Demirci_EU Neurology 10/03/2010 09:55 Page 103
Imaging
Functional Magnetic Resonance Imaging –
Implications for Detection of Schizophrenia
Oguz Demirci
1
and Vince D Calhoun
1,2
1. The Mind Research Network, Albuquerque; 2. Department of Electrical and Computer Engineering, University of New Mexico
Abstract
Functional magnetic resonance imaging (fMRI) is an invaluable non-invasive instrument that has been used to investigate physiological
disturbances that lead to manifest psychiatric illnesses. It is hoped that efficient application of fMRI can be utilised to characterise and diagnose
mental illnesses such as schizophrenia. Although there are various fMRI research studies presenting very promising diagnosis results for
schizophrenia, we believe that there is much to be done to develop effective diagnostic tools for clinical purposes. We present specific examples
based mostly on our past and recent work together with various examples from the recent literature. We discuss where we currently stand in
the efforts of fMRI being used for diagnosis of schizophrenia, examine common possible biases and offer some solutions with the hope that
fMRI can be more efficiently used in diagnostic research.
Keywords
Functional magnetic resonance imaging (fMRI), schizophrenia, bias, classification, detection
Disclosure: Data collection was funded by the Department of Energy, grant DE-FG02-99ER62764.
Acknowledgements: The authors would like to thank the Mind Research Network staff for their efforts during the data collection process. This work was funded by the US
National Institutes of Health (NIH), under grants 1R01 EB 000840, 1R01 EB 005846 and 2R01 EB000840.
Received: 25 March 2009 Accepted: 23 July 2009
Correspondence: Oguz Demirci, The Mind Research Network, 1101 Yale Boulevard, Albuquerque, NM 87131, US. E:
oguzdemirci@gmail.com
Functional magnetic resonance imaging (fMRI) is a fairly new tool that Among these mental illnesses, schizophrenia is a neurodevelopmental
has been used to measure brain activation utilising the dependency disorder that might result from several factors such as genetic
of the magnetic properties of haemoglobin on the amount of oxygen inheritance, disturbance of the in utero environment and exposure to
it carries. Blood-oxygen-level-dependent (BOLD) signals measure the biological and psychosocial factors in infancy and early childhood.
3
It
alterations in cerebral blood flow that mark functional brain activity.
1
is extremely important to be able to determine people with a high risk
The intrinsic BOLD contrast makes fMRI an invaluable non-invasive of schizophrenia to prevent the onset of schizophrenia in persons with
instrument for the investigation of the underlying physiological prodromal symptoms and to reduce the severity of the illness in those
disturbances that lead to manifest psychiatric disorders. The brain is who already have schizophrenia via early diagnosis and intervention.
3
imaged at discrete time intervals while a subject is required to carry
out a task or presented with a stimulus. There is no gold standard in the diagnosis of schizophrenia and there
are complications in the objective evaluation of the examinations.
The success of the operation depends on three aspects: the scanning Interviews and symptom history are the main factors that determine the
sequence used, the design of the stimulus paradigm and the methods diagnosis, but conclusions may change because different combinations
used for data analysis.
2
Possible failures during any of these three of symptoms may be observed in various patients, and these symptoms
steps can cause unfavourable evaluation of the measured functional may change over time for a particular patient.
4
This makes schizophrenia
activity and affect the reliability of the conclusions drawn. The fact a complex disorder to diagnose even for an expert. Biological markers –
that these three steps are often carried out by different scientists defined as objective, measurable phenomena that may identify subjects
requires strong collaboration among groups. at increased risk of development of disease – should be sought in order
to intervene as soon as possible so as to improve prognosis.
3
Objective
It is hoped that successful application and analysis of fMRI in clinical diagnosis methods are better obtained using biologically
neurological disorders can be used to characterise and diagnose measured quantities such as fMRI. Therefore, fMRI has been used in
mental illnesses such as Alzheimer’s disease, schizophrenia, schizophrenia research studies to evaluate prognostic and diagnostic
bipolar disorder, mild traumatic brain injury and addiction. Both methods. We would like to provide an overview of schizophrenia
healthy controls and patients can be scanned during various research using fMRI data and give specific examples based mostly on
tasks, and responses to these stimuli can be measured and our past and recent work.
compared to discover the differences between the two groups and
investigate how the brain function of patients differs from that of fMRI data is available in the form of 3D high-resolution images that
healthy controls. change over time (tens of thousands of voxels). Extraction of useful
© TOUCH BRIEFINGS 2009 103
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132