⁹⁹mTc-ethyl cysteinate dimer cranial single-photon emission computed tomography and serial cranial magnetic resonance imaging in a girl with isolated sulfite oxidase deficiency.

Isolated sulfite oxidase deficiency, a rare autosomal recessive inherited disorder, is easily misdiagnosed as the more common hypoxic-ischemic encephalopathy. A female term infant was diagnosed with isolated sulfite oxidase deficiency. Magnetic resonance imaging at ages 13 days, 2 months, and 10 months indicated diffuse edema with posterior predominance, followed by progressive multicystic encephalomalacia and brain atrophy with relatively sparing of the thalami. Single-photon emission computed tomography using (99m)Tc-ethyl cysteinate dimer at 2 months revealed decreased uptake in the frontal lobes. The characteristic neuroimaging findings in isolated sulfite oxidase deficiency help differentiate it from hypoxic insult. The correct diagnosis is helpful in genetic counseling for parents.