Artificial Neural Networks in Medical Diagnosis

Abstract

Artificial neural networks are finding many uses in the medical diagnosis application. The goal of this paper is to evaluate artificial neural network in disease diagnosis. Two cases are studied. The first one is acute nephritis disease; data is the disease symptoms. The second is the heart disease; data is on cardiac Single Proton Emission Computed Tomography (SPECT) images. Each patient classified into two categories: infected and non-infected. Classification is an important tool in medical diagnosis decision support. Feed-forward back propagation neural network is used as a classifier to distinguish between infected or non-infected person in both cases. The results of applying the artificial neural networks methodology to acute nephritis diagnosis based upon selected symptoms show abilities of the network to learn the patterns corresponding to symptoms of the person. In this study, the data were obtained from UCI machine learning repository in order to diagnosed diseases. The data is separated into inputs and targets. The targets for the neural network will be identified with 1's as infected and will be identified with 0's as non-infected. In the diagnosis of acute nephritis disease; the percent correctly classified in the simulation sample by the feed-forward back propagation network is 99 percent while in the diagnosis of heart disease; the percent correctly classified in the simulation sample by the feed-forward back propagation network is 95 percent.

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IJCSI International Journal of Computer Science Issues, Vol. 8, Issue 2, March 2011
ISSN (Online): 1694-0814 www.IJCSI.org
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Artificial Neural Networks in Medical Diagnosis
Qeethara Kadhim Al-Shayea
MIS Department, Al-Zaytoonah University of Jordan
Amman, Jordan
Abstract
Artificial neural networks are finding many uses in the medical
diagnosis application. The goal of this paper is to evaluate
artificial neural network in disease diagnosis. Two cases are
studied. The first one is acute nephritis disease; data is the
disease symptoms. The second is the heart disease; data is on
cardiac Single Proton Emission Computed Tomography
(SPECT) images. Each patient classified into two categories:
infected and non-infected. Classification is an important tool in
medical diagnosis decision support. Feed-forward back
propagation neural network is used as a classifier to distinguish
between infected or non-infected person in both cases. The
results of applying the artificial neural networks methodology
to acute nephritis diagnosis based upon selected symptoms
show abilities of the network to learn the patterns
corresponding to symptoms of the person. In this study, the
data were obtained from UCI machine learning repository in
order to diagnosed diseases. The data is separated into inputs
and targets. The targets for the neural network will be
identified with 1's as infected and will be identified with 0's as
non-infected. In the diagnosis of acute nephritis disease; the
percent correctly classified in the simulation sample by the
feed-forward back propagation network is 99 percent while in
the diagnosis of heart disease; the percent correctly classified
in the simulation sample by the feed-forward back propagation
network is 95 percent.
Keywords: Artificial Neural Networks, Medical Diagnosis,
Feed-forward back propagation network, Artificial
Intelligence, and Decision Support Systems.
1. Introduction
Artificial neural networks provide a powerful tool to
help doctors to analyze, model and make sense of
complex clinical data across a broad range of medical
applications. Most applications of artificial neural
networks to medicine are classification problems; that is,
the task is on the basis of the measured features to assign
the patient to one of a small set of classes [1].
Er, Yumusak and Temurtas [2] presented a comparative
chest disease diagnosis which was realized by using
multilayer, probabilistic, learning vector optimization,
and generalized regression.
Das, Turkoglu and Sengur [3] used SAS enterprise
miner 5.2 to construct a neural networks ensemble based
methodology for diagnosing of the heart disease. Three
independent neural networks models used to construct
the ensemble model. The number of neural networks
node in the ensemble model was also increased but no
performance improvement was obtained.
Gil, Johnsson, Garicia, Paya and Fernandez [4]
evaluated the work out of some artificial neural network
models as tools for support in the medical diagnosis of
urological dysfunctions. They developed two types of
unsupervised and one supervised neural network.
Altunay, Telatar, Erogul and Aydur [5] analyzed the
uroflowmetric data and assisted physicians for their
diagnosis. They introduced an expert pre-diagnosis
system for automatically evaluating possible symptoms
from the uroflow signals. The system used artificial
neural networks (ANN) and produced a pre-diagnostic
result.
Moein, Monadjemi and Moallem [6] analyzed the real
procedure of medical diagnosis which usually is
employed by physicians and converted to a machine
implementable format. Then after selecting some
symptoms of eight different diseases, a data set contains
the information of a few hundreds cases was configured
and applied to a MLP neural network. The results of the
experiments and also the advantages of using a fuzzy
approach were discussed as well. Outcomes suggest the
role of effective symptoms selection and the advantages
of data fuzzificaton on a neural networks-based
automatic medical diagnosis system.
Heckerling, Canaris, Flach, Tape, Wigton and Gerber
[7] used artificial neural networks (ANN) coupled with
genetic algorithms to evolve combinations of clinical
variables optimized for predicting urinary tract infection.
Francisco, Juan Manuel, Antonio and Daniel [8]
developed a new system from a model based in a multi-
agent system in which each neuronal centre corresponds
with an agent. This system incorporates a heuristic in
order to make it more robust in the presence of possible
inconsistencies. The heuristic used is based on a neural
network (orthogonal associative memory). Knowledge
through training has been added to the system, using
correct patterns of behavior of the urinary tract and
behavior patterns resulting from dysfunctions in two
neuronal centers as a minimum.
Monadjemi and Moallem [9] investigated application of
artificial neural networks in typical disease diagnosis.
The real procedure of medical diagnosis which usually is
employed by physicians was analyzed and converted to
a machine implementable format. The results of the
experiments and also the advantages of using a fuzzy
approach were discussed as well.
Lin [10] presented classification and regression tree
(CART) and case-based reasoning (CBR) techniques to
structure an intelligent diagnosis model aiming to

