|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|5627756||1406354||2017||3 صفحه PDF||ندارد||دانلود کنید|
7T MRI enables us to identify subtle volume changes in brain structures, providing potential biomarkers of mental disorders. Most volumetric approaches require that similar intensity values represent similar tissue types across different persons. By applying colour-coding to T1-weighted MP2RAGE images, we found that the high measurement accuracy achieved by high-resolution imaging may be compromised by inter-individual image intensity variation.To address this issue, we analysed the performance of five intensity standardisation techniques in high-resolution T1-weighted MP2RAGE images. 20 extreme images were standardised to a moderate reference image. We evaluated the mean intensity within two subcortical ROIs of GM and WM and the inter-individual intensity variation of the hypothalamic boundary. For all methods it was required that the correlation between the whole-brain tissue volumes and subject age be preserved during standardisation. The results were compared with T1 maps.ROI-based linear standardisation improved the average image intensity in both subcortical ROIs. It about halved the inter-individual intensity variation of the hypothalamic boundary, outperforming the other methods, while keeping the original correlation between the GM volume and subject age intact. Segmentation-based standardisation traded improvements in all criteria for small changes in the age-related pattern of the GM volume. Piecewise linear matching of histogram modes and its non-linear alternative produced strong improvements in the WM at the cost of worsened GM outcomes. Cumulative histogram matching proved inappropriate for inter-individual intensity standardisation. Although the mapping of the T1 relaxation time with the MP2RAGE sequence is especially robust to artefacts, little evidence was obtained that substantiated the T1 mapâs theoretical superiority over the T1-weighted images.ROI-based linear standardisation reduced the inter-individual intensity differences of T1-weighted MP2RAGE images without changing the inherent biological information. This method will be the basis for the precise structural analysis of the hypothalamus in a larger, high-resolution MR dataset of psychiatric patients.
Journal: Clinical Neurophysiology - Volume 128, Issue 10, October 2017, Pages e320-e322