Lower gastrointestinal endoultrasound
SummaryFollowing a brief history of transrectal ultrasonography, the author explains the fundamentals that led to his research on rectal echographic layers and then describes his theory as applied to the anatomical interpretation of these layers. Personal cases of preoperative staging with transrectal echography provide a basis for the critical evaluation of this method and its proposed role in clinical application.
A comparison of computed tomography and endorectal ultrasound in staging rectal cancer
Endorectal ultrasound was used prospectively to stage 85 patients with rectal cancer. All patients had surgical exploration and histological analysis. Demonstration of tumour, extension into perirectal fat and lymph node involvement were evaluated. Eighty-one tumours were successfully imaged by endorectal ultrasound. The results suggest that: (1) endorectal ultrasound is more accurate than CT in detecting the site of tumour; (2) endorectal ultrasound is more accurate than CT in detecting perirectal fat infiltration; (3) endorectal ultrasound is slightly more accurate than CT in detecting level II lymph node involvement.
An Essay on the Nature and Significance of the Normative Nature of Economics
It is conventional in economics to distinguish between the normative and the positive. The normative has to do with goodness and badness, and with what ought and ought not to be done;1 and the positive has to do with objective description and/or explanation, with what is and with what is necessary given some normative end. The normative has to do with desirability; the positive has to do with truth (in the sense of either descriptive accuracy or serviceability of a means to a given end).2