Thiamine deficiency in infants: MR findings in the brain

Abstract

Background and purpose: Thiamine deficiency is extremely rare in infants in developed countries. To our knowledge, its MR findings in the brain have not been reported. The purpose of this study was to investigate the brain MR findings in infants with encephalopathy due to thiamine deficiency.

Methods: The study group included six infants aged 2-10 months with encephalopathy who had been fed with solely soy-based formula devoid of thiamine from birth. All underwent MR evaluation at admission and follow-up (total of 14 examinations). In one patient, MR spectroscopy (MRS) was performed.

Results: In five patients T2-weighted, fluid-attenuated inversion recovery, or proton-attenuated sequences showed bilateral and symmetric hyperintensity in the periaqueductal area, basal ganglia and thalami. Five had lesions in the mammillary bodies, and three, in the brain stem. In all six patients, the frontal region (cortex and white matter) was clearly involved. At presentation, MRS of the periaqueductal area showed a lactate doublet. On long-term follow-up, three of four patients had severe frontal damage; in two, this occurred as part of diffuse parenchymal loss, and in one, it was accompanied by atrophy of the basal ganglia and thalami.

Conclusion: Thiamine deficiency in infants is characterized by involvement of the frontal lobes and basal ganglia, in addition to the lesions in the periaqueductal region, thalami, and the mammillary bodies described in adults. MRS demonstrates a characteristic lactate peak.

Fig 1.

Patient 1. Images at presentation (A) and follow-up 5 (B–E) and 45 (F) days later. A, Axial T2-weighted image shows abnormal hyperintensity in the mammillary bodies (arrow) and tectum. B–D, Axial T2-weighted images show abnormal hyperintensity in the periaqueductal region, thalami, basal ganglia, and frontal area. Lesions are bilateral and symmetric. E, DWI (ADC) shows restricted diffusion in the basal ganglia. Thalami have hypointensity and hyperintensity, which are presumed to represent cytotoxic and vasogenic edema, respectively. F, Axial T2-weighted image shows diffuse parenchymal loss, severe atrophy of the caudate nuclei, and necrosis of the putamina.

Fig 2.

Patient 2. Axial T2-weighted images. A, At presentation, large area of hyperintensity is present in the pons. B, Involvement of the frontal region, up to the motor cortex, is extensive.

Fig 3.

Patient 4. Axial images at presentation. A, T2-weighted image. B, T1-weighted contrast-enhanced image shows extensive frontal injury. Note enhancement of both cortex and white matter.

Fig 4.

Patient 5. A, T2-weighted image shows subtle abnormal findings, slight hyperintensity of the anterior frontal region, and localized areas of blurring of the cortical stripe. B, DWI (ADC) indicates restricted diffusion compatible with cytotoxic edema.

Fig 5.

Patient 6. Proton MRS image from the periaqueductal region (TR/TE = 1500/144). A, At presentation. Note the negative doublet of lactate. NAA/Cr ratio is reduced 1.11. B, Five weeks later, the lactate doublet is no longer seen. NAA peak is higher than before.