Iglehart Charles, Monti Martin, Cain Joshua, Tourdias Thomas, Saranathan Manojkumar
Department of Electrical and Computer Engineering, University of Arizona, Tucson, AZ, USA.
Department of Psychology, University of California Los Angeles, Los Angeles, CA, USA.
Brain Struct Funct. 2020 Jun;225(5):1631-1642. doi: 10.1007/s00429-020-02085-8. Epub 2020 May 21.
The thalamus consists of several histologically and functionally distinct nuclei increasingly implicated in brain pathology and important for treatment, motivating the need for development of fast and accurate thalamic parcellation. The contrast between thalamic nuclei as well as between the thalamus and surrounding tissues is poor in T1- and T2-weighted magnetic resonance imaging (MRI), inhibiting efforts to date to segment the thalamus using standard clinical MRI. Automatic parcellation techniques have been developed to leverage thalamic features better captured by advanced MRI methods, including magnetization prepared rapid acquisition gradient echo (MP-RAGE), diffusion tensor imaging (DTI), and resting-state functional MRI (fMRI). Despite operating on fundamentally different image contrasts, these methods claim a high degree of agreement with the Morel stereotactic atlas of the thalamus. However, no comparison has been undertaken to compare the results of these disparate parcellation methods. We have implemented state-of-the-art structural-, diffusion-, and functional imaging-based thalamus parcellation techniques and used them on a single set of subjects. We present the first systematic qualitative and quantitative comparison of these methods. The results show that DTI parcellation agrees more with structural parcellation in the larger thalamic nuclei, while rsfMRI parcellation agrees more with structural parcellation in the smaller nuclei. Structural parcellation is the most accurate in the delineation of small structures such as the habenular, antero-ventral, and medial geniculate nuclei.
丘脑由几个在组织学和功能上不同的核组成，这些核越来越多地与脑部病理学相关，并且对治疗很重要，这激发了对快速准确的丘脑分割技术的需求。在T1加权和T2加权磁共振成像（MRI）中，丘脑核之间以及丘脑与周围组织之间的对比度较差，这限制了迄今为止使用标准临床MRI对丘脑进行分割的努力。已经开发了自动分割技术，以利用先进MRI方法（包括磁化准备快速采集梯度回波（MP-RAGE）、扩散张量成像（DTI）和静息态功能MRI（fMRI））更好地捕捉到的丘脑特征。尽管这些方法基于根本不同的图像对比度进行操作，但它们声称与丘脑的莫雷尔立体定向图谱高度一致。然而，尚未对这些不同分割方法的结果进行比较。我们实施了基于最先进的结构、扩散和功能成像的丘脑分割技术，并将它们应用于同一组受试者。我们首次对这些方法进行了系统的定性和定量比较。结果表明，DTI分割在较大的丘脑核中与结构分割的一致性更高，而静息态功能磁共振成像（rsfMRI）分割在较小的核中与结构分割的一致性更高。结构分割在描绘诸如缰核、前腹侧核和内侧膝状体核等小结构方面最为准确。
