title: Image stacking with entropy values in conventional angiography: initial experience.
abstract: The entropy method for stacking a series of angiographic images is presented and compared with the maximum opacity method, which is already established. The entropy method comprises calculation of the entropy of the time course for each image pixel. This accentuates image areas where a contrast agent bolus is passing. Quantitative analysis of the contrast-to-noise ratio and qualitative analysis of 11 cases were performed, the latter by eight independent viewers. Results indicate that the entropy images show more vascular detail in small peripheral vessels and increased contrast-to-noise ratio by up to a factor of 1.97 compared with maximum opacity images.
authors.affiliation: Department of Neuroradiology, University of Heidelberg Medical Center, Im Neuenheimer Feld 400, D-69120 Heidelberg, Germany. holger_schmitt@med.uni-heidelberg.de
authors.forename: Holger
authors.initials: H
authors.lastname: Schmitt
authors.forename: Michael
authors.initials: M
authors.lastname: Grass
authors.forename: Sabine
authors.initials: S
authors.lastname: Heiland
authors.forename: Stefan
authors.initials: S
authors.lastname: Hahnel
authors.forename: Klaus
authors.initials: K
authors.lastname: Sartor
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D000792:Angiography / Q000379:methods*; D019277:Entropy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged