OpenClinical logo


The applications accessible from this site are for demonstration purposes only. They have not been validated for clinical use and must not be used for real patient encounters.

Demonstrations of clinical applications
LEXMED    auf Deutsch    In English Learning Expert System for Medical Diagnosis
Computer-aided diagnosis of acute abdominal pain

developed by clinical domains keywords
FH Ravensburg-Weingarten, University of Applied Sciences in Baden-Württemberg, 1997-1999; Research Group for Automated Reasoning at the Technical University of Munich, 1995-1999 (PIT expert system shell); PIT-Systems OHG, Munich. Acute abdominal pain, suspected appendicitis Diagnostic decision support, probabilistic reasoning, expert systems
status access demonstrator
Advanced prototype Users can register and try out LEXMED free of charge at FH Ravensburg-Weingarten.

Example uses of the PIT in applications requiring probablilistic reasoning.



LEXMED (Learning Expert System for Medical Diagnosis) supports computer aided diagnosis of acute abdominal pain, particularly suspected appendicitis.

LEXMED combines probabilistic reasoning based on the concept of Maximum Entropy with the induction of probabilistic knowledge from data. The basic knowledge source of LEXMED was a database of 15,000 patient records which has been used to compute probabilistic rules. These rules were combined with further explicit probabilistic rules elicited from medical experts to cover cases not represented in the database.

PIT logo Decision support in LEXMED is provided by the PIT (Probability Induction Tool), a probabilistic reasoning engine designed to deal with incomplete and uncertain knowledge. The PIT, which is based on the principle of Maximum Entropy, computes a unique probability model while maintaining all necessary additional assumptions as minimal and as clear as possible.

Based on the probability distribution computed by PIT, the expert system proposes treatments of relatively low average cost. LEXMED has been undergoing evaluation in the municipal hospital in Weingarten (Baden-Württemberg, Germany) since June 1999 where an accuracy rate of 88% has been achieved.

Part of LEXMED data entry screen
LEXMED data entry screen

LEXMED has been in use at the Weingarten Municipal Hospital since June 1999. About 200 physicians, mainly from Germany, Austria and Switzerland have registered with Lexmed.

LEXMED is to be extended to diagnose other causes of acute abdominal pain. The developers of LEXMED are looking for partners in this project.

M. Schramm and W. Ertel. Reasoning with Probabilities and Maximum Entropy: The System PIT and its Application in LEXMED. In K. Inderfurth et al (ed), Operations Research Proceeedings, pages 274-280. Springer Verlag, 1999.

[]   []

" "

W. Ertel and M. Schramm. Combining Data and Knowledge by MaxEnt-Optimization of Probability Distributions. In PKDD'99 (3rd European Conference on Principles and Practice of Knowledge Discovery in Databases), volume 1704 of LNCS, pages 323-328, Prague, 1999. Springer Verlag.

[]   []

" "

W. Ertel and M. Schramm. Combining Expert Knowledge and Data via Probabilistic Rules with an Application to Medical Diagnosis. In UAI-2000 Workshop on Fusion of Domain Knowledge with Data for Decision Support, Stanford CA.

[]   []

" "

M. Schramm, W. Ertel, and W. Rampf. Automatische Diagnose von Appendizitis mit LEXMED. Submitted to "Der Chirurg", 2001.

[]   []

" "

contact links
Prof. Dr. Wolfgang Ertel , FH Ravensburg-Weingarten Postfach 1261 D-88241 Weingarten, Germany.
 bullet  LEXMED  auf Deutsch  auf Deutsch  bullet  PIT-Systems OHG, Munich  bullet  LEXMED on PIT-Systems OHG, Munich
Prof. Dr. Wolfgang Ertel, FH Ravensburg-Weingarten
Entry on OpenClinical: 19 May 2001
Last main update: 04 April 2002
Search this site
Privacy policy User agreement Copyright Feedback

Last modified:
© Copyright OpenClinical 2002-2011