MR imaging - an unreliable and potentially misleading diagnostic modality in patients with intracerebral calcium depositions. Case report.

BACKGROUND: Since magnetic resonance imaging (MRI) is a method of choice for establishing the correct diagnosis in a great majority of neurologic disorders, especially in detection the causes of seizures and both acute and slowly progressive neurologic disturbances, computerized tomography is becoming more frequently excluded from obligate spectrum of diagnostic protocol.

METHODS: MRI was performed on 1.5 T MR scanner in two patients, in one suffering from pseudohypoparathyroidism, and in another with Fahr disease, while CT was initially excluded from the diagnostic protocol. In third patient, 11-year-old boy with hypercalcemia, both CT and MRI were indicated because of seizure attack.

RESULTS: Completely normal appearing brain parenchyma was seen on T2W images in a patient with clinical diagnosis of pseudohypoparathyroidism while extensive intracerebral calcifications were noted after additionally performed computerized tomography of the brain. In another patient with Fahr disease and neurologic symptoms, extensive calcifications were evident on CT, while MR examination had revealed bilateral symmetric lesions of prolonged T2W signal in the basal ganglia, supratentorial white matter and cerebellum, most compatible toxic/metabolic demyelination. In the third patient, a boy with hypercalcemia, marked left parietal cortical calcification was noted on CT, while MRI, including T2 gradient-echo sequence was inconclusive.

CONCLUSIONS: MRI, without CT, can be not only confusing, but even misleading diagnostic modality for detection of not only subtle, but also extensive cerebral calcifications. The benefit of gradient-echo T2 sequence, that is usually included in MR protocol when intracranial calcifications are suspected, is also rather limited.