Remote effect of brain retraction on regional cerebral blood flow and cerebrovascular reserve on single photon emission computed tomography.

BACKGROUND

The purpose of this study is to evaluate the effect of brain retraction 1 year or more after intracranial aneurysm clipping, demonstrated by a regional cerebral blood flow (rCBF) imaging technique.

METHODS AND RESULTS

rCBF and cerebrovascular reserve (CV) were evaluated in 40 patients 12-25 months after operation, using single photon emission computed tomography (SPECT) with Tc-99m-hexamethylpropylene amine oxime (HMPAO) combined with acetazolamide test. The images were analysed semiquantitatively, focusing on regions of interest (ROIs) chosen for places retracted during the operation. The regions of hypoperfusion in the retracted tissue were clearly visible in 26 cases. Assymmetry of measured activity, expressed in the Assymmetry Index, reached 12% (SEM +/- 8). After injection of acetazolamide during hypercapnia, the assymmetry decreased.

CONCLUSIONS

The results confirm the negative role of brain retraction. However, these consequences seem to be diminished by good vasoreactivity.