title: Hypodensity extractor: a phantom study.
abstract: We report on the extraction procedures of low-contrast symptomatic hypodensity optimized for a computed tomography-based diagnosis. The specific application is brain imaging with enhanced perception of hypodense areas which are direct symptoms of acute ischemia. A standard low-contrast phantom, as commonly employed in dosimetry and imaging quality evaluation, was used to derive numeric criteria for assessing the extraction effectiveness. Our proposed procedure is based on multiscale analysis of the image data expanded over the frames of wavelets, curvelets or complex wavelets, followed by nonlinear approximation of the symptom signatures. Apparent subtle density changes in the phantom were evaluated using computational metrics and subjective ratings. We discuss the advantages and disadvantages of our proposed optimized hypodensity extraction procedures.
authors.affiliation: Faculty of Mathematics and Information Science, Warsaw University of Technology, 00-662 Warsaw ul. Koszykowa 75, Poland. Electronic address: ostrekg@mini.pw.edu.pl.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Ostrek
authors.affiliation: Faculty of Mathematics and Information Science, Warsaw University of Technology, 00-662 Warsaw ul. Koszykowa 75, Poland.
authors.forename: Artur
authors.initials: A
authors.lastname: Przelaskowski
authors.affiliation: Faculty of Mathematics and Information Science, Warsaw University of Technology, 00-662 Warsaw ul. Koszykowa 75, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Jóźwiak
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging*; D002545:Brain Ischemia / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
keywords: Computed tomography; Hypodensity extraction; Image assessment; Ischemic stroke; Low-contrast phantom