1 MHz monitoring probes
Using 1 MHz monitoring probes, it is possible to examine patients with hyperostoses and those with complicated insonation windows. The advantage of a 1 MHz probe compared to a 2 MHz probe lies in the ability to take measurements at high flow velocities at greater depths, e.g. in the case of vasospasms or deep-seated stenoses of the basilar artery.
The 1 MHz monitoring probe can penetrate to a depth of approx. 30–150 mm.
4 MHz monitoring probes
The 4 MHz monitoring probe reaches all arteries and veins located within the penetration depth of this frequency. 4 MHz monitoring probes are specifically suited for intracranial examinations on neonates. The 4 MHz monitoring probe can penetrate to a depth of approx. 12–30 mm.
Note: In the USA, the 4MHz probe is strictly for adolescent and adult studies.
2+2.5 MHz monitoring probes
The 2+2.5 MHz probe has been specifically developed for the transcranial differentiation of emboli in the Circle of Willis. Unlike other probes, this probe offers a greater bandwidth of 2 MHz to 2.5 MHz, enabling examinations in the dual-frequency mode. The 2+2.5 MHz monitoring probe can penetrate to a depth of approx. 30–150 mm.
Note: The multi-frequency 2+2.5 MHz is meant for exclusive use with the software module for emboli differentiation and is currently not approved for use in the USA.
2 MHz MRSafe probes
MRSafe (Magnetic Resonance Safe) probes do not contain any magnetic components. Therefore, it is possible for the patient to keep the probes on while undergoing an MRI scan. MRSafe probes are available with 3 m and 5 m cable lengths.
Note: MRI and Doppler cannot be used at the same time for technical reasons.