ABSTRACT
Objective To examine the reliability and similarity of amplitude of low-frequency fluctuation (ALFF)for different scan duration.Methods 10 min 10 s resting state fMRI data acquired from 13 healthy volunteers separately were divided into 10 pieces of the same length.The reliability and similarity of ALFF were assessed for each scan length (1-10 min).Results Spatial maps of ALFF steadily appeared in each time period (1-10 min);but during the time evolution,both spatial distribution and extent of ALFF increased gradually.At only one minute,there were detectable statistical differences within the group.When the time ran-ging from 5 to 10 min,relatively stable ALFF results in the group achieved.Conclusion ALFF is a relatively stable index,it can be easily affected by scan duration.In the case of 1-5 min,it should be carefully analyzed and interpretated particularly.