TCCS constitutes a diagnostic tool commonly used in the neurological patients. However, its use in the neurocritically ill patients within the ICU is less common although it represents clear advantages over transcranial Doppler (TCD) .
TCCS allows the non-invasive morphological study of the brain parenchyma using the B-mode. It is especially useful in the study of midline shift in patients with brain injury  and cerebrovascular disease , as evidenced in our patient. Measurement was performed as described earlier [5, 7] by placing the transducer in the temporal window and the axial plane, locating the mesencephalon with its classic butterfly-wing structure. Later, the transducer was moved 10° cephalad, locating the third ventricle (diencephalic plane), which is identified by a double hyperecogenic image in the center of the sonogram. The measurement was taken from the center of the third ventricle to the source of the ultrasound wave, which corresponds to the external side of the skull (distance A). The identical maneuver was repeated on the contralateral side (distance B). The following mathematical formula was then applied: Midline shift = (A − B)/2. Other commonly used applications using the B-mode are the evaluation of the ventricular system size  and the study of intraparenchymal hematomas .
Using color-mode, the main advantage over conventional TCD is based on the identification of the basal arteries of the Circle of Willis. This identification allows the examiner to perform angle-corrected and sample volume-adjusted determinations, resulting in an increase in the number  and quality of the vessels studied .
In cases with a poor acoustic window or in incomplete studies with the color-mode, some authors support the use of UCA. Based on their biochemical properties , the UCA generates an increase of the acoustic signal which results in quantitative and qualitative improvements in TCCS examinations . In addition, the use of UCAs permits the minimally invasive study of the cerebral perfusion using ultrasound perfusion imaging techniques in patients with neurological disorders, especially those with ischemic cerebrovascular disease . In our patient, we used the bolus kinetic approach, evaluating different regions of interest (ROIs) in which we studied the TICs. Different derived parameters after infusion of UCAs have been studied . The peak intensity, peak width, and time to peak intensity have been correlated with cerebral perfusion. A delay in the time to peak intensity has been suggested to constitute the most accurate parameter for studying cerebral perfusion in cerebrovascular disease because its value shows low intraindividual variability and is not influenced by the depth of the insonation plane [6, 12]. A delay of close to 4 s compared with the unaffected hemisphere may identify hypoperfused areas . In our patient, we obtained a flat TIC in the left hemisphere, suggesting an absence of perfusion in this hemisphere.
In conclusion, this case illustrates some of the applications of TCCS at bedside in ICU patients. These sonographic explorations are useful in the monitoring of ICU patients, and may avoid hazardous transfers to the radiology department for the patient.