LEIGH'S DISEASE

6 months old child with history of seizures. No history of hypoxic injury.




Axial T1 wt images show
homogenous hypointensity in bilateral caudate nuclei and anteromedial thalami.



Axial T2 wt images show homogenous hyperintensity in bilateral caudate nuclei,
lentiform nuclei, antero medial thalami, cerebral peduncles and periaqueductal gray matter.



All the above mentioned areas show restricted diffusion

·        Leigh disease (subacute necrotizing encephalomyelopathy) is a mitochondrial disease that results from a disorder in the respiratory chain production of adenosine triphosphate.

·        Inherited, progressive, neurodegenerative disease of infancy or early childhood with variable course and prognosis.

·        Clinical manifestations can be highly variable, affecting children and (rarely) young adults and typically causing central hypotonia, developmental regression or arrest, ophthalmoplegia, respiratory and bulbar dysfunction, and ataxia.

·        Characteristic pathologic abnormalities include microcystic cavitation, vascular proliferation, neuronal loss, and demyelination of the midbrain, basal ganglia, and cerebellar dentate nuclei and, occasionally, of the cerebral white matter.

·        MR imaging findings include symmetric areas of T2 prolongation in the basal ganglia, periaqueductal region, and cerebral peduncles, with putaminal involvement being a consistent feature.

·        The cerebral white matter is rarely affected. Enhancement may be seen at MR imaging and may correspond to the onset of acute necrosis

·        When Leigh disease is suspected, MR spectroscopy (best performed with long echo times) may reveal the presence of abnormally high lactate levels in the basal ganglia, which together with elevated serum and CSF lactate levels supports the diagnosis.

References :

1.     Leukodystrophy in Children: A Pictorial Review of MR Imaging Features,  May 2002 RadioGraphics, 22, 461-476

2.     Differential Diagnosis for Bilateral Abnormalities of the Basal Ganglia and Thalamus, January 2011 RadioGraphics, 31, 5-30

PERSISTANT OCCIPITAL SINUSES

Abnormal sinuses seen originating from torcula heterophili and coursing posterolaterally.

The sinuses are joining the internal jugular veins bilaterally.

·        Occipital sinuses usually communicate cranially at the torcular Herophili and caudally at the foramen magnum, where a multitude of variations may exist.

·        Occipital sinuses have been reported in up to 10% of normal subjects and may be associated with atretic transverse/sigmoid sinus segments and internal jugular vein. Correlation with CT may bolster confident diagnosis by demonstrating a smaller caliber sigmoid sinus groove and/or jugular foramen.

·        Occipital venous network is believed to regress once most of the venous flow passes through the major dural sinuses when children assume the upright position.

·        Accidental discovery of a persistent occipital sinus during posterior fossa surgery can result in catastrophic hemorrhage and/or occlusion of the occipital sinus that may lead to venous thrombosis/infarction.