The difference between acute or chronic probes is how Transonic calibrate the probes according to their intended use. The calibrations differ to compensate for the different acoustic conditions in acute and chronic studies.
- In acute applications, the use of acoustic couplant gel is required to measure blood flow while the animal is sedated under anaesthesia.
- Measurements can be taken for as long as 1-2 days in an acute setting as long as the animal remains sedated under anaesthesia.
- Chronic applications rely on the growth of fibrotic tissue infiltration to stabilize the probe; this tissue growth generally takes a couple of days.
NOTE: Chronic protocols are generally evaluated in relative terms as changes in flow over time, so once the probe is implanted and the animal has recovered, measurements can be taken while the animal is in its natural environment and behavior, eating, sleeping, walking etc. for days, months or even years after the initial implant.