Diagnostic ultrasound ( PDFDrive )

CHAPTER 45 Neonatal and Infant Brain Imaging 1513
he anterior fontanelle remains open until approximately
2 years of age but is suitable for scanning only until about
12 to 14 months. he smaller the fontanelle, the smaller is
the acoustic window and the more diicult the examination
will be. 7,13
Every efort should be made to maintain normal body temperature
in premature infants when performing ultrasound. heir
small size results in a high surface-to-volume ratio and rapid
heat loss when they are exposed. Overhead warming lamps,
blankets, and warmed coupling gel should be routinely used. If
the infant is in an Isolette, heat loss may be minimized by using
access side holes as an entry site for the transducer.
Handwashing and cleansing of the transducer between patients
are of paramount importance to avoid the spread of infection
in the intensive care nursery. Simple cleansing of the transducer
head with a manufacturer-approved disinfectant should be
adequate. When absolute sterility is required, such as during
operative sonography, the transducer can be placed inside a sterile
surgical glove or sterile transducer cover with coupling gel. Sterile
aqueous gel or saline solution can be used as a coupler outside
the sterile cover.
Standard brain scanning includes sagittal and coronal planes
through the anterior fontanelle and should also routinely include
at least two axial views: through the posterior fontanelle and the
mastoid fontanelle. Coronal images acquired through the posterior
fontanelle may be useful as well, to compare ventricular size.
Magniied views with high-frequency transducers are essential
to study near-ield pathology such as extraaxial luid for hemorrhage
or infection and dural venous sinuses. Whenever possible,
the transducer should be held irmly between the thumb and
index inger, and the lateral aspect of the hand should rest on
the infant’s head for stability. Video clips should be obtained
routinely for any abnormality to improve ultrasound diagnosis,
avoid repeating a scan on an unstable newborn, and allow review
of complex images and prompt diagnosis without delaying the
patient worklow. Real-time imaging enables the appreciation
of subtle changes in echogenicity more easily than static images.
Lesions that afect gray-white matter diferentiation as well as
focal nonhemorrhagic infarcts may cause mild changes in
echogenicity. 3
Coronal Imaging
Coronal images are obtained by placing the scan head of the
transducer transversely across the anterior fontanelle (Fig. 45.1,
Video 45.1). he plane of the ultrasound beam should then sweep
in an anterior-to-posterior direction, completely through the
brain. Care must be taken to maintain symmetrical imaging of
the brain and skull. An initial sweep of the brain to obtain parallel
alignment of the thick glomus of the choroid plexus in each
trigone is a good method to obtain symmetry. At least six standard
coronal images should be obtained during this anterior-toposterior
sweep. 13
Coronal Brain Scans: Normal Structures
MIDLINE STRUCTURES
Interhemispheric issure
Cingulate sulcus
Corpus callosum
Cavum septi pellucidi
Cavum vergae (when present)
Third ventricle
Fourth ventricle
Brainstem
Vermis of cerebellum
PARAMEDIAN STRUCTURES
Frontal lobe
Parietal lobe
Occipital lobe
Frontal horn of lateral ventricle
Body of lateral ventricle
Temporal horn of lateral ventricle
Trigone of lateral ventricle
Choroid plexus
Glomus of choroid plexus
Caudate nucleus
Internal capsule
Thalamus
Lentiform nucleus
Tentorium cerebelli
Cerebellar hemisphere
Sylvian issure
Cisterna magna
A B C D EF
FH
SR
CN
M
IR
BV
TH
PR
FIG. 45.1 Coronal Brain Ultrasound Planes Through Anterior
Fontanelle. A to F correspond to front to back. 3, Third ventricle; 4,
fourth ventricle; BV, body of lateral ventricle; CB, cerebellum; CC, cerebral
cortex; CN, caudate nucleus; CP, choroid plexus; FH, frontal horn; IR,
infundibular recess; M, massa intermedia; OH, occipital horn; PR, pineal
recess; SR, supraoptic recess; TH, temporal horn. See also Video 45.1.
(With permission from Rumack CM, Manco-Johnson ML. Perinatal and
infant brain imaging: role of ultrasound and computed tomography. St
Louis: Mosby; 1984. 7 )
3
4
CC
CP
CB
OH