Cerebral molecular image with 11C-PIB PETCT in the evolution of cognitive impairment

24 de June de 2019

Last May, the British journal “Nuclear Medicine Communications” published the work entitled “A 5-year longitudinal evaluation in patients with mild cognitive impairment by 11C-PIB PET / CT: a visual analysis” that gathers results of the longitudinal study that the Service of Nuclear Medicine of the University Hospital Marqués de Valdecilla (HUMV) and the Molecular Imaging group of IDIVAL (in collaboration with the Cognitive Impairment Unit of the Neurology Service) has been carrying out during the development of the FISS PI/01656 project. In addition, the journal has distinguished it by choosing for its cover, the cerebral PET images showed in the work.

The cerebral cortical deposit of β-amyloid protein has been postulated as the disturbing event that may be at the origin of the changes that lead to the synaptic dysfunction and cerebral degeneration of Alzheimer's disease. These initial phenomena have been monitored “in vivo” due to the development of radiotracers with high affinity for β-amyloid, among which the B of Pittsbourgh compound marked with Carbon 11 (11C-PIB) stands out as reference. The Radiopharmacy Unit of the Nuclear Medicine service of the HUMV is the only Spanish center that synthesizes this radiotracer, authorized by the Spanish Medicines and Medical Devices Agency.

Not all cognitive impairments are due to Alzheimer's disease, and even when correctly identified, patients do not evolve the same. Identifying those individuals with different paths is very important for the research of therapies or individualized preventive strategies. Thus, it has recently been described under the acronym LATE (Limbic-predominant age-related TDP-43 encephalopathy) a type of degenerative frame so far confused with Alzheimer's disease, which may not respond to the same therapeutic targets as this disease, and with differential characteristics in the molecular image. Characterizing and knowing the neurobiological substrate is the necessary primary step to deal with the disease correctly. This is where the value and transcendence of the evolutionary study that is being carried out in this project is focused.
The project entitled “Evolutionary study at 5 years in a population with Mild Cognitive Impairment (MCI) previously evaluated with 11C-PIB and 18F-FDG PET / CT” led by Dr. Jiménez Bonilla of the Service of Nuclear Medicine of the HUMV has been developed for two years, with the collaboration of patients and relatives. In the published work, topographic patterns of amyloid brain deposition and its association with clinical evolution are identified. It is in the frontal, temporo-parietal and basal ganglia region where the variations of this deposit are mainly appreciated.

Currently, the evaluation of amyloid deposit variations is being combined with the information on cerebral metabolism of previous and evolutive glucose, taking into account neuropsychological profiles and demographic and biochemical factors. In that sense, initial results have also been communicated. We trust that this knowledge will help reduce the burdens that these diseases pose for patients and their families.