Anne Koenig | PubMed Health

PubMed2002

Theoretical framework for a dynamic cone-beam reconstruction algorithm based on a dynamic particle model.

Dynamic cone-beam reconstruction algorithms are required to reconstruct three-dimensional (3D) image sequences on dynamic 3D CT combining multi-row two-dimensional (2D) detectors and sub-second scanners. The speed-up of the rotating gantry allows one to improve the temporal resolution of the image sequence, but at the same time, it implies increase in the dose delivered during a given time period to keep constant the signal-to-noise ratio associated with each frame. The alternative solution proposed in this paper is to process data acquisition on several half-turns in order to reduce the dose delivered per rotation with the same signal-to-noise ratio. In order to compensate for time evolution and motion artefacts, we propose to use a dynamic particle model to describe the object evolution during the scan. In this article, we first introduce the dynamic particle model and the dynamic CT acquisition model. Then, we explain the principle of the proposed dynamic cone-beam reconstruction algorithm. Lastly, we present preliminary results on simulated data.

Algorithms↗

PubMed2002

Serum cholesterol level comparison: control subjects, anxiety disorder patients, and obsessive-compulsive disorder patients.

OBJECTIVE: To determine whether panic disorder is associated with elevated serum cholesterol levels. Serum cholesterol levels of panic disorder patients are reported to be elevated. This could explain the higher-than-expected cardiovascular mortality in this population. Some evidence exists wherein cholesterol levels are also increased in patients with general anxiety disorder and phobias. To date, there are only 2 reports on cholesterol levels of obsessive-compulsive disorder (OCD) patients, giving controversial results. METHOD: We compared serum cholesterol levels of anxiety disorder patients, OCD patients, and normal control subjects with each other (n = 60 in each group). Serum cholesterol was measured in each subject before treatment. Subjects of the 3 groups were matched by age and sex. RESULTS: Patients with anxiety disorders and OCD had elevated cholesterol levels, compared with normal control subjects. Cholesterol levels in OCD patients were comparable with those in patients with phobia. CONCLUSIONS: Our data support the assumption that elevation in cholesterol level is not a specific feature of panic disorder (as most assumed), but more generally associated with anxiety disorders. Increased cholesterol levels in patients with anxiety disorders and OCD may be of clinical relevance.

Adult↗