z reformation introduced to control the spiral slice width of the final images and give an overview of the reformation functions chosen.

Baculovirus P35 interacts with a subunit of human RNA polymerase II and can enhance promoter activity in human cells.

The early protein P35 from the baculovirus Autographa californica nucleopolyhedrovirus is a direct inhibitor of caspases and can block apoptosis in a wide variety of systems. In addition, it has been linked to the regulation of viral gene expression, shut-down of protein synthesis in infected insect cells and malignant transformation of mouse fibroblasts. By yeast-two-hybrid screening we identified the RPB11a subunit of human RNA polymerase II as an interaction partner of P35.

Individually weight-adapted examination protocol in retrospectively ECG-gated MSCT of the heart.

The standard protocol in multislice spiral CT (MSCT) angiography for coronary arteries with fixed tube current-time settings leads to an overexposure and thus to an unnecessary high radiation dose in patients with lower weight when compared to heavier patients. The purpose of this study was to estimate the effect of reducing the radiation dose by adapting the tube current-time settings individually. Fifty patients underwent retrospectively ECG-gated MSCT of the heart.

Multi-detector row CT versus coronary angiography: preoperative evaluation before totally endoscopic coronary artery bypass grafting.

Purpose: To assess multi-detector row spiral computed tomography (CT) for preoperative evaluation of patients undergoing totally endoscopic coronary artery bypass grafting and to correlate the data with coronary angiographic and intraoperative findings.

Materials And Methods: Thirty-six patients preoperatively underwent multi-detector row CT (4 x 1-mm collimation, pitch of 1.5, 500-msec rotation time, retrospective electrocardiographic gating, 1.

Spatial domain filtering for fast modification of the tradeoff between image sharpness and pixel noise in computed tomography.

In computed tomography (CT), selection of a convolution kernel determines the tradeoff between image sharpness and pixel noise. For certain clinical applications it is desirable to have two or more sets of images with different settings. So far, this typically requires reconstruction of several sets of images.

Detection of coronary calcifications: feasibility of dose reduction with a body weight-adapted examination protocol.

Objective: The purpose of this study was to assess the applicability of individual body weight-adapted tube current time settings in multidetector CT for detection of coronary calcifications and to evaluate the effect of reducing the radiation dose on the coronary calcium score. SUBJECTS AND METHODS. One hundred patients underwent retrospectively ECG-gated MDCT for detection of coronary calcifications.

Image reconstruction and image quality evaluation for a 16-slice CT scanner.

We present a theoretical overview and a performance evaluation of a novel approximate reconstruction algorithm for cone-beam spiral CT, the adaptive multiple plane reconstruction (AMPR), which has been introduced by Schaller, Flohr et al. [Proc. SPIE Int.

Advances in cardiac imaging with 16-section CT systems.

Rationale And Objectives: The authors present advances in electrocardiographically (ECG) gated cardiac spiral scanning with recently introduced 16-section computed tomographic (CT) equipment.

Materials And Methods: The authors discuss the technical principles of ECG-gated cardiac scanning. They give an overview on system properties and on the detector design.

Spatial domain image filtering in computed tomography: feasibility study in pulmonary embolism.

Our objective was to evaluate the clinical feasibility of spatial domain filtering as an alternative to additional image reconstruction using different kernels in chest CT. Spatial domain filtering generates smooth images from sharp images and thus avoids the need for additional reconstructions when two sets of images are desired. Forty adult patients with clinical suspicion of pulmonary embolism were examined utilizing multi-slice CT (Somatom Volume Zoom, Siemens, Germany).

Performance evaluation of a multi-slice CT system with 16-slice detector and increased gantry rotation speed for isotropic submillimeter imaging of the heart.

Background: 4-slice CT scanners have shown limitations in clinical application for noninvasive coronary CT angiography (CTA). We evaluate advances in ECG-gated scanning of the heart and the coronary arteries with recently introduced 16-slice CT equipment (SOMATOM Sensation 16, Siemens, Forchheim, Germany).

Materials And Methods: The technical principles of ECG-gated cardiac scanning, scan parameters, and detector design of the new scanner are presented.

Clustering in rampage murders.

A study of 81 incidents of rampage murders in the USA from 1988 to 1999 yielded no evidence for clustering.

Low-dose multislice spiral computed tomography in acute lung injury: animal experience.

Rationale And Objectives: To compare low-dose multislice spiral CT (MSCT) with a standard protocol for the evaluation of acute lung injury (ALI) in an animal model.

Materials And Methods: Eleven healthy intubated pigs (weight: 32.4 kg +/- 1.

Defining the optimum upper heart rate limit during exercise: a study in pacemaker patients with heart failure.

Aims: There is no non-invasive method to determine the individual optimum of maximum exercise heart rate. Knowledge of this value is of particular interest in patients with structural heart disease who are prone to tachycardia intolerance. The purpose of this study was to define the optimal maximum heart rate using cardiopulmonary exercise testing and exercise Doppler echocardiography and to compare the results of both approaches.

New technical developments in multislice CT, part 2: sub-millimeter 16-slice scanning and increased gantry rotation speed for cardiac imaging.

