|
Description:
|
Most of the technical development and applications of ASL (arterial spin labeling ) imaging have mainly focused on the superior cortical regions of the brain . However , optimal ASL measurements to quantify cerebral blood flow (CBF ) in specific brain regions may require optimized parameters , improved techniques , or new imaging schemes based upon physiological or anatomic characteristics of those brain regions . In this thesis , the advantages of this region -targeted approach are demonstrated by performing quantitative perfusion studies of two representative brain regions , the cerebellum in the inferior part of the brain and the hippocampus in the mid -brain .
To minimize or eliminate the venous artifacts found in cerebellum perfusion studies using traditional FAIR (flow -sensitive alternating inversion recovery ) technique , FAIR ASST (FAIR with active suppression of superior tagging technique ) , as well as MDS FAIR , (modulated dual saturation pulse trains for FAIR ) was developed and compared to PICORE (proximal inversion with a control for off -resonance effects ) for quantifying cerebellum perfusion . The data indicate that FAIR ASST yields more robust CBF (cerebral blood flow ) measurements .
OPTIMAL FAIR (orthogonally -positioned tagging imaging method for arterial labeling of FAIR ) was developed and shown to reduce the heterogeneity of within -slice transit time and to minimize partial volume effects , improving quantitative CBF maps for cerebellum and hippocampus .
These techniques were optimized and applied to the study of perfusion abnormalities in brain regions important to the study of Gulf War Syndrome . Together with regionally optimized parameters , these ASL methods provide more reliable , efficient , accurate , and artifact -free CBF measurements than methods previously available . |