| Regional CBF (rCBF) Thermal Diffusion Probe (TDP) | Local CBF (lCBF) Laser Doppler Flowmetry (LDF) | Transcranial Doppler (TCD) | |
| Basic principle -indicator | Thermal diffusion in a spherical volume around the tip of the probe | Red blood cell movement within the microcirculation beside the probe | Major vascular Doppler effect coupled with two-dimensional ultrasonography |
| Applicability | Continuous at bedside | Continuous at bedside | Continuous at bedside |
| Application fields | Intraoperative (to be developed) ICU | Intraoperative (to be re-evaluated and developed) ICU | Intraoperative ICU |
| Device | Minimally invasive (2 - 2.5 cm below the dura) | Minimally invasive (1cm below the dura) | Non-invasive (main advantage) |
| Limitations of use | -Measurement and monitoring of rCBF only in the spherical area (1 - 1.5 cm diameter) around the probe tip -Site-dependent measurement | -Measurement and monitoring of lCBF only in the 1 or 2 mm surrounding the probe tip -Site-dependent measurement | -Arterial CBF in medium size vessels (MCA > ACA > PCA) -Not tissue monitoring -Possible instability of the probe |
| Cost-investment | -Monitoring -Probe (single use) | -Monitoring -Probe (single use) | -Monitoring -Probe (reusable) -Fixation system for probes |
| Technical expertise, management & nursing | Basic Time-consuming | Basic Time-consuming | Advanced |
| Specific infrastructure for insertion | Special need (minimally invasive, ICU, or OR) Probe tunneled or bolted | Special need (minimal invasive, ICU or OR) Probe tunnelled or bolted | No need |
| Ischaemia detection | Local or regional Cortical and subcortical (following the insertion’s adequacy) | Local Cortical (following the insertion’s adequacy) | Hemispheric or global |
| CPP correlation | Vasoreactivity and autoregulation | Vasoreactivity and autoregulation | Variable Vasoreactivity and autoregulation |
| Numeric values | -Normal: 40 - 70 mL·100−1·min−1 | -Normal: 80 mL·100−1·min−1 (temporo-sylvian cortex) and 60 - 65 mL·100−1·min−1 (fronto-latero-dorsal cortex) | -Normal: 30 - 80 mL·100−1·min−1 Following the artery and based on the velocity assessment |