Unit:
Κατεύθυνση Ιατρική Φυσική-ΑκτινοφυσικήLibrary of the School of Health Sciences
Author:
Papavramidis Nikolaos
Supervisors info:
Αστρακάς Λουκάς, Επίκουρος Καθηγητής, Τμήμα Ιατρικής, Πανεπιστήμιο Ιωαννίνων
Καλέφ-Εζρά Τζων, Καθηγητής, Τμήμα Ιατρικής, Πανεπιστήμιο Ιωαννίνων
Κουρκουμέλης Νικόλαος, Επίκουρος Καθηγητής, Τμήμα Ιατρικής, Πανεπιστήμιο Ιωαννίνων
Original Title:
Διασφάλιση Ποιότητας στη Λειτουργική Μαγνητική Απεικόνιση - fMRI
Translated title:
Quality Assurance in Functional Magnetic Resonance Imaging - fMRI
Summary:
This study was carried out with the aim of performing quality assurance and creating reference values in functional Magnetic Resonance Imaging, using a new Phillips 3T MRI scanner, recently installed at the University Hospital of Ioannina. Quality assurance was carried out by examining the long and short term stability of the imaging system in accordance to the protocols of AAPM and FBIRN, as well as assessing the influence of some peripheral factors, such as the room’s lights, the ambient lights along with system projector and functional MRI support system SensaVue, which is used for delivering visual stimulus to the patient. Although the AAPM protocol is not specialized to assess system stability, it extracts some key indices, such as distortions and ghosting, which are important for functional imaging exams. The analysis was performed using the scanner’s phantom, and two different brain coils. The indices were calculated using a script developed in Matlab, which also exported the images described in the FBIRN protocol. The indices calculated were SNR, SFNR, Percent Fluctuation and Drift with the first three directly associated with system’s stability over time, since they are produced based using the 200 dynamic scans of the center slice of the phantom. The study showed that the imaging system is characterized by good long and short term variability, and the peripheral factors do not affect its operation or stability.
Main subject category:
Health Sciences
Keywords:
Image quality, Magnetic resonance, Functional MRI, AAPM and FBIRN protocols, System stability
