Petoe Matthew A, Byblow Winston D, de Vries Esther J M, Krishnamurthy Venkatesh, Zhong Cathy S, Barber P Alan, Stinear Cathy M
Department of Medicine, University of Auckland, Auckland, New Zealand ; Centre for Brain Research, University of Auckland, Auckland, New Zealand.
Centre for Brain Research, University of Auckland, Auckland, New Zealand ; Department of Sport & Exercise Science, University of Auckland, Auckland, New Zealand.
Neuroimage Clin. 2013 Dec 26;4:695-700. doi: 10.1016/j.nicl.2013.12.006. eCollection 2014.
The integrity of descending white matter pathways, measured by fractional anisotropy from DW-MRI, is a key prognostic indicator of motor recovery after stroke. Barriers to translation of fractional anisotropy measures into routine clinical practice include the time required for manually delineating volumes of interest (VOIs), and inter-examiner variability in this process. This study investigated whether registering and then editing template volumes of interest 'as required' would improve inter-examiner reliability compared with manual delineation, without compromising validity. MRI was performed with 30 sub-acute stroke patients with motor deficits (mean NIHSS = 11, range 0-17). Four independent examiners manually delineated VOIs for the posterior limbs of the internal capsules on T1 images, or edited template VOIs that had been registered to the T1 images if they encroached on ventricles or basal ganglia. Fractional anisotropy within each VOI and interhemispheric asymmetry were then calculated. We found that 13/30 registered template VOIs required editing. Edited template VOIs were more spatially similar between examiners than the manually delineated VOIs (p = 0.005). Both methods produced similar asymmetry values that correlated with clinical scores with near perfect levels of agreement between examiners. Contralesional fractional anisotropy correlated with age when edited template VOIs were used but not when VOIs were manually delineated. Editing template VOIs as required is reliable, increases the validity of fractional anisotropy measurements in the posterior limb of the internal capsule, and is less time-consuming compared to manual delineation. This approach could support the use of FA asymmetry measures in routine clinical practice.
通过扩散加权磁共振成像（DW-MRI）的分数各向异性测量的下行白质通路完整性，是中风后运动恢复的关键预后指标。将分数各向异性测量转化为常规临床实践的障碍包括手动勾勒感兴趣区域（VOIs）所需的时间以及该过程中检查者之间的变异性。本研究调查了“按需”配准然后编辑模板感兴趣区域是否会比手动勾勒提高检查者间的可靠性，同时不影响有效性。对30例有运动功能缺损的亚急性中风患者（平均美国国立卫生研究院卒中量表[NIHSS] = 11，范围0 - 17）进行了磁共振成像检查。四名独立检查者在T1图像上手动勾勒内囊后肢的VOIs，或者如果模板VOIs侵犯脑室或基底神经节，则编辑已配准到T1图像的模板VOIs。然后计算每个VOI内的分数各向异性和半球间不对称性。我们发现30个配准的模板VOIs中有13个需要编辑。编辑后的模板VOIs在检查者之间的空间相似性高于手动勾勒的VOIs（p = 0.005）。两种方法产生的不对称值相似，且与临床评分相关，检查者之间的一致性接近完美。使用编辑后的模板VOIs时，对侧分数各向异性与年龄相关，但手动勾勒VOIs时则不然。按需编辑模板VOIs是可靠的，提高了内囊后肢分数各向异性测量的有效性，并且与手动勾勒相比耗时更少。这种方法可以支持在常规临床实践中使用分数各向异性不对称测量。
