The basal and Virtual Navigator system insonation rate are reported in Table 1, with the p value of the Chi-square for trend. The comparison between the basal insonation rate and the Virtual Navigator insonation rate showed a significant difference for the SRS (p = 0.016) and for the TS (p = 0.038). The application of the Virtual Navigator system for brain imaging has been initially tried in neurosurgery, during the surgical procedure. In this condition the ultrasound study is easy, because of the removal of the skull bone, but the real-time ultrasound images without the skull bone are not always perfectly correspondent to the neuroradiological slices, achieved before skull removal. Moreover, TCCS gives

Luminespib access to a limited portion of the brain anatomy thought an intact skull, but the standard insonation planes are suitable for the imaging of main intracranial arteries and veins. Its main limitation is the quality of the temporal bone window; because a suboptimal window does not allow the visualization of all intracranial large vessels. Our hypothesis is that the use of a second imaging modality as a reference could increase the number of Doppler-sampled segments

of the intracranial veins and sinuses in comparison with the basal insonation rate. Instead of acquire brain MR with surface external magnetic landmarks, as in abdominal imaging, for a better coupling between ultrasound and radiological study, a previously performed standard brain MRI was DAPT uploaded into the machine platform. The coupling of the ultrasound planes with the corresponding reconstructed oblique MR planes was manually Urease performed

in a reference plane and the sonologist checked it in real time in the axial scanning planes. The landmarks to be correspondent in the two imaging modalities were: the petrous edge in the pontine plane, the mesencephalon and the edge of sphenoid wing in the midbrain plane, and the third ventricle and the epiphysis in the diencephalic plane. The following step was to assess the correct locking of ultrasound and MRI in coronal scanning planes. Our basal insonation data were similar to the insonation rates reported in the literature [1] and [2]. The insonation rate with the Virtual Navigator system improved for all examined segments, with a significant value for SRS and TS. The insonation rate of 96.67% for the BVR is in agreement with the anatomic data about 5.6% of BVR draining into the lateral mesencephalic vein [6]. The improvement of the insonation rate of the TS is good, although only the contralateral approach was used and it is possible that adding the ipsilateral approach could cause a further improvement of the insonation rate, particularly for hypoplasic sinuses. The possibility of combining the ultrasound examination with a reference modality in real time can improve the identification of the main cerebral vein and sinuses, therefore increasing their insonation rate.