Inherited Cerebellar Ataxia in Childhood: A Pattern-Recognition Approach Using Brain MRI

Ataxia-telangiectasia. A, Axial T2 image shows cortical thinning and fissure enlargement in the vermis and cerebellar hemispheres. B, Midline sagittal T2 image demonstrates an atrophic vermis but normal volume of the brain stem. Although nonspecific, this pattern of diffuse cerebellar atrophy suggests a degenerative disease.

Infantile neuronal ceroid lipofuscinosis. Coronal T1 image (A) shows cerebral and cerebellar atrophy. Coronal FLAIR image (B) demonstrates diffuse abnormal signal intensity affecting the cortex of both cerebellar hemispheres. Compare the signal intensity of the cerebellar cortex with occipital cortex.

Acute stage of maple syrup disease. Axial T2 images (A and B) show diffuse signal change affecting deep cerebellar white matter (arrows) and midbrain (arrowheads). Trace from diffusion-weighted imaging shows reduced diffusivity in several regions of the midbrain (C).

Cerebrotendinous xanthomatosis. Axial T2 image shows signal change affecting the deep cerebellar white matter (arrows). Notice the abnormal hypointensity in the gray matter of the cerebellar nuclei (arrowheads).

Hypomyelination with congenital cataracts. Axial FLAIR images (A and B) demonstrate diffuse signal-intensity abnormality (arrows) in the cerebellar (A) and cerebral (B) white matter.

Adrenoleukodystrophy (A and B) and peroxisomal acyl-coenzyme A oxidase deficiency (C). Axial T2 (A) shows pontine corticospinal tract lesions (arrows), and postcontrast axial T1 (B) demonstrates bilateral and symmetric white matter demyelination and inflammation (enhancement, arrowheads) involving the parietal lobes and splenium of the corpus callosum. Cerebellar white matter and pontine corticospinal tract lesions (C) are also shown in a patient with peroxisomal acyl-coenzyme A oxidase deficiency.

Mitochondrial disorder. Sagittal T1 (A) and axial FLAIR (B) images show abnormal signal intensity (arrowheads) in the dorsal midbrain.

Complex II mitochondriopathy. Axial T2 images demonstrate hyperintense signal in the pons. (A, note sparing of corticospinal tracts, white arrowheads) and hilum of the dentate nucleus (B).

Diffusivity changes in mitochondrial disorder. Axial DWI images show brain stem reduced diffusion in the central tegmental tracts (A), cerebral peduncles (B), and subthalamic regions. Single-voxel proton MR spectroscopy (C) from the same patient shows reduced NAA and markedly elevated lactate (doublet at 1.33 cpm).

Localized cerebellar hypoplasia. Fetal coronal T2 image (A) shows a left-sided cerebellar hematoma (arrow). Postnatal coronal T2 image (B) demonstrates hypoplasia of the left cerebellar hemisphere.

Cerebellar hypoplasia. Sagittal T1 image of a neonate shows severe brain stem and vermis hypoplasia. The superior vermis is below the intercollicular sulcus and above the obex. Note severe supratentorial atrophy, suggesting prenatal onset of volume loss.

Congenital disorder of glycosylation (type Ia). Coronal T2 image shows a small cerebellum with very small cerebellar folia and enlarged fissures. This pattern probably reflects a process that begins in utero (hypoplasia) and progresses in infancy (atrophy).

Joubert syndrome and related disorders (ciliopathies). Sagittal T1 (A) and axial T2 (B) images show a small dysgenetic vermis (arrows) and large horizontal superior cerebellar peduncles (arrowheads, molar tooth sign).

Rhomboencephalosynapsis. Axial T2 (A) and coronal T2 (B) images show continuity of the deep cerebellar white matter across the midline due to complete absence of the vermis.

Cerebellar cortical dysgenesis. Axial T1 images (A and B) and a coronal T1 image (C) demonstrate abnormal cerebellar foliation. The cause of this is usually unknown. Hydrocephalus is also present (C).