Nonlinear image registration is a prerequisite for various medical image analysis applications. Many data acquisition protocols suffer from problems due to breathing motion which has to be taken into account for further analysis. Intensity based nonlinear registration is often used to align differing images, however this requires a large computational… (More)
PURPOSE CT angiography (CTA) has been established for detection and therapy planning of intracranial aneurysms. The analysis of aneurysms at the level of the skull base, however, remains difficult because bone prevents a free view. We report initial clinical results of an approach for automatic bone elimination from CTA data. MATERIAL AND METHODS Before… (More)
BACKGROUND AND PURPOSE Bone-subtraction techniques have been shown to enhance CT angiography (CTA) interpretation, but motion can lead to incomplete bone removal. The aim of this study was to evaluate 2 novel registration techniques to compensate for patient motion. MATERIALS AND METHODS Fifty-four patients underwent bone-subtraction CTA (BSCTA) for the… (More)
Nonlinear image registration is a prerequisite for a variety of medical image analysis tasks. A frequently used registration method is based on manually or automatically derived point landmarks leading to a sparse displacement field which is densified in a thin-plate spline (TPS) framework. A large problem of TPS interpolation/approximation is the… (More)
Maximum intensity projection (MIP) studies of CT angiography (CTA) images are a widely used tool for artery and vein visualization especially in the brain. Due to their high CT intensity bone structures lead to visualization artifacts in MIP studies, therefore they have to be removed to get an undistorted view of the vessel structures. Often this removal is… (More)
We present a concept to integrate constraints and triggers into an object oriented geo database kernel and propose an extension of the underlying object definition language to specify constraints and triggers. To reduce the number of constraints, we provide a mechanism to determine all objects which are subject to constraints and triggers.
INTRODUCTION The aim if this study is to find out if contrast between gray (GM) and white matter (WM) on non-enhanced brain CT (NECT) can be enhanced by using a frequency selective non-linear blending. METHODS Thirty consecutive patients (40 % female; mean age 67.73 ± 12.71 years), who underwent NECT of the brain, were retrospectively included in this… (More)
PURPOSE Ischemic brain edema is subtle and hard to detect by computed tomography within the first hours of stroke onset. We hypothesize that non-enhanced CT (NECT) post-processing with frequency-selective non-linear blending ("best contrast"/BC) increases its accuracy in detecting edema and irreversible tissue damage (infarction). METHODS We… (More)