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transcranial_doppler

Transcranial Doppler

Transcranial Doppler sonography (TCD) is widely used in neurointensive care.

Transcranial Doppler (TCD), for instance, is primarily a technique for diagnosing various intracranial vascular disorders such as emboli, stenosis or vasospasm 1) , but has been broadly utilised for non-invasive ICP monitoring due to its ability to detect changes in cerebral blood flow velocity (FV) derived from ICP variations. TCD has also been used for non-invasive estimation of cerebral perfusion pressure (CPP), based on some parameters derived from FV, such as diastolic flow velocity (FVd) 2) and critical closing pressure (CrCP) 3). Considering the assumption that CPP equals the difference of arterial blood pressure (ABP) and ICP, nICP can be estimated as nICP = ABP – nCPP.

The Transcranial Doppler (TCD) and the more recent Transcranial Color Doppler (TCCD) are tests that measure the blood flow velocity through the brain's blood vessels. Used to help in the diagnosis of emboli, stenosis, vasospasm from a subarachnoid hemorrhage, and other problems.

TCD is effective to detect Sickle Cell Disease, (in order) established for Ischemic cerebrovascular disease, Subarachnoid hemorrhage, Arteriovenous malformations and Cerebral circulatory arrest and possibly useful for Perioperative monitoring and Menigeal infection.

The equipment used for these tests is becoming increasingly portable, making it possible for a clinician to travel to a hospital, doctor's office or nursing home for both inpatient and outpatient studies. It is often used in conjunction with other tests such as MRI, MRA, carotid duplex ultrasound and CT scans.

TCD-based indices, mean velocity index, Mx and autoregulation index (ARI).

Transcranial Doppler (TCD) ultrasonography is an important tool for noninvasive detection and monitoring of vasospasm and other pathological conditions of the intracranial vessels.

Provides excellent orientation, also allowing diagnostic procedures on pathological vascular structures.

Three patients who underwent computed tomographic angiography scanning for reasons not related to this study were examined by neuronavigated image-guided TCD. The Doppler probe was fitted with reflective markers and tracked by a commercially available Kolibri image guidance system.

Image-guided TCD allowed identification of all major intracranial vessels. Unilateral acquisition of reliable Doppler signals for the internal carotid artery, carotid T, middle cerebral artery, middle cerebral artery bifurcation, and anterior cerebral artery required 14 ± 6 minutes. Preregistration of these targets and detection by neuronavigation alone shortened examination times significantly to 8 ± 2 minutes. Registering the optimal examination trajectories on the neuronavigational device and applying navigational pilot software shortened times for repetitive examination further to 4 ± 1 minutes and ensured that the examination was done at the exact same spot under the same angle as in previous examinations.

Image guidance can be applied easily and efficiently to TCD. It provides anatomic orientation and may help to standardize investigation protocols, define pathological vascular territories for repeat investigations, and thus reduce interinvestigator variations. Image guidance may also extend the use of TCD to situations of a pathological or variant vascular anatomy 4).

see Transcranial Doppler for subarachnoid hemorrhage.

see Transcranial color coded duplex sonography

1)
Sloan MA, Alexandrov AV, Tegeler CH, Spencer MP, Caplan LP, Feldmann E, Wechsler LR, Newell DW, Gomez CR, Babikian VL, Lefkowitz D, Goldman RS, Armon C, Hsu CY, Goodin DS. Assessment: transcranial Doppler ultrasonography: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology. 2004;62(9):1468–1481. doi: 10.1212/WNL.62.9.1468.
2)
Czosnyka M, Matta BF, Smielewski P, Kirkpatrick PJ, Pickard JD. Cerebral perfusion pressure in head-injured patients: a noninvasive assessment using transcranial Doppler ultrasonography. J Neurosurg. 1998;88:802–808. doi: 10.3171/jns.1998.88.5.0802.
3)
Varsos GV, Kolias AG, Smielewski P, Brady KM, Varsos VG, Hutchinson PJ, Pickard JD, Czosnyka M. A noninvasive estimation of cerebral perfusion pressure using critical closing pressure. J Neurosurg. 2015;123(3):638–648. doi: 10.3171/2014.10.JNS14613.
4)
Kantelhardt SR, Greke C, Keric N, Vollmer F, Thiemann I, Giese A. Image guidance for transcranial Doppler ultrasonography. Neurosurgery. 2011 Jun;68(2 Suppl Operative):257-66; discussion 266. doi: 10.1227/NEU.0b013e31821553b2. PubMed PMID: 21389880.
transcranial_doppler.txt · Last modified: 2016/08/23 08:27 (external edit)