Conclusion
Dopamine transporter single photon emission computed tomography revealed abnormal findings in patients with FTLD-MND, which may manifest even before the onset of MND symptoms. We believe that the possibility of future development of MND should be considered if DAT-SPECT shows abnormal findings in FTLD.
Methods
Twenty patients with FTLD who underwent DAT single photon emission computed tomography (DAT-SPECT) were screened, and six patients with a final diagnosis of FTLD-MND were ultimately included. The patients' DAT-SPECT findings were analyzed visually and quantitatively. Neuronal loss and astrogliosis in brain regions (substantia nigra, caudate, and putamen) that could possibly affect DAT findings were evaluated in the three pathologically confirmed cases. Result: All six patients with FTLD-MND showed abnormal visual DAT-SPECT findings. In addition, in a quantitative assessment, the specific binding ratio in the striatum calculated by the Southampton method was below the lower limit of the 95% prediction interval of the healthy controls by age in all the present cases. Interestingly, three of the six patients showed abnormal findings on DAT-SPECT more than half a year before the onset of MND. Neuronal loss and astrogliosis in brain regions that may affect DAT findings were observed in three pathologically confirmed cases.