[Evaluation of regional cerebral blood flow changes in panic disorder with Tc99m-HMPAO SPECT]

To evaluate the differences in regional cerebral blood flow (rCBF) and rCBF asymmetry index values of panic disorder patients and a control group, using Tc99m-HMPAO SPECT. In addition, the influence of comorbid agoraphobia on the rCBF and rCBF asymmetry index values of the panic disorder patients was also investigated.

The rCBF and rCBF asymmetry index values of 22 panic disorder patients, 9 with agoraphobia and 13 without agoraphobia, and 19 healthy controls were obtained using SPECT. Both (1) the panic disorder and control groups and (2) panic disorder groups with and without agoraphobia were compared in terms of the measured values.

A decrease in blood perfusion in the bilateral frontal region, a relative increase in blood perfusion in the right medial frontal and right superior frontal regions and a relative blood flow increase in the right medial frontal region according to rCBF asymmetry index values were determined in panic disorder patients. In the patients with agoraphobia, the decrease in blood perfusion in the right occipital region, and the relative increase in the right superior temporal region according to rCBF asymmetry index values were significantly higher than those in subjects without agoraphobia.

The decrease in the rCBF in the bilateral inferior frontal regions in panic patients may be related to the amygdala activation decreasing cerebral blood flow in the frontal region and/or the hyperactivation of the locus ceruleus. The explanations of the etiology of panic disorder are valid only if they are supported with clinical evidence from future studies.