Dementia: Symptoms, Causes, Types & PET CT as a Diagnostic Tool

Talk to Health Expert

06 Jul, 2025

Dr. Nikunj Jain

Dr. Nikunj Jain

Co-Founder and HOD - Nuclear Medicine ,

MBBS, DRM, DNB, FEBNM, FANMB, Dip. CBNC

Dementia is the state or group of diseases that affect the thinking, reasoning, personality, mood and behavior of the person. 50% of the people around the world have any type of dementia after the age of 85 years. This decline in the mental conditioning affects the daily routine of the person and finds it difficult to do the routine daily work. Dementia is attached with the degradation of brain function from the previously higher level of functioning.  There may be various reasons for the condition but main cause of the condition is considered as Alzheimer’s disease. There are various tests used for the detection of the dementia and these include neurocognitive testing, MRI, CT etc. PET CT is one of the advanced testing methods used for the detection of dementia. The tests uses radioactive tracer mostly 18-fluorodeoxyglucose (18F-FDG), that is why it is also called FDG-PET scan.

Dementia

Dementia is not any disease but it is the mental state of the patient and functioning of the brain. This is an umbrella category which can include various diseases and leads to the condition of dementia. The person suffering with dementia should have 2 or more of these difficulties.

  • Memory
  • Reasoning
  • Language
  • Coordination
  • Mood
  • Behavior

Dementia effects the normal function of brain thus leads to the control, coordination, reasoning etc. problems. These affect the daily activities of the person and will not be able to daily routine tasks effectively.

What are the different types of Dementia?

Dementia is having 3 main groups that include:

Primary dementia (condition in which dementia is main reason)

  • Alzheimer’s disease
  • Vascular dementia
  • Lewy body dementia
  • Frontotemporal dementia (FTD)
  • Mixed dementia

Secondary dementia (dementia due to other condition or disease)

  • Huntington’s disease
  • Parkinson’s disease
  • Creutzfeldt-Jakob disease
  • Wernicke-Korsakoff syndrome
  • Traumatic brain injury

Reversible dementia 

  • Normal pressure hydrocephalus (NPH)
  • Vitamin deficiency
  • Infections
  • Metabolic and endocrine conditions
  • Medication side effects
  • Brain tumor
  • Subdural hematomas

What are the symptoms of Dementia?

There are various symptoms which are related to dementia. Symptoms have been classified into early and later stage symptoms and these include:

 Early stage symptoms of dementia:

  • Forgetting recent events easily
  • Misplacing common items
  • Repeating of comments over a short period of time
  • Difficulty in remembering dates, years or months
  • Difficulty in coming up with right words quickly
  • Mood swings, behavioral changes

Late stage symptoms of dementia:

  • Decline in the memory of remembering or making decisions.
  • Decline in problem solving abilities
  • Daily tasks like TV remote, cooking, paying bills becomes more challenging
  • Increase in the state of confusion, anxiety, depression etc.
  • Experiencing hallucination
  • Need help in daily activities

What are the causes of Dementia?

Dementia is the state of damage to the brain and can be caused various factors that can damage the brain. These causes include:

  • Blocked vein to the brain
  • Decreased oxygen flow to brain
  • Deprived nutrients to brain
  • Alzheimer’s disease
  • Vascular dementia
  • Parkinson’s disease
  • Brain Stroke
  • Brain Infections
  • Injuries to brain
  • Lifestyle
  • Normal pressure hydrocephalus

What does PET CT scan detect in the Dementia?

PET CT diagnostic tool can detect various types of condition in dementia and these include:

  • Type of dementia
  • Early diagnosis of disease
  • Progression of disease
  • Severity of disease
  • Treatment effect 

What are the different types of tests used for the detection of Dementia other than PET CT scan?

There are various tests used for the detection of dementia other than PET CT scan. These include physical examination, laboratory tests, imaging tests etc.

  • Laboratory Test
  • For infection
  • Inflammation
  • Underactive thyroid
  • Vitamin deficiency
  • Imaging Tests
  • CT
  • MRI
  • PET CT
  • Neurocognitive testing
  • Reasoning
  • Problem solving
  • Planning
  • Language
  • Memory
  • Judgment

Conclusion

Dementia is not any disease but it is the mental state of the patient and functioning of the brain. Dementia is the state or group of diseases that affect the thinking, reasoning, personality, mood and behavior of the person. 50% of the people around the world have any type of dementia after the age of 85 years. Dementia condition is divided into 3 type’s primary dementia, secondary dementia and reversible. There are various causes for the condition of dementia like blockage of veins to brain, Alzheimer’s disease, vascular dementia, Parkinson’s disease etc. Person suffering from the condition of dementia can have symptoms like weak memory, difficulty in reasoning and problem solving, forgetting the events easily, not able to remember the items etc. Early detection of the condition can help to slow down the condition or cure it. There are various tests used for the detection of dementia and these include laboratory tests, imaging test and neurocognitive tests etc..

 

In News

Download Our App

Get Our Mobile App
for Easy Access

Book tests, view reports, and manage your health records on the go. Experience convenient healthcare with Molecular Diagnostics and Therapy.

  • Book tests & home collection
  • View reports instantly
  • Track health history
  • Get notifications & reminders
  • Easy appointment management
Your Health Companion
Scan to download Molecular Diagnostics and Therapy App

Scan to download the app