IJCSI International Journal of Computer Science Issues, Vol. 8, Issue 2, March 2011
ISSN (Online): 1694-0814 www.IJCSI.org
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provide a comprehensive analytic framework to raise the
accuracy of liver disease diagnosis.
Mazurowski, Habas, Zurada, Lo, Baker and Tourassi
[11] investigated the effect of class imbalance in training
data when developing neural network classifiers for
computer aided medical diagnosis. The investigation is
performed in the presence of other characteristics that
are typical among medical data, namely small training
sample size, large number of features, and correlations
between features.
Zhang, Yan, Zhao and Zhang [12] presented a method
for developing a fully automated computer aided
diagnosis system to help radiologist in detecting and
diagnosing micro-calcifications in digital format
mammograms.
Higuchi, Sato, Makuuchi, Furuse, Takamoto and Takeda
[13] tested a three-layered artificial neural network
analysis of phonocardiogram recordings to diagnose,
automatically and objectively, the condition of the heart
in patients with heart murmurs.
2. Artificial Neural Networks
An artificial neural network (ANN) is a computational
model that attempts to account for the parallel nature of
the human brain. An (ANN) is a network of highly
interconnecting processing elements (neurons) operating
in parallel. These elements are inspired by biological
nervous systems. As in nature, the connections between
elements largely determine the network function. A
subgroup of processing element is called a layer in the
network. The first layer is the input layer and the last
layer is the output layer. Between the input and output
layer, there may be additional layer(s) of units, called
hidden layer(s). Fig.1 represents the typical neural
network. You can train a neural network to perform a
particular function by adjusting the values of the
connections (weights) between elements
Fig.1 A typical neural network
Medical Diagnosis using Artificial Neural Networks is
currently a very active research area in medicine and it is
believed that it will be more widely used in biomedical
systems in the next few years. This is primarily because
the solution is not restricted to linear form. Neural
Networks are ideal in recognizing diseases using scans
since there is no need to provide a specific algorithm on
how to identify the disease. Neural networks learn by
example so the details of how to recognize the disease is
not needed [14].
Based on the way they learn, all artificial neural
networks are divided into two learning categories:
supervised and unsupervised. In supervised learning, the
network is trained by providing it with input and output
patterns. During this phase, the neural network is able to
adjust the connection weights to match its output with
the actual output in an iterative process until a desirable
result is reached. An ANN of the unsupervised learning
type, such as the self-organizing map, the neural
network is provided only with inputs, there are no
known answers. The network must develop its own
representation of the input stimuli by calculating the
acceptable connection weights. That is self-organization
by clustering the input data and find features inherent to
the problem.
2.1 The Proposed Diagnosis Model
Feed-forward neural networks are widely and
successfully used models for classification, forecasting
and problem solving. A typical feed-forward back
propagation neural network is proposed to diagnosis
diseases. It consists of three layers: the input layer, a
hidden layer, and the output layer. A one hidden with 20
hidden layer neurons is created and trained. The input
and target samples are automatically divided into
training, validation and test sets. The training set is used
to teach the network. Training continues as long as the
network continues improving on the validation set. The
test set provides a completely independent measure of
network accuracy. The information moves in only one
direction, forward, from the input nodes, through the
hidden nodes and to the output nodes. There are no
cycles or loops in the network. The proposed neural
networks are shown in Fig.2 and Fig.3.
Fig.2 The proposed acute nephritis diagnosis neural network

