Abstract

The discovery of BOLD fMRI at MGH in May 1991 was 1) built on the ongoing effort to develop new MR techniques for perfusion measurement with intrinsic blood contrast, 2) supported by the critical MGH expertise and experience on magnetic susceptibility and deoxyhemoglobin research, 3) inspired by the breakthrough in brain fMRI using dynamic susceptibility contrast (DSC) of the external contrast agent Gd-DTPA, 4) facilitated by the flow-BOLD insight of a hypoxia experiment, and 5) made possible by the availability of clinical echo planar imaging (EPI). The simultaneous demonstration of flow-weighted fMRI derived its intellectual origin from work on steady state arterial spin labeling (ASL). The free-wheeling and fertile intellectual environment structured by Dr. Thomas Brady and Dr. Bruce Rosen at the MGH-NMR Center provided the indispensable support for highly risky ideas to roam and succeed. The paper offers a first person account of the steps that led to the May experiment and its aftermath.