Margaret Pui MD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: to determine use of magnetization transfer ratio (MTR) and apparent diffusion coefficient (ADC) in children with chromosome abnormalities Methods and Materials: Magnetization transfer (MT) and diffusion-weighted (DW) MRI was performed on 96 children (50 boys, 46 girls, age range 0.01-18 yrs, average 3.98 yrs) with developmental delay and seizures. The normal control group consisted of 85 boys and 48 girls (newborn to 18 yrs) with brain tumors who underwent MRI before treatment using a 1.5T magnet. These children were separated into groups according to gender and age. Axial 2D FLASH images were acquired (160/14/150/1 acquisition/14 slices, 177x256 matrix, 5mm thick/1mm gap, 20cm FOV) with and without MT pulse (1.5 kHz frequency offset, 8000). Axial DW images were obtained using fat-saturated single-shot SE-EPI (220/139/900/4/19/5/1, EPI factor 128, b=0, 900 in 3 directions). ROIs were drawn on the cortical gray matter, frontal and parietal deep white matter, caudate nucleus, putamen, globus pallidus, thalamus, substantia nigra, tectum, middle cerebellar peduncle, and cerebrospinal fluid on the FLASH and diffusion trace images and ADC map using T1W and T2W images as guide. MTR was calculated by (SI0-SIm)/SI0x100; SI0 and SIm were signal intensities of ROI on the FLASH images without and with MT pulse respectively. The MTRs and ADCs were compared to the age- and sex-matched normal control using paired sample t-test. Statistical significance was defined as pŁ0.05. Results: In 9 children with chromosome abnormality, MTRs of globus pallidus (44.25±1.18), putamen (42.42±2.27), and thalamus (43.94±3.73) were significantly higher (p=0.031, 0.021, 0.003) than normal (42.16±1.73, 40.85±0.34, 41.54±3.08). ADCs of globus pallidus (1.06 x10-3±0.66 x10-8), putamen (10-3±1.24x10-8), substantia nigra (1.05x10-3±0.84 x10-8), and frontal white matter (1.25 x10-3±3.87 x10-8) were also higher (p=0.05, 0.026, 0.027, 0.042) than normal (0.9 x10-3±0.47 x10-8, 0.91x10-3±1.04 x10-8, 0.99x10-3±0.21 x10-8, 1.16 x10-3±4.45 x10-8). The T1 and T2 signal intensities were normal in these regions. There was no significant difference in MTRs and ADCs of other structures in this group. In the other 87 children without chromosome abnormality, MTRs and ADCs were not significantly different from normal. Conclusion: MTR and ADC are elevated in the gray nuclei and frontal white matter of children with chromosome abnormalities. MT and DW imaging shows promise in differentiating chromosome disorder from other causes of developmental delay in children.      

Pui MD, M, Use of Cerebral Magnetization Transfer and Diffusion MRI in Children with Chromosome Abnormalities.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3101552.html