Risk of Developing Dementia and Associated Factors in Patients With Normal Brain FDG PET

Completed

• Conditions: Cognitive Disorder; Neurodegenerative Diseases

• Registration Number: NCT04804722
• Lead Sponsor: Central Hospital, Nancy, France

Brief Summary

Brain 18F-FDG PET (positron emission tomography) is recognised as having a good negative predictive value in the search for a neurodegenerative origin of cognitive disorders. Indeed, a ratio of 0.1 on the occurrence of worsening cognitive disorders has been reported in case of normal brain FDG PET.

However, the risk of developing objective cognitive disorders in patients with no cognitive complaints is estimated at 8% per year and the risk of developing dementia in patients with mild cognitive disorders at 22% per year.

Cerebral 18F-FDG PET is a prognostic factor for the occurrence of unusual clinical manifestations (MCI) or the conversion of MCI to Alzheimer's disease, but we do not really know the impact on the longer term occurrence of cognitive impairment in patients with normal cerebral 18F-FDG PET.

Only a longitudinal study will allow us to really know the true negative predictive value of a normal 18F-FDG PET scan and the factors associated with a risk of dementia in these subjects. This will allow us to better understand the prognostic impact of a normal brain 18F-FDG PET scan and to identify a sub-population that remains at risk, including in the case of normal brain 18F-FDG PET.

Detailed Description

Brain 18F-FDG PET is known to have a good negative predictive value in the search for a neurodegenerative origin to cognitive disorders. Indeed, a ratio of 0.1 on the occurrence of worsening cognitive disorders has been reported in case of normal brain FDG PET.

However, in patients without cognitive complaints, the risk of developing objective cognitive impairment is estimated to be 8% per year and the risk of developing dementia in patients with mild cognitive impairment 22% per year.

Brain 18F-FDG PET is a prognostic factor for the occurrence of MCI or for the conversion of MCI to Alzheimer's disease , but we do not really know the impact on the longer-term occurrence of cognitive impairment in patients with a normal brain 18F-FDG PET.

Also, it is commonly accepted that a normal brain 18F-FDG PET scan can rule out a neurodegenerative origin for cognitive impairment.

However, the detection sensitivity of brain 18F-FDG PET is about 90% . Furthermore, we do not know the pathophysiological factors that cause false negative PET scans and it would be interesting to study them (age, sex, medical history, results of neuropsychological tests, etc.).

Based on subjects available freely on the internet, an American team showed that brain 18F-FDG PET was predictive of cognitive decline in subjects with no or minor cognitive disorders.

Only a longitudinal study will allow to really know the true negative predictive value of a normal 18F-FDG PET scan and the factors associated with a risk of dementia in these subjects. This will allow us to better understand the prognostic impact of a normal brain 18F-FDG PET scan and to identify a subpopulation that remains at risk, including in case of normal brain 18F-FDG PET.

Study Timeline

• Study First Submitted: 2021-03-16
• Study First Submitted QC: 2021-03-16
• Study First Posted: 2021-03-18
• Study Start: 2022-01-20
• Status Verified: 2023-07
• Primary Completion: 2023-07-01
• Study Completion: 2023-07-01
• Last Update Submitted: 2023-07-05
• Last Update Posted: 2023-07-06

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 100

Inclusion Criteria

• Adult patient who had a PET scan with 18F-FDG in the brain at least 3 years previously
• Patients referred for PET scans for cognitive disorders, whether or not they have been diagnosed
• Patients referred for PET scans for neurodegenerative pathology 18F-FDG PET brain scan interpreted as normal

Exclusion Criteria

• Brain 18F-FDG PET scan considered abnormal after semi-quantitative analysis

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Normal brain 18F-FDG PET	3 years	Number of patients with normal brain 18F-FDG PET who developed dementia with a clinical follow-up of at least 3 years

Secondary Outcome Measures

Name	Time	Method
Predictive parameters for the occurrence of dementia	3 years	Predictive parameters for the occurrence of dementia in patients with normal brain 18F-FDG PET with a clinical follow-up of at least 3 years

Trial Locations

Locations (1)

Nuclear medicine Department CHRU de NANCY; 🇫🇷 Vandoeuvre les Nancy cedex, France