Functional mapping of activated human primary cortex with a clinical MR imaging system.

Functional activation of the human brain can be visualized with magnetic resonance (MR) imaging, but most studies so far have used echo-planar imaging or magnetic fields of 2 T and above, neither of which are at present widely available. The authors used a standard 1.5-T MR imaging system to map regions of the brain that are activated with visual and motor tasks, using a long echo time (60 msec) fast low-angle shot sequence. Eleven visual and 14 motor studies were performed, and activation was seen in all cases. Up to 15% signal intensity change was apparent in gray matter but not in white matter. The precise anatomic location and extent of activation were defined by reference to T1-weighted images acquired during the same examination. This method of relating brain structure to function uses equipment that is widely available, which has considerable implications for the investigation of many neurologic and neurosurgical diseases and for our understanding of brain function and dysfunction.