Ultrasonic tissue displacement/strain imaging of brain function

摘要

Tissue Pulsatility Imaging (TPI) is an ultrasonic technique developed to measure tissue displacement or strain in the brain due to blood flow over the cardiac and respiratory cycles. Such measurements can be used to facilitate the mapping of brain function as well as to monitor cerebral vasoreactivity. Significantly, because tissue scatters ultrasound to a greater extend than does blood, using ultrasound to measure tissue displacement or strain in the brain is easier to implement than using ultrasound to measure blood flow in the brain. Significantly, transcranial Doppler sonography (TCD) has been used to measure blood flow in the brain to map brain function and monitor cerebral vasoreactivity; however, TCD can only acquire data through the three acoustic windows in the skull, limiting the usefulness of TCD. TPI is not so limited.

主权项

1. A method for using ultrasound to measure at least one of a tissue displacement in a brain of a subject and a tissue strain in the brain of the subject, for mapping brain function, the method comprising the steps of:
(a) collecting ultrasound data for the brain while the subject is in a relaxed state, thereby collecting relaxed data, the relaxed data including ultrasound data for one or more first sample volumes within the brain of the subject while the subject is in the relaxed state; (b) collecting ultrasound data for the brain while the subject is in a stimulated state, thereby collecting stimulated data, the stimulated data including ultrasound data for one or more second sample volumes within the brain of the subject while the subject is in the stimulated state, the one or more second sample volumes spatially corresponding to the one or more first sample volumes, the stimulated state being achieved in response to application of a mental stimulus selected from a group of stimuli consisting of:
(i) a first mental stimulus based on motion;(ii) a second mental stimulus based on sound;(iii) a third mental stimulus based on taste;(iv) a fourth mental stimulus based on touch; and(v) a fifth mental stimulus based on vision; (c) comparing the collected relaxed data to the collected stimulated data, wherein comparing the collected relaxed data to the collected stimulated data includes comparing information indicative of tissue displacement in the one or more first sample volumes with information indicative of tissue displacement in the spatially corresponding one or more second sample volumes; (d) identifying, based on the comparison of the collected relaxed data to the collected stimulated data, at least one of (i) tissue displacement in at least one of the one or more second sample volumes within the brain of the subject associated with the application of the mental stimulus and (ii) tissue strain in at least one of the one or more second sample volumes within the brain of the subject associated with the application of the mental stimulus, the identified at least one of tissue displacement and tissue strain being present in the collected stimulated data and absent from the collected relaxed data; and (e) correlating the applied mental stimulus with a specific structure in the brain using the identified at least one of tissue displacement and tissue strain present in the collected stimulated data and absent from the collected relaxed data.