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