IJCSI International Journal of Computer Science Issues, Vol. 8, Issue 2, March 2011
ISSN (Online): 1694-0814 www.IJCSI.org
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Fig.3 The proposed heart disease diagnosis neural network
Feed-forward neural network allows signals to travel
one-way only; from source to destination; there is no
feedback. The hidden neurons are able to learn the
pattern in data during the training phase and mapping
the relationship between input and output pairs. Each
neuron in the hidden layer uses a transfer function to
process data it receives from input layer and then
transfers the processed information to the output neurons
for further processing using a transfer function in each
neuron.
The output of the hidden layer can be represented by
YNx1 = f(WNxM XM,1 + bN,1 ) (1)
where Y is a vector containing the output from each of
the N neurons in a given layer, W is a matrix containing
the weights for each of the M inputs for all N neurons, X
is a vector containing the inputs, b is a vector containing
the biases and f(·) is the activation function [15].
3. Experimental Results
3.1 Data Analysis
Symptoms, images or signals are the data used in
medical diagnosis. The data set is obtained from UCI
Machine Learning Repository.
3.1.1 Acute Nephritis Diagnosis Data
The data was created by a medical expert as a data set to
test the expert system, which will perform the
presumptive diagnosis of one of the urinary system
diseases.
The main idea of this data set is to construct the neural
network model, which will perform the presumptive
diagnosis of acute nephritis. Acute nephritis of renal
pelvis origin occurs considerably more often at women
than at men. It begins with sudden fever, which reaches,
and sometimes exceeds 40C. The fever is accompanied
by shivers and one- or both-side lumbar pains, which are
sometimes very strong.
This dataset contains 120 patients. Table 1 presents the
patient symptom data which are considered as diagnosis
variables. The dataset contains 120 samples. 90 sample
used in training the network while 30 samples used in
testing the network.
Table 1: Diagnosis variable of datasets used in the study
Patients symptom data
N
o. Diagnosis Variable Name
1 Temperature of patient {35C-42C}
2 Occurrence of nausea {yes, no}
3 Lumbar pain {yes, no}
4 Urine pushing
(Continuous need for urination)
{yes, no}
5 Micturition pains {yes, no}
6 Burning of urethra, itch, swelling of
urethra outlet {yes, no}
3.1.2 Heart Disease Diagnosis Data
The dataset describes diagnosing of cardiac Single
Proton Emission Computed Tomography (SPECT)
images. Each of the patients is classified into two
categories: normal and abnormal. The database of 267
SPECT image sets (patients) was processed to extract
features that summarize the original SPECT images. As
a result, 44 continuous feature patterns were created for
each patient. The pattern was further processed to obtain
22 binary feature patterns. SPECT data has 267
instances that are described by 23 binary attributes. The
dataset contains 267 samples. 80 sample used in training
the network while 187 samples used in testing the
network.
3.2 Performance Evaluation
Neural network toolbox from Matlab 7.9 is used to
evaluate the performance of the proposed networks.
Acute nephritis of renal pelvis origin is the first disease
to be diagnosed. A two-layer feed-forward network with
6 inputs and 20 sigmoid hidden neurons and linear
output neurons was created.
Such net can fit multi-dimensional mapping problems
arbitrarily well, given consistent data and enough
neurons in its hidden layer as shown in Fig.2.
Levenberg-Marquardt back propagation algorithm was
used with train the network. Training automatically
stops when generalization stops improving, as indicated
by an increase in the mean square error (MSE) of the
validation samples.
The results of applying the artificial neural networks
methodology to distinguish between healthy and
unhealthy person based upon selected symptoms showed
very good abilities of the network to learn the patterns
corresponding to symptoms of the person. The network
was simulated in the testing set (i.e. cases the network
has not seen before). The results were very good; the
network was able to classify 99% of the cases in the
testing set. Fig.4 shows the training state values.
Best validation performance is 2.8548e-007 at epoch 7
as shown in Fig.5. The mean squared error (MSE) is the
average squared difference between outputs and targets.
Lower values are better while zero means no error.

