Diagnostic ultrasound ( PDFDrive )

CHAPTER 45 Neonatal and Infant Brain Imaging 1523
CA
C
O
A
B
C
D
FIG. 45.16 Choroid Plexus and Calcar Avis. (A) and (B) Posterior fontanelle views of lateral ventricle. (A) Normal choroid plexus glomus (c)
does not extend into the occipital horn (O). (B) Calcar avis (CA) can be seen projecting into the occipital horn and imitates hemorrhage. Continuity
with the adjacent brain identiies this structure. (C) Axial view of the lateral ventricles shows “dangling” choroid plexus in a newborn with
hydrocephalus from aqueductal stenosis. (D) Coronal view of the lateral ventricles shows dependent choroid plexus.
or occipital horn. he choroid plexus is also present in the roof
of the fourth ventricle. 24 (see 45.9A) Small cysts in the choroid
plexus are common, but at times areas that appear to be cysts
are in fact small vessels.
he glomus of the choroid plexus is oten doubled and thus
appears lobulated (Fig. 45.16). Some authors have termed this
appearance a “split” choroid plexus. 41 It may be mistaken for
clot adhering to the choroid plexus. Color Doppler ultrasound
will diferentiate the normal highly vascular choroid from similarly
echogenic, but avascular, clot (see Fig. 45.8C). Coronal views
may also show a lattened or truncated choroid plexus at the
level of the thickest portion at the trigone, probably related to
the angle of the transducer to the choroid. 41 If there is a large
ventricle, the choroid will normally “dangle,” or hang down toward
the dependent ventricle, when the infants are lying on their side
(see Fig. 45.16D).
Pitfalls in Neurosonography
Peritrigonal blush on sagittal view (anisotrophic effect)
Choroid plexus shapes affected by position
Normal choroid plexus: split, lobulated, or truncated
Dangling choroid (in hydrocephalus)
Normal choroidal vessels vs. choroid plexus cyst
Normal choroid plexus vs. hemorrhage around the
choroid
Asymmetrical normal-sized ventricles
Dandy-Walker malformation false-positive diagnosis due to
angled view through the lower cerebellum