ComputerunterstützteDiagnoseverfahren

Klaus-Peter Adlassnig

Section on Medical Expert and Knowledge-Based Systems

Core Unit for Medical Statistics and InformaticsMedical University of Viennawww.meduniwien.ac.at/mes

International JournalArtificial Intelligence in Medicine

Editor-in-Chiefwww.intl.elsevierhealth.com/journals/aiim

Computers in Clinical Medicine

• step 1: patient administration– admission, transfer, discharge, and cost billing

• step 2: documentation of patients’ medical data– electronic health record: life-long, multimedia

• step 3: patient data retrieval– medical research databases– quality assurance in the medical institution

• step 4: software-based clinical decision support– quality assurance for the particular patient

Clinical Decision Supportquality assurance of clinical decision making:

for the particular patient

• determination of correct diagnoses– data interpretation and monitoring– single or differential diagnosis

* further diagnostic investigations* all pathological signs are accounted for

• selection of optimal therapies– treatment recommendations– contraindication alerts– drug interaction warnings

• assessment of prognosis– development of illness

• optimal management for the patient– clinical reminders– medical protocols, guidelines, and pathways

symptomssigns

test resultsclinical findings

biosignalsimages

diagnosestherapies

nursing data•••

standardizationtelecommunication

chip cards

anatomybiochemistryphysiology

pathophysiologypathologynosology

therapeutic knowledgedisease management

•••

subjective experienceintuition

knowledge-based systems

information systems

patient’s medical data physician’s medical knowledge

induction

deduction

manypatients

single patient

diagnosistherapy

prognosismanagement

generalknowledge

•••

generalknowledge

telemedicine telemedicineintegration

• Der sog. »schmerzlose Ikterus« ist keineswegs typisch für die Pankreaskopftumoren (weniger als 20%). Vielmehr sind die häufigsten Frühsymptome Schmerzen mit unbestimmten Verdauungsstörungen und Gewichtsverlust.

• Unter den Tumormarkern hat das Ca 19-9 eine relative Semispezifität für das Pankreaskarzinom. Es eignet sich zur Differenzierung von chronischer Pankreatitis und Karzinom ...

differential diagnosis

from: J.A.Pinard et al. (2003) Maternal Serologic Screening for Toxoplasmosis. Journal of Midwifery & Women’s Health 48, 308–316.

Structure of Knowledge-Based Systems in Medicine

medical problem solving methods

medicalknowledge bases

patient’s medical data

• rule-based recommendations• differential diagnosis• laboratory test interpretation • ICU monitoring• device control

• rules with recommendations• disease profiles• interpretive reports• pathophysiological state models• device control rules

• patient data• symptoms, signs, test results• laboratory test results• patient data• patient and device data

expertsystem

informationsystem

Knowledge-Based Methodologyin Medicine

• knowledge– modeling of knowledge

* diagnostic knowledge, therapy recommendations, prognostic information, best medical-practice management guidelines

– modeling based on linguistic concepts* recounted patient history, perception of characteristic signs,

interpreted laboratory measurements, concepts of pathophysiological states, diagnostic, therapeutic, and prognostic concepts

– objective and subjective medical knowledge* definitional, causal, statistical, and heuristic knowledge

– health knowledge* medical standards, work plans, legal requirements, etc.

• data– data-to-symbol conversion

* 1st step to intelligence– recounted, perceived, observed, and measured medical data

* patient history, physical examinations, laboratory tests, and clinical investigations

Medical Knowledge• knowledge representation and processing

– decision tables, trees, and graphs– decision rules and frames

⇒ n-ary relationships between medical entities

• standardization, e.g.,– ARDEN syntax (and FuzzyARDEN)– j.MD– MedFrame– guideline languages, e.g., ARDEN Syntax, PROforma, GLIF

• general basis– ICD—International Classification of Diseases

– SNOMED—Systematized Nomenclature of Medicine

– LOINC—Logical Observation Identifiers Names and Codes

– UMLS—Unified Medical Language System

– FMA—Foundational Model of Anatomy

Towards a Clinical Science

patient’s medical dataand

healthcare processesfor

machine processing

patient’s medical dataand

healthcare processesfor

human processing

≠

…measuring everything measurable and trying to make measurable that which has not been measurable so far …

Galileo Galilei

Knowledge-Based Patient Carepaper chart,

partially electronic

⇑physician

medical knowledge base

expert system

patient record⇑

medicaldecision support logic

electronic health care record

⇑

⇑⇑⇑ ⇑ ⇑health care personnel

fully electronic, integrated system

Numeric and Symbolic Levels in Knowledge-Based Systems

Uncertainty in Medicine• imprecision (=fuzziness) of medical concepts

– due to the unsharpness of boundaries of linguistic concepts; gradual transition from one concept to another

– modelled by fuzzy sets• uncertainty of medical conclusions

– due to the uncertainty of the occurrence and co-occurrence of imprecise medical concepts

– modelled by SigmaCounts (unconditioned and conditioned frequencies of fuzzy sets)

• incompleteness of medical data and medical theory– due to only partially known data and partially known explanations for

medical phenomena– modelled by fuzzy intervalls

Medical problem solving is theprocess of making adequate decisions

with inadequate information.

