Diagnostic ultrasound ( PDFDrive )

CHAPTER 49 The Pediatric Spinal Canal 1675
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B
FIG. 49.3 Lumbosacral Spine in a 2-Week-Old Infant. (A) Extended–ield-of-view image reveals detailed anatomy of the course and contour
of the lumbosacral spine. The hypoechoic cord is visible (C), sacral and lumbar vertebral bodies are labeled, and the lumbosacral junction can be
determined where S1 tilts posteriorly. (B) Split image in the same patient. The same landmarks can be documented with a dual image. Often this
is technically easier than the panoramic view. See also Video 49.1.
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B
FIG. 49.4 Brainstem, Cisterna Magna, and Cerebellar Hemispheres. (A) Sagittal view of the craniocervical junction using the foramen
magnum as a window. The arrow indicates the posterior margin of the foramen magnum. Visualization of the cerebellum and medulla (M) is also
possible on this view. (B) On transverse view, the cisterna magna (C) and cerebellar hemispheres (H) are well shown.
cauda equina, and the normal thickness is 1 to 2 mm 21 (Fig.
49.8, Video 49.2). Sometimes it can be diicult to separate the
ilum terminale from the nerve roots in the cauda equina to
obtain a good measurement. Filar cysts (Fig. 49.9) can be seen
within or on the ilum terminale and caudal to the conus medullaris
and should be considered a variant of normal development
when there is no other suggestion of pathology. 7,22 he incidence
of ilar cyst is up to 11.8% in the newborn period. 20 Detection
is inversely related to age up to 6 months. hese cysts are not
seen on most neonatal or adult MRI studies. here is no proven
explanation for their origin; possibilities include a true cyst, a
pseudocyst, an embryonic remnant, or a developmental phenomenon
that regresses with age. hey do not require further
imaging or follow-up. 20