PMC8492953_01
(A) Transverse T2W MR images at the level of the third ventricle, (B) transverse T1W MR images at the level of the caudal aspect of the lateral ventricles and rostral colliculi of the mesencephalon, (C) transverse T2W MRI image at the caudal aspect of the cerebellum, (D) mid-sagittal T2W MR image. The asterisk (*) in (A,B) demarcates the communication between the left lateral ventricle and the subarachnoid space and represents the porencephaly. Also, in (A), communication between the left lateral and right lateral ventricle is visible due to partial absence of the septum pellucidum and no corpus callosum is identifiable. In (B), fusion of the rostral colliculi is appreciated. In (C), the black arrow points toward the irregular and apparently incomplete separation between right and left cerebellar hemisphere (not confirmed on post-mortem examination; likely represents in situ displacement). Partial herniation of the left hemisphere over the midline into the right hemisphere is visible (not confirmed on post-mortem examination; likely represents in situ displacement). In (D), the corpus callosum and mesencephalic aqueduct are hard to identify and increased fluid signal between cerebral gyri and cerebellar folia is seen, which can also be appreciated in (A-C).
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F1
Several abnormalities were identified (see Figure 1): the ventricular system was severely enlarged with asymmetric dilation of the lateral ventricles bilaterally and dilation of the third ventricle with abnormal shape and partial absence of the septum pellucidum. This resulted in a connection between the subarachnoid space and the ventricles (porencephaly; compare Figure 1B with Figure 3E). In conclusion, the main findings on post-mortem examination were partial agenesis and hypoplasia of the corpus callosum, fornix and septum pellucidum, obstructive internal hydrocephalus and porencephaly, which morphologically reflected the MR images (see Figures 1, 3).
Transverse T2W images of the brain at the level of interthalamic adhesion of (A) our current case with a hypoplastic/absent interthalamic adhesion (white arrow) in comparison with the interthalamic adhesion in (B) of a calf without brain lesions (at 7 months of age). Also note the ventriculomegaly and thin white matter tracts (corona radiata), thin cortex and increased CSF signal ventral to the thalamus in (A) compared to (B).
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F2
The interthalamic adhesion was subjectively small, which can be appreciated when comparing the images to those of another calf taken at 7 months of age (see Figure 2).
Macroscopic photographs of the bovine encephalon of this case report and corresponding reference images (fixated in formalin) at approximately the same level-courtesy of dr. FG Wouterlood and dr. P. Voorn, Dept Anatomy and Neurosciences, AmsterdamUMC, VU, Amsterdam, The Netherlands. (A) Dorsal view of the cerebrum and cerebellum in situ after removal of the dorsal and caudal parts of the skull and dura mater. (B) Rostrocaudal view of a transverse slab at the level of the olfactory recesses. (C) Rostrocaudal view of a transverse slab at the level of the septal area. (D) Rostrocaudal view of a transverse slab at the level of the interthalamic adhesion. (E) Rostrocaudal view of a transverse slab at the level of the rostral mesencephalon. (F) Rostrocaudal view of a transverse slab at the level of the caudal mesencephalon. (G) Rostrocaudal view of a transverse slab at the level of the cerebellum, fourth ventricle, and medulla. (H) Caudorostral view of the cerebrum and cerebellum in situ after removal of the dorsal and caudal parts of the skull and dura mater. (I) laterolateral view of the cerebrum in situ after removal of the dorsal and caudal parts of the skull and dura mater. The anatomical terms differ from those of the Nomina Anatomica Veterinaria, as the images are composed and labeled by human neuroanatomists/-scientists.
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F3
The Netherlands). This revealed revealed diffuse, moderately enlarged hemispheres most prominently on the left side, covered by diffuse moderately edematous leptomeninges (see Figure 3). This resulted in a connection between the subarachnoid space and the ventricles (porencephaly; compare Figure 1B with Figure 3E). In conclusion, the main findings on post-mortem examination were partial agenesis and hypoplasia of the corpus callosum, fornix and septum pellucidum, obstructive internal hydrocephalus and porencephaly, which morphologically reflected the MR images (see Figures 1, 3).