Abstract #1177

Acute Vs. Tonic Muscular Pain: Changes in Cerebral Blood Flow as Imaged by Arterial Spin Labeling

Daron Gordon Owen^1,2, Collin Franklin Clarke³, Sugantha Ganapathy³, Frank S. Prato^1,4, Keith S. St. Lawrence^1,2

¹Imaging Program, Lawson Health Research Institute, London, Ontario, Canada; ²Medical Biophysics, The University of Western Ontario, London, Ontario, Canada; ³Anesthesia and Perioperative Medicine, The University of Western Ontario, London, Ontario, Canada; ⁴Imaging, St. Joseph's Hospital, London, Ontario, Canada

The cerebral representation of acute pain is well established, whereas that of tonic pain is not due to difficulties in applying functional imaging to prolonged stimuli. We used arterial spin labeling (ASL) to investigate the neural activation associated with tonic muscular pain. The use of ASL allows direct comparison between studies. Compared to our previous study incorporating both acute and tonic phases, we observed smaller CBF changes, and only in bilateral insula and frontal gyrus, despite similar pain levels. A likely explanation is that the acute phase of the previous study induced anxiety and distress, whereas our tonic pain stimulus did not.