Anonymous

Genese medizinischer ExpertensystemeMedizinische

Expertensysteme

Medizinische

Künstliche Intelligenz

Medizinische Informatik

Medizin(Kliniker)

KI(Informatiker)

Diagnose

Therapie

Prognose

Patientenmanagement

Informatik

Philosophie

Psychologie

Linguistik

A Sampling of Intelligences—I

from: Gardner, H. (1998) A Multiplicity of Intelligences. Scientific American Presents Vol. 9, No. 4, 19–23.

A Sampling of Intelligences—II

from: Gardner, H. (1998) A Multiplicity of Intelligences. Scientific American Presents Vol. 9, No. 4, 19–23.

Artificial Intelligence (1)

• Definition 1: AI is a field of science and engineering concerned with the computational understanding of what is commonly called intelligent behavior, and with the creation of artifacts that exhibit such behavior.

– from: Shapiro SC. Artificial intelligence. In: Shapiro SC, editor. Encyclopedia of Artificial Intelligence. 2nd ed., vol. 1. New York: Wiley, 1992, pp.54–7.

• Definition 2: AI is the science of artificial simulation of human thought processes with computers.

– from: Feigenbaum EA, Feldman J. editors. Computers & Thought. Menlo Park: AAAI Press 1995, back cover.

Artificial Intelligence (2)

• It is the decomposition of entire thought processes and their separate artificial simulation—also of simple instances of “thought”—that make the task of AI manageable.

• A functionality-driven science of AI that extends humans through computer systems step by step can immediately be established.

⇓artificial-intelligence-augmented systems

– from: Adlassnig KP. Artificial-intelligence-augmented systems. Artificial Intelligence in Medicine 24, 2002, pp. 1–4.

Medizinische Experten-und wissensbasierte

Systeme

MedizinischeDokumentation

Wissensbasierte Überprüfung aufDatenvollständigkeit und -konsistenz,

wissensbasierte Dokumentations-und Informationssysteme

Laboratoriums-medizin

Wissensbasierte Alarm-module, wissensbasierte

Interpretationsprogramme

Wissensbasierte adaptiveBefundungs- und Betrachtungs-stationen, digitale anatomische

Atlanten, wissensbasierte Bildverarbeitung

BildgebendeMedizin

Wissensbasierte Konsultationssysteme

für Diagnose und Therapie, wissensbasierte Monitoringsystemezur diagnostischen Früherkennung

und TherapieüberwachungKlinische

Medizin undIntensivmedizin

Wissensbasiertes Studiendesign

MedizinischeStatistik und

BiometrieWissensbasierte Analyse und

Design von Biomolekülen, wissens-basierte Suchverfahren in molekular-

biologischen Datenbanken

Bioinformatik

BiomedizinischeTechnik

Wissensbasierte Methodenin der Biomechanik,

Robotertechnik

Ein selbstbalancierender, 28gelenkiger adaptiver Zweibeiner;eine elektrochemische Reduktionsfabrik samt gesonderter Stauräume für spezielle Energieextrakte in Speicherbatterien, mit denen dann Tausende

hydraulischer und pneumatischer Pumpen mit anhängenden Motoren betrieben werden;

100 000 Kilometer Kapillaren;... gesteuert wird dieser ganze außerordentlich komplexe Mechanismus mit hervorragender Präzision von einem Gefechtsturm aus; darin befinden sich

teleskopische und mikroskopische Entfernungsmesser, die selbsttätig registrieren und protokollieren, ferner ein Spektroskop und anderes mehr;

das Kommando im Gefechtsturm steht in enger Verbindung mit der klimatisierten Luftaufnahme und der Hauptzufuhr für Brennstoff....

R. Buckminster Fuller, “A Definition of a Man”

in Raymond Kurzweil, „Das Zeitalter der Künstlichen Intelligenz“, 1993 Carl Hanser Verlag, München Wien

1. knowledge representation• formalization and representation of medical knowledge in a

knowledge base

2. knowledge acquisition• knowledge transfer from the expert to the computer

(possible contribution to standardization; filling of “white patches”)

3. inference method• connection between single data of a patient with stored medical

knowledge

4. evaluation of correctness and applicability5. man/machine interface and network integration6. legal aspects

Project Phases

Knowledge Representation• formalization and representation of medical knowledge in

a knowledge base− questions:

∗ degree of structuralization (degree of theory formation in the domain)

∗ type of knowledge (definitional, causal, statistical, heuristic)∗ imprecision, uncertainty, and incompleteness

− formal models:∗ logical models (two- and many-valued)∗ rules (with and without uncertainty)∗ objects (direct representation of complex structures)∗ networks (associative or causal)