Preliminary study of conventional MRI and 1H-MR spectroscopy in diagnosis of acute bilirubin encephalopathy

Abstract

Objective To investigate the characterized imaging in conventional MRI, get information about the metabolites in basal ganglia from proton MR Spectroscopy(1H-MRS) of acute bilirubin encephalopathy(ABE) and find out the relationship between those changes and bilirubin levels. Methods Twenty-eight patients with acute bilirubin encephalopathy and 15 normal neonates underwent MR and 1H-MRS examinations T1 WI, T2WI and DWI were collected via conventional MRI scanning of all neonates. All patients underwent multi-voxels scanning and 15 of them had single voxel scanning. 1H-MRS used point resolved spectroscopy (PRESS) both in multi-voxels and single voxel scanning. The data of them were acquired from the ROIs placed in basal ganglia and globus pallidus, respectively. The metabolites including NAA choline, Lactate, glutamate and glutamine, myoinositol and creatine were quantitatively analyzed to compare them between the control group and the case group. Equality of variance between patient data and normal values were tested by using the two-tailed t test. The case group was divided into three groups of 342.0 μmol/L 513.0 μmol/L including 8,9,11 patients, respectively. Analysis of variance was used for statistics. Results Conventional magnetic resonance imaging showed symmetrical high signal of T1WI in globus pallidus of 23 patients. The case group and the control group were significantly different. Single voxel 1H-MRS revealed that the relative concentrations of Glx/Gr and mI/Cr in the control group were 0.95±0.23, 0.57±0.20, respectively, While those in case group were 1.45±0.37, 0.74±0.23, respectively. There were significant differences between two groups (t =2. 13,4. 40,P =0.04,0.00 respectively). Multi-voxels scanning 1H-MRS revealed that Glx / Cr were 0.51±0.36 in case group and 0.29±0.18 in control group. There was also a significant difference between two groups (t =2.17,P =0.03). And the values of Cho/Cr, NAA/Cr and Lac/Cr were not significantly different. The results were same in multi-voxels 1H-MRS. Total bilirubin level and the concentration of metabolites in the brain do not have obvious correlation. Conclusions ABE has a characteristic signature which is symmetrical high signal of T1 WI in globus pallidus on conventional MBI; The values of mI/Cr and Glx/Cr remarkably increase as detected by 1H-MRS, which is generally in agreement with what has been known about bilirubin pathology. Key words: Kernicterus; Magnetic resonance imaging; Magnetic resonance spectroscopy; Jaundice, neonatal