Changes in CT cerebral blood flow and volume associated with rapid maxillary expansion in a rabbit model.

OBJECTIVE

To evaluate hemodynamic changes of the brain under the high forces of a rapid maxillary expansion (RME) appliance in a rabbit model.

MATERIALS AND METHODS

Twenty-four male New Zealand white rabbits were selected (12 weeks old, mean weight 3.01 ± 0.22 kg). A modified acrylic resin bonded RME appliance was used for expansion. A series of perfusion computed tomography examinations was performed before expansion (T0), on the fifth day of expansion (T1), at the end of the expansion process (T2), and after 10 days of retention (T3). Cerebral blood flow, cerebral blood volume, and mean transit time maps were recorded and parametrics evaluated. Statistical analyses were performed with analysis of variance with post hoc tests.

RESULTS

Mean cerebral blood flow showed an increase from T0 to T2 and then a decrease from T2 to T3, but the change was not statistically significant. Mean cerebral blood volume and mean transit time increased significantly from T0 to T2, and all perfusion parameters increased from T0 to T3.

CONCLUSIONS

RME is a safe orthopedic method despite the high expansion force. Perfusion computed tomography is effective for evaluating the hemodynamic changes of the brain caused by some orthopedic therapies. The increase in both cerebral blood volume and cerebral blood flow may help to explain why RME could alleviate the symptoms of enuretic children.