"mean flow velocity (adults) usually between 46 to 86 cm/s 13"
"may also demonstrate "internalization," or change in the flow pattern to low-resistance"
"within three days status post-SAH, an increase in the middle cerebral artery baseline velocity by more than 21 cm/seconds/day is considered highly suggestive of vasospasm"
"Transcranial Doppler (TCD) is a sonographic study of intracranial structures and blood vessels, used most commonly to identify the haemodynamic state present in the circle of Willis and in the vertebrobasilar circulation 1."
"low APGAR scores"
"delta RI (i.e. calculated with and without compression to the anterior fontanelle) should be ascertained before any therapeutic drainage"
"intra/peri-operative evaluation of cerebral perfusion"
"behind the elliptical globe the homogenous, linear hypoechoic optic nerve should be identified, invested in a hyperechoic sheath"
"Spectral Doppler"
"high resistance pattern (supplied by the external carotid artery) with a mean velocity between 16-26 cm/s"
Expected headings
"Indications"
"Procedure"
"Neonates"
"Adults"
"Spectral Doppler"
"Stroke and intracranial haemorrhage"
"Cerebral circulatory arrest"
"An extension of the non-imaging, continuous wave Doppler assessment popular among neurointensivists, the imaging of cerebral structures with grey-scale and superimposed colour flow and spectral Doppler analysis is now possible using the same windows, techniques, and diagnostic goals. Transcranial Doppler (TCD) encompasses two main techniques: nonimaging TCD (niTCD) and TCD imaging (TCDi) 1; this article will not make this distinction, as the non-imaging modality will not be further discussed. "TCD" and "transcranial Doppler" will be used to refer to combined 2D parenchymal imaging with or without Doppler modalities."
"Neurosonography of the fetal brain, although based on similar principles, will not be discussed; this article will focus on neonatal, paediatric, and adult indications for sonographic studies of the brain and cerebral vasculature, particularly as they pertain to point-of-care ultrasound."
"The performance of a transcranial Doppler study differs based on relevant patient anatomy, most notably regarding the status of fontanelle closure; in neonates, these open fontanelles may provide acoustic windows for insonation of intracerebral structures."
"Four acoustic windows persist after fontanelle closure; the transtemporal, orbital, suboccipital and retromandibular windows 11. The transtemporal window is the most easily accessible window, and the most widely used at the point of care; some authors define various "sections" of the transtemporal window (i.e. probe positions); the cardinal probe position is superior to the zygomatic arch and nasal to the pinna of the ear 20, with subsequent adjustments in probe position from anterosuperior ("frontal" section) to slightly caudad ("anterior" section) and sequentially posterior ("medial" and "posterior" sections) 10."
"Four acoustic windows persist after fontanelle closure; the transtemporal, orbital, suboccipital and retromandibular windows 11. The transtemporal window is the most easily accessible window, and the most widely used at the point of care; some authors define various "sections" of the transtemporal window (i.e. probe positions); the cardinal probe position is superior to the zygomatic arch and nasal to the pinna of the ear 20, with subsequent adjustments in probe position from anterosuperior ("frontal" section) to slightly caudad ("anterior" section) and sequentially posterior ("medial" and "posterior" sections) 10."
"Four acoustic windows persist after fontanelle closure; the transtemporal, orbital, suboccipital and retromandibular windows 11. The transtemporal window is the most easily accessible window, and the most widely used at the point of care; some authors define various "sections" of the transtemporal window (i.e. probe positions); the cardinal probe position is superior to the zygomatic arch and nasal to the pinna of the ear 20, with subsequent adjustments in probe position from anterosuperior ("frontal" section) to slightly caudad ("anterior" section) and sequentially posterior ("medial" and "posterior" sections) 10."
"the Nyquist limit may have to be adjusted for smaller vessels such as the posterior cerebral artery (PCA); the ipsilateral PCA will appear as blue and red flow signals just posterior and anterior to the ipsilateral cerebral peduncle, respectively"
"Velocities obtained are analysed using principles derived from the Doppler equation and the modified Bernoulli principle; erroneous results (e.g. through angle dependence) may be mitigated through the use of derived parameters as follows 13:"
"Four acoustic windows persist after fontanelle closure; the transtemporal, orbital, suboccipital and retromandibular windows 11. The transtemporal window is the most easily accessible window, and the most widely used at the point of care; some authors define various "sections" of the transtemporal window (i.e. probe positions); the cardinal probe position is superior to the zygomatic arch and nasal to the pinna of the ear 20, with subsequent adjustments in probe position from anterosuperior ("frontal" section) to slightly caudad ("anterior" section) and sequentially posterior ("medial" and "posterior" sections) 10."
"Four acoustic windows persist after fontanelle closure; the transtemporal, orbital, suboccipital and retromandibular windows 11. The transtemporal window is the most easily accessible window, and the most widely used at the point of care; some authors define various "sections" of the transtemporal window (i.e. probe positions); the cardinal probe position is superior to the zygomatic arch and nasal to the pinna of the ear 20, with subsequent adjustments in probe position from anterosuperior ("frontal" section) to slightly caudad ("anterior" section) and sequentially posterior ("medial" and "posterior" sections) 10."