CT AND MR OF THE BRAIN IN THE DIAGNOSIS OF ORGANIC ACIDEMIAS - EXPERIENCES FROM 107 PATIENTS

The results of CT and/or MRI of the brain in 107 patients with differe nt types of organic acidemia are presented. The CSF spaces were wide i n more than two-thirds of the patients, in 46 slightly-to-moderately a nd in 26 markedly-to-severely dilated. Marked widening of the opercula e was found in all 5 patients with glutaric acidemia type 1, but open opercula was also found in other organic acidemias. White matter chang es were found in about half the patients, in 28 mildly-to-moderately p ronounced, in another 28 marked or severe. Basal ganglia or central pa thway pathology was seen in a total of 34 patients, i.e. 32%. These ch anges in 25 patients involved the caudate and/or lentiform nuclei: in 14 cases the T-2 signal was increased and volume loss was present, in 9 cases increased T-2 signal with preserved volume was found (in one o f these the changes were transient), In 2 patients, both with ethylmal onic aciduria (cause unknown), only small high T-2 spots were seen in the caudate heads and the putamina. In 4 patients, all suffering from methylmalonic acidemia, only the globus pallidus was affected. In 3 pa tients, all with beta-ketothiolase deficiency, high T-2 intensity chan ges were seen only in the postero-lateral putamina. The remaining 8 pa tients represent a variety of different locations of lesions, The CT o r MRI findings in many patients with organic acidemias should alert th e radiologist that a neurometabolic disorder may be present; in some c ases the location and appearance of the lesions may even suggest the c orrect diagnosis.