Motor Activation by Single‐Photon Emission Computed Tomography: A Comparison of Xenon‐133 and Technetium‐99m HM‐PAO “Split‐Dose” Methods

Single‐photon emission computed tomography (SPECT) was used to investigate the feasibility of the technetium 99m‐hexamethylpropyleneamineoxime ( 99m Tc HM‐PAO) split‐dose method to evidence changes in regional cerebral blood flow during a motor activation task, in comparison with a quantitative method using the inhalatory xenon‐133. Four subjects were studied twice with both methods, at rest and during finger opposition movements. On the activated cerebral hemisphere, a significant increase in regional cerebral blood flow was observed over the motor cortical areas. The average increases were + 28.1 ± 5.6% for the xenon‐133 method and + 12.3 ± 5.2% for the 99m Tc HM‐PAO method. By using the linearization algorithm for the 99m Tc HM‐PAO method, a mean increase of + 22.5 ± 8.9% was calculated. This study demonstrated that the split‐dose method allows the motor activation SPECT studies with 99m Tc HM‐PAO to be done in a single session.