Interposed between the confluence of the frontal and parietal bones, the anterior fontanelle is a commonly used anatomic landmark, as well as the first window insonated. All available windows should be interrogated in both a sagittal and coronal plane, sweeping through sonographic landmarks with anteroposterior rocking and tilting of the probe. The mastoid and posterior fontanelles should also be used as sonographic windows if available, although their closure usually occurs before age 6 months. NeonatesĪn adequate sonographic window may often be obtained at the anterior fontanelle in infants less than 12-14 months of age. The performance of a transcranial Doppler study differs based on relevant patient anatomy, most notably in regards to the status of fontanelle closure in neonates, these open fontanelles may provide acoustic windows for insonation of intracerebral structures. Trauma to the head, eye, or orbital structures Sonography of the eye has a wide array of applications in point-of-care ultrasonography indications for its use alone, distinct from the other elements of a transcranial Doppler exam, include 17: Sonographic examination of the orbit will also be discussed, as the measurement of the optic nerve sheath diameter (OSND) and spectral waveform analysis of the ophthalmic artery are essential parts of a complete transcranial Doppler examination. Suspicion for intraventricular hemorrhage Indications for transcranial Doppler more specific to pediatric age groups, especially pertaining to neonates, include:īoth scores, at one and five minutes, under 7 Intra/peri-operative evaluation of cerebral perfusionĬonfirmation of cerebral circulatory arrest General indications for the use of transcranial Doppler ultrasonography include:Ĭlinical suspicion of cerebral vasculopathyĮvaluation for complications of subarachnoid hemorrhage Neurosonography of the fetal brain, although based on similar principles, will not be discussed this article will focus on neonatal, pediatric, and adult indications for sonographic studies of the brain and cerebral vasculature, especially as it pertains to point-of-care ultrasound. "TCD" and "transcranial Doppler" will be used to refer to the combined 2D parenchymal imaging with or without the use of Doppler modalities.Īdvantages of TCD over its "conventional" predecessor include an ability to identify structural perturbations, including the presence of masses and/or midline shift, and the presence of sonoanatomical landmarks to guide placement of a pulsed wave Doppler gate 18. Some may refer to the imaging modality to be discussed below as transcranial color-coded duplex sonography (TCCS) and the non-imaging based continuous wave Doppler modality as transcranial Doppler (TCD) this article will not make this distinction, as the latter (non-imaging) modality will not be further discussed. An extension of the non-imaging, continuous wave Doppler assessment popular among neurointensivists, the imaging of cerebral structures with grey-scale and superimposed color flow and spectral Doppler analysis is now possible using the same windows, techniques, and diagnostic goals.
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