Applied Radiology

Diagnosis

Fahr disease (familial cerebral ferrocalcinosis, bilateral striadopallidodentate calcinosis)

Findings

Noncontrast CT demonstrates diffuse calcification of basal ganglia, subcortical white matter, and dentate nuclei of the cerebellum. MR images demonstrate subtle FLAIR hyperintensity at the margins of calcification in the cerebellum and to a lesser extent the basal ganglia.

Discussion

Fahr disease is a rare neurodegenerative disorder characterized by progressive psychosis, cognitive impairment, dementia, movement disorders, and parkinsonian symptoms. The condition is thought to be heritable with variable expressivity and typically presents ages 40 to 60. Prognosis is generally poor and there is no known effective treatment.¹

CT classically demonstrates diffuse mineralization of the globus pallidus, putamen, caudate, thalamus, cerebellum, corona radiata, and subcortical white matter. Calcification begins several decades prior to neurological deterioration. MR occasionally reveals a similar distribution of T2/FLAIR hyperintensities, which have been postulated to represent a progressive metabolic or inflammatory process preceding calcification.²

The differential for basal ganglia calcification is broad, but the widespread calcification, including dentate nuclei calcification, narrows the differential to Fahr disease and disorders of calcium metabolism, specifically hypoparathyroidism and pseudohypoparathyroidism.³ However, with the appropriate clinical history and normal serologic studies, this pattern is pathognomonic for Fahr disease.

1. Shenoy AM, Volpe D, Ensrud ER. Fahr’s disease. Pract Neurol. 2009;9(2):100-1.
2. Avrahami E, Cohn DF, Feibel M, et al. MRI demonstration and CT correlation of the brain in patients with idiopathic intracerebral calcification. J Neurol. 1994;241:381-384.
3. Hedge AN, Mohan S, Lath N, Lim CCT. Differential diagnosis for bilateral abnormalities of the basal ganglia and thalamus. Radiographics. 2011;31:5-30.