3T PET/MR equipment for the administration of sensory stimuli and motor task in research and diagnostics

During physical and/or mental activity several brain areas are involved. To detect these activations the use of specific imaging techniques and well-designed tasks are essential in clinical and diagnostic settings. The largest section of the human brain is the cerebral cortex, which is linked to higher-order cognitive processes. Magnetic resonance is a non-invasive technique that uses a strong magnetic field and radiofrequency waves to create detailed images of organs and tissues. In neurological clinics and research, functional magnetic resonance imaging (fMRI) is used to assess small regional blood flow changes within the cortex, detected during a scan procedure which also involves task performance. This thesis aims to investigate the setup of stimulation protocols for functional studies based on the accessory instrumentation equipment recently installed in the Marche University Hospital. The equipment reviewed is produced by a Norwegian company called NordicNeuroLab. This company provides several modular solutions for both clinical and research fMRI needs, thanks to many hardware and software tools. NordicAktiva software thanks to an intuitive interface allows to select different paradigms and manage the stimuli delivery. For this project, three paradigms were applied to a healthy young subject during an fMRI procedure, with a 3T Signa PET/MR scanner. The first paradigm was a General Motor Left task (open and close left hand), the second was an Auditory task (with classic music) and the third was a Visual Checkerboard task (with goggles mounted on the scanner). Each task lasts 5m 12s, with 5 alternating 30s-cycles of resting and active states. Functional and T1-weighted images were acquired and then preprocessed and analysed using BrainVoyager software. For pre-processing, brain extraction, motion correction, slice time correction, temporal filtering, co-registration, and normalization steps were performed. In the results for the motor task strong activation of contralateral motor cortex was present, as expected. In the auditory task, the music stimulation shows a bilateral activity in the primary auditory cortex. The visual stimulation with the flickering checkerboard exhibits strong activity within the occipital part of the cortex as well as in the posterior parietal area. To improve stimuli delivery protocol, the use of software like nordicAktiva is game-changing, however, setting up the trial duration in the main code is a quite time-demanding procedure. A big limitation in this analysis is the involvement of just one healthy subject. A larger group of subjects could be essential for brain mapping statistical study. Also, it could be better to include in the investigation neuropathological patients since they have difficulty staying motionless in the scanner and even performing some tasks, leading to incomplete or incorrect data. In conclusion, the employment of protocols for stimuli delivery during fMRI investigation is essential for brain mapping in clinical and diagnostics settings. Researchers must precisely plan their methodology and use well-suited paradigms, considering several features related to the psychophysical status of the subject.