Diagnostic ultrasound ( PDFDrive )

CHAPTER
46
Duplex Sonography of the Neonatal
and Infant Brain
Thierry A.G.M. Huisman and Andrea Poretti
SUMMARY OF KEY POINTS
• Duplex sonography is a valuable, functional addition to
anatomic sonography of the pediatric brain.
• Various quantitative metrics can be extracted from the
low curves, including peak systolic, end-diastolic low
velocity, time average maximum mean blood low velocity,
and resistive index.
• The quantitative markers may be inluenced or altered by
mechanical ventilation, patent ductus arteriosus,
extracorporeal membrane oxygenation (ECMO),
arteriovenous shunting, and pathologies that are affected
by cerebral hemodynamic autoregulation.
• In hypoxic ischemic injury and general brain edema, the
resistive index values typically drop to low values.
• Duplex sonography may help to identify and explore
arterial and venous malformations such as the vein of
Galen aneurysmal malformation.
CHAPTER OUTLINE
SONOGRAPHIC TECHNIQUE
Approaches
Doppler Optimization
Safety Considerations
Doppler Measurements and Factors
That Change Resistive Index
NORMAL HEMODYNAMICS
Normal Arterial Blood Flow Patterns
Normal Venous Blood Flow Patterns
INTENSIVE CARE THERAPIES AND
CEREBRAL HEMODYNAMICS
Mechanical Ventilation
Extracorporeal Membrane Oxygenation
Therapeutic Hypothermia and Brain
Cooling
DIFFUSE NEURONAL INJURY
Hypoxic Ischemic Injury and
Asphyxia
Cerebral Edema
Brain Death
INTRACRANIAL HEMORRHAGE
AND STROKE
Focal Arterial Ischemic Stroke
HYDROCEPHALUS
VASCULAR MALFORMATIONS
INTRACRANIAL TUMORS
NEAR-FIELD STRUCTURES
Differentiation of Subarachnoid From
Subdural Fluid Collections
Dural Venous Sinus Thrombosis
UNCOMMON VASCULAR
APPLICATIONS
PITFALLS OF DUPLEX SONOGRAPHY
Continuous and pulsed echo technique, or duplex sonography
in which gray-scale tissue imaging is combined with blood
low sampling, has been in use for the past decades in the
evaluation of normal and abnormal neonatal intracranial
hemodynamics. 1-3 In addition, color Doppler sonography renders
valuable information about the direction of the blood low in
relation to the transducer. his technique allows better understanding
of altered intracranial low or exploring the complex
angioarchitecture of vascular malformations. Continuing improvements
in transducer design and sensitivity allow routine imaging
of the intracranial vasculature in newborns and young infants,
including the identiication of low in submillimeter arteries (e.g.,
lenticulostriate arteries) and patency of dural venous sinuses
(e.g., superior and inferior sagittal sinus) of the brain. 4 he wide
dynamic range and high sensitivity of power Doppler sonography,
in which blood low is represented as various shades of a single
color (amplitude-coded color or color low Doppler energy), is
especially helpful to depict low-velocity and low-amplitude blood
low. Power Doppler sonography, however, lacks information
about low direction. Furthermore, analysis of the sampled low
spectra/curves and postprocessing sotware programs ofer
extraction of objective semiquantitative data (e.g., peak systolic
velocity [PSV], end-diastolic low velocity [EDV], resistive
index [RI], and time-averaged mean blood low velocity [TAV]).
hese semiquantitative data can be collected serially, giving
valuable real-time information about progression of disease or
recovery. Analysis of the shape of the spectral pattern with delayed
systolic low acceleration, lattened systolic upstroke, slow diastolic
deceleration, or reversal of low during diastole may provide
important information about the cerebral hemodynamics. his
chapter describes how brain ultrasonography combining multiplanar,
multiapproach anatomic and functional/hemodynamic
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