2,588 research outputs found
De schaduwen van vandaag en morgen
Rede, uitgesproken bij de aanvaarding van het ambt van gewoon lector in de Röntgendiagnostiek aan de Erasmusuniversiteit te Rotterdam op 23 februari 197
Total-liver-volume perfusion CT using 3-D image fusion to improve detection and characterization of liver metastases
The purpose of this study
was to evaluate the feasibility of a totalliver-
volume perfusion CT (CTP)
technique for the detection and characterization
of livermetastases. Twenty
patients underwent helical CT of the
total liver volume before and 11 times
after intravenous contrast-material
injection. To decrease distortion artifacts,
all phases were co-registered
using 3-D image fusion before creating
blood-flow maps. Lesion-based sensitivity
and specificity for liver metastases
of first the conventional four
phases (unenhanced, arterial, portal
venous, and equilibrium) and later all
12 phases including blood-flow maps
were determined as compared to intraoperative
ultrasound and surgical exploration.
Arterial and portal venous
perfusion was calculated for normalappearing
and metastatic liver tissue.
Total-liver-volume perfusion values
were comparable to studies using
single-level CTP. Compared to fourphase
CT, total -liver-volume CTP
increased sensitivity to 89.2 from
78.4% (P=0.046) and specificity to
82.6 from 78.3% (P=0.074). Total -
liver-volume CTP is a noninvasive,
quantitative, and feasible technique.
Preliminary results suggest an improved
detection of liver metastases for
CTP compared to four-phase CT
A Taxonomy of Best-Reply Multifunctions in 2x2x2 Trimatrix Games
This paper provides an overview of the various shapes the best- reply multifunctions can take in 2×2×2 trimatrix games. It is shown that, unlike in 2×2 bimatrix games, the best replies to the opponents’ pure strategies do not completely determine the structure of the Nash equilibrium set.non-cooperative games;best-reply multifunction;Nash equilibrium
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