Page 178 - Atlas of Small Animal CT and MRI

Figure 2.3.3 Small Cerebellum – Probable Cerebellar Hypoplasia (Canine) MR

3.5mo M Cocker Spaniel cross with neurologic
signs referable to the cerebellum. The cerebel-
lum is small, and the surface contours appear
unusually well defined because of increased
cerebrospinal fluid volume surrounding the
cerebellar folia. The fourth ventricle and
cerebellomedullary cistern are also larger than
expected. This diagnosis was not confirmed by
biopsy or postmortem examination.

(a) T1, SP (b) T2, SP

Figure 2.3.4 Presumptive Cerebellar Vermian Hypoplasia (Canine) MR

(a) T1, SP (b) T1, TP (c) T1, TP

(d) T2, TP (e) T2, TP
Adult dog of unknown age and unknown clinical signs. The representative transverse images are at the level of the rostral (b,d) and caudal
(c,e) cerebellum. The volume of the caudal fossa is larger than expected, and the cerebellum is markedly reduced in size (a: arrow). The
fluid surrounding the cerebellum within the caudal fossa is likely compartmentalized cerebrospinal fluid within a grossly distended cerebel-
lopontine cistern. Both cerebellar hemispheres are hypoplastic (b–e: asterisks), and the central cleft (c: arrow) is indicative of aplasia of
the caudal aspect of the cerebellar vermis. There is free communication (e: black double‐headed arrow) of the fourth ventricle (e: small
arrow) with a markedly enlarged cerebellomedullary cistern (e: large arrow). Although not confirmed by postmortem exam, the constella-
tion of imaging findings is characteristic of Dandy–Walker syndrome with cerebellar vermal hypoplasia/aplasia described in people.

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