In brain tumor surgery we are confronted mainly with two types of difficulties: (i) the identification of the tumor and its limitations in relation to the healthy brain; (ii) the identification of functional cerebral regions, ie implicated in neurological function (motor skills, sensitivity, language, vision, cognition, etc.). The reference method currently used to improve the quality of resection of brain tumors while minimizing neurological risk for patients is so called "wakeful" surgery with direct electrical stimulation (DES) of the brain. The investigators routinely use ultrasound to localize the tumor within the brain, but to date there is no pre- or intra-operative imaging tool to reliably identify tumors and functional brain regions. There is therefore a need for innovative imaging in this field.

For this reason, the investigators propose to evaluate the interest of a new High Frequence Ultrasound Doppler (HFUD) (VEVO ®, Visualsonics, Toronto, Canada) in the surgical management of patients operated in an awake condition for a brain tumor. The ultra high frequency allows to reach a spatial resolution of 30 μm, 5 to 10 times better than MRI and conventional ultrasound. The Doppler mode allows the detection of microvascular flows of speeds less than 1 mm / second. The safety of this device is demonstrated and validated by CE marking (December 2015).

Inclusion Criteria:

• operated patient of a cerebral tumor in an awake condition
• age> 18 years
• neurological condition allowing the realization of the tests in the operating room

Exclusion Criteria:

• not indicated for "awake" surgery
• refusal of participation of the patient
• pregnant or nursing women