Despite all promising advances, some challenges remain for ECG-gated multislice CT examinations of the heart and the coronary arteries with current 4-slice detectors: adequate visualization of stents and severely calcified coronary arteries, examination of patients with higher heart rates and patients, who cannot adequately hold their breath for at least 30 sec. The new generation of multislice CT systems offering simultaneous acquisition of up to 16 sub-millimeter slices and gantry rotation times shorter than 0.5 sec has the potential to overcome these limitations.

Strategies for cardiac CT imaging.

We review the scanning techniques for cardiac CT imaging with single slice and multislice scanners. Combined with prospective triggering for transaxial scanning and retrospective gating for helical scanning the potential advantages and the basic limitations are discussed. Based on those theoretical considerations, the major conclusion is that high resolution data sets with isotropic spatial resolution can be acquired with quadslice, spiral scanning, only.

New technical developments in multislice CT--Part 1: Approaching isotropic resolution with sub-millimeter 16-slice scanning.

The introduction of multislice CT was a breakthrough with regard to increased scan speed, improved axial resolution and better utilization of the tube output. The new generation of multislice CT scanners offering simultaneous acquisition of up to 16 sub-millimeter slices represents an important leap on the way towards true isotropic scanning. We present an evaluation of a state-of-the-art 16-slice CT system (SOMATOM Sensation 16, Siemens AG, Forchheim, Germany).

[Visualization of coronary arteries in CT as assessed by a new 16 slice technology and reduced gantry rotation time: first experiences].

Purpose: First evaluation of image quality of a new 16-slice multidetector-row computed tomography (MDCT) for the assessment of coronary artery disease and lesion detection of the coronary arteries.

Materials And Methods: On a newly developed 16-slice CT scanner (SOMATOM Sensation 16, Siemens, Forchheim, Germany) a calcium score as well as a contrast-enhanced CT angiography (CTA) were performed on 4 patients with retrospective ECG-gating and a gantry rotation time of 420 ms to exclude or follow-up coronary heart disease. CTA was performed after injecting 120 ml contrast media intravenously.

A retrospectively ECG-gated multislice spiral CT scan and reconstruction technique with suppression of heart pulsation artifacts for cardio-thoracic imaging with extended volume coverage.

A method for cardio-thoracic multislice spiral CT imaging with ECG gating for suppression of heart pulsation artifacts is introduced. The proposed technique offers extended volume coverage compared with standard ECG-gated spiral scan and reconstruction approaches for cardiac applications: Thin-slice data of the entire thorax can be acquired within one breath-hold period using a four-slice CT system. The extended volume coverage is enabled by a modified approach for ECG-gated image reconstruction.

[A differentiated approach to the diagnosis of pulmonary embolism and deep venous thrombosis using multi-slice CT].

Purpose: To establish a differentiated protocol for multi-slice CT (MSCT) examinations in cases of clinically suspected pulmonary embolism (PE) using pulmonary CT-angiography (CTA) and indirect CT-phlebography (CTP).

Materials And Methods: 161 patients with suspected PE were examined using an MSCT (SOMATOM Volume Zoom; Siemens, Forchheim, Germany). After intravenous administration of 120 ml of contrast material, a thin collimation chest-CT scan was performed (120 kV, 100 mAs, collimation: 4 x 1 mm).

Inhibition of polarizing activity in the anterior limb bud is regulated by extracellular factors.

Anterior-posterior patterning of the developing limb is largely viewed as a function of polarizing activity. Recent evidence in polydactylous mutants, however, indicates that development of proper pattern also requires the involvement of inhibitory pathways in the anterior limb that prevent secondary polarizing zone formation, thus limiting the number of digits produced. We report the novel finding that grafts of extracellular matrix from the Mouse Posterior Limb Bud-4 cell line can induce supernumerary digits, including digits with posterior phenotype, from anterior chick limb mesenchyme.

A human RNA polymerase II subunit is encoded by a recently generated multigene family.

Background: The sequences encoding the yeast RNA polymerase II (RPB) subunits are single copy genes.

Results: While those characterized so far for the human (h) RPB are also unique, we show that hRPB subunit 11 (hRPB11) is encoded by a multigene family, mapping on chromosome 7 at loci p12, q11.23 and q22.

Multi-slice computed tomography as a screening tool for colon cancer, lung cancer and coronary artery disease.

Recent promising trials that use low-dose CT for the early detection of lung cancer have reinvigorated the interest in screening approaches. At the same time the development of fast image acquisition techniques, such as multislice CT, have sparked renewed interest in cardiac imaging within the radiological community. In addition to special cardiac capabilities, multislice CT has several other features such as high acquisition speed and low-dose requirements that may make this modality a universal radiological screening tool.

Implementation of a cone-beam reconstruction algorithm for the single-circle source orbit with embedded misalignment correction using homogeneous coordinates.

We present an efficient implementation of an approximate cone-beam image reconstruction algorithm for application in tomography, which accounts for scanner mechanical misalignment. The implementation is based on the algorithm proposed by Feldkamp et al. and is directed at circular scan paths.