Orjan Smedby

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Tortuosity of an artery can disturb fluid mechanics and cause flow separation, which might in turn promote atherogenesis. This study discusses theoretically several quantitative measures of arterial tortuosity and curvature in two dimensions and tests them with computations from digitized femoral arteriograms. When reproducibility, sensitivity to scaling(More)
PURPOSE To describe and present some preliminary results for a novel algorithm for segmentation with gray-scale connectedness as a means to separate arteries and veins in magnetic resonance angiography (MRA). MATERIALS AND METHODS The proposed algorithm, SeparaSeed, uses the gray-scale degree of connectedness as a tool to find the zone surrounding each(More)
BACKGROUND Conventional magnetic resonance imaging (MRI) has relatively long scan times for routine examinations, and the signal intensity of the images is related to the specific MR scanner settings. Due to scanner imperfections and automatic optimizations, it is impossible to compare images in terms of absolute image intensity. Synthetic MRI, a method to(More)
PURPOSE to compare gadolinium-enhanced magnetic resonance angiography (Gd-MRA), digital subtraction angiography (DSA) and duplex of the iliac arteries with intra-arterial pressure gradient measurement as the reference method. MATERIALS AND METHODS Gd-MRA, DSA and duplex examinations of the iliac arteries were performed in 30 patients (60 arteries) with(More)
BACKGROUND There is an unsettled discussion about whether the distribution of local anesthetic is free or inhibited when performing brachial plexus blocks. This is the first study to use magnetic resonance imaging (MRI) to help answer this question. METHODS Thirteen patients received axillary block by a catheter-nerve stimulator technique. After locating(More)
BACKGROUND To define and evaluate coronary contrast opacification gradients using prospectively ECG-gated single heart beat 320-detector row coronary angiography (CTA). METHODS AND RESULTS Thirty-six patients with normal coronary arteries determined by 320 x 0.5-mm detector row coronary CTA were retrospectively evaluated with customized image(More)
31P-MRS using DRESS was used to compare absolute liver metabolite concentrations (PME, Pi, PDE, gammaATP, alphaATP, betaATP) in two distinct groups of patients with chronic diffuse liver disorders, one group with steatosis (NAFLD) and none to moderate inflammation (n=13), and one group with severe fibrosis or cirrhosis (n=16). All patients underwent liver(More)
For visual grading experiments, which are an easy and increasingly popular way of studying image quality, hitherto used data analysis methods are often inadequate. Visual grading analysis makes assumptions that are not statistically appropriate for ordinal data, and visual grading characteristic curves are difficult to apply in more complex experimental(More)
Despite a long tradition, conventional anatomy education based on dissection is declining. This study tested a new virtual reality (VR) technique for anatomy learning based on virtual contrast injection. The aim was to assess whether students value this new three-dimensional (3D) visualization method as a learning tool and what value they gain from its use(More)
PURPOSE To obtain information on the morphology of the tympanic and mastoid portions of the facial nerve canal, and on the appearance of unusual vascular channels and anomalies such as dehiscences. MATERIAL AND METHODS One hundred and two temporal bone preparations were examined by conventional radiography to evaluate mastoid pneumatization. Of these, 73(More)