Abnormalities of the basal ganglia and thalami S.Alj, M.Ouali Idrissi, N. Cherif El Idrissi El Ganouni, O.Essadki, A.Ousehal Radiology department, Ibn Tofail Hospital, Cadi Ayyad University, Marrakech. NR4

Introduction Several diseases may cause MR signal abnormalities of the basal ganglia and thalami. Signal abnormalities are usually non specific. Analysis of the clinical manifestations, type of signal, location of the lesions and associated abnormalities can help to achieve the correct diagnosis.

Methods and patients The study included : patients with signal abormalities of basal ganglia and thalami in MRI. MRI technique: -MRI 1,5 Tesla. -with T1, T2, T2*,Flair and diffusion sequences.

Results 1-Epidemiological features: Thirteen patients were included in the study. There was seven women and 6 men. Patients were aged between 8 and 70 years (mean age= 27,15).

Results 2-Clinical manifestations: symptomsNumber seizure5 decreasing of consciousness4 stroke3 Visual impairment1

Results 3-Imaging features: 3.1-Location of the signal abnormalities 3.2-Associated abnormalities: White matter abnormalities were found in 4 patients Abnormalities locationCase number Basal ganglia10 Nucleus dentatus5 Thalami2

Results 3.3-etiology: EtiologyNumber of cases Fahr’s disease4 Neurolupus2 Wilson disease1 Multiple sclerosis1 Behcet disease1 Creusfeldt Jacob disease1 Hypoglycemia1 No etiology found2

Figure 1: Fahr’s disease Calcifications of the basal ganglia and thalami on CT Bilateral and symetric hyperintensity of the basal ganglia and thalami on T1 WI

Fahr’s disease Comment Rare clinical entity characterized by bilateral calcifications of the basal ganglia, thalami, dentate nuclei of the cerebellum, and the white matter of the cerebral hemisphere Clinical manifestations: characterized by movement disorders, dementia and behavioral disorders Computed tomography: calcifications are visible as high- density areas. Magnetic resonance image: the calcifications have different signal intensities. It’s probably related to the stage of the disease, and the volume of the calcium deposit.

Figure 2: Wilson disease. T2-weighted MR image depicts bilaterally symmetric areas of abnormal T2 hypersignal in the thalamus, putamina and caudate nuclei.

Wilson disease Comment caused by the accumulation of copper resulting from a deficiency of ceruloplasmin. Clinical manifestations : dysarthria, tremors, ataxia, Parkinsonian symptoms, and psychiatric problems. The Kayser-Fleisher rings in the cornea is characteristic when found. MRI : - areas of T2 hyperintensity in the putamen (a common finding), -Other locations of the signal abnormalities : globus pallidus, caudate nuclei, and thalamus (ventrolateral aspect ). -The cortical and subcortical regions, mesencephalon, pons, vermis, and dentate nuclei may also be involved.

Figure 3: Creutzfeldt Jacob disease 30 years aged patient with rapidely progressive demantia. Bilateral hyperintensities on FLAIR WI of cerebral cortex and basal ganglia.

Creutzfeldt jacob disease(CJD) Comment fatal neurodegenerative disorder caused by prions Four main subtypes: sporadic, familial, iatrogenic, and variant CJD Clinical manifestations: rapidly progressive dementia, myoclonus. Electroencephalography : Characteristic periodic sharp-wave complexes. MRI of sporadic CJD: diffusion-weighted MR imaging: increasingly important for the diagnosis Bilateral restricted diffusion of cerebral cortex and basal ganglia.

Figure 4:Hypoglycemia 70 years aged patient type 2 diabetic. Bilateral FLAIR hypersignal in the temporal and occipital cerebral cortex, and basal ganglia.

Hypoglycemia Comment Brain damage is dependent on the severity and duration of hypoglycaemia Clinical manifestation s:patients with severe hypoglycemia have coma and are typically diabetic receiving treatment with oral hypoglycemic agents MRI: -bilateral T2 prolongation in the cerebral cortex, hippocampi, and basal ganglia. -transient white matter abnormalities DW MR findings, involving the splenium of the corpus callosum, internal capsules and corona radiata have been reported in milder hypoglycemia

Figure 4:Neuro-Behçet Disease 40 years aged patient with Behcet disease. Hyperintense lesions of the left midbrain, cerebellar hemispheres and the basal ganglia.

Neuro-Behçet Disease multisystemic, recurrent inflammatory disorder of unknown cause Clinical manifestations: triad of uveitis, oral ulcers, and genital with neurological ulcers manifestations (headache, dysarthria, cerebellar signs, sensory signs) MRI: -lesions hyperintense on T2-WI, hypointense on T1-WI, enhance after contrast material administration -Involving the brainstem, basal ganglia (bilateral involvement in one-third of cases), and thalamus. -Less commonly, the white matter of the cerebral hemispheres and cervicothoracic spinal cord are involved.

Other Comment Other inflammatory and demyelinating disease may present with basal ganglia and thalami lesions (Multiple sclerosis, systemic lupus with neurological manifestations..) Clinical manifestations: variety of neurological deficits MRI: (MS) -Gray matter T2-hypointensity, -suggestive of excessive iron deposition -associated with worsening disability in patients with MS

Conclusion Signal abnormalities of basal ganglia are usually non specific. Clinical manifestations and the location of this signal abnormalities led to diagnosis. The etiologies vary widely corresponding generally to uncommon diseases (such Fahr’s disease), or to a rare manifestation of some commun pathologies (such multiple sclerosis).

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