Functional brain imaging using a blood oxygenation sensitive steady state.
Blood oxygenation level dependent (BOLD) functional MRI (fMRI) is an important method for functional neuroimaging that is sensitive to changes in blood oxygenation related to brain activation. While BOLD imaging has good spatial coverage and resolution relative to other neuroimaging methods (such as positron emission tomography (PET)), it has significant limitations relative to other MRI techniques, including poor spatial resolution, low signal levels, limited contrast, and image artifacts. These limitations derive from the coupling of BOLD functional contrast to sources of image degradation. This work presents an alternative method for fMRI that may over-come these limitations by establishing a blood oxygenation sensitive steady-state (BOSS) that inverts the signal from deoxygenated blood relative to the water signal. BOSS fMRI allows the imaging parameters to be optimized independently of the functional contrast, resulting in fewer image artifacts and higher signal-to-noise ratio (SNR). In addition, BOSS fMRI has greater functional contrast than BOLD. BOSS fMRI requires careful shimming and multiple acquisitions to obtain a precise alignment of the magnetization to the SSFP frequency response.
Miller
Karla L
KL
Department of Electrical Engineering, Stanford University, Stanford, California 94305-9510, USA. bison@stanford.edu
Hargreaves
Brian A
BA
Lee
Jongho
J
Ress
David
D
deCharms
R Christopher
RC
Pauly
John M
JM
D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D012815:Signal Processing, Computer-Assisted
D006454:Hemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen