There are currently around 900,000 people living with dementia in the UK. This is projected to increase to 1.6 million people by 2040. This sharp rise is mainly due to accelerated population ageing.
The total cost of care for people with dementia in the UK is £34.7 billion. This is set to rise sharply over the next two decades, to £94.1 billion by 2040 (Wittenberg et al, 2019).
Early diagnosis of dementia is extremely important in terms of prognosis as it opens the door for initiating early treatment which can slow the progression of the disease, yielding better therapeutic outcomes. Diagnosis of dementia is largely dependent on clinical examination. Utility of various neuroimaging techniques such as computerised tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT) and biomarkers can significantly aid in early diagnosis of dementia especially in those without any clinical evidence of neurocognitive impairment.
Gifford et al (2000) showed that there is considerable uncertainty in the evidence behind clinical prediction rules on the use of neuroimaging to identify dementia, and that if clinicians applied these rules they may miss treatable conditions.
Most clinical guidelines therefore recommend that at least one structural imaging procedure be performed routinely in each patient with suspected dementia. NICE guidelines state ‘offer structural imaging to rule out reversible causes of cognitive decline and to assist with subtype diagnosis, unless dementia is well established and the subtype is clear’ (NICE, 2018).
In this module we review the role of neuroimaging in dementia assessment. The module also provides a practical guide for improving the clinician’s skill in the appropriate use and evaluation of brain scans.