Brain perfusion imaging in amyotrophic lateral sclerosis: extent of cortical changes according to the severity and topography of motor impairment.

In amyotrophic lateral sclerosis (ALS), attempts have been made to correlate the extent of cortical lesions with the intensity of motor dysfunction in ALS patients. Our aim was to compare the cerebral perfusion as measured by SPECT with the topography and severity of motor impairment as measured by ALSFRS. Fifty-five patients with sporadic ALS were included. 99mTc-ECD brain perfusion tomographic studies were performed and reconstructed slices analysed with a voxel-based statistical method (Statistical Parametric Mapping). Correlations between ALSFRS total score and sub-scores were calculated. We observed a positive correlation between the degree of involvement of the motor functions as measured by the ALSFRS score and the perfusion decrease of the cerebral cortex. Analysis of the ALSFRS sub-scores revealed that the cortical involvement was important for lower limbs score, moderate for bulbar score and below the level of statistical significance for the respiratory and upper limb scores. The decrease of perfusion was asymmetrical (right hemisphere) and observed mainly in the lateral premotor cortex, the insula and the cingulate cortex. Our study confirms that in ALS the cortical involvement is asymmetrical and predominant in the premotor region and the insula.