Time-harmonic ultrasound elastography of the brain
Bernhard Kreft, Heiko Tzschätzsch, Judith Bergs, Jürgen Braun, Ingolf Sack
Cerebral stiffness (CS) is related to many structural and physiological changes in the brain. Magnetic resonance elastography (MRE) is feasible to measure CS with high spatial resolution. However, MRE suffers from poor temporal resolution. Time-harmonic ultrasound elastography (THE) in contrast provides measurements within one second and can be used to measure fast alterations in CS due to changes of intracranial pressure (ICP).
Shear waves of multiple frequencies are generated in the brain with a special patient bed modified with a vibration unit. Radiofrequency data is acquired with a research ultrasound scanner in one second. The shear wave speed (SWS), representing the tissue stiffness, is calculated with the k-MDEV-algorithm and compounded to an elastogram.
Cerebral THE shows to be sensitive to structural changes due to ageing as well as to ICP changes induced by the Valsalva maneuver. Therefore, THE has the potential to measure ICP non-invasively for the first time and can be of great use in many neurological applications.
Tzschatzsch, H., et al. (2018). „In vivo time-harmonic ultrasound elastography of the human brain detects acute cerebral stiffness changes induced by intracranial pressure variations.“ Sci Rep 8(1): 17888.