This prospective study aims:

1. to compare cognitive performance in different clinical groups of participants with mild cognitive impairment (MCI) or mild dementia [Alzheimer's Disease (AD), Vascular Cognitive Impairment (VCI) and Fronto-temporal Dementia (FTD)] to determine whether scores reveal differential profiles between the groups,
2. to demonstrate differences in imaging markers between different dementia syndromes and healthy volunteers using ultra high-field MRI at 7T.

The imaging arm of the study include:

1. to demonstrate differences in brain iron levels between different dementia syndromes and healthy volunteers using ultra high-field MRI, quantitative susceptibility mapping (QSM) at 7T.
2. to demonstrate variations in the resting oxygen usage as an important biomarker to discriminate between different dementia syndromes.
3. to demonstrate cerebral blood flow changes in the brain, particularly in the hippocampus region, and its correlation with different dementia syndromes using Arterial Spin Labelling MRI technique.
4. to demonstrate increased blood brain barrier leakage in the brain, particularly in the hippocampus region, and its correlation with Alzheimer's Disease (AD) and Vascular Cognitive Impairment (VCI) using a new dynamic contrast-enhanced MRI (DCE-MRI) technique.

Inclusion Criteria:

1. Ability to give informed consent.
2. Either pathological, genetic or imaging biomarker evidence to suggest Fronto-temporal Lobar Degeneration, Alzheimer's Disease or Vascular Cognitive Impairment, or defined clinical diagnoses.

Exclusion Criteria:

1. Lack of mental capacity to consent to study involvement.
2. Not speaking English before age 5 years.
3. Learning disability.
4. MRI contraindications

Patients with Alzheimer's disease, Frontotemporal dementia, Vascular Cognitive Impairment