Stereotaxic white matter atlas based on diffusion tensor imaging in an ICBM template

Abstract

Brain registration to a stereotaxic atlas is an effective way to report anatomic locations of interest and to perform anatomic quantification. However, existing stereotaxic atlases lack comprehensive coordinate information about white matter structures. In this paper, white matter-specific atlases in stereotaxic coordinates are introduced. As a reference template, the widely used ICBM-152 was used. The atlas contains fiber orientation maps and hand-segmented white matter parcellation maps based on diffusion tensor imaging (DTI). Registration accuracy by linear and non-linear transformation was measured, and automated template-based white matter parcellation was tested. The results showed a high correlation between the manual ROI-based and the automated approaches for normal adult populations. The atlases are freely available and believed to be a useful resource as a target template and for automated parcellation methods.

Fig. 1

(A) Procedures for WMPM-based ROI-drawing and automated methods for pixel intensity (FA) measurements. In this study, four different approaches are compared: manual; hybrid; Automated I; and Automated II. (B and C): 26 anatomical regions (13 in an axial (B) and 13 in a coronal (C) slice) defined by the WMPM and used for the FA measurements in this study. Except for the ROI for the corpus callosum, the ROIs were placed in both hemispheres. For the manual and hybrid approaches, ROIs are manually delineated using the WMPM as a guide. For Automated I and II, the WMPM is applied automatically after brain normalization.

Fig. 1

(A) Procedures for WMPM-based ROI-drawing and automated methods for pixel intensity (FA) measurements. In this study, four different approaches are compared: manual; hybrid; Automated I; and Automated II. (B and C): 26 anatomical regions (13 in an axial (B) and 13 in a coronal (C) slice) defined by the WMPM and used for the FA measurements in this study. Except for the ROI for the corpus callosum, the ROIs were placed in both hemispheres. For the manual and hybrid approaches, ROIs are manually delineated using the WMPM as a guide. For Automated I and II, the WMPM is applied automatically after brain normalization.

Fig. 2

Various contrasts obtained from the ICBM-DTI-81 atlas. (A) – (D): An axial slice from ICBM-152 (A) and aDWI (B), minimally diffusion-weighted (C), and FA maps (D) from ICBM-DTI- 81. (E) – (H): Color-coded orientation maps from ICBM-DTI-81 at four different axial slices.

Fig. 3

Two-dimensional (A) – (D) and three-dimensional (E) presentation of the WMPM. For the two-dimensional view, the WMPM is superimposed on the ICBM-152 (left) and ICBM-DTI-81 (right). The[SM29] abbreviations are: ACR: anterior corona radiata; ALIC: anterior limb of the internal capsule; BCC: body of the corpus callosum; CgC: cingulum in the cingulate cortex; CgH: cingulum in the hippocampus; CP: cerebral peduncle; CST: corticospinal tract; EC: external capsule; FX: fornix; GCC: genu of the corpus callosum; ICP: inferior cerebellar peduncle; MCP: middle cerebellar peduncle; ML: medial lemniscus; PLIC: posterior limb of the internal capsule; RLIC: retrolenticular part of the internal capsule; PTR: posterior thalamic radiation; SCC: splenium of the corpus callosum; SCP: superior cerebellar peduncle; SCR: superior corona radiata; SLF: superior longitudinal fasciculus; SS: sagittal stratum

Fig. 4

Cumulative fraction of landmarks as a function of error.

Fig 5

Correlation plots between different quantification approaches described in Fig. 1. The hybrid method is used as a reference and compared to the other three approaches.