[Calcification of the basal nuclei in hypoparathyroidism. The computed and magnetic resonance tomographic aspects]

Six female patients with hypoparathyroidism (2 idiopathic and 4 postoperative cases following total thyroidectomy) were examined with brain CT scans; 4 of them underwent MR exams too. Two patients presented with no symptoms, 4 exhibited extrapyramidal syndrome, tetany, fainting seizures or ischemic attacks and only 2 presented with abnormal calcium-phosphorus balance. CT showed calcifications of the basal nuclei in 5 patients. The caudate nucleus was always affected (100%). The calcifications were in the putamen, globus pallidus and thalamus in 4 cases (80%), in the dentate nuclei, centrum semiovale and cerebral cortex in 2 cases (40%) and in the mesencephalic gray matter in 1 case (20%). In one case only CT failed to detect the abnormalities, which were nevertheless depicted by MRI. In the other 3 patients who underwent MRI, CT findings were confirmed as low-signal areas on SE T1- and T2-weighted MR scans where the calcifications were present, but areas of increased signal intensity were also evident on SE T2-weighted images; in one patient, low-signal areas were surrounded by a ring of increased signal intensity on SE T1-weighted scans. Low-signal areas reflect an early stage of calcium deposition; on the other hand, high-signal areas are probably caused by proteins and mucopolysaccharides or by liquid pools secondary to endothelial membrane incompetence. CT better defined the site and extent of the calcifications which may be found in both idiopathic and postoperative hypoparathyroidism, in symptomatic or asymptomatic patients. On the other hand, MRI seems to be capable of depicting the various stages of calcium deposition on the basis of the presence of reduced or increased SE T2 signal intensity.