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Fig.4
Fig.5
Table 2: The Mean Square Error (MSE) and Regression values for the
training, validation and testing.
MSE R
Training 5.11986e-8 9.99999e-1
Validation 2.85475e-7 9.99999e-1
Testing 1.13132e-6 9.99997e-1
The percent correctly classified in the simulation sample
by the feed-forward back propagation network is 99
percent. The MSE is equal to 3.96199e-5 and the
regression is equal to 9.99936e-1.
Heart disease is the second disease to be diagnosed. A
two-layer feed-forward network with 22 inputs and 20
sigmoid hidden neurons and linear output neurons was
created.
Such net can fit multi-dimensional mapping problems
arbitrarily well, given consistent data and enough
neurons in its hidden layer as shown in Fig.3.
Levenberg-Marquardt back propagation algorithm was
used with train the network. The results of applying the
artificial neural networks methodology to distinguish
between normal and abnormal person based upon binary
feature patterns extracted from SPECT images showed
very good abilities of the network to learn the patterns.
The network was simulated in the testing set. The results
were very good; the network was able to classify 95% of
the cases in the testing set. Fig.6 shows the training state
values.
Best validation performance is 0.088329 at epoch 3 as
shown in Fig.7.
Fig.6
Fig.7
Table 3: The Mean Square Error (MSE) and Regression values for the
training, validation and testing.
MSE R
Training 4.86802e-3 9.92593e-1
Validation 8.83292e-2 8.50794e-1
Testing 7.47611e-2 8.72846e-1
The percent correctly classified in the simulation sample
by the feed-forward back propagation network is 95
percent. The MSE is equal to 2.78711e-2 and the
regression is equal to 9.50148e-1.

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4. Conclusions
This study aimed to evaluate artificial neural network in
disease diagnosis. The feed-forward back propagation
neural network with supervised learning is proposed to
diagnose the disease. Artificial neural networks showed
significant results in dealing with data represented in
symptoms and images. Results showed that the proposed
diagnosis neural network could be useful for identifying
the infected person.
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Qeethara Kadhim Abdul Rahman Al-Shayea, has received Ph. D. in
Computer Science, Computer Science Department, University of
Technology, Iraq, 2005. She received her M.Sc. degree in Computer
Science, Computer Science Department from University of
Technology, Iraq, 2000. She has received her High Diploma degree in
information Security from Computer Science Department, University
of Technology, Iraq, 1997. She has received B. Sc. Degree in
Computer Science Department from University of Technology, Iraq,
1992. She joined in September (2001-2006), Computer Science
Department, University of Technology, Iraq as assistant professor. She
joined in September 2006, Department of Management Information
Systems Faculty of Economics & Administrative Sciences Al-
Zaytoonah University of Jordan as assistant professor. She is interested
in Artificial intelligent, image processing, computer vision and coding
theory.