In general, gradient-echo (GE) BOLD contains extravascular (EV) contributions from all sized vessels, while spin-echo (SE) BOLD is sensitive to microvessels. Based on simulation, the EV BOLD signal is dependent linearly on B0 for macrovessels, and quadratically on B0 for microvessels. Here, we performed GE and SE BOLD fMRI of α-chloralose anesthetized rats responding to forepaw stimulation on an ultrahigh magnetic field of 15.2T. Stimulation-induced R2 change was quadratically on B0, indicating that microvessel contributions are dominant. SE BOLD at ultrahigh fields can detect precise activation sites and can be used for high-resolution fMRI to detect fine functional structures.
How to access this content:
For one year after publication, abstracts and videos are only open to registrants of this annual meeting. Registrants should use their existing login information. Non-registrant access can be purchased via the ISMRM E-Library.
After one year, current ISMRM & ISMRT members get free access to both the abstracts and videos. Non-members and non-registrants must purchase access via the ISMRM E-Library.
After two years, the meeting proceedings (abstracts) are opened to the public and require no login information. Videos remain behind password for access by members, registrants and E-Library customers.
Keywords