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The continuous progress achieved in medical imaging technology in the past decades has led to considerable improvement in patient care. In consequence of this progress, neuroimaging (imaging the structure or function of the brain) has gained an increasingly important role in research and clinical practice.
Dementia, a psychiatric/mental disorder defined as progressive loss in cognitive skills such as learning, memory, orientation and language, is a devastating and irreversible brain syndrome. Due to its increasing prevalence (especially in aging populations), long duration, caregiver burden and high financial cost of care, dementia has emerged as one of our major public health problems affecting 20% of those over 80 years of age. As a result there is an increasing demand for a more accurate and earlier diagnosis and the value of neuroimaging in improving the diagnostic process is becoming widely accepted.
Neuroimaging assessments may aid in the diagnosis of neurodegeneration as opposed to healthy aging, improve differential diagnosis, assist in the prediction of conversion to dementia in individuals at a higher risk of developing the disorder, improve the tracking of disease progression and finally may serve as an outcome measure for assessing drug efficacy. Hence, in clinical settings the diagnosis of dementia is increasingly taken based on combined analysis of data such as the patient's cognitive skills, demographic status, family history of dementia and neuroimaging findings (such as the degree and distribution of atrophy).
In addition to the improvement in patient care, recent advances in neuroimaging technology also have increased the need for tools to analyze and interpret the growing amount of neuroimaging data acquired. Accordingly, various semi-/fully automatic tools for analysis and interpretation of such data are made available by research centers as well as medical imaging companies.
In view of the above, this work aims to provide a non-exhaustive summary of neuroimaging studies in psychiatric disorders with special emphasis on dementia and drug discovery. State of the art studies employing both structural (CT, MRI, etc.) and functional (fMRI, PET, SPECT, etc.) neuroimaging techniques and their potential contribution to diagnostic research as well as to drug discovery will be discussed. The work will also include a brief introduction on the related advances and open questions from an image processing standpoint, and finally present our recent research effort on computer-based measurement of dementia-related neuroimaging findings as compared with experts' visual assessments for improved disease understanding, diagnosis, prognosis, and therapy planning.